JP2010049285A - Abnormality determining method, and abnormality determining apparatus, and image forming apparatus using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality determining apparatus capable of avoiding mistaken determinations due to the normal value of information obtained by an information obtaining portion 501 differing according to the content of specific information such as operating mode setting, and deterioration in determination precision due to a change in the user of a detection subject. <P>SOLUTION: The abnormality determining apparatus includes an information storage portion 503 for storing normal index information serving as an index of a normal state of the detection subject, the information obtaining portion 501 for obtaining a plurality of types of information, and an abnormality determining portion 502 for determining the presence of an abnormality in the detection subject on the basis of the normal index information stored in the information storage portion 503, and the information obtained by the information obtaining portion 501. The information storage portion 503 stores a plurality of pieces of normal index information having different values. The abnormality determining portion 502 switches, at a prescribed timing, normal index information to be used to determine the presence of an abnormality in the detection subject from the plurality of pieces of normal index information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an abnormality determination method for determining presence / absence of abnormality of a subject to be examined based on an acquisition result obtained by an information acquisition unit that acquires information on a thing, and an abnormality determination apparatus and an image forming apparatus using the abnormality determination method.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a facsimile machine, and a printer, maintenance such as replacement of consumables (for example, toner) and parts (for example, a photoreceptor) and repair at the time of failure is necessary. When a failure occurs, the device is stopped from the occurrence to the completion of repair, which causes a large time loss for the user. Therefore, it is desirable to reduce the downtime by predicting the occurrence of a failure in the image forming apparatus, the arrival of the life of parts, and the like, thereby providing the user with a preparation period necessary for maintenance. Further, not only the image forming apparatus but also various apparatuses such as manufacturing equipment and electrical appliances are desired to reduce downtime.

  As an image forming apparatus capable of such prediction, predetermined information in the apparatus is acquired by a sensor or the like as information acquisition means, and an abnormality of the apparatus is detected early by comparing the acquired result with normal index information stored in advance. What to do has been proposed. For example, Patent Document 1 proposes an image forming apparatus that detects drive load information of a drive source, which is predetermined information, and detects an abnormality in the drive system at an early stage by comparing the detection result with a standard value that is normal index information. ing. According to such a configuration, it is possible to provide the user with a repair preparation period such as arranging replacement parts by detecting the abnormality of the drive system before the failure occurs.

  However, this image forming apparatus does not always detect an abnormality at a timing suitable for the user. This is for the reason explained below. That is, for example, a user who is familiar with an image forming apparatus may be able to repair a failure of the image forming apparatus even if it cannot be repaired by a general user. In this case, there is no request for repair from the user to the repair service organization. Nevertheless, if a service person is dispatched based on the prediction of the occurrence of a failure, the service cost will increase due to the generation of useless labor. Also, for example, depending on the type of failure, the degree of detection may vary greatly from user to user. Some users suspect a paper feed system failure even if the frequency of paper jams is small, and some users do not feel a paper feed system failure even if the frequency of occurrence is relatively high. Even if a service person is dispatched to the latter user at the stage where a paper feed system abnormality has started to occur only slightly, a repair request is often not generated. Even when such a dispatch is performed, the service cost is increased.

  As a device capable of detecting an abnormality at a timing suitable for a user, a remote failure diagnosis system described in Patent Document 2 is known. This remote failure diagnosis system receives basic data for diagnosis transferred from each of a plurality of image forming apparatuses to be diagnosed by a central diagnostic apparatus, and various abnormalities in individual image forming apparatuses based on the basic data. Is to diagnose. The various abnormalities include a paper feed abnormality and an image quality abnormality. By diagnosing various abnormalities, it is possible to predict in advance the occurrence of failures in the paper feed system and the image forming system due to their progress. Furthermore, this remote fault diagnosis system considers the user's proficiency level and fault detection level of the image forming apparatus when diagnosing various abnormalities. As a result, it is possible to perform a diagnosis suitable for each user for abnormality, and to reduce the service cost. In addition, as a result of intensive studies, the present inventors have found that, among various abnormalities, in particular, an abnormality in image quality increases a variation in the degree of detection for each user.

  Conventionally, an MTS (Maharanobis Taguchi System) method described in Non-Patent Document 1 is known as a method for measuring the normality of the state of things. This MTS method measures the normality of the state of things as follows. That is, first, a plurality of normal values related to set information composed of a plurality of types of information indicating the state of the subject to be examined are acquired, and a normal set data group is constructed. Taking a health check as an example, normal values consisting of sex, various blood test results, height, weight, etc. obtained from a healthy person are acquired in advance from a plurality of healthy persons, and a normal set data group is constructed. Next, a multidimensional space is constructed based on the normal group data group. Then, the Mahalanobis distance indicating the position in the multidimensional space of the set information acquired from the person to be examined is obtained, and how much the set information is similar to the normal set data group is evaluated. According to the MTS method, it is possible to comprehensively determine whether the test target is normal based on the relationship between the pieces of information.

  The present inventors have empirically learned that, in a conventional image forming apparatus, in addition to what causes a fault such as an abnormality in a drive system as a failure, a cause in which the cause is not clearly specified occurs. is doing. In the case of the latter failure, if there is no noticeable abnormality in the individual parts at the machine location (process cartridge, etc.) that seems to be involved in the failure, Failure (occurrence of abnormal images, etc.) is corrected.

  In the image forming apparatus disclosed in Patent Document 1 in which an abnormality of the apparatus is detected early by comparing a result of obtaining predetermined information such as driving load information with normal index information, the occurrence of a failure is detected by early detection of the abnormality. Can be predicted in advance. However, since this failure occurs due to the progress of the abnormality, it has not been possible to predict the occurrence of a failure whose cause is not clearly specified.

  Therefore, the present inventors are developing a new abnormality determination device that can predict in advance the occurrence of a failure whose cause is not clearly specified by using the MTS method (hereinafter, this abnormality determination device will be referred to as the abnormality determination device). Called development equipment). This development apparatus stores multidimensional spatial data constructed based on a normal combination data group composed of the photosensitive member charge amount, temperature, paper feed speed, and the like of the image forming apparatus to be examined. Then, regarding the combination data (test data) acquired with the image forming operation, the Mahalanobis distance in the multidimensional space is obtained to determine whether or not it is abnormal. In such a configuration, it is possible to predict the occurrence of a failure whose cause is not clearly specified, unlike the image forming apparatus disclosed in Patent Document 1, by determining abnormality of combination data detected by a sensor or the like.

However, the present inventors have found that this development apparatus may be erroneously detected as normal even though it is abnormal.
Specifically, for example, in a general image forming apparatus, it is possible to select a high-speed mode that prioritizes high-speed printing over high-quality image and a high-image-quality mode that prioritizes high image quality. Many. In such a configuration in which a plurality of operation modes can be selected, the normal value of the paper conveyance speed in the apparatus varies depending on the setting of the operation mode. The normal value of the paper conveyance speed is about 100 [mm / sec] in the high speed mode, whereas it is about 50 [mm / sec] in the high image quality mode. Nevertheless, if multidimensional spatial data is constructed based on a normal data group acquired while mixing these multiple operation modes, the detected data value of the paper conveyance speed of 75 [mm / sec] is abnormal. In spite of wanting to be detected, it is mistakenly detected as normal. In general image forming apparatuses, there are detection data having different normal values depending on the environment (temperature and humidity) such as toner bulk density and electrical resistance value. Nevertheless, if multidimensional spatial data is constructed based on normal data groups detected in a plurality of environments, the same erroneous detection occurs. These false detections are due to the fact that the normal value of the information acquisition result by the information acquisition means differs depending on the content of specific information such as the setting of the operation mode and the environment. This occurs when the determination is made based on only one normal data group. However, the same erroneous detection may occur if the method is to determine an abnormality using only one normal index information such as a normal data group, only when the abnormality is determined using the MTS method.

  On the other hand, the remote fault diagnosis system of Patent Document 2 diagnoses a fault in consideration of the user's proficiency level and fault detection level, but if the user changes, the proficiency level and fault detection suitable for a new user are changed. The degree cannot be considered. For this reason, the occurrence of a failure could not be notified at a timing suitable for a new user.

  Accordingly, a first object of the present invention is to provide the following abnormality determination method, and an abnormality determination apparatus and an image forming apparatus using the same. That is, avoiding erroneous determination due to the normal value of the information acquired by the information acquisition means differing depending on the content of the specific information such as the operation mode setting, and a decrease in determination accuracy due to change of the user to be examined An abnormality determination method that can

  The second object of the present invention is to provide an abnormality that can avoid erroneous determination due to the normal value of the information acquired by the information acquiring means being different depending on the content of specific information such as operation mode setting. It is to provide a determination method and the like.

  Note that the remote fault diagnosis system disclosed in Patent Document 2 individually diagnoses a plurality of abnormalities that occur in an image forming apparatus to be diagnosed. For this reason, as the types of abnormality to be diagnosed increase, the amount of calculation for diagnosis increases and the control becomes complicated.

  If it is the development apparatus mentioned above, such complication of control can be suppressed. This is for the reason explained below. That is, in the development apparatus, the presence or absence of various abnormalities in the test object such as the image forming apparatus is comprehensively determined as one comprehensive abnormality rather than individually. The presence / absence of a general abnormality that is determined as “abnormal” when at least one of various abnormalities has occurred is comprehensively determined. Unlike the remote fault diagnosis system of Patent Document 2 in which the control becomes more complicated as the number of types of abnormality to be used for determination increases by such a determination, the control becomes complicated due to an increase in the types of abnormality to be determined. be able to.

  However, this development device does not determine the presence or absence of various abnormalities in consideration of the user's proficiency level or the degree of failure detection. For this reason, the determination accuracy regarding the presence or absence of an abnormality does not always match the user, and there is a possibility that an unnecessary abnormality may be detected or the detection time may be too late depending on the user.

  In addition, as in the development device, instead of capturing the presence or absence of individual abnormalities, it is a method that captures how far the normal state has deviated. Maintenance support becomes complicated. This is because it is difficult to specify what kind of abnormality that can be included in the overall abnormality has occurred.

  Therefore, a third object of the present invention is to provide the following abnormality determination method and the like. That is, it is possible to determine the presence / absence of an abnormality with accuracy according to each user while suppressing the complexity of control by individually determining the presence / absence of various abnormalities and the complexity of maintenance support after the determination. An abnormality determination method that can be performed.

In order to achieve the first object, the invention according to claim 1 is based on normal index information that is an index of a normal state of a subject to be examined and acquired information by an information acquiring unit that acquires a plurality of types of information. Then, in the abnormality determination method for determining the presence or absence of abnormality of the test object, a plurality of items having different values are prepared as the normal index information, and among the plurality of normal index information, the test target What is used for determining whether or not there is an abnormality in is switched at a predetermined timing.
The invention according to claim 2 is the abnormality determination method according to claim 1, wherein a normal data group that is a collection of normal data acquired from the test subject in a normal state is used as the normal index information. It is characterized by switching at timing.
The invention of claim 3 is characterized in that, in the abnormality determination method of claim 1, a threshold for comparison with a predetermined calculation result is switched as the normal index information at the predetermined timing. .
According to a fourth aspect of the present invention, information storage means for storing normal index information that is an index of the normal state of the subject to be examined, information acquisition means for acquiring a plurality of types of information, and information storage means are stored. An abnormality determination device comprising: a determination means for determining presence or absence of abnormality of the subject to be examined based on the normal index information and the information acquired by the information acquisition means, wherein the information storage means is the normal As index information, a plurality of items having different values are stored, and the determination means uses among the plurality of normal index information to determine whether there is an abnormality in the test subject. The switching is performed at a predetermined timing.
Further, the invention of claim 5 is the abnormality determination device according to claim 4, wherein a normal data group that is a collection of normal data acquired from the test subject in a normal state is used as the normal index information. The determination means is configured to switch at timing.
Further, the invention of claim 6 is the abnormality determination device according to claim 4, wherein the determination means is configured to switch, as the normal index information, a threshold for comparison with a predetermined calculation result at the predetermined timing. It is characterized by comprising.
The invention of claim 7 is the abnormality determination device according to claim 4, 5 or 6, wherein the information acquisition means acquires a threshold value for comparison with a predetermined calculation result and the test subject in a normal state. A normal data group that is a collection of normal data that has been stored, and the Mahalanobis distance is calculated based on the normal data group and the information acquired by the information acquisition means, and the calculation result The determination means is configured to determine the presence / absence of abnormality of the subject to be tested based on the comparison with the threshold value.
In the invention of claim 8, in the abnormality determination device according to any one of claims 4 to 7, the determination means is configured to switch the normal index information according to the installation environment of the test object. It is characterized by.
The invention according to claim 9 is the abnormality determination device according to claim 8, further comprising an environment detection means for detecting humidity, temperature or atmospheric pressure, and switching the normal index information according to a detection result by the environment detection means. Further, the above-described determination means is configured.
The invention according to claim 10 is the abnormality determination device according to any one of claims 4 to 7, wherein the information acquisition unit is configured to acquire the operation mode information of the test object as one of the plurality of types of information. In addition, the determination unit is configured to switch the normal index information according to the acquisition result of the operation mode information by the information acquisition unit.
The invention according to claim 11 is the abnormality determination device according to any one of claims 4 to 7, wherein the information acquisition is performed so that user operation history information for the subject to be examined is acquired as one of the plurality of types of information. In addition, the determination means is configured to switch the normal index information according to the operation history information by the information acquisition means.
The invention according to claim 12 is the abnormality determination device according to any one of claims 4 to 7, wherein the information on the environmental history is acquired as one of the plurality of types of information at the installation location of the subject to be examined. In addition to configuring the acquisition unit, the determination unit is configured to switch the normal index information according to the environmental history information by the information acquisition unit.

In order to achieve the second object, the invention of claim 13 is an information storage step for storing normal index information, which is an index of the normal state of the subject to be examined, in the information storage means, and information on things by the information acquisition means. An abnormality determination method for performing an information acquisition step of acquiring the normal index information in the storage unit, and a determination step of determining an abnormality of the test object based on an acquisition result by the information acquisition unit, A plurality of information acquisition units that acquire different types of information are used, and the normal index information is at least one of a plurality of types of information individually acquired by the plurality of information acquisition units. Depending on the content of the specific information, a plurality of items each having a different content are used, and the determination by the information acquisition means is performed from the plurality of normal index information in the determination step. It is characterized in that use to identify those corresponding to distribution of acquisition result in the determination of the abnormality.
Further, the invention of claim 14 is an information storage means for storing normal index information that is an indicator of the normal state of the subject to be examined, an information acquisition means for acquiring information on things, and normal index information in the storage means, And a determination means for determining abnormality of the test object based on the acquisition result by the information acquisition means, wherein the information acquisition means includes a plurality of pieces of information that acquire different types of information from each other. In addition, as the normal index information, according to the content of the specific information that is at least any one of a plurality of types of information individually acquired by the plurality of information acquisition means, a plurality of items having different contents are used. In addition, the determination means specifies the one corresponding to the acquisition result of the specific information by the information acquisition means from among the plurality of normal index information and uses it for the determination of abnormality. That is for the features.
Further, the invention of claim 15 is the abnormality determination device according to claim 14, wherein a plurality of normal index information having different contents are constructed based on a plurality of acquisition results for various types of information composed of the plurality of types of information. A normal index information construction means is provided.
The invention according to claim 16 is the abnormality determination device according to claim 14 or 15, wherein each of the plurality of normal index information uses an inverse matrix of a data group, and the determination means is based on the inverse matrix. It is characterized in that the Mahalanobis distance is calculated and used to determine abnormality.
The invention according to claim 17 is the abnormality determination device according to claim 16, wherein a plurality of normal index information having different contents are constructed based on a plurality of acquisition results for various types of information including the plurality of types of information. A normal index information construction unit is provided, and the information storage unit stores a plurality of temporary normal index information having different contents, and the predetermined condition is not satisfied within a predetermined period. When at least one of the normal index information is not able to be constructed, the normal index construction means is configured to perform a process of supplementing it with the temporary normal index information. It is characterized by this.
Further, the invention of claim 18 is the abnormality determination device of claim 16, wherein a plurality of normal index information having different contents are constructed based on a plurality of acquisition results for various types of information composed of the plurality of types of information. A normal index information constructing means and a data receiving means for receiving data from the outside are provided, and at least one of the plurality of normal index information is obtained because a predetermined condition is not established within a predetermined period. The normal index information construction means is configured to perform a process of supplementing it with the normal index information received by the data receiving means when the data cannot be constructed. It is.
According to a nineteenth aspect of the present invention, there is provided a recording medium conveying means for conveying a recording medium, a visible image forming means for forming a visible image on a recording medium conveyed by the recording medium conveying means, and the whole or a part of the apparatus. An image forming apparatus including an abnormality determination device that determines an abnormality of the image forming apparatus uses any one of claims 14 to 18 as the abnormality determination means.
According to a twentieth aspect of the present invention, in the image forming apparatus according to the nineteenth aspect, as one of the plurality of information acquisition units, a device that acquires temperature information, humidity information, or an operation mode setting value is used. As the normal index information, information having different contents according to temperature, humidity, or operation mode set value is used.

In order to achieve the third object, the invention according to claim 21 is an information acquisition step of acquiring information of a thing by an information acquisition means, and whether or not there is an abnormality in a subject to be examined based on the acquisition information by the information acquisition means And a determination step for performing a predetermined calculation based on the information acquired by the information acquisition means and a calculation result in the calculation step are compared with a predetermined threshold value. An abnormality determination that determines whether there is an abnormality when the calculation result reaches the threshold, exceeds the threshold, or falls below the threshold in the comparison step. In the method, a comprehensive abnormality determination step for determining whether or not there is a general abnormality that can include a plurality of types of abnormality by comparing the calculation result based on a plurality of types of the acquired information and a threshold for general abnormality, and the general abnormality determination step Only when it is determined that the general abnormality is present, the presence / absence of individual abnormality, which is each of a plurality of types of abnormality that can be included in the general abnormality, is set to at least one of the plurality of types of acquired information for each individual abnormality. A plurality of individual abnormality determination steps that are sequentially determined by comparing the calculation result based on the above-described calculation results with the individual abnormality threshold values, and the individual abnormality abnormality threshold values and the individual abnormality abnormality threshold values. At least one of the individual abnormality threshold values is initially set according to information of a user who uses the test object.
The invention according to claim 22 is the abnormality determination method according to claim 21, wherein each of the plurality of individual abnormality threshold values is initially set according to the information of the user.
The invention according to claim 23 is the abnormality information method according to claim 21 or 22, wherein at least one of the overall abnormality threshold value and the plurality of individual abnormality threshold values is set as environmental information on which the test object is installed. The initial setting is also made according to the above.
The invention according to claim 24 is the abnormality determination method according to claim 21, 22 or 23, wherein at least one of the overall abnormality threshold and the plurality of individual abnormality thresholds is set to the installation location of the subject to be examined. It is characterized in that the initial setting is performed in accordance with information on the frequency of visits of the maintenance / inspection workers or distance information from the maintenance / inspection service providing organization to the installation location.
The invention according to claim 25 is the abnormality determination method according to any one of claims 21 to 24, wherein the total abnormality is used for determining whether or not there is an abnormality in a new subject when the subject is replaced with an old one. The threshold value for use and the plurality of individual abnormality threshold values are each initially set to the same value as that used in each individual abnormality determination step in the determination of the presence or absence of an abnormality in the old test object. is there.
According to a twenty-sixth aspect of the present invention, in the abnormality determination method according to any one of the twenty-first to twenty-fifth aspects, at least one of the plurality of individual abnormality thresholds is set according to user repair request history information based on occurrence of abnormality. It is characterized by updating.
The invention of claim 27 is the abnormality determination method according to any of claims 21 to 26, wherein the normal data group stored in the information storage means in the calculation step of the comprehensive abnormality determination step, and the above Based on the acquired information by the information acquisition means, the Mahalanobis distance is obtained as the calculation result, and the normal data is determined based on the presence / absence of the comprehensive abnormality in the comprehensive abnormality determination step and the inspection result of the test object. It is characterized by updating the group.
The invention of claim 28 is characterized in that an information acquisition means for acquiring information of an object, and a predetermined calculation is performed based on the information acquired by the information acquisition means, and if the calculation result reaches a predetermined threshold, Presence / absence of comprehensive abnormality that can include a plurality of types of abnormality in an abnormality determination device comprising a determination unit that determines presence / absence of abnormality of the test object when the threshold value is exceeded or falls below the threshold value A plurality of types of abnormalities that can be included in the total abnormality only when it is determined by comparing the calculation result based on the plurality of types of acquired information with a threshold value for the general abnormality, and the total abnormality is determined to exist. Each individual abnormality is sequentially determined by comparing the calculation result based on at least one of the plurality of types of acquired information and the individual abnormality threshold for each individual abnormality. And a data input means for receiving at least one data input of the overall abnormality threshold and a plurality of individual abnormality thresholds individually corresponding to each individual abnormality and storing them in the information storage means Is provided.
According to a twenty-ninth aspect of the present invention, in the abnormality determination device according to the twenty-eighth aspect, the data input means is configured to accept each of the plurality of individual abnormality threshold values.
The invention according to claim 30 is the abnormality determination device according to claim 28 or 29, wherein as the data input means, data input of the overall abnormality threshold value or the individual abnormality threshold value sent via a communication line is accepted. It is characterized by using things.
The invention of claim 31 is characterized in that information acquisition means for acquiring information on an object and predetermined calculation based on the acquired information by the information acquisition means and when the calculation result reaches a predetermined threshold, Presence / absence of comprehensive abnormality that can include a plurality of types of abnormality in an abnormality determination device comprising a determination unit that determines presence / absence of abnormality of the test object when the threshold value is exceeded or falls below the threshold value A plurality of types of abnormalities that can be included in the total abnormality only when it is determined by comparing the calculation result based on the plurality of types of acquired information with a threshold value for the general abnormality, and the total abnormality is determined to exist. Each individual abnormality is sequentially determined by comparing the calculation result based on at least one of the plurality of types of acquired information and the individual abnormality threshold for each individual abnormality. And a threshold setting means for setting at least one of the overall abnormality threshold and a plurality of individual abnormality thresholds individually corresponding to each individual abnormality. is there.
The invention of claim 32 is characterized in that, in the abnormality determination device of claim 31, the threshold setting means is configured to set each of the plurality of individual abnormality thresholds.
The invention according to claim 33 is the abnormality determination device according to claim 31 or 32, wherein the threshold value setting means performs a predetermined question to the user, and the user inputs the question to the data input means. The information of the user is acquired based on the answer data for.
The invention according to claim 34 is the abnormality determination device according to claim 33, wherein at least one of the overall abnormality threshold and a plurality of individual abnormality thresholds individually corresponding to each individual abnormality is obtained by the user. The threshold value setting means is configured to change based on predetermined data input to the data input means.
The invention according to claim 35 is the abnormality determination device according to any one of claims 31 to 34, wherein the total abnormality threshold is changed in accordance with a rate of change of the calculation result for the general abnormality. The threshold setting means is configured.
The invention of claim 36 is the abnormality determination device according to any one of claims 31 to 35, wherein the calculation is performed based on a normal data group stored in the information storage means and an acquisition result by the information acquisition means. The determination means is configured to determine a Mahalanobis distance as a result, and to determine the presence / absence of the comprehensive abnormality based on a comparison result between the Mahalanobis distance and the comprehensive abnormality threshold value. .
The invention of claim 37 is the abnormality determination device according to any one of claims 31 to 36, wherein the determination frequency of the presence or absence of the general abnormality is changed according to the calculation result of the general abnormality. The determination means is configured.
Further, the invention of claim 38 is a function for limiting the function of the subject to be examined according to the type when any of the individual abnormalities occurs in the abnormality determination device of any of claims 31 to 36. The limiting means is provided.
The invention of claim 39 is an image forming apparatus comprising a visible image forming means for forming a visible image on a recording medium and an abnormality determining means for determining an abnormality of the apparatus. The abnormality determination device according to any one of 4 to 12, any one of claims 14 to 18, or any one of claims 28 to 38 is used.

In the first to twelfth aspects of the present invention, a plurality of normal data groups for obtaining the Mahalanobis distance are prepared as normal index information that is an index of the normal state of the test subject, and specific information such as operation mode setting is prepared. If they are switched according to the contents of the information, it is possible to avoid erroneous determination due to the normal value of the information acquired by the information acquiring means being different according to the contents of the specific information.
Also, as normal index information, prepare multiple thresholds for comparison with the calculation result obtained by the calculation based on the acquisition information by the information acquisition means, depending on the content of specific information such as user information input by the user By switching between them, it is possible to avoid a decrease in determination accuracy due to a change in the user to be examined.

  In the inventions according to claims 13 to 20, a plurality of types of information are acquired by a plurality of information acquisition means. Then, the normal index information corresponding to the acquisition result of the specific information (for example, the operation mode) that is at least one of the plurality of types of information is converted into a plurality of normal index information having different contents depending on the contents of the specific information. It is specified from among the above and used to determine abnormality. In such a determination, it is possible to select and use information suitable for the specific information at the time of abnormality determination from a plurality of normal index information having different contents depending on the content of the specific information. Therefore, it is possible to avoid an erroneous determination due to the normal value of the information acquisition result by the information acquisition means being different depending on the content of the specific information.

In the inventions according to claims 21 to 39, it is determined whether or not there is a general abnormality that can include a plurality of types of abnormality in the test subject. In addition, when it is determined that there is a general abnormality, the presence or absence of a plurality of individual abnormalities that can be included in the general abnormality is individually determined to identify what type of abnormality has occurred. Then, it is not necessary to check the presence of all individual abnormalities every time it is determined whether there is a general abnormality. It is possible to suppress complication of control due to the individual determination of the presence or absence. Further, by determining what type of abnormality has occurred when it is determined that the general abnormality is “present”, it is possible to suppress complication of maintenance after the determination.
Furthermore, in the abnormality determination method according to claims 21 to 27, a plurality of individual abnormality threshold values necessary for determining the presence or absence of each individual abnormality are determined according to user information such as proficiency level and failure detection level. Thus, it is possible to determine the presence or absence of each individual abnormality with accuracy according to each user.
Further, among the abnormality determination devices according to claims 28 to 38, the apparatus having the configuration according to claim 28 sets a plurality of individual abnormality threshold values necessary for determining the presence / absence of each individual abnormality to a serviceman or user. Can be initialized or updated by inputting to the data input means according to the user information. And by such initial setting and update, the presence or absence of each individual abnormality can be determined with the accuracy according to each user.
Further, in the abnormality determination device according to claims 28 to 38, the apparatus having the configuration according to claim 31 is configured such that the threshold setting means sets a plurality of individual abnormality thresholds necessary for determining the presence or absence of each individual abnormality. By performing initialization or updating according to user information acquired from the user, the presence or absence of each individual abnormality can be determined with accuracy according to the individual user.
Therefore, in any of the inventions of claims 28 to 39, it is possible to suppress the complexity of control by individually determining the presence / absence of various abnormalities and the complexity of handling maintenance after the determination, and to each user. The presence / absence of an abnormality can be determined with a corresponding accuracy.

The perspective view which shows the resistance change element of the temperature sensor mounted in the copying machine used as the test object of the abnormality determination apparatus which concerns on 1st Embodiment. The perspective view which shows the resistance change element different from FIG. FIG. 3 is a perspective view showing a humidity sensor mounted on the copier. Sectional drawing which shows the vibration sensor mounted in the copying machine. FIG. 3 is a block diagram showing an electric circuit of a toner density sensor mounted on the copier. FIG. 3 is a schematic configuration diagram illustrating a density detection unit of the toner density sensor. FIG. 2 is a schematic configuration diagram showing a potential measurement system mounted on the copier. The block diagram which shows the principal part of the electric circuit in the abnormality determination apparatus. 6 is a graph showing a relationship between a toner charge amount and a toner density in the copier. The block diagram which shows a part of electric circuit in the 1st modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 2nd modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 3rd modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 4th modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 5th modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 6th modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 7th modification apparatus of the abnormality determination apparatus. The block diagram which shows a part of electric circuit in the 8th modification apparatus of the abnormality determination apparatus. FIG. 6 is a schematic configuration diagram illustrating a printer according to a second embodiment. FIG. 2 is a block diagram showing a part of an electric circuit of the printer. The graph which shows the relationship between the square value of the Mahalanobis distance calculated by MTS method using the inverse matrix containing the information of belt linear velocity and drum linear velocity, and belt linear velocity and drum linear velocity. 6 is a graph showing the relationship between the square value of the Mahalanobis distance calculated by the MTS method using the inverse matrix A for mode 1 and the belt linear velocity and drum linear velocity in the printer. 4 is a graph showing a relationship between a square value of a Mahalanobis distance calculated by an MTS method using an inverse matrix for mode 2 and a belt linear velocity and a drum linear velocity in the printer. 6 is a flowchart illustrating an example of a flow of abnormality determination control performed by the control unit of the printer. The graph which shows the relationship between the square value of Mahalanobis distance computed by the conventional MTS method, temperature, and a toner electrical resistance value. 6 is a graph showing a relationship between a square value of a Mahalanobis distance calculated by an MTS method using an inverse matrix for a temperature range t1, a temperature, and a toner electric resistance value in the printer. 6 is a graph showing the relationship between the square value of the Mahalanobis distance calculated by the MTS method using the inverse matrix for the temperature range t2, the temperature and the toner electrical resistance value in the printer. 4 is a graph showing a relationship between a square value of a Mahalanobis distance calculated by an MTS method using an inverse matrix for a temperature range t3, a temperature, and a toner electric resistance value in the printer. The flowchart which shows an example of the inverse matrix construction process implemented by the control part of a modification apparatus. 6 is a flowchart illustrating a main part of an inverse matrix construction process performed by the control unit of the printer according to the first embodiment of the deformation apparatus. 9 is a flowchart illustrating a main part of inverse matrix construction processing performed by a control unit of a printer according to a second embodiment of the deformation apparatus. 1 is a schematic configuration diagram illustrating the copier that is an image forming apparatus that can be a test target of an abnormality determination apparatus to which the present invention is applied. FIG. 2 is a schematic configuration diagram illustrating a printer unit of the copier. The elements on larger scale which show the tandem part of the copier. FIG. 2 is a block diagram showing a part of an electric circuit of the copier. The block diagram which shows the principal part of the electric circuit in the abnormality determination apparatus which concerns on 3rd Embodiment. The connection diagram which shows the example which comprised the same abnormality determination apparatus separately from the copier. The connection diagram which shows another example which comprised the same abnormality determination apparatus with the copier separately. FIG. 3 is a diagram illustrating an example in which the abnormality determination apparatus is configured integrally with the copier. The flowchart which shows a series of processes from the normal data acquisition process for constructing an inverse matrix to a matrix conversion process. The flowchart which shows the procedure which calculates the Mahalanobis distance D. The graph which shows an example of the relationship between Mahalanobis distance D about the total abnormality in the copier, and elapsed time (operating time). FIG. 42 is a graph showing the relationship between Mahalanobis distance D and elapsed time when total abnormality is determined at a time interval of 4 t in the same copier showing the characteristics as shown in FIG. The graph which shows an example of the relationship between Mahalanobis distance D and elapsed time when the determination frequency of comprehensive abnormality is made higher in the stage where Mahalanobis distance D about comprehensive abnormality has approached the abnormality detection threshold to some extent. FIG. 3 is a schematic diagram showing an example of a display screen of an operation display unit of the copier when function restriction is performed by function restriction means. The block diagram which shows the principal part of the electric circuit in the abnormality determination apparatus which concerns on 4th Embodiment. The figure which attached the extended line which makes easy to understand the change of Mahalanobis distance D to the graph which shows an example of the relationship between Mahalanobis distance D about the total abnormality in the copier, and elapsed time. FIG. 3 is a schematic diagram illustrating an example of an image output to a data display unit in accordance with detection of abnormality of a photoreceptor deterioration system. The graph which shows the relationship between the square value of Mahalanobis distance calculated by MTS method, temperature, and a toner electrical resistance value.

Hereinafter, a first embodiment of an abnormality determination device to which the present invention is applied will be described.
The abnormality determination apparatus according to the first embodiment is configured to determine whether there is an abnormality in a copying machine as an image forming apparatus as a test target. The configuration of the copying machine that is the test target of the abnormality determination apparatus is the same as the copying machine that is the test target of the abnormality determination apparatus according to the third embodiment to be described later. The configuration of this copier will be described in detail in a third embodiment to be described later.

  Examples of information acquired from a copier as an image forming apparatus include sensing information, control parameter information, input information, and image reading information. Hereinafter, these pieces of information will be described in detail.

(A) Sensing information As sensing information, it is considered as a target for acquiring drive relations, various characteristics of recording media, developer characteristics, photoreceptor characteristics, various electrophotographic process states, environmental conditions, various characteristics of recorded matter, and the like. . The outline of the sensing information is as follows.

(A-1) Driving information • The rotational speed of the photosensitive drum is detected by an encoder, the current value of the driving motor is read, and the temperature of the driving motor is read.
Similarly, the drive state of a cylindrical or belt-like rotating part such as a fixing roller, a paper transport roller, or a drive roller is detected.
-Detect sound generated by driving with a microphone installed inside or outside the device.

(A-2) Paper transport status ・ The position of the leading and trailing edges of the transported paper is read by a transmissive or reflective optical sensor or contact type sensor to detect that a paper jam has occurred. The deviation of the passage timing of the leading and trailing edges of the paper and the fluctuation in the direction perpendicular to the feeding direction are read.
Similarly, the paper moving speed is obtained based on the detection timing between a plurality of sensors.
The slip between the paper supply roller and the paper during paper supply is obtained by comparing the measured value of the rotation speed of the roller with the amount of movement of the paper.

(A-3) Various characteristics of a recording medium such as paper This information greatly affects the image quality and stability of sheet conveyance. There are the following methods for acquiring information on this paper type.
-The thickness of the paper should be equal to the amount of movement of the member pushed up when the paper is sandwiched between two rollers and the relative positional displacement of the rollers is detected by an optical sensor or the paper enters. Find by detecting.
-The surface roughness of the paper is such that a guide or the like is brought into contact with the surface of the paper before transfer, and vibrations or sliding noises caused by the contact are detected.
-For the gloss of paper, a light beam with a specified opening angle is incident at a specified incident angle, and a light beam with a specified opening angle reflected in the specular reflection direction is measured by a sensor.
The paper rigidity is obtained by detecting the amount of deformation (curvature) of the pressed paper.
The judgment as to whether or not the paper is recycled is made by irradiating the paper with ultraviolet rays and detecting its transmittance.
The determination as to whether the paper is a backing paper is performed by irradiating light from a linear light source such as an LED array and detecting the light reflected from the transfer surface with a solid-state image sensor such as a CCD.
Whether or not the sheet is for OHP is determined by irradiating the paper with light and detecting regular reflection light having a different angle from the transmitted light.
-The amount of water contained in the paper is determined by measuring the Kyushu of infrared or microwave light.
-The amount of curl is detected by an optical sensor, contact sensor, etc.
-The electrical resistance of the paper is measured directly by contacting a pair of electrodes (such as paper feed rollers) with the recording paper, or by measuring the surface potential of the photoconductor or intermediate transfer body after paper transfer, and recording from that value. Estimate the resistance of the paper.

(A-4) Developer Characteristics The characteristics of the developer (toner carrier) in the apparatus affect the basic function of the electrophotographic process. Therefore, it becomes an important factor for the operation and output of the system. Obtaining developer information is extremely important. Examples of the developer characteristics include the following items.
-For toner, list charge amount and distribution, fluidity / cohesion / bulk density, electrical resistance, amount of external additive, consumption or remaining amount, fluidity, toner concentration (mixing ratio of toner and carrier) Can do.
-As for carriers, magnetic properties, coat film thickness, spent amount, etc. can be mentioned.

It is usually difficult to detect such items alone in a copying machine. Therefore, it is detected as a comprehensive characteristic of the developer. The overall characteristics of this developer can be measured, for example, as follows.
A test latent image is formed on the photoconductor, developed under predetermined development conditions, and the reflection density (light reflectance) of the formed toner image is measured.
A pair of electrodes is provided in the developing device, and the relationship between applied voltage and current is measured (resistance, dielectric constant, etc.).
-Install a coil in the developing device and measure the voltage-current characteristics (inductance).
-A level sensor is provided in the developing device to detect the developer capacity. The level sensor includes an optical type and a capacitance type.

(A-5) Photoreceptor characteristics The photoreceptor characteristics are closely related to the function of the electrophotographic process as well as the developer characteristics. Information on the photoconductor characteristics includes photoconductor film thickness, surface characteristics (friction coefficient, unevenness), surface potential (before and after each process), surface energy, scattered light, temperature, color, surface position (flare), linear velocity Potential decay rate, resistance / capacitance, surface moisture content, and the like. Among these, the following information can be detected in the copying machine.
・ Detect the current flowing from the charging member to the photoconductor, and simultaneously compare the change in capacitance with the change in film thickness with the voltage-current characteristics with respect to the voltage applied to the charging member and the preset dielectric thickness of the photoconductor. Thus, the film thickness is obtained.
-The surface potential and temperature can be determined by a conventionally known sensor.
-The linear velocity is detected by an encoder attached to the rotating shaft of the photoconductor.
-Scattered light from the surface of the photoreceptor is detected by an optical sensor.

(A-6) Electrophotographic process state As is well known, toner image formation by electrophotographic method is uniform charging of a photoreceptor, latent image formation (image exposure) by laser light, etc., charged toner (colored particles) Development by transfer, transfer of toner image onto transfer material (in the case of color, overlay on the recording medium that is the intermediate transfer body or final transfer material, or over development on the photoconductor during development), toner on the recording medium This is done in the order of image fixing. Various information at each of these stages greatly affects the output of images and other systems. Obtaining these is important in evaluating the stability of the system. Specific examples of the information acquisition of the electrophotographic process state include the following.
The charging potential and the exposure portion potential are detected by a conventionally known surface potential sensor.
The gap between the charging member and the photosensitive member in non-contact charging is detected by measuring the amount of light that has passed through the gap.
・ Electromagnetic waves from electrification are captured by a broadband antenna.
・ Sound generated by charging ・ Exposure intensity ・ Exposure light wavelength

Further, as a method for acquiring various states of the toner image, the following can be mentioned.
The pile height (the height of the toner image) is obtained by measuring the depth from the vertical direction with a displacement sensor and the light shielding length from the horizontal direction with a linear sensor of parallel light.
The toner charge amount is measured by a potential sensor that measures the potential of the electrostatic latent image on the solid part and the potential when the latent image is developed, and the ratio to the adhesion amount converted from the reflection density sensor at the same location. Ask for.
The dot fluctuation or dust is detected by detecting the dot pattern image with an infrared light area sensor on the photosensitive member and with an area sensor having a wavelength corresponding to each color on the intermediate transfer member, and performing appropriate processing.
The offset amount (after fixing) is obtained by reading the corresponding locations on the recording paper and the fixing roller with optical sensors and comparing them.
An optical sensor is installed after the transfer process (on the PD and on the belt), and the transfer remaining amount is determined based on the amount of reflected light from the transfer residual pattern after the transfer of the specific pattern.
-Detect color unevenness during overlay with a full-color sensor that detects the recording paper after fixing.

(A-7) The characteristics, image density, and color of the formed toner image are optically detected (either reflected light or transmitted light may be used. The projection wavelength is selected depending on the color). In order to obtain density and single color information, it may be on a photoconductor or an intermediate transfer body, but it is necessary on paper to measure a color combination such as color unevenness.
For gradation, the reflection density of the toner image formed on the photosensitive member or the toner image transferred to the transfer member is detected by an optical sensor for each gradation level.
Sharpness is obtained by reading an image in which a line repetition pattern is developed or transferred using a monocular sensor having a small spot diameter or a high-resolution line sensor.
The graininess (roughness) is obtained by reading a halftone image and calculating a noise component by the same method as the sharpness detection.
The registration skew is obtained from the difference between the registration roller ON timing and the detection timing of both sensors by providing optical sensors at both ends in the main scanning direction after registration.
Color misregistration is detected by a monocular small-diameter spot sensor or high-resolution line sensor at the edge portion of the superimposed image on the intermediate transfer member or recording paper.
Banding (density unevenness in the feed direction) measures density unevenness in the sub-scanning direction with a small-diameter spot sensor or high-resolution line sensor on the recording paper, and measures the signal amount of a specific frequency.
Glossiness (unevenness) is provided so that a recording paper on which a uniform image is formed is detected by a regular reflection optical sensor.
・ Fog is a method of reading the image background with an optical sensor that detects a relatively wide area on the photoconductor, intermediate transfer member, or recording paper, or image information for each area of the background with a high-resolution area sensor. And the number of toner particles contained in the image is counted.

(A-8) The physical characteristics, image flow, and fading of the printed matter of the copying machine are detected on the photosensitive member, intermediate transfer member, or recording paper by a toner image with an area sensor, and the acquired image information is converted into an image. Process and judge.
・ Chile is obtained by taking an image on recording paper with a high-resolution line sensor or area sensor and calculating the amount of toner scattered around the pattern area.
The trailing edge blank and the solid cross blank are detected by a high resolution line sensor on the photosensitive member, the intermediate transfer member, or the recording paper.
・ Curls, undulations, and folds are detected by a displacement sensor. In order to detect a fold, it is effective to install a sensor near the both ends of the recording paper.
-For the dirt and scratches on the edge surface, the area sensor is used to capture and analyze the edge surface when paper discharge has accumulated to some extent by the area sensor installed vertically on the paper discharge tray.

(A-9) For detection of environmental conditions and temperature, a thermocouple system that takes out a thermoelectromotive force generated at a contact point between dissimilar metals or between a metal and a semiconductor as a signal, and the resistivity of the metal or semiconductor varies depending on the temperature. Resistivity change element using this, pyroelectric element that generates a potential on the surface due to bias in the arrangement of charges in the crystal due to the rise in temperature in certain crystals, and magnetic characteristics depending on temperature A thermomagnetic effect element or the like that detects a change in temperature can be employed.
・ For humidity detection, there are optical measurement methods that measure the light absorption of H ₂ O or OH groups, humidity sensors that measure changes in the electrical resistance of materials due to the adsorption of water vapor, etc. Detection is performed by measuring a change in electric resistance of the oxide semiconductor accompanying gas adsorption.
Although there are optical measurement methods and the like for detection of airflow (direction, flow velocity, gas type), an air bridge type flow sensor that can be made smaller in consideration of mounting on a system is particularly useful.
・ Pressure-sensitive materials are used to detect atmospheric pressure and pressure, and mechanical displacement of the membrane is measured. A similar method is used for vibration detection.

(B) Control parameter information Since the operation of the copying machine is determined by the control unit, it is effective to directly use the input / output parameters of the control unit.

(B-1) Image Forming Parameters Direct parameters output by the control unit through image processing for image formation include the following examples.
・ Setting values of process conditions by the control unit, such as charging potential, development bias value, fixing temperature setting value, etc. ・ Similarly, setting values of various image processing parameters such as halftone processing and color correction. Various parameters to be set, such as paper transport timing, execution time of preparation mode before image formation, etc.

(B-2) User operation history / frequency of various operations selected by the user such as the number of colors, number of sheets, image quality instruction, etc./frequency of the paper size selected by the user

(B-3) Power consumption / Total power consumption or its distribution, change amount (differentiation), cumulative value (integration) in whole period or specific period unit (1 day, 1 week, 1 month, etc.)

(B-4) Consumables consumption information-Use amount or distribution, change amount (differentiation), cumulative value of toner, photoconductor, paper in whole period or specific period unit (1 day, 1 week, 1 month, etc.) ( Integration)

(B-5) Failure occurrence information ・ Frequency or distribution of failure occurrence (by type), change amount (differentiation), cumulative value (integration) of whole period or specific period unit (1 day, 1 week, 1 month, etc.)

(C) Input image information The following information can be acquired from image information sent directly from the host computer as data, or image information obtained after image processing is performed by reading a document image with a scanner.
The cumulative number of colored pixels is obtained by counting image data for each GRB signal for each pixel.
The original image can be separated into characters, halftone dots, photographs, and backgrounds by the method described in, for example, Japanese Patent No. 2621879, and the ratio of the character part, halftone part, etc. can be obtained. Similarly, the ratio of color characters can be obtained.
The toner consumption distribution in the main scanning direction can be obtained by counting the cumulative value of the colored pixels for each area divided in the main scanning direction.
The image size is obtained from the distribution of colored pixels in the image size signal or image data generated by the control unit.
-Character type (size, font) is obtained from character attribute data.

  Next, a specific method for acquiring various information in the copying machine to be examined will be described. The following describes a method for acquiring various types of information in the copying machine. When the abnormality determination apparatus is configured integrally with a copying machine, the information acquisition means described below can function as the information acquisition means of the abnormality determination apparatus as it is. In addition, when the abnormality determination apparatus is configured separately from the copying machine, various information acquired by the information acquisition means of the copying machine described below is received by the reception means that is the information acquisition means of the abnormality determination apparatus. You can do it.

(1) Temperature A copying machine to be inspected includes a temperature sensor that acquires temperature information, using a variable resistance element that is simple in principle and structure and that can be miniaturized. FIG. 1 is a perspective view showing a thin film type variable resistance element in this temperature sensor. This variable resistance element can be manufactured as follows. First, an insulating film 952 is formed on a substrate 951, and a thin film sensing portion 953 made of a metal or semiconductor material is provided thereon. Further, pad electrodes 954 are provided at both ends of the sensing portion 953, and finally a lead wire 955 is connected. In this resistance change element, when the ambient temperature changes, the electrical resistance of the sensing unit 953 changes accordingly. Therefore, the change may be extracted as a voltage or current change. Since the sensing portion 953 is a thin film, the entire element can be made small and easy to incorporate in the system.

  FIG. 2 is a perspective view showing a variable resistance element having a configuration different from that shown in FIG. 1 differs from the variable resistance element of FIG. 1 in that a thin film sensing unit 953 is installed on a thin film bridge 957 floating in a hollow state from a substrate 951 via a spacer 956. With such a structure, heat dissipation from the sensing unit 953 is prevented, and the temperature response of the sensing unit 953 is accelerated. With this structure, only the radiant heat from the measured part can be detected, which is suitable for non-contact measurement.

(2) Humidity A humidity sensor that can be miniaturized is useful. The basic principle is that when water vapor is adsorbed on moisture-sensitive ceramics, the ionic conduction is increased by the adsorbed water and the electrical resistance of the ceramics is reduced. The material of the moisture-sensitive ceramics is a porous material, and generally alumina-based, apatite-based, ZrO ₂ -MgO-based, etc. are used. FIG. 3 is a perspective view showing a humidity sensor mounted on a copying machine to be examined. Comb electrodes 962 are provided on an insulating substrate 961, and terminals 963 are connected to both ends thereof. Further, a moisture sensitive layer 964 (generally moisture sensitive ceramics) is provided and the whole is covered with a case 965. When water vapor is adsorbed to the moisture-sensitive ceramics via the case 965, the electric resistance decreases, and this may be measured as a voltage or current change.

(3) Vibration The vibration sensor is basically the same as a sensor that measures atmospheric pressure and pressure, and a silicon-based sensor that can be miniaturized is particularly useful in consideration of mounting in a system. It is possible to measure the movement of a vibrator fabricated on a thin silicon diaphragm by measuring the change in capacitance between the opposing electrodes provided facing the vibrator, or by using the piezoresistance effect of the Si diaphragm itself. it can. FIG. 4 is a cross-sectional view showing a vibration sensor mounted on a copying machine to be examined. A counter electrode 972 is provided over the insulating substrate 971. Next, a thin diaphragm 974 and a vibrator 975 are provided on the silicon substrate 973, and a step portion 976 is formed to maintain a distance from the counter electrode 972, and the substrate 971 having the counter electrode 972 previously manufactured is bonded. When vibration or pressure is applied from the surroundings in this state, the vibrator 975 vibrates accordingly, and this may be measured as a change in capacitance with the counter electrode 972.

(4) Toner density (for 4 colors)
The toner density is detected for each color. A conventionally known toner density sensor can be used. For example, the toner concentration can be detected by a sensing system that measures changes in the magnetic permeability of the developer in the developing device as described in JP-A-6-289717. FIG. 5 is a block diagram showing an electric circuit of a toner density sensor mounted on a copying machine to be examined. FIG. 6 is a schematic configuration diagram showing a density detection unit of the toner density sensor. For example, a reference coil 983 is differentially connected to a detection coil 982 disposed in the vicinity of a developer 981 formed by mixing a magnetic carrier and nonmagnetic toner. The inductance of the detection coil 982 fluctuates with respect to the magnetic permeability change due to increase or decrease of the toner concentration (directly magnetic carrier), whereas the inductance of the reference coil 983 is not affected by the change of the toner concentration. It has become. An AC drive source 984 that oscillates and drives at, for example, 500 [kHz] is connected to the series circuit of the two coils 982 and 983 so as to drive both the coils 982 and 983. A differential output is taken out from the connection point between the coils 982 and 983, and the output is connected to the phase comparator 985. One output of the AC drive source 984 is separately connected to the phase comparator 985. And configured to compare the phase of the voltage from the drive source 984 and the differential output voltage. In the illustrated example, a sensitivity setting resistor 986 (R1) is connected in parallel to at least one of the two coils, that is, the detection coil 982 and the reference coil 983. Sensitivity characteristics can be controlled by slowing down the sensitivity to changes. Both coils 982 and 983 are wound around a cylindrical coil support 987 adjacent to each other in the vertical direction in the figure, and a detection coil 982 is provided on the side close to the developer 981 in order to detect a change in permeability. The reference coil 983 is arranged on the far side so that the magnetic permeability does not change even if the toner concentration changes.

(5) Photoconductor uniform charging potential (for 4 colors)
A uniform charged potential is detected for each color photoconductor (40K, Y, M, C). FIG. 7 is a schematic configuration diagram showing a potential measurement system mounted on a copying machine to be examined. In the same figure, the code | symbol 931 has shown the sensor part board | substrate attached facing a target object (not shown). Reference numeral 932 denotes a signal processing unit substrate that sends a drive signal to the sensor unit substrate and receives a sensor output. In the sensor unit substrate, a sound 933 as a chopping means and a piezoelectric element 934 are provided. The piezoelectric element 934 is driven by a drive signal from the signal processing unit substrate 932. This potential measurement system uses a self-excited oscillation method based on a loop in which when one piezoelectric element 934 is driven, vibration caused by the piezoelectric element 934 is transmitted to the other piezoelectric element 934a through sound 933 and returned to the drive source. Reference numeral 935 denotes a measurement electrode (hereinafter referred to as an electrode) that receives lines of electric force from the object. Reference numeral 936 denotes an amplifier that amplifies the amount of time change of the electric lines of force S received by the electrode 935. In the signal processing unit substrate 932, a piezoelectric element drive circuit 937, a filter 938, and a piezoelectric element drive circuit 939 are provided. Filter 938 shapes the waveform. The phase shift circuit 939 has a purpose of offsetting the phase difference between the drive signal mixed in the sensor and the actual drive signal by 180 degrees so as to cancel each other. In general, the phase difference between two signals varies depending on the mixing path. The attenuator 940 has a role of adjusting the magnitude of the phase-adjusted correction signal. The adder circuit 941 adds the correction signal and the sensor output. A processing circuit 942 processes the final signal output to determine the potential of the object. Reference numerals 943 and 944 denote adjustment volumes for the phase shift circuit and the attenuator, respectively. In such a configuration, by adjusting and optimizing the amount of phase shift and the attenuator gain, a signal having an opposite phase and the same level can be added as a correction signal to the mixed signal based on the drive signal. Only the sensor output based on the target object can be detected. Further, by providing the adjusting means, it is possible to cope with the characteristic change accompanying the secular change by the adjustment, and the reliability as the sensor is improved.

(6) Potential after photoconductor exposure (for 4 colors)
The surface potential of the photoconductor (40K, Y, M, C) after optical writing is detected in the same manner as in (5).

(7) Colored area ratio (for 4 colors)
From the input image information, a colored area ratio is obtained for each color from the ratio of the cumulative value of pixels to be colored and the cumulative value of all pixels, and this is used.

(8) Amount of developed toner (for 4 colors)
The toner adhesion amount per unit area in each color toner image developed on the photoconductor (40K, Y, M, C) is obtained based on the light reflectance by the reflective photosensor. The reflection type photosensor irradiates an object with LED light and detects the reflected light with a light receiving element. Since a correlation is established between the toner adhesion amount and the light reflectance, the toner adhesion amount can be obtained based on the light reflectance.

(9) Inclination of paper leading edge position An optical sensor that detects transfer paper at both ends in a direction orthogonal to the conveyance direction at some point in the paper feed path from the paper feed roller of the paper feed unit (200) to the secondary transfer nip. A pair is installed to detect both ends near the leading edge of the transferred transfer paper. For both light sensors, the time to pass is measured with reference to the time when the drive signal of the paper feed roller is transmitted, and the inclination of the transfer paper with respect to the feed direction is obtained based on the time deviation.

(10) Paper discharge timing The transfer paper after passing through the pair of discharge rollers for discharging the transfer paper to the outside of the apparatus is detected by an optical sensor. In this case as well, the measurement is performed with reference to the time when the paper feed roller drive signal is transmitted.

(11) Photoconductor total current (for four colors)
A current flowing from the photoconductor (40K, Y, M, C) to the ground is detected. Such a current can be detected by providing a current measuring means between the substrate of the photoreceptor and the ground terminal.

(12) Photoconductor driving power (for four colors)
Driving power (current × voltage) consumed by the driving source (motor) of the photosensitive member during driving is detected by an ammeter, a voltmeter, or the like.

  FIG. 8 is a block diagram showing a main part of an electric circuit in the abnormality determination device. In this figure, the abnormality determination apparatus includes an information acquisition unit 501 that is information acquisition means for acquiring information on an object, an abnormality determination unit 502 that is determination means, an information storage unit 503 that is information storage means, and a data input unit 504 that is data input means. Etc. Moreover, the determination result output part 505 which outputs the determination result by an abnormality determination means is also provided.

  The information acquisition unit 501 acquires at least two or more of the various types of information described above from a copying machine (not shown) that is a test target. A plurality of pieces of information acquired by the information acquisition unit 501 are sent to the abnormality determination unit 502. The abnormality determination unit 502 includes a calculation unit (CPU 501a in the illustrated example) for performing various calculations necessary for determination of abnormality. Then, the information sent from the information acquisition unit 501 is used as it is for calculation processing for abnormality determination or used after being stored in the information storage unit 503. Specifically, a predetermined calculation is performed based on various information sent from the information acquisition unit 501, and based on a comparison result between the calculation result and a predetermined threshold stored in the information storage unit 503. Then, it is determined whether there is an abnormality in the copying machine.

The determination result by the abnormality determination unit 502 is output by the determination result output unit 505. In addition to printout, image display output, audio output, etc. for allowing the user of the copier to recognize the determination result, this output also includes a mode in which the determination result information is output to some external device such as a personal computer or a printer. It is a concept that includes. The output of various modes informs that a failure is near, informs numerical values such as the Mahalanobis distance described later, and conveys graphs and characters. Examples of output modes include those listed below.
(O-1) The determination result is displayed on a display means such as a display.
(O-2) A language, an alarm sound, etc. are output to sound generation means such as a speaker.
(O-3) Character information and the like are printed out on a recording medium such as transfer paper.
(O-4) The determination result is output as electronic information to an external machine through a wired line or a wireless line.

  By such output, the determination result by the abnormality determination unit 502 is recognized by the user of the copying machine, the serviceman at a remote place, and the like. The information acquisition unit 501 includes a RAM, a ROM, a hard disk, and the like, and stores information such as a control program and an algorithm in addition to various types of information acquired by the information acquisition unit 501. Note that the determination result may be stored in storage means (for example, a memory) of an external device such as each copying machine, printer server, or monitoring center.

When an abnormality is found by the determination, it is desirable that some processing is performed on the copying machine to be examined in addition to the output of the determination result. For example, the copying machine is forcibly stopped to notify a maintenance request. Further, processing that restricts some functions of the copying machine may be performed. Examples of processing performed when an abnormality is found include those listed below.
(H-1) Limiting the number of output colors in a color copier (h-2) Limiting the image forming speed (h-3) Limiting the number of output pixels (for example, the number of lines) in the halftone portion of the output image (h-4) ) Restriction of halftone reproduction method (h-5) Restriction of paper type (h-6) Restriction of parameter for resist control (h-7) Parameter restriction of image forming process (for example, charging potential, exposure amount, development in electrophotography) Bias, transfer bias, etc.)

  Depending on the type of abnormality that has occurred, a process for prompting the user to replenish or replace consumables or parts may be executed. Further, when the abnormality can be repaired, a process for automatically repairing the abnormality may be executed.

  The information storage unit 503 stores a plurality of normal set data that is a combination of various types of information acquired in advance from a copying machine that is a subject to be tested in a normal state. Hereinafter, the collection of the plurality of normal group data is referred to as a normal group data group.

  The abnormality determination unit 502 is based on the result obtained by the information acquisition unit 501 from the various types of information acquired from the copying machine to be examined and the normal set data group stored in the information recording unit 503 in advance. Find the distance of Mahalanobis. The Mahalanobis distance will be described in detail in a second embodiment and a third embodiment described later. The Mahalanobis distance is an index indicating the normality of things as follows. Specifically, in a multidimensional space obtained based on a normal set data group that is a collection of normal set data consisting of a combination of multiple types of information, from a combination of the same multiple types of information acquired from the test subject The coordinates at which the acquired data is located are shown. The farther the coordinates are from the coordinate group where the normal group data group is located, the farther the test object is from the normal state. The Mahalanobis distance indicates how far the former coordinates are from the latter coordinate group. If the Mahalanobis distance exceeds a preset threshold, it is determined that the abnormality to be examined is “present”.

  In such a determination method, a normal group data group (acquired data table, normalized data table, correlation coefficient matrix R, or inverse matrix A, which will be described later) for obtaining the Mahalanobis distance is a normal state of the subject to be examined. Functions as normal index information. Moreover, the threshold value compared with the Mahalanobis distance also functions as normal index information that is an index of the normal state of the test object.

  The information storage unit 503 of the abnormality determination device stores a plurality of pieces of information corresponding respectively to a plurality of pieces of specific information having different contents as the normal set data group described above. This specific information is one of a plurality of types of information acquired from a copying machine that is the subject of inspection. For example, it is information such as an operation mode setting value indicating whether it is a high-speed printing mode or a low-speed printing mode. In determining the abnormality, the normal set data group used for calculating the Mahalanobis distance is switched to the one corresponding to the content of the specific information acquired from the copying machine. For example, when the content of the specific information acquired from the copying machine is a value indicating the high-speed printing mode, the data is switched to the one for the high-speed printing mode among the plurality of normal set data groups.

  FIG. 9 is a graph showing the relationship between the toner charge amount and the toner density in the copier (example when the toner charge polarity is positive). In an image forming apparatus such as a copying machine, the toner charge amount and the toner density in the developer have a strong correlation (inverse correlation). As the toner density increases, the toner charge amount decreases. Further, the toner charge amount and the toner density have a correlation with the environment. For example, a region surrounded by a line indicated by LL in the drawing is a collection of normal set data including a combination of a toner charge amount and a toner density acquired from a copying machine in a normal state under a low temperature and low humidity environment. This is a two-dimensional space obtained based on a normal group data group. If the normal set data acquired from the copying machine to be examined is within this area, it may be determined that the copying machine is normal. However, if it is outside the area, the copier is likely to be abnormal. Therefore, the Mahalanobis distance from the normal set data group is obtained based on the normal set data group acquired from the normal copying machine and the toner charge amount and toner density acquired from the copy machine to be tested. The presence or absence of abnormality can be determined by comparing with a threshold value.

  However, a region surrounded by a line indicated by LL in the drawing is a normal two-dimensional space between the toner charge amount and the toner density in the copying machine under a low temperature and low humidity environment. Under a high temperature and high humidity environment, the normal two-dimensional space shifts to a region indicated by HH in the figure. In this case, even if the normal set data group acquired from the copying machine to be examined is located within the area surrounded by the line indicated by LL, the area surrounded by the line indicated by HH If not, the test subject should be judged abnormal. However, when a normal group data group obtained in a low temperature and low humidity environment and a normal group data group obtained in a high temperature and high humidity environment are combined and regarded as one normal group data group, a line indicated by HH is used. Even if it is outside the enclosed area, it may be determined to be normal if it is within the area enclosed by the line indicated by LL.

  In view of this, the abnormality determination device stores in advance in the information storage unit 503 a plurality of items that individually correspond to specific information such as environment information, for example, as normal group data groups. Then, the normal group data group to be used is switched and used according to the contents of the specific information. In this way, for example, in a low-temperature and low-humidity environment, it is possible to use only a collection of normal set data that falls within the LL region in the figure as a normal set data group. Also, in a high-temperature and high-humidity environment, it is possible to use only a collection of normal group data that falls within the HH region in the figure as a normal group data group. As a result, it is possible to avoid erroneous determination due to the normal value of the information acquired by the information acquisition unit 501 being different depending on the content of the specific information.

Next, each modified device of the abnormality determination device according to the first embodiment will be described.
[First Modification]
FIG. 10 is a block diagram showing a part of an electric circuit in the first modified apparatus. In the first modified apparatus, the data input unit 504 receives specific information (for example, an operation mode setting value and environment information) input by the user. The information storage unit 503 stores the received specific information. The abnormality determination unit 502 identifies one of the plurality of normal set data groups stored in the information storage unit 503 corresponding to the content of the specific information stored in the information storage unit 503, and stores the information Read from the unit 503. Then, the Mahalanobis distance is calculated based on various information acquired by the information acquiring unit 501 (acquired information by the sensors A, B... X, etc.) and the normal set data group read from the information storage unit 503. . This is effective when adjusting or changing past judgment results or when a service person tests during maintenance.

  Instead of storing the specific information in the information storage unit 503, the specific information may be acquired by the information acquisition unit 501 and sent from the information acquisition unit 501 to the abnormality determination unit 502.

[Second Modification]
FIG. 11 is a block diagram showing a part of an electric circuit in the second modification device. In the second modification apparatus, the information acquisition unit 501 acquires various types of information acquired by the sensors A and B installed in the copying machine from a data transmission unit (not shown) of the copying machine. Information acquired by the sensor X installed inside the copying machine is received by the data input unit 504 as specific information. The received specific information is stored in the information storage unit 503. The abnormality determination unit 503 specifies one of the plurality of normal set data groups stored in the information storage unit 503 corresponding to the content of the specific information stored in the information storage unit 503, and stores the information. Read from the unit 503. Then, the Mahalanobis distance is calculated based on the various types of information acquired by the information acquisition unit 501 and the normal set data group read from the information storage unit 503. When the contents of specific information such as the environment (temperature and humidity) in the copying machine and the surface potential of the photoconductor change, the abnormality determination unit 502 can be notified automatically. Then, the normal group data group used for calculating the Mahalanobis distance can be switched to one reflecting the change in the content of the specific information.

[Third Modification Device]
FIG. 12 is a block diagram showing a part of an electric circuit in the third modification device. In the third modification apparatus, the information acquisition unit 501 acquires various types of information acquired by the sensors A and B installed in the copying machine from a data transmission unit (not shown) of the copying machine. Information acquired by a control unit installed inside the copying machine is received by the data input unit 504 as specific information. The received specific information is stored in the information storage unit 503. The abnormality determination unit 503 specifies one of the plurality of normal set data groups stored in the information storage unit 503 corresponding to the content of the specific information stored in the information storage unit 503, and stores the information. Read from the unit 503. Then, the Mahalanobis distance is calculated based on the various types of information acquired by the information acquisition unit 501 and the normal set data group read from the information storage unit 503. When the content of specific information such as control information that can be acquired by the control unit of the copier, for example, color mode usage status information, continuous sheet frequency, or the like, can be automatically notified to the abnormality determination unit 502. Then, the normal group data group used for calculating the Mahalanobis distance can be switched to one reflecting the change in the content of the specific information.

[Fourth Modification Device]
FIG. 13 is a block diagram showing a part of an electric circuit in the fourth modified apparatus. In the fourth modified apparatus, the information acquisition unit 501 acquires various types of information acquired by the sensors A and B installed in the copying machine from a data transmission unit (not shown) of the copying machine. Further, information sent from an external apparatus different from the copying machine to be examined and the fourth modification apparatus is received by the data input unit 504 as specific information. The received specific information is stored in the information storage unit 503. The abnormality determination unit 503 specifies one of the plurality of normal set data groups stored in the information storage unit 503 corresponding to the content of the specific information stored in the information storage unit 503, and stores the information. Read from the unit 503. Then, the Mahalanobis distance is calculated based on the various types of information acquired by the information acquisition unit 501 and the normal set data group read from the information storage unit 503. When the content of specific information sent from an external device such as a remote diagnosis system changes, this can be automatically notified to the abnormality determination unit 502. Then, the normal group data group used for calculating the Mahalanobis distance can be switched to one reflecting the change in the content of the specific information.

[Fifth Modification Device]
The fifth modified apparatus is different from the first modified apparatus to the fourth modified apparatus in the following points. That is, the information storage unit 503 stores only one normal set data group. Of the specific information changing to various values, only the normal group data group corresponding to the specific information of a specific value is stored (hereinafter, this normal group data group is referred to as a standard normal group data group). Abnormality determination unit 502, when the content of the specific information obtained from data input unit 504 or information acquisition unit 501 is different from the content of the specific information corresponding to the standard normal set data group stored in information storage unit 503 In this case, the standard normal data group is corrected. Specifically, each data in the standard normal set data group is corrected so as to have a value corresponding to the content of the specific information obtained from the data input unit 504 or the information acquisition unit 501.

As a method for correcting each data of the standard normal set data group, for example, there is a method for correcting each data in the acquired data table described in the second embodiment or the third embodiment described later. Further, each data in the normalized data table may be corrected. Further, each data in the correlation coefficient matrix R and the inverse matrix A may be corrected. Moreover, you may correct | amend each average value y (y1 ... yk) in the formula shown by the number 2 of 2nd Embodiment mentioned later, or the number 7 of 3rd Embodiment. Further, instead of the formulas shown in the formulas 2 and 7, the formula shown in the following formula 1 may be used.

  In the method of correcting the average value y, a plurality of correction coefficients having different values depending on the content of the specific information are prepared, and the average value y is multiplied by the correction coefficient corresponding to the value of the specific information at the time of abnormality determination. Good. Note that this correction coefficient is determined by a preliminary test.

  Also in the method using the equation (1), a plurality of correction coefficients k having different values are prepared in accordance with the contents of the specific information. These correction coefficients k are also determined by a preliminary test. For example, when the number of types of information is 20 (j = 1, 2,..., 20), all types (j) may be corrected by multiplying by the same correction coefficient k. Further, if the normal value cannot be expressed appropriately by simply multiplying all types (j) by the same correction coefficient k, a correction coefficient k may be prepared for each type (k1, k2,. ... k20).

  By correcting the standard normal group data group in this way, the information storage unit 503 does not need to store a plurality of normal group data groups each having a different value for each content of the specific information. Only the normal normal group data group needs to be stored. Thereby, the storage capacity of the information storage unit 503 can be reduced.

  FIG. 14 is a block diagram showing a part of an electric circuit in the fifth modification device. In the fifth modified apparatus, the data input unit 504 receives specific information (for example, operation mode setting value, environment information, etc.) input by the user. The information storage unit 503 stores the received specific information. The abnormality determination unit 502 reads specific information stored in the information storage unit 503. Further, the standard normal set data group stored in the information storage unit 503 is also read. Then, when the standard normal group data group does not correspond to the content of the specific information, correction is performed so that each data in the standard normal group data group has a value corresponding to the content of the specific information. Next, based on various information acquired by the information acquisition unit 501 (acquired information by sensors A, B,... X, etc.) and a normal normal set data group or a corrected normal set data group corrected as necessary. And calculate the Mahalanobis distance.

  Instead of storing the specific information in the information storage unit 503, the specific information may be acquired by the information acquisition unit 501 and sent from the information acquisition unit 501 to the abnormality determination unit 502.

[Sixth Modification Device]
Similarly to the fifth modification device, the sixth modification device stores only the standard normal group data group in the information storage unit 503 as the normal group data group. If necessary, the standard normal set data group is corrected and used to calculate the Mahalanobis distance.

  FIG. 15 is a block diagram showing a part of an electric circuit in the sixth modification device. In the sixth modified apparatus, the information acquisition unit 501 acquires various types of information acquired by the sensors A and B installed in the copying machine from a data transmission unit (not shown) of the copying machine. Information acquired by the sensor X installed inside the copying machine is received by the data input unit 504 as specific information. The received specific information is stored in the information storage unit 503. The abnormality determination unit 503 reads specific information stored in the information storage unit 503. Further, the standard normal set data group stored in the information storage unit 503 is read. Then, when the standard normal group data group does not correspond to the content of the specific information, correction is performed so that each data in the standard normal group data group has a value corresponding to the content of the specific information. Next, the Mahalanobis distance is calculated based on various information acquired by the information acquisition unit 501 and the standard normal group data group or the corrected normal group data group read from the information storage unit 503. Even in such a configuration, the storage capacity of the information storage unit 503 can be reduced.

[Seventh Modification Device]
Similarly to the fifth modification device, the seventh modification device stores only the standard normal group data group in the information storage unit 503 as the normal group data group. If necessary, the standard normal set data group is corrected and used to calculate the Mahalanobis distance.

  FIG. 16 is a block diagram showing a part of an electric circuit in the seventh modified apparatus. In the seventh modified apparatus, the information acquisition unit 501 acquires various types of information acquired by the sensors A and B installed in the copying machine from a data transmission unit (not shown) of the copying machine. Information acquired by a control unit installed inside the copying machine is received by the data input unit 504 as specific information. The received specific information is stored in the information storage unit 503. The abnormality determination unit 503 reads specific information stored in the information storage unit 503. Further, the standard normal set data group stored in the information storage unit 503 is also read. Then, when the standard normal group data group does not correspond to the content of the specific information, correction is performed so that each data in the standard normal group data group has a value corresponding to the content of the specific information. Next, the Mahalanobis distance is calculated based on the various information acquired by the information acquisition unit 501 and the standard normal group data group or the corrected normal group data group. Even in such a configuration, the storage capacity of the information storage unit 503 can be reduced.

[Eighth Modification Device]
Similarly to the fifth modification device, the eighth modification device stores only the standard normal group data group in the information storage unit 503 as the normal group data group. If necessary, the standard normal set data group is corrected and used to calculate the Mahalanobis distance.

  FIG. 17 is a block diagram showing a part of an electric circuit in the eighth modification apparatus. In the eighth modification apparatus, the information acquisition unit 501 acquires various types of information acquired by the sensors A and B installed in the copying machine from a data transmission unit (not shown) of the copying machine. Further, the data input unit 504 receives information sent from an external device different from the subject copying machine or the eighth modification device as specific information. The received specific information is stored in the information storage unit 503. The abnormality determination unit 503 reads specific information stored in the information storage unit 503. Further, the standard normal set data group stored in the information storage unit 503 is also read. Then, when the standard normal group data group does not correspond to the content of the specific information, correction is performed so that each data in the standard normal group data group has a value corresponding to the content of the specific information. Next, the Mahalanobis distance is calculated based on the various information acquired by the information acquisition unit 501 and the standard normal group data group or the corrected normal group data group. Even in such a configuration, the storage capacity of the information storage unit 503 can be reduced.

[Ninth Modification Device]
Also in the ninth modification device, only one normal set data group is stored in the information storage unit 503. However, unlike the first embodiment and the first to eighth modified devices described so far, the normal group data group as the normal index information is not switched. Instead, the threshold value as normal index information is switched at a predetermined timing. This threshold value is used for comparison with the Mahalanobis distance, and when this value is switched, the degree of abnormality when it is determined as “abnormal” is changed.

  The switching of the threshold value is performed when the content of user information input by the data input unit 504 or acquired by the information acquisition unit 501 changes. When the user uses the copying machine, the user information as personal information or group information is input to the copying machine or the ninth modification apparatus. If the input user information does not change from the previous copy, the copy is performed by the same user or user group as the previous copy. In this case, the Mahalanobis distance is obtained without switching the above threshold.

  On the other hand, when the input user information is different from the previous copy, the copy is performed by a different user or user group than the previous copy. At this time, the user's degree of failure detection may be different from the previous user. Therefore, the information storage unit 503 stores a dedicated threshold value for each user (or user group) individually. Then, when the input user information is different from the previous copy, the abnormality determination unit 502 switches the above threshold value to that corresponding to a new user. In such a configuration, it is possible to avoid a decrease in determination accuracy due to a change in the user of the copying machine to be tested by switching the threshold value according to the user information.

Next, the abnormality determination device according to each example in which a more characteristic configuration is added to the abnormality determination device according to the first embodiment will be described.
[Example 1]
In the abnormality determination device according to the first embodiment, a plurality of data having different values for each value of the setting environment of the copying machine to be examined is stored in the information storage unit 503 as a normal set data group as normal index information. ing. The installation environment is information indicating that the environment where the copying machine is installed is a low-temperature and low-humidity environment, a medium-temperature and medium-humidity environment, a high-temperature and high-humidity environment, or the like. Then, the user inputs information on the installation environment into the data input unit 504. The abnormality determination unit 502 corresponds to the information on the installation environment input by the user among the plurality of normal group data groups stored in the information storage unit 503. Switch to. In such a configuration, it is possible to avoid erroneous determination due to the normal value of the information acquired by the information acquisition unit 501 being different depending on the installation environment of the copying machine.

  If the threshold value is switched according to the installation environment information instead of the normal group data group as normal index information, the user's degree of abnormality detection changes as the copying machine installation environment changes. It is possible to avoid a decrease in determination accuracy due to this.

[Example 2]
The abnormality determination device according to the second embodiment includes an environment detection sensor serving as an environment detection unit that detects at least one of temperature, humidity, and atmospheric pressure. In addition, as the normal set data group as the normal index information, a plurality of items having different values are stored in the information storage unit 503 for each value of the environment information detected by the environment detection sensor. The abnormality determination unit 502 corresponds to the value of the environmental information detected by the environment detection sensor among the plurality of normal group data groups stored in the information storage unit 503 as the normal group data group used for calculating the Mahalanobis distance. Switch to what you want. Even in such a configuration, it is possible to avoid erroneous determination due to the normal value of the information acquired by the information acquisition unit 501 being different depending on the environment of the copying machine.

  In addition, when the threshold value is switched according to the environment information detected by the environment detection sensor instead of the normal group data group as normal index information, the degree of abnormality detection of the user changes with the change of environment. It is possible to avoid a decrease in determination accuracy due to the operation.

[Example 3]
In the abnormality determination device according to the third embodiment, a plurality of data having different values is stored in the information storage unit 503 for each value of the operation mode information of the copying machine as a normal set data group as normal index information. . Examples of the operation mode information include those listed below.
-Output color information indicating whether the output is single color or multi-color-Information indicating whether the operation is a print operation or a copy operation-Information indicating whether the print mode is a high-speed print mode or a low-speed print mode Information indicating the set value of the uniform charging potential on the surface, information indicating the target toner concentration, information indicating the target fixing temperature

  The normal value of each data in the normal group data group may vary greatly depending on whether the operation mode of the copying machine is a single color output or a multicolor output. For example, in the case of monochrome output, which is a single color output, in most cases, only the K photoconductor is charged among the Y, M, C, and K photoconductors described later. For this reason, when the uniform charging potential of each photoconductor is acquired as acquisition information, the uniform charging potential of the Y, M, and C photoconductors is detected as almost zero. Therefore, when the uniformly charged potential of these photoconductors is detected near zero, it can be determined that the photoconductor is normal. However, if it is detected as a numerical value far from zero, it should be determined as abnormal. On the contrary, in the case of four-color full-color output, each photoconductor is charged uniformly, so that each uniform charged potential is detected in the vicinity of a certain value. Nevertheless, if it is detected near zero, it should be determined as abnormal. In such a case, if the normal set data group is constructed by reflecting the uniform charging potential of each photoconductor in the case of monochromatic output and in the case of multicolor output, the toner density described above is used. In the same way as the relationship between the toner charge amount and the toner charge amount, there is a risk of erroneous determination. It is possible to avoid such a misjudgment by storing the normal group data group separately and switching these two normal group data groups according to whether they are single color output or multicolor output. Become.

  The normal value of each data in the normal group data group may vary greatly depending on whether the operation mode of the copying machine is a printing operation or a copying operation. For example, since a document is not read by a scanner during a printing operation, when the moving speed of a reading device or a light source in the scanner is acquired as acquisition information, the moving speed is zero. Therefore, when those moving speeds are detected near zero, it may be determined that the speed is normal. However, if the moving speed is detected as a numerical value far from zero, it should be determined as abnormal. On the other hand, during the copy operation, the document is read by the scanner, so that the moving speed of the reading device and the light source in the scanner is detected as a certain speed. Therefore, when those moving speeds are detected in the vicinity of the constant speed, it may be determined that the speed is normal. However, if the moving speed is detected as zero, it should be determined as abnormal. In such a case, if the moving speed of the scanner reading device or light source during the printing operation and the moving speed of the reading device or light source during the copying operation are combined together, a normal set data group is constructed. In the same way as the relationship between the toner density and the toner charge amount described above, there is a risk of erroneous determination. It is possible to avoid the erroneous determination by separately storing the normal group data group and switching the two normal group data groups depending on whether the print operation or the copy operation is performed. .

  The normal value of each data in the normal group data group may vary greatly depending on whether the operation mode of the copying machine is the high-speed print mode or the low-speed print mode. For example, in the high-speed print mode, the surface movement speed of the photoreceptor and the paper passing speed are detected at a relatively high speed. Therefore, if it is detected at or near this speed, it may be determined that the speed is normal. However, if it is detected at a relatively low speed, it should be determined as abnormal. On the contrary, in the low-speed print mode, the surface moving speed and the sheet passing speed of the photosensitive member are detected at a relatively low speed. Therefore, if it is detected at or near this speed, it may be determined that the speed is normal. However, if it is detected at a relatively high speed, it should be determined as abnormal. In such a case, if the surface moving speed and the sheet passing speed of the photoconductor are combined together in the high-speed print mode and in the low-speed print mode, a normal group data group is constructed as described above. In the same manner as the relationship between the toner density and the toner charge amount, there is a risk of erroneous determination. It is possible to avoid these erroneous determinations by storing the normal group data group separately and switching these two normal group data groups according to whether they are in the high-speed print mode or the low-speed print mode. become.

  The normal value of each data in the normal set data group may vary greatly depending on the set value of the uniform charging potential of the photoconductor. Specifically, since the development performance with toner varies depending on the environment, the set value of the uniformly charged potential of the photoconductor may be changed for the purpose of stabilizing the development performance. In such a case, if the normal set data group corresponding to the set value is not used, an erroneous determination may occur in the same manner as the relationship between the toner density and the toner charge amount described above. By storing a plurality of normal group data groups corresponding to each set value of the uniform charging potential and switching the normal group data group to be used according to the actual installation value, it becomes possible to avoid such erroneous determination. .

  The normal value of each data in the normal group data group may vary greatly depending on the target toner density. Specifically, since the developing performance with toner varies depending on the environment, the toner concentration of each color developer may be changed for the purpose of stabilizing the developing performance. In such a case, if the normal set data group corresponding to the target toner density is not used, an erroneous determination may occur in the same manner as the relationship between the toner density and the toner charge amount described above. By storing a plurality of normal group data groups corresponding to each target toner density and switching the normal group data group to be used according to the actual target toner density, it is possible to avoid such erroneous determination.

  The normal value of each data in the normal set data group may vary greatly depending on the target fixing temperature. Specifically, the fixability of the toner image on the transfer paper varies depending on the environment and the toner adhesion amount, and therefore the fixing temperature may be changed for the purpose of stabilizing the fixability. In such a case, if the normal set data group corresponding to the target fixing temperature is not used, an erroneous determination may occur in the same manner as the relationship between the toner density and the toner charge amount described above. By storing a plurality of normal group data groups corresponding to each target fixing temperature and switching the normal group data group to be used according to the actual target fixing temperature, it is possible to avoid such erroneous determination.

[Example 4]
In the abnormality determination apparatus according to the fourth embodiment, a plurality of items having different values are stored in the information storage unit 503 for each value of the user operation history information for the copying machine as a normal set data group as normal index information. ing. Then, among the plurality of normal group data groups, the one corresponding to the operation mode information with the highest user operation history is specified, and the normal group data group used for the calculation of Mahalanobis is switched to the one corresponding to the specific result. It has become. In such a configuration, it is possible to select any one of a plurality of normal set data groups according to the operation mode information with the highest operation frequency of the user in the past. Thereby, it is possible to avoid complication of control by acquiring operation history information and switching the normal group data group for each printing operation or copying operation.

[Example 5]
In the abnormality determination device according to the fifth embodiment, a plurality of items having different values are stored in the information storage unit 503 for each value of environmental history information in the copying machine as a normal set data group as normal index information. . Then, from among a plurality of normal group data groups, the one corresponding to the environment with the highest appearance frequency is specified, and the normal group data group used for calculating Mahalanobis is switched to one corresponding to the specific result. . With such a configuration, it is possible to select any one of a plurality of normal set data groups according to the environment having the highest appearance frequency in the copying machine. Thereby, it is possible to avoid complication of control by acquiring environment information and switching the normal group data group for each printing operation or copying operation.

Next, a second embodiment in which the present invention is applied to an electrophotographic printer (hereinafter simply referred to as a printer) which is an electrophotographic image forming apparatus will be described.
First, the basic configuration of the printer according to the second embodiment will be described. FIG. 18 is a schematic configuration diagram showing the printer. In this figure, the printer includes four sets of process units 801Y, M, C, and K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). ing. Hereinafter, the subscripts Y, M, C, and K of the respective symbols indicate members for yellow, magenta, cyan, and black, respectively.

  The process units 801Y, 801, M, C, and K that are arranged in parallel so as to be aligned in the horizontal direction have drum-shaped photoconductors 811Y, M, C, and K that are latent image carriers. In addition to these process units 801Y, M, C, and K, the printer includes an optical writing unit 802, a paper feed cassette 803, a registration roller pair 804, a paper transport unit 805, a fixing unit 806, an in-machine temperature sensor 807, and the like. Yes. In addition, four toner replenishing devices (not shown) and a power supply unit are also provided.

  The optical writing unit 802 includes a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and scans the laser light L on the surface of each photoconductor 811Y, M, C, K based on image data. .

  The process units 801Y, M, C, and K have substantially the same configuration except that the color of the toner to be used is different. Taking the Y process unit 801Y as an example, this also includes a charging unit 812Y, a developing device 813Y, a cleaning unit 814Y, a charge eliminating unit 815Y, a Y optical sensor 816Y, and the like in addition to the photoreceptor 811Y.

  As the charging unit 812Y, a charging charger that charges the photoreceptor 811Y by corona discharge from a corotron or the like can be used. Further, a system in which a transfer bias is applied to a charging roller or a charging brush disposed rotatably at a position facing the photoconductor 811Y may be used.

  In the Y photoconductor 811Y, a scale portion (not shown) in which a mirror surface and a non-mirror surface are repeated over the entire circumference of the drum peripheral surface is provided near one end in the axial direction of the drum shape. The Y optical sensor 816Y is composed of a reflective photosensor, and irradiates light from a light emitting element (not shown) toward the scale portion. This light is reflected by the surface of the scale portion and then received by a light receiving element (not shown) of the Y optical sensor 816Y. The Y optical sensor 816Y outputs a voltage signal corresponding to the amount of light received by the light receiving element to a control unit (not shown). The mirror surface and the non-mirror surface of the scale portion of the photoconductor 811Y alternately pass at the position facing the Y optical sensor 816Y, so that the Y optical sensor 816Y has a frequency week according to the linear velocity of the photoconductor 811Y. A pulse voltage is output. Similarly, the M, C, K optical sensors 816M, C, K output a pulse voltage of a frequency week corresponding to the linear velocity of the photoconductors 811M, C, K.

  When the surface of the photoreceptor 811 uniformly charged by the charging unit 812Y is scanned with the laser light L modulated and deflected by the optical writing unit 802, an electrostatic latent image is formed on the exposure unit. This electrostatic latent image is developed into a Y toner image by a developing device 813Y described later. In other process units 801M, C, and K, M, C, and K toner images are similarly formed on the photoreceptors 811M, C, and K, respectively.

  The paper feed cassette 803 stores a plurality of transfer papers P as recording bodies in a bundle of paper sheets, and presses a paper feed roller 803a against the uppermost transfer paper P. Then, the sheet feeding roller 803a is rotated at a predetermined timing, and the transfer sheet P is sent out to the sheet feeding path. A registration roller pair 804 is disposed at the end of the paper feed path, and the transferred transfer paper P is synchronized with the Y toner image formed on the photoreceptor 811Y of the Y process unit 801Y. Feed out from the end of the paper feed path at the timing to get.

  The paper transport unit 805 is disposed below each of the process units 801Y, M, C, and K. The paper transport belt 851, the driving roller 852, the tension roller 853, the four transfer chargers 854Y, M, C, K, etc. It also has an optical sensor 855 for the belt. The paper conveying belt 851 has a horizontally long posture so as to face each of the photoconductors 811Y, M, C, and K by a driving roller 852 that is rotated counterclockwise in the drawing by a driving system (not shown) and a tension roller 853. It is stretched by. Then, as the drive roller 852 rotates, it is moved endlessly in the counterclockwise direction in the drawing, and the transfer positions for Y, M, C, and K that are opposed to the respective photoconductors 811Y, M, C, and K are set. Pass sequentially. At these transfer positions, the transfer chargers 854Y, M, C, and K are disposed inside the loop of the paper transport belt 851 so as to face the photoconductors 811Y, M, C, and K through the paper transport belt 851, respectively. Yes. Then, a transfer electric field is formed between the photoconductors 811Y, M, C, and K. In this printer, transfer chargers 854Y, M, C, and K are provided as transfer means. Instead, a transfer bias applying member is applied to a transfer bias applying member such as a transfer roller. Also good.

  In the paper conveyance belt 851, a scale portion (not shown) in which a bright portion and a dark portion are repeated over the entire circumference of the belt peripheral surface is provided near one end in the width direction. The belt optical sensor 855 includes a reflective photosensor, and irradiates light from a light emitting element (not shown) toward the scale portion. This light is reflected by the surface of the scale portion and then received by a light receiving element (not shown) of the belt optical sensor 855. The belt optical sensor 855 outputs a voltage signal corresponding to the amount of light received by the light receiving element to a control unit (not shown). When the dark portion and the bright portion of the scale portion of the paper conveyance belt 851 pass alternately at the position opposite to the belt optical sensor 855, the belt optical sensor 855 causes the frequency corresponding to the linear velocity of the paper conveyance belt 851. The pulse voltage of the week will be output.

  The transfer paper P sent out by the registration roller pair 804 is held on the front surface (loop outer surface) of the paper transport belt 851 of the paper transport unit 805, and the transfer for Y, M, C, K described above. Pass through the positions sequentially. The Y, M, C, and K toner images developed on the photoreceptors 811Y, M, C, and K of the process units 801Y, M, C, and K are transfer positions for Y, M, C, and K, respectively. Under the action of the transfer electric field, the image is transferred onto the transfer paper P in a superimposed manner. A full-color image is formed on the transfer paper P by this superposition transfer.

  The transfer paper P on which a full-color image is formed is conveyed from the right side to the left side in the figure along with the endless movement of the paper conveyance belt 851, and the fixing unit 806 disposed on the left side in the figure of the paper conveyance unit 805. Is passed on. The fixing unit 806 includes a heat source such as a halogen lamp and is rotated in the clockwise direction in the drawing, and a fixing unit 806 that is rotationally driven so as to move in the same direction at the contact portion while being in contact with the fixing roller 806a. A fixing nip is formed by the pressure roller 806b. Then, the transfer paper P delivered from the paper transport unit 805 is transported from the right side to the left side in the drawing while being sandwiched between the fixing nips. During this conveyance, the full color image is fixed on the surface of the transfer paper P by nip pressure or heating.

  In the Y process unit 801Y, the surface of the photoreceptor 811Y that has passed through the Y transfer position with rotation is subjected to a cleaning process of the transfer residual toner by the cleaning unit 814Y. As the cleaning unit 814Y, a cleaning member such as a blade or a brush may be brought into contact with the surface of the photoreceptor 811Y to mechanically scrape and remove the transfer residual toner. Further, a system in which a cleaning bias is applied to a rotating member such as a cleaning roller that rotates while being in contact with the photosensitive member 811Y to electrostatically remove the transfer residual toner may be used.

  The surface of the photoconductor 811Y that has been subjected to the cleaning process by the cleaning unit 814Y is uniformly charged again by the charging unit 812Y after being subjected to the neutralization process by the neutralization unit 815Y such as a neutralization lamp.

  The developing device 813Y of the process unit 801Y for Y includes a developer agitation means (not shown) composed of a developing roll, a screw, a paddle, etc., which is rotatably arranged so as to expose a part from the housing opening, and a magnetic permeability sensor (not shown). Etc. In the housing of the developing device 813Y, a two-component developer (not shown) including a magnetic carrier and a frictionally chargeable Y toner is accommodated. The two-component developer is carried on the surface of the developing roll while being stirred and conveyed by the developer stirring means. Then, along with the rotation of the developing roll, the layer thickness is regulated by passing through a regulation position by a regulation member (not shown), and then conveyed to the development region facing the photoconductor 811Y. Y toner is adhered to the latent image. This adhesion forms a Y toner image on the photoreceptor 811Y. The two-component developer that has consumed Y toner by development is returned to the housing of the developing device 813Y as the developing roll rotates.

  The above four toner supply devices for Y, M, C, and K (not shown) detachably support toner containers that store Y, M, C, and K toners, respectively. The Y, M, C, and K toners in the Y, M, C, and K toner containers are replenished into the Y, M, C, and K developing devices 813Y, M, C, and K. Yes. Each of these Y, M, C, and K toner containers is provided with a pair of electrodes facing each other through a predetermined gap, and resistance detection is performed between the electrodes via a lead extending from the printer body side. A bias is applied. These leads are connected to current detection sensors for Y, M, C, and K toners, respectively, and based on the current detection value and the resistance detection bias value, Y, M, C, and K toners are used. The electrical resistance values are respectively obtained.

  The magnetic permeability sensor of the developing device 813Y outputs a voltage having a value corresponding to the magnetic permeability of the two-component developer accommodated in the developing device 813Y. Since the magnetic permeability of the two-component developer has a certain degree of correlation with the toner concentration of the two-component developer, this magnetic permeability sensor outputs a voltage having a value corresponding to the Y toner concentration. The value of the output voltage is sent to the above-described control unit (not shown). The control unit stores Y Vtref, which is a target value of the output voltage from the magnetic permeability sensor, in storage means such as a RAM. Also, data for Vtref for M, Vtref for C, and Vtref for K, which are target values of output voltages from the permeability sensors mounted on the developing devices 813M, C, and K of the other process units 801M, C, and K, are also stored. is doing. The Y Vtref is used for driving control of a Y toner replenishing device (not shown). Specifically, the control unit drives and controls a Y toner replenishing device (not shown) so that the value of the output voltage from the magnetic permeability sensor of the Y developing device 813Y approaches the V Vref for Y. Y toner is supplied into the developing device 813Y. By this replenishment, the Y toner density of the two-component developer in the Y developing device 813Y is maintained within a predetermined range. The same toner replenishment control is performed for the other developing devices 813M, C, and K.

  FIG. 19 is a block diagram showing a part of the electric circuit of the printer. In the figure, a control unit 900 is a control unit that controls the entire printer, and includes a CPU 900a that performs arithmetic processing, a RAM 900b that is a storage unit, a ROM 900c, and the like. The controller 900 having such a configuration is connected to an in-machine temperature sensor 807 that detects the in-machine temperature using a known technique. Further, the above-described magnetic permeability sensors in the developing devices (813Y, M, C, and K) for the respective colors are also connected. Further, the above-described Y, M, C, and K optical sensors 816Y, M, C, and K provided in the respective process units (801Y, M, C, and K) are also connected. In addition, the above-described Y, M, C, and K current detection sensors 809Y, M, C, and K that detect current values flowing in Y, M, C, and K toners housed in toner containers of respective colors (not shown) are also included. It is connected. Furthermore, various drive circuits 901, an image processing unit 903, an operation display unit 808, various bias power supply circuits 904, and the like are also connected.

  In such a configuration, the magnetic permeability sensor of each color developing device (813Y, M, C, K) functions as an information detection unit that acquires information on the two-component developer that is a matter. The Y, M, C, and K optical sensors 816Y function as information detection means for acquiring information on the light reflectance of the photoreceptors 811Y, M, C, and K, which are things. The fixing temperature sensor 806c functions as an information detection unit that acquires information on the surface temperature of the fixing roller (806a), which is a matter. The belt optical sensor 855 functions as an information detection unit that acquires information on the light reflectance of the paper transport belt (851), which is a matter. The Y, M, C, and K current detection sensors 809Y, M, C, and K acquire information on the current values that flow through the Y, M, C, and K toners stored in a toner container (not shown), respectively. It functions as information detection means. The control unit 900 also functions as an information acquisition unit that acquires information stored in the RAM 900b and ROM 900c serving as storage units, information transmitted from various connected devices, and the like. As described above, the printer includes a plurality of information acquisition units that acquire different information.

  The various drive circuits 901 are circuits for controlling ON / OFF of drive in various drive sources 902 such as a main motor (not shown) based on a control signal from the control unit. However, since it is necessary to control ON / OFF of the light source in the optical writing unit 2 described above at a considerably high speed, an image processing unit 903 that controls the driving is provided separately from the control unit. . The image processing unit 903 controls the driving of the light source of the optical writing unit 802 and the polygon motor (the driving source of the polygon mirror) based on an image signal sent from the outside such as a personal computer.

  The operation display unit 808 includes a display unit (not shown) including a liquid crystal display that displays an image, and an operation unit (not illustrated) including a numeric keypad that receives operation information from the user. Based on a control signal from the control unit 900, a predetermined image is displayed on the display unit, and operation information received by the operation display unit is transmitted to the control unit 900. The operation display unit 808 having such a configuration also functions as an information acquisition unit that acquires operation information as a thing.

  The various bias power supply circuits are circuits for controlling various bias values such as a developing bias applied to the developing roll based on a control signal from the control unit 900.

  In the present invention, examples of information acquired by the information acquisition means include sensing information, parameter storage information, and image information.

  The sensing information is information acquired by various sensors such as an optical sensor, a voltage sensor, and a current sensor. In the image forming apparatus, information such as dimensions, driving speed, time (timing), weight, current value, voltage value, vibration, sound, magnetic force, light quantity, temperature, humidity, atmospheric pressure, airflow, various gas concentrations, etc. is acquired by the sensor. Is possible.

  Examples of the driving speed include rotational speeds of rotating members such as a driving motor, a fixing roller, a driving roller, a registration roller, and a conveying roller, and can be detected by a known encoder or the like.

  Examples of the current value include a current value of a drive motor and a transfer current value, and can be detected by a known ammeter. In addition, a pair of electrodes (such as a pair of transport rollers) are brought into contact with each other via a test object (transfer paper or the like), and a current value between the electrodes is measured, or a surface potential of the test object is measured. It is also possible to detect the electrical resistance value of the test object.

  Examples of the sound include sound generated from a drive motor and a drive transmission system, and can be detected by a known microphone or the like. Based on the magnitude of the generated sound, sudden stress applied to the drive motor or drive transmission system can be detected. Further, the surface roughness of the transfer paper is detected by bringing a guide member or the like into contact with the surface of the transfer paper before the toner image is transferred, and detecting vibration sound or sliding sound generated by the contact. It is also possible.

  Examples of the temperature include air temperature, fixing roller surface temperature, drive motor temperature, and the like, and can be detected by a known temperature sensor.

  The amount of light can be detected by a reflection type photo sensor, a transmission type photo sensor, or the like, and can be used for detection of paper conveyed in the conveyance path, detection of the amount of toner adhering to the photoreceptor, and the like. It can also be used to detect the moving speed of paper, belts, etc. in the conveyance path due to a detection tamming shift of a predetermined light quantity or more between a plurality of photosensors. Further, slippage between the pair of paper transport rollers and the paper can also be detected by using the rotational speed of the pair of paper transport rollers detected by the encoder or the like. Further, the glossiness of the transfer paper surface can be detected by detecting the amount of light incident on the transfer paper surface at a predetermined incident angle in a predetermined reflection direction. Further, by detecting the amount of transmitted ultraviolet light in the thickness direction of the transfer paper, it is possible to detect whether the transfer paper is high-quality paper, recycled paper, or OHP. Moreover, the light emitted from each light source group such as an LED array is reflected on the surface of the transfer paper, and each reflected light is detected by a plurality of light receiving elements such as a CCD, so that the surface of the transfer paper is the front surface. Or the back side can be detected. Further, the amount of moisture contained in the transfer paper can also be detected by detecting the amount of absorption of infrared or μ-wave light by the amount of reflected light or the amount of transmitted light.

  For the above dimensions, the relative position displacement of both rollers when the paper is sandwiched between a pair of conveyance rollers is detected by an optical sensor or the like, or the amount of movement of the member pushed up when the paper enters is detected. The thickness of the paper calculated | required by doing is mentioned. Further, the rigidity of the transfer paper can be detected by detecting the deformation amount (curvature amount) of the transfer paper pressed with a predetermined force. In addition, the curl amount of the transfer paper can be detected using a photo sensor, a contact sensor, or the like.

  The characteristics of the developer (one component or two components) affect the basic function of the electrophotographic process, and thus are important factors for the operation and output of the system. Therefore, knowing the characteristics of the developer is extremely important in determining abnormality. As characteristics of the toner, the adhesion amount to the latent image carrier, the charge amount and its distribution, the fluidity, the aggregation degree, the bulk density in the two-component developer, the electric resistance, the dielectric constant, the external additive amount, the consumption amount, the container Examples include the remaining amount in the interior and the concentration in the two-component developer.

  With respect to the amount of the developer attached to the latent image carrier, a light reflectance (reference toner image) obtained by forming a test electrostatic latent image on the latent image carrier and developing it on a predetermined development condition ( It can be detected by measuring (light reflection amount). Further, the electrical resistance and dielectric constant of the developer can be detected by providing a pair of electrodes in the developing device and measuring the relationship between the applied voltage and the current. Further, the inductance of the developer can be detected by providing a coil in the developing device and measuring the voltage-current characteristic in the coil. Further, by providing an optical type or electrostatic capacity type sensor in the developer container (including the developing device), the remaining amount of the developer in the container can be detected.

  Similar to the characteristics of the developer, the characteristics of the photoreceptor are closely related to the function of the electrophotographic process. Photoreceptor characteristics include photosensitive film thickness, surface characteristics (coefficient of friction, unevenness), surface potential (before and after each process), surface energy, scattered light, temperature, surface position (flare), linear velocity, potential decay rate, resistance -Capacitance, surface moisture content, etc.

  The photosensitive film thickness of the photoreceptor can be detected as follows. That is, the current value from the charging member such as a charging roller contacting the photoconductor to the photoconductor is detected. Then, the photosensitive film thickness can be obtained by comparing the voltage applied to the charging member with the voltage-current characteristic with respect to the dielectric thickness of the photoconductor examined in advance. Further, the surface potential and temperature of the photoreceptor can be detected by a known surface potential sensor or temperature sensor. In addition, the gap between the charging member and the photosensitive member in the non-contact charging method can be detected by measuring the amount of light that has passed through the gap. Further, electromagnetic waves caused by charging can be detected by a broadband antenna.

  The characteristics of the toner used are also an important factor useful for determining the abnormality of the apparatus. Further, the charge amount of the toner can be obtained based on the potential detection value of the solid latent image portion of the photoconductor and the toner adhesion amount per unit area with respect to the solid image. Further, the amount of toner scattered around the dots (pixel images) on the transfer body can be obtained as follows. That is, it is obtained by comparing a dot pattern image on a photoconductor imaged by an infrared light area sensor or the like with a dot pattern image similarly obtained on a transfer body. Also, regarding the offset amount of the toner that is reversely transferred to the fixing member such as the fixing roller in accordance with the fixing process, the reflected light amount on the transfer paper before fixing and the reflected light amount on the fixing member after fixing the transfer paper. It can be obtained by comparison. Further, the amount of residual toner at the transfer source such as a photoconductor can be obtained based on the change in the light reflection amount at the transfer source and the transfer destination before and after the transfer. Further, the amount of so-called fog toner that adheres to the non-image portion of the photoconductor is detected by reading the image background portion with an optical sensor that detects a relatively wide wavelength range on the photoconductor or transfer body. be able to. Alternatively, it can be obtained by reading image information for each area of the background portion with a high-resolution area sensor and counting the number of toner particles contained in the image.

  In the image forming apparatus, the characteristics of the formed toner image are also an important factor for determining abnormality of the apparatus. The height of the toner image can be obtained based on the depth measured from the vertical direction by the displacement sensor and the light shielding length measured from the horizontal direction by the parallel light linear sensor. The image density of the formed toner image can be obtained based on the amount of light detected by the optical sensor (the amount of reflected light or the amount of transmitted light). Further, the color of the toner image can be obtained by detecting the reflected light or the projection wavelength of the transmission hole. To obtain image density and color information, the toner image on the photosensitive member or intermediate transfer member may be used as a test object. However, in order to measure color combinations such as color unevenness, the test object is used as a toner image on transfer paper. There is a need. Further, the gradation of the image can be obtained by detecting the reflection density of the toner image formed on the photoconductor for each gradation level or the toner image transferred to the transfer body with an optical sensor.

  The quality of the formed image, that is, the image quality is also an important factor for determining the abnormality of the apparatus. The sharpness of the toner image can be obtained by reading a repetitive pattern of a line image on a photosensitive member or a transfer member using a monocular sensor having a small spot diameter or a high-resolution line sensor. Further, the granularity (roughness) of the toner image can be obtained by reading a halftone image in the same manner as in the case of sharpness and calculating a noise component as a preliminarily obtained result. Further, the relative inclination of the toner image on the transfer paper due to the deviation of the paper posture can be detected as follows. That is, two paper detection sensors for detecting the transfer paper at both ends in the width direction are provided, and the transfer paper is obtained based on a difference in detection timing between the two. Further, the color misregistration in the superimposed toner image can be obtained by detecting the edge portion of the superimposed image on the intermediate transfer member or the transfer paper with a monocular small-diameter spot sensor or a high resolution line sensor. For toner image density unevenness in the paper feed direction caused by slippage of paper, rollers, etc., the density unevenness in the sub-scanning direction on the transfer paper is measured by a small-diameter spot sensor or high-resolution line sensor, and the signal amount at a specific frequency Can be obtained by measuring Further, the uneven glossiness of the toner image can be obtained by detecting the toner image on the transfer paper with a regular reflection optical sensor. Further, image flow and image fading can be obtained by detecting a toner image on the photosensitive member or transfer member with an area sensor and processing the obtained image information. In addition, the trailing edge blank and the solid cross blank in the image can be obtained by detecting the toner image on the photosensitive member or the transfer member with a high resolution line sensor.

  As the temperature sensor for detecting the temperature, a thermocouple sensor that detects the temperature based on a thermoelectromotive force generated at a contact point where dissimilar metals or metals and a semiconductor are joined can be used. Further, a resistivity changing element type utilizing the fact that the resistivity of metal or semiconductor changes with temperature may be used. In addition, a pyroelectric element type utilizing the generation of charges due to a bias in the arrangement of charges in the crystal as the temperature rises in a certain type of crystal may be used. Further, a thermomagnetic effect element type that detects a change in magnetic characteristics due to temperature may be used.

As the humidity sensor for detecting the humidity, an optical measuring method for measuring light absorption of H ₂ O or OH group, or a method for measuring a change in electric resistance value of a material due to adsorption of water vapor may be used. it can. Further, various gases can be detected by a known gas sensor that basically measures a change in electric resistance of an oxide semiconductor accompanying gas adsorption. The airflow (direction and flow velocity) can be detected by an optical measurement method or the like, but a smaller air bridge type flow sensor is particularly useful in consideration of mounting on the system. In addition, the atmospheric pressure can be detected by using a pressure sensitive material, a method of measuring the mechanical displacement of the membrane, a method of measuring vibration, or the like.

  The parameter storage information, which is one of information acquired by the information acquisition means, is parameter information stored in a storage means such as a RAM. In the image forming apparatus, control parameters, operation history, power consumption, consumable consumption, various image forming condition (mode) setting history, warning history, and the like can be stored in the storage unit as parameter information.

  The control parameter is information set by the control unit such as a charging potential, a developing bias value, and a fixing temperature value. In addition to charging potential, etc., various image processing parameter settings such as halftone processing and color correction, various parameters set by the control unit for operation of the device (paper transport timing, preparation mode before image formation) Execution time).

  Examples of the operation history include history information of operations performed by the user for specifying paper size, number of colors, number of sheets, image quality instruction, and the like. Examples of the power consumption include total power consumption for the whole period or a specific period unit (1 day, 1 week, 1 month, etc.), its distribution, change amount (differentiation), cumulative value (integration), and the like. The above-mentioned consumable consumption includes consumption of consumables such as toner and paper in the whole period or a specific period unit (1 day, 1 week, 1 month, etc.).

  The image information, which is one piece of information acquired by the information acquisition means, is information that is input from the outside of the image forming apparatus or read by a scanner or the like as output image information. Cumulative number of colored pixels, character portion ratio, halftone portion ratio, color character ratio, toner consumption distribution in the main scanning direction, RGB signal (total toner amount in pixel units), document size, document with border, character type (size) , Font) and the like can be cited as image information. The accumulated number of colored pixels can be obtained by counting image data for each GRB signal for each pixel. The character portion ratio can be obtained based on the ratio between the character portion and the halftone portion by separating the original image into characters, halftone dots, photos, and background. Further, the ratio of color characters can be obtained in the same manner. Further, the toner consumption distribution can be obtained based on the count value by counting the accumulated value of the colored pixels for each region divided in the main scanning direction. Further, the image size can be obtained based on the distribution of colored pixels in the image size signal or image data generated by the control unit. The character type (size, font) can be obtained based on the character attribute data included in the image information.

  In the present invention, the “information acquired by the information acquisition means” includes information calculated or specified based on the acquired information in addition to information itself acquired by a sensor or the like such as a current value. It is a concept.

  Next, a characteristic configuration of the printer will be described. This printer is configured to determine whether or not there is an abnormality by the MTS method for various types of information obtained by various types of information acquisition means. In order to make such a determination, an inverse matrix, which is normal index information acquired in advance from a prototype (printer standard machine), is stored in the ROM 900c serving as storage means. Further, the control unit 900 determines whether or not the group information composed of all or a part of a combination of various information actually acquired is abnormal based on the inverse matrix, and the operation display unit 808 according to the result. The failure occurrence warning information is displayed on the screen. In other words, in the present printer, the control unit 900 functions as a determination unit that determines an abnormality of the printer to be examined. In addition to the operation display unit 808, a notification method using sound, printing, lamp display, or the like may be used as notification means for notifying the user of failure occurrence caution information.

Table 1 shown below is an acquisition data table for explaining an information acquisition process for constructing the inverse matrix based on various information acquired from a prototype without abnormality. This acquisition data table shows an example in which n sets of group information composed of k types of information are acquired to form an inverse matrix.

In the information acquisition process, first, k types of information (y ₁₁ , y ₁₂ ... Y _1k ) constituting the first set information are acquired by the sensor, the control unit 100, etc., and stored in the data table. Are respectively stored in the storage means. Next, k types of information (y ₂₁ , y ₂₂ ... Y _2k ) constituting the second group information are acquired by the sensor, the control unit 100, etc., respectively, and the second row in the data table is obtained. Each data is stored in the storage means. Thereafter, the group information from the third group to the n-th group is acquired in the same manner, and stored in the storage means as the data of the third row... Nth row in the data table. Finally, an average and a standard deviation (σ) of n pieces of k information constituting each set information are obtained and stored in the storage means as data of n + 1 and n + 2 rows, respectively. The

When the information acquisition process is completed, an information normalization process is performed in which a normalized data table as shown in Table 2 below is constructed. This normalized data table is constructed based on the above-described acquired data table.

Data normalization is a process for converting each acquired information into variable information instead of absolute value information. Normalized data for each information is calculated based on the following relational expression. Note that i in the following expression is a code indicating any one of the n sets of group information. Further, j is a code indicating that it is any one of k types of information.

When the information normalization step is finished, a correlation coefficient calculation step is performed next. In this correlation coefficient calculation step, all combinations ( _k C ₂ types) in which two different types can be established among k types of normalized data in each of n sets of normalized data groups are based on the following equation. Correlation coefficient r _pq (r _qp ) is calculated.

Once the correlation coefficients r _pq (r _qp ) have been calculated for all combinations, then k × k pieces, with the diagonal element being 1 and the other p rows and q columns elements being correlation coefficients r _pq The correlation coefficient matrix R is constructed. The contents of this correlation coefficient matrix R are shown in the following equation.

When such a correlation coefficient calculation process is completed, a matrix conversion process is then performed. Through this matrix conversion step, the correlation coefficient matrix R expressed by Equation 4 is converted into an inverse matrix A (R ⁻¹ ) expressed by the following equation. Instead of the inverse matrix A, a cofactor matrix of the correlation coefficient matrix R may be used (the same applies hereinafter).

In this printer, an inverse matrix A constructed by a series of processes such as an information acquisition process, an information normalization process, a correlation coefficient calculation process, and a matrix conversion process as described above is stored in the ROM (900c) at the time of factory shipment. Pre-stored. Based on the following formula, the Mahalanobis distance D in the multi-dimensional space by the inverse matrix A is used for the combination information consisting of all or part of various information actually acquired by a plurality of sensors at the shipping destination. To calculate.

  The control unit (900) compares the Mahalanobis distance D thus obtained with a preset threshold value. If the Mahalanobis distance D (hereinafter referred to as the Mahalanobis distance) is larger than the threshold value, it is determined that the acquired group information is abnormal data greatly deviating from the normal distribution, and the operation display unit (808). Is displayed on the screen.

  According to this printer having such a configuration, the occurrence of a failure whose cause is not clearly specified is predicted by determining an abnormality in the measured value of the set information including a combination of all or part of various information by the MTS method. be able to. However, the present inventors have found that a prototype printer that performs such a prediction may be erroneously detected as normal even though it is abnormal. The cause of this false detection was related to the setting of the operation mode.

  In this printer, two operation modes, a plain paper print mode and an OHP print mode, can be selected based on a user operation on the operation display unit (808). When the plain paper printing mode is selected, a setting condition of a process linear velocity of 100 [mm / sec] (linear velocity of each photoconductor, paper conveyance belt 851, each conveyance roller, registration roller pair 804, fixing roller 806a, etc.) An image is formed below. On the other hand, when the OHP print mode is selected, an image is formed under the process linear speed setting condition of 50 [mm / sec].

  In the prototype printer, the inventors have described the linear velocity of the paper transport belt (851) and the linear velocity of each photoconductor (811Y, M, C, K) while mixing the two operation modes described above. It acquired based on the detection result by the optical sensor. Specifically, 200 transfer sheets are measured while measuring the linear velocity (hereinafter referred to as belt linear velocity) of the paper conveying belt (851) and the linear velocity (hereinafter referred to as drum linear velocity) of each photoconductor. A reference image was formed. Among these 200 sheets, the first 100 sheets were formed with reference images on high-quality paper in the plain paper printing mode (hereinafter also referred to as mode 1). For the subsequent 100 sheets, a reference image was formed on the OHP sheet in the OHP printing mode (hereinafter also referred to as mode 2). Then, an inverse matrix A was constructed based on the group information of 200 normal data groups acquired along with the printout of 200 sheets of transfer paper.

FIG. 20 shows the square value of the Mahalanobis distance D calculated by the MTS method using the inverse matrix A, the linear velocity of the paper transport belt (851) (hereinafter referred to as the belt linear velocity), and the line of each photoconductor. It is a graph which shows the relationship with speed (henceforth a drum linear speed). Using the inverse matrix A that establishes such a relationship, the Mahalanobis distance D is calculated for the set information shown in the following Table 3 acquired at the time of subsequent printout, and the printer abnormality is determined. To do.

In Table 3, the set information of the sample number _{S 5} and _{S 6} are each belt linear velocity and the drum linear velocity is greatly deviated from a normal range 100 [mm / sec] or 50 [mm / sec]. Therefore, it should be determined as abnormal regardless of mode 1 or mode 2. However, since the square of Mahalanobis distance D is a relatively small value, it is erroneously determined to be normal.

  Therefore, in the printer according to the second embodiment, as the inverse matrix A that is normal index information, a plurality of items having different contents according to specific information such as the operation mode are stored in the ROM (900c). Taking the case where the specific information is an operation mode as an example, based on a plurality of sets of information (for example, belt linear velocity and drum linear velocity) acquired under the condition that the operation mode is set to mode 1, the reverse for mode 1 is performed. A matrix A is constructed and stored. Further, an inverse matrix A for mode 2 is constructed and stored based on a plurality of sets of information acquired under the conditions set for mode 2. Then, at the time of printout at the shipping destination, among these two inverse matrices A, the one corresponding to the acquisition result of the operation mode setting value by the CPU (900a) is identified and used for abnormality determination. I have to. When the operation mode setting value acquired at the time of printout is mode 1, the inverse matrix A for mode 1 is used, while when the operation mode setting value is mode 2, the inverse matrix A for mode 2 is used. It is.

FIG. 21 is a graph showing the relationship between the square value of the Mahalanobis distance D calculated by the MTS method using the inverse matrix A for mode 1, and the belt linear velocity and the drum linear velocity. FIG. 22 is a graph showing the relationship between the square value of the Mahalanobis distance D calculated by the MTS method using the inverse matrix A for mode 2 and the belt linear velocity and drum linear velocity. It set information of the sample number S ₅ in Table 3 shown above, in any of the graph, the square of the Mahalanobis distance D becomes very large value of 5 to 10, which may be determined readily abnormal I understand. As described above, in this printer, it is possible to avoid erroneous determination due to the normal distribution of the inverse matrix A being different depending on the content of the specific information.

  FIG. 23 is a flowchart illustrating an example of a flow of abnormality determination control performed by the control unit (900). In this abnormality determination control, first, the progress of the control flow is waited until one job is started (step 1: hereinafter, step is denoted as S). The one job is an operation of each device for performing printout on one transfer sheet. If it is determined that one job has been started (Y in S1), then group information consisting of actual measured values such as the belt linear velocity and drum linear velocity is acquired (S2), and then the operation mode setting value and the like are specified. Information is acquired (S3). And the thing corresponding to this specific information is specified from the some inverse matrix A memorize | stored in said ROM (900c) (S4). Next, after the Mahalanobis distance D for the set information in S2 is calculated by the MTS method using the inverse matrix A (S5), it is determined whether or not it exceeds a predetermined threshold (S6). If the Mahalanobis distance D exceeds the threshold (Y in S6), there is a high possibility that an abnormality has occurred in the printer for some reason. Therefore, after it is determined that an abnormality has occurred and failure occurrence caution information is displayed on the operation display unit (8), a series of control flows is returned to S1. On the other hand, when the Mahalanobis distance D does not exceed the threshold value (N in S6), since the possibility of occurrence of an abnormality is low, a series of control flows are returned to S1 without being determined as abnormal.

  In addition, in order to make an understanding easy, the example which calculates | requires Mahalanobis distance D in the two-dimensional space which consists of belt linear velocity and drum linear velocity was demonstrated. However, more various abnormalities can be detected by obtaining the Mahalanobis distance D in a space having more dimensions. Specific information such as the operation mode setting value may or may not be included in the inverse matrix A.

  Further, the example in which the specific information is the operation mode setting value has been described, but the present invention can also be applied to the case where the specific information is humidity information or temperature information. For example, the electrical resistance value of each color toner calculated based on the current value acquired by the above-described Y, M, C, K toner current detection sensors (809Y, M, C, K) depends on the in-machine temperature. The normal value distribution is different. Therefore, for a plurality of sets of information including information on the electrical resistance value of the toner, a plurality of inverse matrices A having different values depending on the temperature are stored, and those corresponding to the actual measured values of the toner electrical resistance at the shipping destination are stored. May be used for abnormality determination. In the example of the high speed mode and the high image quality mode due to the difference in the linear speed described above, it is necessary to determine an intermediate value such as a linear speed of 70 [mm / sec] or 80 [mm / sec] as abnormal. On the other hand, the present inventors considered that it is not necessary to set a normal value distribution for each temperature because an intermediate value can be treated as normal with respect to a factor whose value continuously changes such as temperature. . However, the present inventors have found that even when a factor that varies continuously such as temperature is used, storing and using a plurality of normal value distributions contributes to accurate abnormality determination.

  For example, FIG. 48, FIG. 25, FIG. 26, and FIG. 27 are graphs showing normal value distributions in which the temperature is plotted on the vertical axis and the electrical resistance value of the toner measured by the method described later is plotted on the horizontal axis. It is. FIG. 25, FIG. 26, and FIG. 27 show normal value distributions mapped by performing image formation 100 times in the vicinity of 25 ° C., 35 ° C., and 40 ° C., respectively. Further, FIG. 48 shows a normal value distribution created based on all of the measurement data of a total of 300 times measured 100 at each of these three temperatures. When the distribution of FIG. 48 is compared with FIGS. 25, 26, and 27, the distribution of FIG. 48 has a larger range that is considered normal than the distribution circles of FIGS. Furthermore, the central points of the distribution of FIGS. 25, 26 and 27 (temperature 25 ° C. and electric resistance 1.0, temperature 35 ° C. and electric resistance 0.9, temperature 40 ° C. and electric resistance 0.7) A region deviated from the connecting line segment, for example, a point such as a temperature of 31.6 ° C. and an electric resistance of 0.75, is also regarded as normal. According to the experiments by the present inventors, each point in this example (temperature 25 ° C. and electric resistance 1.0, temperature 35 ° C. and electric resistance 0.9, temperature 40 ° C. and electric resistance 0.7), When the center value of normal values mapped in a space composed of a plurality of parameters does not lie on a single line (indicating a non-linear change), the obtained normal value distribution is on a line connecting the center values of normal values. It was confirmed that it spreads greatly compared to. In this example, the temperature is 35 ° C. and the electric resistance is 0.9 at the line segment connecting the point of the temperature of 25 ° C. and the electric resistance of 1.0 and the point of the temperature of 40 ° C. and the electric resistance of 0.7. The normal range has expanded not only in the direction toward the point but also in the opposite direction. If the center value of normal values mapped in a space composed of a plurality of parameters is on a single straight line, the accuracy of abnormality determination can be achieved without creating a separate normal value distribution for each predetermined temperature value. Does not drop that much. For example, even if abnormality determination is performed at a temperature of 25 ° C. and a temperature of 35 ° C. by only one normal value distribution shown in FIG. 24 created based on 200 measurement values that are the basis of the graphs of FIGS. Compared with the case where abnormality determination is performed using the two normal value distributions shown in FIGS. 25 and 26, the accuracy does not decrease so much. However, in many cases, the center value of the normal value is expected to change nonlinearly. For this reason, even when a parameter that changes continuously, such as temperature, is used, unless the normal value distribution is properly used in accordance with the measured temperature value, the accuracy of abnormality determination is reduced.

  When the specific information can take a continuous value, a normal value distribution is not created for each temperature value. For example, “less than 0 ° C.”, “0 ° C. or more and less than 10 ° C.”, “10 ° C. or more and 20 ° C.” The temperature is divided into a predetermined temperature range, such as “less than” or “less than 20 ° C. and less than 30 ° C.”, and a normal value distribution used for abnormality determination is selected according to which temperature range the measured temperature belongs to That is realistic. In this way, when the specific information is divided into predetermined ranges, the normal value distribution may change in accordance with the value of the specific information within one range. For example, even within the same range of “20 ° C. or more and less than 30 ° C.”, the normal value distribution formed by other factors at 21 ° C. and the normal value distribution formed by other factors at 29 ° C. can change. For this reason, it is good also considering specific information itself as one of the factors like this example. If the temperature range is divided finely, the accuracy of abnormality determination is improved, but the storage capacity increases because a large number of inverse matrices need to be stored. Therefore, in order to save the storage capacity without significantly reducing the accuracy of abnormality determination, it is effective to take a wider range of specific information in which the center value of the normal value changes relatively linearly than other ranges. is there. For example, instead of storing the three distributions shown in FIG. 25 (near 25 ° C.), FIG. 26 (near 35 ° C.), and FIG. 27 (near 40 ° C.), FIG. 24 (near 25 ° C. to 35 ° C.) and FIG. If the two distributions (near 40 ° C.) are stored, the number of stored normal value distributions can be reduced to two while improving the accuracy of abnormality determination as compared with FIG.

  The toner resistance value was determined as follows. That is, first, a pair of electrodes facing each other with an interval of about 1 cm is provided in the developing device, and the voltage V applied to one of the electrodes and the current I flowing to the other are measured, and the electric resistance A = Find V / I. The electric resistance value A thus obtained was divided by the electric resistance value B measured at a temperature of 25 ° C., and the value of A / B was taken as a factor. The resistance value of the toner varies depending on the apparatus settings such as the distance between the electrodes and the state of the developer. However, since it is not the absolute resistance value but the variation that is important in the abnormality determination, the relative value as described above. There is no problem even if it is treated as an electric resistance value.

  In the printer, the plurality of information acquisition means constituting the abnormality determination device include those listed below. That is, optical sensors for Y, M, C, K (816Y, M, C, K), fixing temperature sensor (806c), optical sensor for belt (855), current detection sensors (809Y, M, C, K) , CPU (900a), operation display unit (808), and the like. In addition, the RAM (900b) and the ROM (900c) function as storage means constituting the abnormality determination device. Further, the CPU (900a) functions as an abnormality determination unit that constitutes the abnormality determination device.

  Next, a modified apparatus of the printer according to the second embodiment will be described. The basic configuration of the modified apparatus is the same as that of the printer according to the second embodiment, and a description thereof will be omitted.

  This printer stores a plurality of inverse matrices A having different contents according to the contents of the specific information in the storage means, and specifies the inverse matrix A according to the acquisition result of the specific information from the second point. This is the same as the printer according to the embodiment. However, the printer according to the second embodiment is that the plurality of inverse matrices A are not stored in the machine-writable ROM (900c) but are stored in the machine-writable RAM (900b). And different. Further, the inverse matrix A is not stored in advance in the RAM at the time of factory shipment. A plurality of inverse matrices based on a plurality of acquisition results for various types of information (including set information as well as specific information) consisting of a plurality of information acquired by the CPU (900a) during the initial operation period at the shipping destination. A is to be constructed. In other words, the CPU (900a) is also different from the printer according to the second embodiment in that the CPU (900a) functions as a normal index information construction unit that constructs a plurality of inverse matrices having different contents based on the result of acquiring the set information. In the initial operation period at the shipping destination, since each member in the printer is new, the acquisition result of various information by each information acquisition means is normal data.

  FIG. 28 is a flowchart showing the flow of inverse matrix construction control performed by the control unit (900) of the printer. This inverse matrix construction control is executed during the initial operation period at the shipping destination. Specifically, the initial operation period is a period from when the first print job after shipment is performed until when the nth print job is performed. As a premise that the inverse matrix construction control shown in FIG. 28 is performed, x acquired data tables shown in Table 1 are stored in the RAM (900b) of the printer at the time of factory shipment. However, each acquired data table is in an empty state, and is stored in association with indexes of different numerical ranges. This index corresponds to an actual measurement value of specific information such as an operation mode setting value. That is, for example, three acquired data tables x1, x2, and x3 are stored in association with indexes of numerical ranges of 1 to 5, 6 to 10, and 1 to 15, respectively, and are suitable for specific information of the numerical ranges. Set information is stored.

  When the main power of the printer is turned on for the first time after shipment, inverse matrix construction control is started, and the value of the set number i is initialized to “0” (S1). This group number i is a variable indicating the number of times of measurement of group information composed of k types of information. When one job is started after this is initialized (Y in S2), “1” is added to the set number i (S3). Then, after one set of information consisting of k types of information is acquired (actually measured) by various sensors and data reading (S4), specific information X such as an operation mode setting value is acquired (S5). Next, an index having a numerical value range corresponding to the content (value) of the specific information X is selected from the x acquisition data tables described above (S6), and the acquisition result of the set information is stored therein. (S7). Then, it is determined whether or not the group number i is “n” (S8). If it is not “n” (N in S8), the control flow is looped to S2. By this loop, the (i + 1) th group information is acquired in the next one job and stored in an appropriate acquired data table. On the other hand, when the set number i is “n” (Y in S8), the information acquisition process for the n sets of set information ends, and the information normalization process, the correlation coefficient calculation process, and the matrix conversion process described above. Are performed in order. Specifically, first, x normalized data tables are constructed based on the x acquired data tables (S9). Next, after the correlation coefficient matrix R is constructed based on the respective normalized data tables, x inverse matrices A are constructed (S10).

  In the printer configured as described above, a plurality of inverse matrices A are not constructed based on trial operation of other printer test machines, but are constructed based on various information acquired during initial operation of the printer. Is used. Therefore, it is possible to avoid the deterioration of the determination accuracy due to the fact that the normal value of the information used for determining the abnormality varies from product to product due to the accuracy error of various parts. In addition, since a plurality of inverse matrices A are automatically constructed at the shipping destination, it is possible to avoid an increase in cost caused by constructing each inverse matrix A by performing a trial run for each product at the factory before shipment.

Next, a description will be given of the printers of the modified device embodiments in which a more characteristic configuration is added to the modified device.
[Deformation device embodiment 1]
This modified apparatus automatically constructs a plurality of inverse matrices A during the initial operation period at the shipping destination such as the initial n job operation periods, but the conditions necessary for constructing all the inverse matrices A are It is not always in time. For example, when constructing the inverse matrix A corresponding to the operation mode 1 and the inverse matrix A corresponding to the operation mode 2 using the operation mode setting value as the specific information, a certain number of pieces of group information for each of the inverse matrices A Need to get. However, while printing is frequently performed in the operation mode 1 based on the use of plain paper, printing in the operation mode 2 based on the use of an OHP sheet is very rarely performed. There is generally no. Then, in the initial operation period, a large amount of set information in the state of the operation mode 1 is acquired, but the set information in the state of the operation mode 2 may not obtain a number that can construct the inverse matrix A. . In such a case, if the inverse matrix A corresponding to the operation mode 2 is forcibly constructed on the basis of a small number of pieces of group information, the abnormality determination accuracy in the operation mode 2 is deteriorated.

  Therefore, in the printer according to the first embodiment, prior to shipment from the factory, a plurality of provisional inverse matrices having different contents are stored in advance in the ROM (900c) serving as storage means. The provisional inverse matrix as the provisional normal index information is the same as the plurality of inverse matrices A in the printer according to the second embodiment, and is based on the plurality of pieces of group information acquired with the trial operation of other printer test machines. Is built. The CPU (900a) is configured to supplement a part of the provisional inverse matrix as an inverse matrix A as necessary. Specifically, when the predetermined condition such as the number of printouts in the operation mode 2 is not satisfied within the initial operation period and at least any one inverse matrix A cannot be constructed, the shortage is determined. It is compensated by the provisional inverse matrix.

  FIG. 29 is a flowchart illustrating the flow of inverse matrix construction control performed by the control unit (900) of the printer according to the first modification. In this figure, the steps S1 to S8 are the same as S1 to S8 in FIG. When n sets of information are acquired with n print jobs within the above initial operation period (Y in S8 in FIG. 28), an acquired set number specifying process is performed (S9). This acquired set number specifying process is a process for specifying the number of set information stored inside each of the x acquired data tables. When the acquired set number specifying process is performed, the x pieces of acquired data tables that have stored only the number of sets information that is less than a predetermined threshold are excluded from the use targets as the original material of the inverse matrix A. For this purpose, a table exclusion process is performed (S10). By this table exclusion process, the acquired data table that stores only a set number of pieces of information less than a predetermined threshold is excluded from the use target. Then, a normalized data table is constructed for each acquired data table that is not excluded, that is, an acquired data table that stores a necessary number of sets of information (S11). Next, an inverse matrix A is constructed for each of the obtained normalized data tables. Then, when a predetermined condition is not satisfied within the initial operation period, the number of inverse matrices A becomes less than x and becomes insufficient. Therefore, the deficient inverse matrix A is supplemented from the above provisional inverse matrix, and finally x inverse matrices A are constructed (S13).

  In this printer having such a configuration, all inverse matrices A are required even if predetermined conditions are not met, such as an acquired data table in which only a set number of sets information that is less than the threshold value is generated within the initial operation period. The number of data groups can be more than a few. Thus, it is possible to avoid abnormality determination accuracy caused by forcibly constructing at least one of the plurality of inverse matrices A based on a small number of pieces of group information.

[Deformation device embodiment 2]
The printer according to the second embodiment of the present modification has a feature that the shortage is compensated when at least one inverse matrix A cannot be constructed without satisfying the predetermined condition within the initial operation period. This is the same as the printer according to the first embodiment. However, the temporary inverse matrix for compensation is not stored in the ROM (900c) prior to factory shipment, but the inverse matrix A is received and used by the data receiving means as necessary. Different from the printer according to the first embodiment. Examples of such data receiving means include the operation display unit (808) described above. The operation display unit (808) accepts a plurality of provisional inverse matrices input by user key operations or the like. In addition, a recording medium reading device such as a floppy (registered trademark) disk drive or an optical disk drive is provided as a data receiving means so that a provisional inverse matrix recorded in the floppy disk or the optical disk can be read and received. Good. Further, an image information receiving means (input port) for receiving image information sent from a personal computer or the like may function as a data receiving means, thereby accepting a provisional inverse matrix.

  FIG. 30 is a flowchart illustrating the flow of inverse matrix construction control performed by the control unit (900) of the printer according to the second embodiment of the modification apparatus. In this figure, the steps S1 to S8 are the same as S1 to S8 in FIG. Moreover, about the process of S9-S12, since it is the same as that of S9-S12 in previous FIG. 29, description is abbreviate | omitted. When the inverse matrix A is constructed based on the acquired data table that remains without being excluded in the table exclusion process (S10 in FIG. 29) (S12 in FIG. 29), the presence or absence of the exclusion table is determined (FIG. 30). S13). If there is no exclusion table (N in S13), all the x provisional inverse matrices are constructed based on the set information acquired during the initial operation period, so that provisional inverse matrix compensation is performed. A series of control flow ends. On the other hand, if there is an exclusion table (Y in S13), the user is notified that the input of the deficient inverse matrix A is necessary. This notification is performed, for example, by displaying instruction information such as “Please input the data group described on page 120 of the manual with the numeric keypad” on the operation display section (8). When a plurality of inverse matrices A are input by the user's operation based on the instruction (Y in S15), the input inverse matrix A corresponding to the shortage is compensated, and finally x number of inverse matrices A are filled. An inverse matrix A is constructed.

  Even in this printer having such a configuration, all inverse matrices A are required even if predetermined conditions are not met, such as an acquired data table in which only a set number of sets information that is less than the threshold value was generated within the initial operation period. The number of data groups can be more than a few. Thus, it is possible to avoid abnormality determination accuracy caused by forcibly constructing at least one of the plurality of inverse matrices A based on a small number of pieces of group information.

  In the above, a printer that forms a multicolor image called a full color image has been described. However, the present invention can also be applied to a printer that forms a single color image.

First, before describing an embodiment of an abnormality determination apparatus to which the present invention is applied, an example of an image forming apparatus that is a test target of the abnormality determination apparatus will be described.
FIG. 31 is a schematic configuration diagram showing the copier, which is an image forming apparatus that can be a test target of the abnormality determination apparatus to which the present invention is applied. The copier includes an image forming unit including a printer unit 100 and a paper feeding unit 200, a scanner unit 300, and a document conveying unit 400. The scanner unit 300 is mounted on the printer unit 100, and a document transport unit 400 including an automatic document transport device (ADF) is mounted on the scanner unit 300.

  The scanner unit 300 reads the image information of the document placed on the contact glass 32 by the reading sensor 36 and sends the read image information to a control unit (not shown). Based on the image information received from the scanner unit 300, the control unit controls lasers, LEDs, and the like (not shown) disposed in the exposure device 21 of the printer unit 100 to thereby provide four drum-shaped photoconductors 40K, Y, and M. , C is irradiated with laser writing light L. By this irradiation, an electrostatic latent image is formed on the surface of the photoreceptors 40K, Y, M, and C, and this latent image is developed into a toner image via a predetermined development process. Note that the subscripts K, Y, M, and C added after the reference numerals indicate specifications for black, yellow, magenta, and cyan.

  In addition to the exposure device 21, the printer unit 100 includes primary transfer rollers 62K, Y, M, and C, a secondary transfer device 22, a fixing device 25, a paper discharge device, a toner supply device (not shown), a toner supply device, and the like. Yes.

  The paper feeding unit 200 includes an automatic paper feeding unit disposed below the printer unit 100 and a manual feeding unit disposed on a side surface of the printer unit 100. The automatic paper feed unit separates the two paper feed cassettes 44 arranged in multiple stages in the paper bank 43, the paper feed roller 42 that feeds transfer paper as a recording medium from the paper feed cassette, and the fed transfer paper. A separation roller 45 and the like are sent to the paper feed path 46. Further, it also includes a transport roller 47 that transports transfer paper to the paper feed path 48 of the printer unit 100. On the other hand, the manual feed section includes a manual feed tray 51 and a separation roller 52 that separates transfer sheets on the manual feed tray 51 one by one toward the manual feed path 53.

  A registration roller pair 49 is disposed near the end of the paper feed path 48 of the printer unit 100. The registration roller pair 49 is formed between the intermediate transfer belt 10 serving as an intermediate transfer body and the secondary transfer device 22 at a predetermined timing after receiving the transfer paper sent from the paper feed cassette 44 or the manual feed tray 51. To the secondary transfer nip.

  In the copying machine, an operator sets a document on the document table 30 of the document transport unit 400 when copying a color image. Alternatively, after the document conveying unit 400 is opened and a document is set on the contact glass 32 of the scanner unit 300, the document conveying unit 400 is closed and the document is pressed. Then, a start switch (not shown) is pressed. Then, when an original is set on the original conveying unit 400, after the original is conveyed onto the contact glass 32, immediately after the original is set on the contact glass 32, the scanner unit 300 is driven. Start. Then, the first traveling body 33 and the second traveling body 34 travel, and the light emitted from the light source of the first traveling body 33 is reflected by the document surface and then travels toward the second traveling body 34. Further, after being reflected by the mirror of the second traveling body 34, it reaches the reading sensor 36 via the imaging lens 35 and is read as image information.

  When the image information is read in this way, the printer unit 100 rotates the other two support rollers while rotating one of the support rollers 14, 15, and 16 with a drive motor (not shown). Then, the intermediate transfer belt 10 stretched around these rollers is moved endlessly. Further, laser writing as described above and a development process described later are performed. Then, while rotating the photoconductors 40K, Y, M, and C, monochrome images of black, yellow, magenta, and cyan are formed on them. These are four-color superposed toners that are sequentially superposed and electrostatically transferred at the primary transfer nips for K, Y, M, and C where the photoreceptors 40K, Y, M, and C and the intermediate transfer belt 10 abut. Become a statue. Toner images are formed on the photoreceptors 40K, Y, M, and C.

  On the other hand, the paper feed unit 200 operates one of the three paper feed rollers to feed transfer paper having a size corresponding to the image information, and feeds the transfer paper to the paper feed path of the printer unit 100. Lead to 48. The transfer paper that has entered the paper feed path 48 is sandwiched between the pair of registration rollers 49 and temporarily stops. To the secondary transfer nip which is a part. Then, in the secondary transfer nip, the four-color superimposed toner image on the intermediate transfer belt 10 and the transfer paper are brought into close contact in synchronization. Then, the four-color superimposed toner image is secondarily transferred onto the transfer paper due to the influence of the transfer electric field formed at the nip, the nip pressure, etc., and becomes a full color image combined with the white color of the paper.

  The transfer paper that has passed through the secondary transfer nip is fed into the fixing device 25 by the endless movement of the transport belt 24 of the secondary transfer device 22. Then, after the full color image is fixed by the action of the pressure applied by the pressure roller 27 of the fixing device 25 and the heating by the heating belt, the paper discharge tray 57 provided on the side surface of the printer unit 100 via the discharge roller 56. Discharged to the top.

  FIG. 32 is an enlarged configuration diagram showing the printer unit 100. The printer unit 100 includes a belt unit, four process units 18K, Y, M, and C that form toner images of respective colors, a secondary transfer device 22, a belt cleaning device 17, a fixing device 25, and the like.

  The belt unit moves the intermediate transfer belt 10 stretched around a plurality of rollers endlessly while contacting the photoreceptors 40K, Y, M, and C. In the primary transfer nip for K, Y, M, and C where the photoreceptors 40K, Y, M, and C are brought into contact with the intermediate transfer belt 10, the intermediate transfer belt 10 is moved by the primary transfer rollers 62K, Y, M, and C. Is pressed from the back side toward the photoconductors 40K, Y, M, and C. A primary transfer bias is applied to these primary transfer rollers 62K, Y, M, and C by a power source (not shown). As a result, a primary transfer electric field for electrostatically moving the toner images on the photoreceptors 40K, Y, M, and C toward the intermediate transfer belt 10 is formed in the primary transfer nips for K, Y, M, and C. Has been. Between each of the primary transfer rollers 62K, Y, M, and C, a conductive roller 74 that contacts the back surface of the intermediate transfer belt 10 is disposed. In these conductive rollers 74, the primary transfer bias applied to the primary transfer rollers 62K, Y, M, and C is applied to adjacent process units via the intermediate resistance base layer 11 on the back side of the intermediate transfer belt 10. It prevents the flow.

  The process unit (18K, Y, M, C) supports the photosensitive member (40K, Y, M, C) and several other devices as a single unit on a common support. The unit 100 is detachable. Taking the black process unit 18K as an example, this has a developing unit 61K as developing means for developing the electrostatic latent image formed on the surface of the photoreceptor 40K into a black toner image in addition to the photoreceptor 40K. ing. Further, it also has a photoconductor cleaning device 63K that cleans transfer residual toner adhering to the surface of the photoconductor 40K after passing through the primary transfer nip. In addition, a static elimination device (not shown) that neutralizes the surface of the photoreceptor 40K after cleaning, a charging device (not shown) that uniformly charges the surface of the photoreceptor 40K after static elimination, and the like are also provided. The process units 18Y, 18M, and 18C for other colors have substantially the same configuration except that the color of the handled toner is different. The copier has a so-called tandem configuration in which these four process units 18K, Y, M, and C are arranged to face the intermediate transfer belt 10 along the endless movement direction.

  FIG. 33 is a partially enlarged view showing a part of the tandem section 20 composed of four process units 18K, Y, M, and C. Since the four process units 18K, Y, M, and C have substantially the same configuration except that the colors of the toners to be used are different, K, Y, M, and C attached to the respective reference numerals in FIG. The subscript is omitted. As shown in the drawing, the process unit 18 includes a charging device 60 as a charging unit, a developing device 61, a primary transfer roller 62 as a primary transfer unit, a photoconductor cleaning device 63, a charge eliminating device around the photoconductor 40. A device 64 and the like are provided.

  As the photosensitive member 40, a drum-shaped member is used in which a photosensitive organic layer is applied to a base tube made of aluminum or the like to form a photosensitive layer. However, an endless belt may be used. In addition, as the charging device 60, a charging device to which a charging roller to which a charging bias is applied is rotated while being in contact with the photoreceptor 40 is used. A scorotron charger or the like that performs a non-contact charging process on the photoreceptor 40 may be used.

  The developing device 61 develops a latent image using a two-component developer containing a magnetic carrier and a nonmagnetic toner. An agitator 66 that conveys the two-component developer accommodated in the interior while agitating and supplies the developer to the developing sleeve 65, and the toner of the two-component developer attached to the developing sleeve 65 is the photoreceptor 40K, Y, M. , C, a developing unit 67 for transferring to C.

  The stirring unit 66 is provided at a position lower than the developing unit 67, and includes two screws 68 arranged in parallel to each other, a partition plate provided between the screws, and a toner provided on the bottom surface of the developing case 70. It has a density sensor 71 and the like.

  The developing unit 67 includes a developing sleeve 65 that faces the photosensitive member 40 through the opening of the developing case 70, a magnet roller 72 that is non-rotatably provided inside the developing sleeve 65, a doctor blade 73 that approaches the developing sleeve 65, and the like. ing. The distance at the closest portion between the doctor blade 73 and the developing sleeve 65 is set to about 500 [μm]. The developing sleeve 65 has a non-magnetic rotatable sleeve shape. In addition, the magnet roller 72 that is prevented from being rotated around the developing sleeve 65 has, for example, five magnetic poles N1, S1, N2, S2, and S3 in the rotation direction of the developing sleeve 65 from the position of the doctor blade 73. ing. Each of these magnetic poles applies a magnetic force to the two-component developer on the sleeve at a predetermined position in the rotation direction. As a result, the two-component developer sent from the stirring unit 66 is attracted and carried on the surface of the developing sleeve 65, and a magnetic brush is formed along the magnetic field lines on the sleeve surface.

  The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 73 as the developing sleeve 65 rotates, and then conveyed to the developing area facing the photoreceptor 40. Then, due to the potential difference between the developing bias applied to the developing sleeve 65 and the electrostatic latent image on the photoconductor 40, it is transferred onto the electrostatic latent image and contributes to development. Further, as the developing sleeve 65 rotates, the developing sleeve 65 returns to the developing portion 67 again, and after being separated from the sleeve surface due to the influence of the repulsive magnetic field between the magnetic poles in the magnet roller 72, it is returned to the stirring portion 66. In the stirring unit 66, an appropriate amount of toner is supplied to the two-component developer based on the detection result by the toner density sensor 71. The developing sleeve 65 has, for example, a diameter of 18 [mm], a surface that has been subjected to a sandblasting process and a process of forming a plurality of grooves having a depth of 1 to several mm, and has a surface roughness (Rz) of 10 to 10. It is about 30 [μm].

The developing device 61 may employ a one-component developer that does not include a magnetic carrier, instead of the one that uses a two-component developer. In the copier, the linear velocity of the photosensitive member 40 is 200 [mm / sec], and the linear velocity of the developing sleeve 65 is 240 [mm / sec]. In addition, a photoconductor 40 having a diameter of 50 [mm] is used. Further, the thickness of the photoconductor 40 is set to 30 [μm], the beam spot diameter of the optical system is set to 50 × 60 [μm], and the light quantity is set to 0.47 [mW]. Further, the charging (before exposure) potential V _O of the photosensitive member 40 is set to −700 [V], the post-exposure potential V _{L is set} to −120 [V], and the developing bias voltage is set to −470 [V]. That is, development is performed with a development potential of 350 [V].

  The charge amount of the toner on the developing sleeve 65 is preferably in the range of −10 to −30 [μC / g]. The development gap, which is the gap between the photoreceptor 40 and the development sleeve 65, can be set in the range of 0.8 to 0.4 [mm] as in the conventional case, and the development efficiency can be improved by reducing the value. It is.

  As the photoconductor cleaning device 63, a system in which a cleaning blade 75 made of polyurethane rubber is pressed against the photoconductor 40 is used, but another system may be used. The copier employs a cleaning device 63 provided with a contact conductive fur brush 76 whose outer peripheral surface is in contact with the photoconductor 40 so as to be rotatable in the direction of the arrow in order to improve cleaning performance. A metal electric field roller 77 for applying a bias to the fur brush 76 is rotatably provided in the direction of the arrow in the figure, and the tip of the scraper 78 is pressed against the electric field roller 77. The toner removed from the electric field roller 77 by the scraper 78 falls on the collection screw 79 and is collected.

  The photoconductor cleaning device 63 having such a configuration removes residual toner on the photoconductor 40 with a fur brush 76 that rotates in the counter direction with respect to the photoconductor 40. The toner adhering to the fur brush 76 is removed by the electric field roller 77 to which a bias that rotates in contact with the fur brush 76 in the counter direction is applied. The toner adhering to the electric field roller 77 is cleaned by the scraper 78. The toner recovered by the photoconductor cleaning device 63 is brought to one side of the photoconductor cleaning device 63 by the recovery screw 79 and returned to the developing device 61 by the toner recycling device 80 for reuse.

  The static eliminator 64 is composed of a static elimination lamp or the like, and removes the surface potential of the photoreceptor 40 by irradiating light. The surface of the photoreceptor 40 that has been neutralized in this way is uniformly charged by the charging device 60 and then subjected to an optical writing process.

  A secondary transfer device 22 is provided below the belt unit in the figure. In the secondary transfer device 22, a secondary transfer belt 24 is stretched between two rollers 23 and moved endlessly. One of the two rollers 23 is a secondary transfer roller to which a secondary transfer bias is applied by a power source (not shown), and the intermediate transfer belt 10 and the secondary transfer belt 24 are between the roller 16 of the belt unit. Is sandwiched. Thus, a secondary transfer nip is formed in which both belts move in the same direction at the contact portion while contacting. On the transfer paper fed from the registration roller pair 49 to the secondary transfer nip, the four-color superimposed toner image on the intermediate transfer belt 10 is secondarily transferred collectively under the influence of the secondary transfer electric field and the nip pressure, so that full color is obtained. An image is formed. The transfer sheet that has passed through the secondary transfer nip is separated from the intermediate transfer belt 10 and is conveyed to the fixing device 25 along with the endless movement of the belt while being held on the surface of the secondary transfer belt 24. Instead of the secondary transfer roller, secondary transfer may be performed by a transfer charger or the like.

  The surface of the intermediate transfer belt 10 that has passed through the secondary transfer nip approaches a support position by the support roller 15. Here, the intermediate transfer belt 10 is sandwiched between a belt cleaning device 17 that contacts the front surface (loop outer surface) and a support roller 15 that contacts the back surface. Then, after the transfer residual toner adhering to the front surface is removed by the belt cleaning device 17, it sequentially enters the primary transfer nip for K, Y, M, and C, and the next four-color toner The images are superimposed.

The belt cleaning device 17 has two fur brushes 90 and 91 as cleaning members. In these, a plurality of hairs made of acrylic carbon having a diameter of 20 [mm] are implanted on the rotating core at a density of 6.25 [D / F, 100,000 pieces / inch ² ], and 1 × 10 ⁷ [ Ω] Demonstrate electrical resistance. The fur brushes 90 and 91 mechanically scrape off the transfer residual toner on the belt by rotating the plurality of raised brushes in contact with the intermediate transfer belt 10 in the counter direction with respect to the direction of flocking. In addition, a cleaning bias is applied by a power source (not shown) to electrostatically attract and recover the scraped transfer residual toner.

  With respect to the fur brushes 90 and 91, the metal rollers 92 and 93 are rotating in the forward or reverse direction while being in contact with each other. Among these metal rollers 92 and 93, a negative polarity voltage is applied to the metal roller 92 located on the upstream side in the rotation direction of the intermediate transfer belt 10 by the power source 94. Further, a positive polarity voltage is applied to the metal roller 93 located on the downstream side by the power source 95. The tips of the blades 96 and 97 are in contact with the metal rollers 92 and 93, respectively. In such a configuration, the upstream fur brush 90 first cleans the surface of the intermediate transfer belt 10 with the endless movement of the intermediate transfer belt 10 in the direction of the arrow in the drawing. At this time, for example, when −400 [V] is applied to the fur brush 90 while −700 [V] is applied to the metal roller 92, first, the positive polarity toner on the intermediate transfer belt 10 is moved to the fur brush 90 side. Electrostatic transfer to The toner transferred to the fur brush side is further transferred from the fur brush 90 to the metal roller 92 due to a potential difference, and is scraped off by the blade 96.

  In this way, the toner on the intermediate transfer belt 10 is removed by the fur brush 90, but a lot of toner still remains on the intermediate transfer belt 10. These toners are negatively charged by a negative polarity bias applied to the fur brush 90. This is considered to be charged by charge injection or discharge. Next, by using the fur brush 91 on the downstream side to apply a positive polarity bias and perform cleaning, the toner can be removed. The removed toner is transferred from the fur brush 91 to the metal roller 93 due to a potential difference and scraped off by the blade 97. The toner scraped off by the blades 96 and 97 is collected in a tank (not shown).

  Most of the toner is removed from the surface of the intermediate transfer belt 10 after being cleaned by the fur brush 91, but a little toner is still left. The toner remaining on the intermediate transfer belt 10 is charged with a positive polarity by a positive polarity bias applied to the fur brush 91 as described above. Then, it is transferred to the photoconductors 40 K, Y, M, and C by a transfer electric field applied at the primary transfer position, and is collected by the photoconductor cleaning device 63.

In general, the registration roller pair 49 is often used while being grounded. However, a bias can be applied to remove the paper dust of the transfer paper P. For example, a bias is applied using a conductive rubber roller. A conductive NBR rubber having a diameter of 18 [mm] and a surface of 1 [mm] thickness is used. The electrical resistance is about 10 × 10 ⁹ [Ω · cm] in terms of the volume resistance of the rubber material, and a voltage of about −800 [V] is applied to the toner transfer side (front side). A voltage of about +200 [V] is applied to the back side of the paper.

  In general, in the intermediate transfer method, it is difficult for paper dust to move to the photoconductor, so that it is not necessary to consider paper dust transfer and may be grounded. Further, although a DC bias is applied as the applied voltage, this may be an AC voltage having a DC offset component in order to charge the transfer paper P more uniformly. The paper surface after passing through the registration roller pair 49 to which a bias is applied in this way is slightly charged on the negative side. Therefore, in the transfer from the intermediate transfer belt 10 to the transfer paper P, the transfer conditions may change and the transfer conditions may be changed as compared with the case where no voltage is applied to the registration roller pair 49.

  The copier includes a transfer paper reversing device 28 (see FIG. 31) that extends under the secondary transfer device 22 and the fixing device 25 so as to extend in parallel with the tandem portion 20 described above. As a result, the transfer paper that has undergone the image fixing process on one side is switched to the transfer paper reversing device side by the switching claw, is reversed there, and enters the secondary transfer transfer nip again. Then, after the secondary transfer process and the fixing process of the image are performed on the other side, the sheet is discharged onto a discharge tray.

  The copier also includes information acquisition means for acquiring various information related to the state of the components and phenomena occurring inside. This information acquisition means includes the control unit 1, various sensors 2, the operation display unit 3 and the like shown in FIG. The control unit 1 is a control unit that controls the entire copying machine, and includes a ROM 1c that is an information storage unit that stores a control program, a RAM 1b that is an information storage unit that stores calculation data and control parameters, a CPU 1a that is a calculation unit, and the like. have. The operation display unit 3 includes a display unit (not shown) configured by a liquid crystal display or the like that displays character information and the like, an operation unit (not shown) that receives input information from an operator through a numeric keypad and the like and sends the input information to the control unit 1. Yes. Examples of information that can be acquired by the information acquisition unit configured as described above include sensing information, control parameter information, input information, and image reading information.

Next, various types of information that can be acquired by the information acquisition unit in the image forming apparatus such as a copying machine will be described in detail.
(A) Sensing information Sensing information is considered to be a target for acquiring drive relationships, various characteristics of recording media, developer characteristics, photoreceptor characteristics, various electrophotographic process states, environmental conditions, various characteristics of recorded materials, etc. . The outline of the sensing information is as follows.

(A-1) Driving information / Rotation speed of the photosensitive drum is detected by an encoder, the current value of the driving motor is read, and the temperature of the driving motor is read.
Similarly, the drive state of a cylindrical or belt-like rotating part such as a fixing roller, a paper transport roller, or a drive roller is detected.
-Detect sound generated by driving with a microphone installed inside or outside the device.

(A-2) Paper transport status ・ Uses a transmission or reflection type optical sensor or contact type sensor to detect the position of the leading and trailing edges of the transported paper and detect that a paper jam has occurred. The deviation of the passage timing of the leading and trailing edges of the paper and the fluctuation in the direction perpendicular to the feeding direction are read.
Similarly, the paper moving speed is obtained based on the detection timing between a plurality of sensors.
The slip between the paper supply roller and the paper during paper supply is obtained by comparing the measured value of the rotation speed of the roller with the amount of movement of the paper.

(A-3) Various characteristics of recording media such as paper This information greatly affects the image quality and stability of sheet conveyance. There are the following methods for acquiring information on this paper type.
-The thickness of the paper should be equal to the amount of movement of the member pushed up when the paper is sandwiched between two rollers and the relative positional displacement of the rollers is detected by an optical sensor or the paper enters. Find by detecting.
-The surface roughness of the paper is such that a guide or the like is brought into contact with the surface of the paper before transfer, and vibrations or sliding noises caused by the contact are detected.
-For the gloss of paper, a light beam with a specified opening angle is incident at a specified incident angle, and a light beam with a specified opening angle reflected in the specular reflection direction is measured by a sensor.
The paper rigidity is obtained by detecting the amount of deformation (curvature) of the pressed paper.
The judgment as to whether or not the paper is recycled is made by irradiating the paper with ultraviolet rays and detecting its transmittance.
The determination as to whether the paper is a backing paper is performed by irradiating light from a linear light source such as an LED array and detecting the light reflected from the transfer surface with a solid-state image sensor such as a CCD.
Whether or not the sheet is for OHP is determined by irradiating the paper with light and detecting regular reflection light having a different angle from the transmitted light.
-The amount of water contained in the paper is determined by measuring the Kyushu of infrared or microwave light.
-The amount of curl is detected by an optical sensor, contact sensor, etc.
-The electrical resistance of the paper is measured directly by contacting a pair of electrodes (such as paper feed rollers) with the recording paper, or by measuring the surface potential of the photoconductor or intermediate transfer body after paper transfer, and recording from that value. Estimate the resistance of the paper.

(A-4) Developer characteristics The characteristics of the developer (toner carrier) in the apparatus affect the basic function of the electrophotographic process. Therefore, it becomes an important factor for the operation and output of the system. Obtaining developer information is extremely important. Examples of the developer characteristics include the following items.
-For toner, list charge amount and distribution, fluidity / cohesion / bulk density, electrical resistance, amount of external additive, consumption or remaining amount, fluidity, toner concentration (mixing ratio of toner and carrier) Can do.
-As for carriers, magnetic properties, coat film thickness, spent amount, etc. can be mentioned.
Note that it is usually difficult to detect these items independently in the image forming apparatus. Therefore, it may be detected as a comprehensive characteristic of the developer. This total characteristic can be measured as follows, for example.
A test latent image is formed on the photoconductor, developed under predetermined development conditions, and the reflection density (light reflectance) of the formed toner image is measured.
A pair of electrodes is provided in the developing device, and the relationship between applied voltage and current is measured (resistance, dielectric constant, etc.).
-Install a coil in the developing device and measure the voltage-current characteristics (inductance).
-A level sensor is provided in the developing device to detect the developer capacity. The level sensor includes an optical type and a capacitance type.

(A-5) Photoreceptor characteristics Like the developer characteristics, the photoreceptor characteristics are closely related to the function of the electrophotographic process. Information on the photoconductor characteristics includes photoconductor film thickness, surface characteristics (friction coefficient, unevenness), surface potential (before and after each process), surface energy, scattered light, temperature, color, surface position (flare), linear velocity Potential decay rate, resistance / capacitance, surface moisture content, and the like. Among these, the following information can be detected in the image forming apparatus.
・ Detect the current flowing from the charging member to the photoconductor, and simultaneously compare the change in capacitance with the change in film thickness with the voltage-current characteristics with respect to the voltage applied to the charging member and the preset dielectric thickness of the photoconductor. Thus, the film thickness is obtained.
-The surface potential and temperature can be determined by a conventionally known sensor.
-The linear velocity is detected by an encoder attached to the rotating shaft of the photoconductor.
-Scattered light from the surface of the photoreceptor is detected by an optical sensor.

(A-6) Electrophotographic process state As is well known, electrophotographic toner image formation is performed by uniformly charging the photoreceptor, forming a latent image (image exposure) using laser light, etc., and charged toner (colored particles). Development by transfer, transfer of toner image onto transfer material (in the case of color, overlay on the recording medium that is the intermediate transfer body or final transfer material, or over development on the photoreceptor during development), toner on the recording medium This is done in the order of image fixing. Various information at each of these stages greatly affects the output of images and other systems. Obtaining these is important in evaluating the stability of the system. Specific examples of the information acquisition of the electrophotographic process state include the following.
The charging potential and the exposure portion potential are detected by a conventionally known surface potential sensor.
The gap between the charging member and the photosensitive member in non-contact charging is detected by measuring the amount of light that has passed through the gap.
・ Electromagnetic waves from electrification are captured by a broadband antenna.
・ Sound generated by charging ・ Exposure intensity ・ Exposure light wavelength

(A-7) The characteristics and pile height (height of the toner image) of the formed toner image are obtained by measuring the depth from the vertical direction with a displacement sensor and the light shielding length from the horizontal direction with a linear sensor of parallel light.
The toner charge amount is measured by a potential sensor that measures the potential of the electrostatic latent image on the solid part and the potential when the latent image is developed, and the ratio to the adhesion amount converted from the reflection density sensor at the same location. Ask for.
The dot fluctuation or dust is detected by detecting the dot pattern image with an infrared light area sensor on the photosensitive member and with an area sensor having a wavelength corresponding to each color on the intermediate transfer member, and performing appropriate processing.
The offset amount (after fixing) is obtained by reading the corresponding locations on the recording paper and the fixing roller with optical sensors and comparing them.
An optical sensor is installed after the transfer process (on the PD and on the belt), and the transfer remaining amount is determined based on the amount of reflected light from the transfer residual pattern after the transfer of the specific pattern.
-Detect color unevenness during overlay with a full-color sensor that detects the recording paper after fixing.
Image density and color are detected optically (either reflected light or transmitted light may be used. The projection wavelength is selected depending on the color). In order to obtain density and single color information, it may be on a photoconductor or an intermediate transfer body, but it is necessary on paper to measure a color combination such as color unevenness.
For gradation, the reflection density of the toner image formed on the photosensitive member or the toner image transferred to the transfer member is detected by an optical sensor for each gradation level.
Sharpness is obtained by reading an image in which a line repetition pattern is developed or transferred using a monocular sensor having a small spot diameter or a high-resolution line sensor.
The graininess (roughness) is obtained by reading a halftone image and calculating a noise component by the same method as the sharpness detection.
The registration skew is obtained from the difference between the registration roller ON timing and the detection timing of both sensors by providing optical sensors at both ends in the main scanning direction after registration.
Color misregistration is detected by a monocular small-diameter spot sensor or high-resolution line sensor at the edge portion of the superimposed image on the intermediate transfer member or recording paper.
Banding (density unevenness in the feed direction) measures density unevenness in the sub-scanning direction with a small-diameter spot sensor or high-resolution line sensor on the recording paper, and measures the signal amount of a specific frequency.
Glossiness (unevenness) is provided so that a recording paper on which a uniform image is formed is detected by a regular reflection optical sensor.
・ Fog is a method of reading the image background with an optical sensor that detects a relatively wide area on the photoconductor, intermediate transfer member, or recording paper, or image information for each area of the background with a high-resolution area sensor. And the number of toner particles contained in the image is counted.

(A-8) The physical characteristics, image flow, and fading of the printed matter of the image forming apparatus are detected on the photosensitive member, the intermediate transfer member, or the recording paper by the area sensor, and the acquired image information is displayed. Judge by image processing.
・ Chile is obtained by taking an image on recording paper with a high-resolution line sensor or area sensor and calculating the amount of toner scattered around the pattern area.
The trailing edge blank and the solid cross blank are detected by a high resolution line sensor on the photosensitive member, the intermediate transfer member, or the recording paper.
・ Curls, undulations, and folds are detected by a displacement sensor. In order to detect a fold, it is effective to install a sensor near the both ends of the recording paper.
-For the dirt and scratches on the edge surface, the area sensor is used to capture and analyze the edge surface when paper discharge has accumulated to some extent by the area sensor installed vertically on the paper discharge tray.

(A-9) For detecting environmental conditions and temperature, a thermocouple system that extracts the thermoelectromotive force generated at the contact point between dissimilar metals or between metal and semiconductor as a signal, the resistivity of metal or semiconductor changes with temperature Resistivity change element using this, pyroelectric element that generates a potential on the surface due to bias in the arrangement of charges in the crystal due to the rise in temperature in certain crystals, and magnetic characteristics depending on temperature A thermomagnetic effect element or the like that detects a change in temperature can be employed.
・ For humidity detection, there are optical measurement methods that measure the light absorption of H ₂ O or OH groups, humidity sensors that measure changes in the electrical resistance of materials due to the adsorption of water vapor, etc. Detection is performed by measuring a change in electric resistance of the oxide semiconductor accompanying gas adsorption.
Although there are optical measurement methods and the like for detection of airflow (direction, flow velocity, gas type), an air bridge type flow sensor that can be made smaller in consideration of mounting on a system is particularly useful.
・ Pressure-sensitive materials are used to detect atmospheric pressure and pressure, and mechanical displacement of the membrane is measured. A similar method is used for vibration detection.

(B) Control Parameter Information Since the operation of the image forming apparatus is determined by the control unit, it is effective to directly use the input / output parameters of the control unit.

(B-1) Image Forming Parameters Direct parameters output by the control unit through image processing for image formation include the following examples.
・ Setting values of process conditions by the control unit, such as charging potential, development bias value, fixing temperature setting value, etc. ・ Similarly, setting values of various image processing parameters such as halftone processing and color correction. Various parameters to be set, such as paper transport timing, execution time of preparation mode before image formation, etc.

(B-2) User operation history-Frequency of various operations selected by the user, such as the number of colors, number of sheets, and image quality instructions-Frequency of the paper size selected by the user

(B-3) Power consumption / Total power consumption or its distribution, change amount (differentiation), cumulative value (integration) for the whole period or specific period unit (1 day, 1 week, 1 month, etc.)

(B-4) Consumables consumption information-Total amount or specific period unit (1 day, 1 week, 1 month, etc.) toner, photoconductor, paper usage or distribution, change (differentiation), cumulative value ( Integration)

(B-5) Failure occurrence information ・ Frequency or distribution of failure occurrence (by type), change amount (differentiation), cumulative value (integration) of whole period or specific period unit (1 day, 1 week, 1 month, etc.)

(C) Input image information The following information can be acquired from image information sent directly as data from the host computer or image information obtained after image processing is performed by reading a document image from a scanner.
The cumulative number of colored pixels is obtained by counting image data for each GRB signal for each pixel.
The original image can be separated into characters, halftone dots, photographs, and backgrounds by the method described in, for example, Japanese Patent No. 2621879, and the ratio of the character part, halftone part, etc. can be obtained. Similarly, the ratio of color characters can be obtained.
The toner consumption distribution in the main scanning direction can be obtained by counting the cumulative value of the colored pixels for each area divided in the main scanning direction.
The image size is obtained from the distribution of colored pixels in the image size signal or image data generated by the control unit.
-Character type (size, font) is obtained from character attribute data.

  The various types of information listed above can be acquired by a known technique in a general image forming apparatus. The information acquisition means of the copying machine described so far can acquire at least the following information (1) to (12).

(1) Temperature The copying machine includes a temperature sensor that acquires temperature information using a variable resistance element that is simple in principle and structure and that can be miniaturized.

(2) Humidity A humidity sensor that can be miniaturized is useful. The basic principle is that when water vapor is adsorbed on moisture-sensitive ceramics, the ionic conduction is increased by the adsorbed water and the electrical resistance of the ceramics is reduced. The material of the moisture-sensitive ceramics is a porous material, and generally, an alumina type, an apatite type, a ZrO ₂ —MgO type, or the like is used.

(3) Vibration The vibration sensor is basically the same as a sensor that measures atmospheric pressure and pressure, and a silicon-based sensor that can be miniaturized is particularly useful in consideration of mounting in a system. It is possible to measure the movement of a vibrator fabricated on a thin silicon diaphragm by measuring the change in capacitance between the opposing electrodes provided facing the vibrator, or by using the piezoresistance effect of the Si diaphragm itself. it can.

(4) Toner density (for 4 colors)
The toner density is detected for each color. A conventionally known toner density sensor can be used. For example, the toner concentration can be detected by a sensing system that measures changes in the magnetic permeability of the developer in the developing device as described in JP-A-6-289717.

(5) Photoconductor uniform charging potential (for 4 colors)
For each color photoconductor (40K, Y, M, C), a uniformly charged potential is detected by a known potential sensor or the like.

(6) Potential after photoconductor exposure (for 4 colors)
The surface potential of the photoconductor (40K, Y, M, C) after optical writing is detected in the same manner as in (5).

(7) Colored area ratio (for 4 colors)
From the input image information, a colored area ratio is obtained for each color from the ratio of the cumulative value of pixels to be colored and the cumulative value of all pixels, and this is used.

(8) Amount of developed toner (for 4 colors)
The toner adhesion amount per unit area in each color toner image developed on the photoconductor (40K, Y, M, C) is obtained based on the light reflectance by the reflective photosensor. The reflection type photosensor irradiates an object with LED light and detects the reflected light with a light receiving element. Since a correlation is established between the toner adhesion amount and the light reflectance, the toner adhesion amount can be obtained based on the light reflectance.

(9) Inclination of paper leading edge position An optical sensor that detects transfer paper at both ends in a direction orthogonal to the conveyance direction at some point in the paper feed path from the paper feed roller of the paper feed unit (200) to the secondary transfer nip. A pair is installed to detect both ends near the leading edge of the transferred transfer paper. For both light sensors, the time to pass is measured with reference to the time when the drive signal of the paper feed roller is transmitted, and the inclination of the transfer paper with respect to the feed direction is obtained based on the time deviation.

(10) Paper discharge timing The transfer paper after passing through the pair of discharge rollers (56 in FIG. 31) is detected by an optical sensor. In this case as well, the measurement is performed with reference to the time when the paper feed roller drive signal is transmitted.

(11) Photoconductor total current (for four colors)
A current flowing from the photoconductor (40K, Y, M, C) to the ground is detected. Such a current can be detected by providing a current measuring means between the substrate of the photoreceptor and the ground terminal.

(12) Photoconductor driving power (for four colors)
Driving power (current × voltage) consumed by the driving source (motor) of the photosensitive member during driving is detected by an ammeter, a voltmeter, or the like.

Next, a third embodiment of the abnormality determination device to which the present invention is applied will be described.
In the third embodiment, first, a basic configuration of the abnormality determination device will be described. This abnormality determination device determines whether or not an abnormality has occurred in the copier, which has been described so far, to be examined.

  FIG. 35 is a block diagram illustrating a main part of an electric circuit in the abnormality determination device according to the third embodiment. In this figure, the abnormality determination apparatus includes an information acquisition unit 501 that is information acquisition means for acquiring information on an object, an abnormality determination unit 502 that is an abnormality determination unit, an information storage unit 503 that is an information storage unit, and a data input unit that is a data input unit. 504 etc. are provided. Also provided is a determination result output unit 505 as determination result output means for outputting a determination result by the abnormality determination means.

  The information acquisition unit 501 acquires the above-described information (1) to (12) from the same copying machine (not shown) that is a test target. The information (1) to (12) acquired by the information acquisition unit 501 is sent to the abnormality determination unit 502. The abnormality determination unit 502 includes a calculation unit (CPU 501a in the illustrated example) for performing various calculations necessary for determination of abnormality. Then, the information sent from the information acquisition unit 501 is used as it is for calculation processing for abnormality determination or used after being stored in the information storage unit 503. Specifically, a predetermined calculation is performed based on the information (1) to (12) sent from the information acquisition unit 501, the calculation result, and a predetermined threshold stored in the information storage unit 503. Based on the comparison result, whether or not there is an abnormality in the copier is determined.

  The determination result by the abnormality determination unit 502 is output by the determination result output unit 505. In addition to printout, image display output, audio output, etc. for allowing the user of the copier to recognize the determination result, this output also includes a mode in which the determination result information is output to some external device such as a personal computer or a printer. It is a concept that includes. With this output, the determination result by the abnormality determination unit 502 is recognized by the user of the copier, a serviceman at a remote location, and the like. The information acquisition unit 501 includes a RAM, a ROM, a hard disk, and the like, and stores information such as a control program and an algorithm in addition to various types of information acquired by the information acquisition unit 501. The data input unit 504 accepts data input for storing a threshold value, which will be described later, in the information storage unit 503, and the threshold value data received by the data input unit 504 is sent to the information storage unit 503 via the abnormality determination unit 502. Sent to.

Next, a characteristic configuration of the abnormality determination device according to the third embodiment will be described.
The abnormality determination unit 502 is configured to determine, as an abnormality in the copier, a general abnormality including a plurality of types of abnormality and a plurality of individual abnormalities that are each of the plurality of types of abnormality. Specifically, as the plurality of individual abnormalities, three abnormalities of a paper jam system, a photoreceptor deterioration system, and an image density fluctuation system are respectively determined. A comprehensive abnormality is a combination of these three individual abnormalities.

  In the determination of the three individual abnormalities, the individual abnormality threshold value corresponding to each individual abnormality is read from the information storage unit 503 and compared with the above calculation result. These individual abnormality threshold values are respectively stored in the information storage unit 503 by data input to the data input unit 504 serving as data input means.

  With this abnormality determination device configured as described above, the presence / absence of each individual abnormality is confirmed each time a determination is made by determining the presence / absence of each individual abnormality only when a comprehensive abnormality including three individual abnormalities is detected. This makes it possible to prevent complication of control. When a general abnormality is detected, it is specified which of the three individual abnormalities included in the general abnormality has been detected. And by this specification, the complication of maintenance after the detection of the general abnormality can be suppressed.

  Further, in this abnormality determination apparatus, a serviceman or a user can initially set three individual abnormality thresholds individually used for determining the presence or absence of three individual abnormalities by an input operation to the data input means. Or updated by the user. By such initial setting and updating, the presence or absence of each individual abnormality can be determined with accuracy according to each user.

  The abnormality determination device may be configured integrally with the copy machine to be tested and function as a part of the copy machine, or may be configured separately from the copy machine and transferred from the copy machine. The presence / absence of abnormality may be determined based on the information (1) to (12).

  In the latter case, that is, when this abnormality determination device is configured separately from the copier, as shown in FIG. 36, a plurality of copiers 600 are respectively connected at remote locations using one abnormality determination device 500. Collective management is possible. In addition, as shown in FIG. 37, a plurality of copying machines 600 connected to a plurality of personal computers 700 on a network called an in-house LAN or an intranet are collectively processed by a single abnormality determination device 500 via a communication line. It is also possible to manage. Even in the case of collective management as described above, if a data input unit 504 that accepts data input of a threshold value for individual abnormality sent via a communication line is used, it is possible for a user at a remote location. On the other hand, the data input of the threshold value for individual abnormality can be performed to this abnormality determination apparatus. In addition, if a determination result output unit 505 that outputs a determination result via a communication line is used, the determination result is transmitted to each copying machine installed at a different remote location to notify each user. You can also The communication line may be either wired or wireless, and any form such as an electric line or an optical fiber may be used. When the abnormality determination apparatus is configured separately from the copier, information configured by a control unit, various sensors, operation display units (1, 2, and 3 in FIG. 34) and the like in the copier. The acquisition unit does not function as the information acquisition unit 501 of the abnormality determination device. Receiving means for receiving various information sent from the copier via a wired or wireless communication line functions as the information acquisition unit 501 of the abnormality determination apparatus.

  On the other hand, in the former case, that is, when the abnormality determination device 500 is configured integrally with the copying machine 600 and functions as a part of the copying machine 600 as shown in FIG. It also functions as information acquisition means of the abnormality determination device 500. Specifically, the information acquisition unit configured by the control unit 1, various sensors 2, the operation display unit 3 and the like illustrated in FIG. 34 functions as the information acquisition unit 501 of the abnormality determination device. In this case, the control unit 1 of the copier may be used as an abnormality determination unit (502 in FIG. 35) or an information storage unit (503 in FIG. 35) of the abnormality determination apparatus. Further, the operation display unit 3 of the copier may be used as a data input unit (504 in FIG. 35) and a determination result output unit (505 in FIG. 35) of the abnormality determination apparatus. If a determination result output unit that outputs a determination result via a communication line is used, the occurrence of an abnormality in the copier can be automatically notified to a remote repair service organization.

  As described above, the abnormality determination device may be configured to be either integrated or separate from the copier. Hereinafter, an example in which the abnormality determination device is integrated will be described.

  The abnormality determination apparatus obtains the Mahalanobis distance by the MTS method based on the group information composed of a plurality of types of information ((1) to (12)) acquired by the information acquisition unit 501, and performs the above-described general abnormality or individual The presence or absence of abnormality is judged. In order to realize this determination, a normal group data group acquired in advance is stored in the information storage unit 503. Further, the abnormality determination unit 502 obtains the Mahalanobis distance based on the normal group data group and the group information including a combination of all or a part of the information (1) to (12) described above. ing.

In order to obtain the Mahalanobis distance, it is necessary to construct the normal group data group and its inverse matrix in advance prior to the determination of abnormality. Table 4 shown below is an acquisition used in the normal data acquisition process for constructing the normal group data group based on the information of (1) to (12) acquired from the same copier in an abnormal state. A data table is shown. This acquisition data table shows an example of acquiring n sets of group information composed of k types of information. Note that the acquisition of the information (1) to (12) in the normal data acquisition step is not an information acquisition step that is performed to determine abnormality, but is a step that is performed only to construct the normal group data group. It is. The information acquisition process performed to determine the abnormality is performed in a state where the normal group data group has already been constructed by the normal data acquisition process.

  The normal data acquisition step is performed by acquiring a plurality of sets of information combinations (1) to (12) as normal set information from the same copier that is actually operated in the absence of abnormality. As the copier for which data is to be acquired, a standard machine for acquiring one normal set of data common to a plurality of copier products shipped from the factory may be used. Each may be actually operated and a dedicated normal set data group may be acquired individually.

In the normal data acquisition process, first, k types of information (y ₁₁ , y ₁₂ ... Y _1k ) constituting the first group information are acquired by the information acquisition unit of the copier. . And it is stored in the acquisition data table of Table 4 as the data of the 1st line in the table. Next, k types of information (y ₂₁ , y ₂₂ ... Y _2k ) constituting the second set information are acquired by the information acquisition means, respectively, Stored in the acquisition data table. Thereafter, group information from the third group to the n-th group is acquired in the same manner, and stored in the acquired data table as data of the third row... N-th row in the table. Finally, the average and standard deviation (σ) of n pieces of k information constituting each set of information are obtained and stored in the acquired data table as the data of n + 1 and n + 2 rows, respectively. The Data in the acquired data table constructed in this way is used as the normal group data group.

When the normal data acquisition process is completed in this way, an information normalization process for constructing a normalized data table is then performed. Table 5 shown below shows a normalized data table constructed in this information normalization step, which is constructed based on the acquired data table shown in Table 4.

Data normalization is a process for converting absolute value information of various types of information into variable information. Normalized data of various types of information is calculated based on the following relational expressions. Note that i in the following expression is a code indicating any one of the n sets of group information. Further, j is a code indicating that it is any one of k types of information.

When the information normalization process ends, a correlation coefficient calculation process is performed next. In this correlation coefficient calculation step, all combinations ( _k C ₂ types) in which two different types can be established among k types of normalized data in each of n sets of normalized data groups are based on the following equation. Correlation coefficient r _pq (r _qp ) is calculated.

Once the correlation coefficients r _pq (r _qp ) have been calculated for all combinations, then k × k pieces, with the diagonal element being 1 and the other p rows and q columns elements being correlation coefficients r _pq The correlation coefficient matrix R is constructed. The contents of this correlation coefficient matrix R are shown in the following equation.

When such a correlation coefficient calculation process is completed, a matrix conversion process is then performed. Through this matrix conversion step, the correlation coefficient matrix R expressed by Equation 9 is converted into an inverse matrix A (R ⁻¹ ) expressed by the following equation.

  FIG. 39 is a flowchart showing a series of processes from the normal data acquisition process to the matrix conversion process. In the figure, first, k pieces of information related to the state of the copying machine are acquired while operating the copying machine (step 1-1: hereinafter, step is denoted as S). Next, for each type of information (j), an average value and a standard deviation σ based on the relational expression of Equation 7 are calculated, and a normalized data table is constructed based on the calculation result (S1-2). . Then, after the correlation coefficient matrix R is constructed based on the normalized data table (S1-3), it is converted into an inverse matrix A (S1-4).

  The inverse matrix A is constructed by a series of processes such as the normal data acquisition process, the information normalization process, the correlation coefficient calculation process, and the matrix conversion process as described above. It is also possible to have the apparatus implement. In the case of carrying out all of them, it is not always necessary to previously store the normal set data group in the information storage means of the copier at the time of factory shipment. At the time of initial operation where there is a very high possibility that no abnormality has occurred at the shipping destination, the information of (1) to (12) is acquired as normal group information and the normal group data group and the inverse matrix A are constructed. Because you can. Since the copier product immediately after shipment is a normal product that has just been inspected, the acquisition result of various information during the initial operation can be handled as a normal value. When none of the series of steps described above is performed by the abnormality determination device, it is necessary to store the inverse matrix A in advance in the information storage unit of the copier at the time of shipment from the factory. In addition, as the inverse matrix A stored in advance, a matrix constructed based on the normal set data group acquired from the above-mentioned standard machine may be used in common for each copying machine product, or individually for each copying machine product. Alternatively, a normal set data group may be acquired and constructed. The normal group data group may be stored in advance, and the abnormality determination apparatus may be caused to perform the conversion of the inverse matrix A from the normal group data group.

  As described above, as the normal group data group, the data acquired from the standard machine may be used in common for each copier product, or each copier product is actually operated and dedicated normal group data. Groups may be acquired individually. In the latter case, it is possible to avoid deterioration in determination accuracy due to variations in the normal values of various information used for determining abnormality due to accuracy errors of various components. Furthermore, if the abnormality determination device is configured to acquire the normal group data group at the initial operation after the factory shipment, it is troublesome to perform a trial operation for each product in the factory and acquire each normal group data group before the shipment. An increase in cost can also be avoided.

Regardless of how the normal set data group is acquired, the inverse matrix A constructed as described above is stored in the information storage unit 503 of the abnormality determination apparatus when determining abnormality. Then, the abnormality determination unit 502 calculates the Mahalanobis distance (hereinafter referred to as “the Mahalanobis distance”) based on the all-kind information including all of (1) to (12) acquired by the information acquisition unit 501, the inverse matrix A, and D) (referred to as Mahalanobis distance).

FIG. 40 is a flowchart showing a procedure for calculating the Mahalanobis distance D. In this procedure, first, k types of data x ₁ , x ₂ ,..., X _{k in} an arbitrary state are acquired (S2-1). The data types correspond to y ₁₁ , y _{12 ,.} Next, each acquired data is normalized to X ₁ , X ₂ ,..., X _k based on the relational expression (7). Then, the square of the Mahalanobis distance D is calculated according to the relational expression (11) determined using the element a _kk of the inverse matrix A that has already been constructed. “Σ” in the figure represents the sum of the subscripts p and q. In the copier, the information of (1) to (12) described above is acquired. Of these, the information of (4) to (8), (11) and (12) is for four colors (4 Therefore, _k in x _k is 5 + 7 × 4 = 33 [type].

  The abnormality determination unit 502 determines the presence / absence of a general abnormality by comparing the Mahalanobis distance D for all types of group information (group information consisting of 33 types of information) obtained in this manner with a total abnormality threshold. As the Mahalanobis distance D becomes larger than “1”, it indicates that the test data is farther from the normal state. Therefore, when the Mahalanobis distance D exceeds the total abnormality threshold, it is determined that the total abnormality is “present”.

When this abnormality determination device determines that a general abnormality is “present”, each of the three individual abnormalities (paper jamming system, photoreceptor deterioration system, and image density fluctuation system) included in the general abnormality is next. Determine presence or absence. Table 6 shown below is a table showing an example of the relationship between each individual abnormality in the copier and set information necessary for determining the presence or absence thereof.

  As shown in Table 6, regarding abnormalities in the paper jam system, the following 7 items 13 out of 12 items 33 types (5 items + 7 items × 4 colors) from (1) to (12) described above. The determination can be made based on group information composed of types of information. That is, (1) Temperature, (2) Humidity, (3) Vibration, (7) Colored area ratio × 4 colors, (8) Development toner amount × 4 colors, (9) Inclination of paper tip position, and ( 10) It is a paper discharge timing. Hereinafter, this group information is referred to as first group information.

  Further, the abnormality of the photoreceptor deterioration system can be determined based on the set information including the following seven items and 22 types of information. (1) Temperature, (2) Humidity, (5) Photoconductor uniform charging potential x 4 colors, (6) Photoconductor exposure potential x 4 colors, (7) Colored area ratio x 4 colors, (11) Photoconductor total current × 4 colors and (12) Photoconductor drive power × 4 colors. Hereinafter, this group information is referred to as second group information.

  Also, the abnormality of the image density fluctuation system can be determined based on the following 7 items 22 types of group information. (1) Temperature, (2) Humidity, (4) Toner density x 4 colors, (5) Photoconductor uniform charging potential x 4 colors, (6) Photoconductor exposure potential x 4 colors, ( 7) Color area ratio × 4 colors, and (8) Development toner amount × 4 colors. Hereinafter, this group information is referred to as third group information.

  As is apparent from Table 6, the first, second, and third set information have different information combinations. This is because the combination of information useful for determining an abnormality varies with the type of abnormality. In the example of Table 6, the type of abnormality that has occurred can be narrowed down by obtaining the Mahalanobis distance D for each of the first, second, and third sets of information. Therefore, when the abnormality determination device determines that the total abnormality is “present”, the abnormality determination device obtains the Mahalanobis distance D based on the first, second, and third set information, respectively. Then, the obtained Mahalanobis distance D is compared with the individual abnormality threshold value to determine whether or not there is an abnormality in the paper jam system, the photoreceptor deterioration system, and the image density fluctuation system. It should be noted that the individual abnormality threshold values for individually determining abnormalities in the paper jamming system, the photoreceptor deterioration system, and the image density fluctuation system, which are individual abnormalities, are different from the above-described overall abnormality threshold values. It is common. Therefore, the three Mahalanobis distances D obtained on the basis of the first, second, and third sets of information are the individual abnormalities for the paper jam system, the photoreceptor deterioration system, and the image density fluctuation respectively corresponding to each individually. Compared with the threshold value.

  In order to obtain these three Mahalanobis distances D, in addition to the first, second, and third set information acquired from the copier, an inverse matrix A having the same combination as those is required. For example, in the case of the same table, an inverse matrix A composed of information of 12 items and 33 types (5 items + 7 items × 4 colors) is commonly used for each of the first, second, and third sets of information. Then, it becomes impossible to accurately determine the abnormality. In the case of the first set information, it is necessary to obtain the Mahalanobis distance D using an inverse matrix A composed of the same seven items and 13 types of information. Therefore, prior to determination, it is necessary to prepare an inverse matrix A for obtaining the Mahalanobis distance D for each category.

  There are roughly two methods for preparing the inverse matrix A for each set of information. The first method is a method in which a dedicated inverse matrix A is constructed. The second method is a method of storing only the inverse matrix A for all kinds of group information composed of all kinds of information included in each group information. In the case of this method, the individual inverse matrix A for the first, second, and third set information is changed to any combination of normal values selected from the inverse matrix A that is a set of all kinds of set information. Each will be built based on. For example, in the example of Table 6, only the inverse matrix A composed of a set of all-type set information (12 items, 33 types) is stored. Then, the inverse matrix A composed of the first set of information corresponding to the paper jam system is constructed by selecting 13 items and 13 types of information from all kinds of set information. In this method, the amount of information stored and stored in the information storage unit 503 can be reduced compared to the first method.

  In addition, although the example which determines not only comprehensive abnormality but each individual abnormality based on Mahalanobis distance D was demonstrated, you may make it use other calculation results different from Mahalanobis distance D about each individual abnormality.

  In this abnormality determination device, a service person or a user inputs three individual abnormality threshold values for a paper jam system, a photoreceptor deterioration system, and an image density fluctuation to the data input unit 504 in accordance with user information. Then, it can be initialized or updated. The user information to be reflected in each of the three individual abnormality thresholds includes the level of proficiency for maintenance of the copier and the degree of failure detection. The reason for reflecting these pieces of information on the individual abnormality threshold is as described above. Further, as the user information, the purpose of use of the copier, the type of business, the department, the relationship between the paper size and the frequency of use, the relationship between the type of output image and the output frequency, etc. may be reflected in the individual abnormality threshold. . Of course, when the purpose of the copier is to produce a book product such as an instruction manual, or to create a personal printout or to temporarily output an image, the image quality required, and thus The user's degree of failure detection will be different. Also, the required image quality and frequency of occurrence vary depending on the user's industry and department. In addition, regardless of individual differences, it is possible that a failure may not be felt at all or may be felt depending on the size of the paper. For example, image disturbance due to the occurrence of scratches near the end of a drum-shaped photoconductor occurs near the end of a relatively large size sheet, but does not occur on a relatively small size sheet. For this reason, this type of image disturbance is easily detected by a user who uses a relatively large size of paper regardless of individual differences in the degree of detection. In addition, the deterioration of image quality is more easily perceived by a user who frequently outputs a photographic image because a photographic image is easier to feel than a text document image regardless of individual differences. Therefore, if the purpose of use, type of business, department, relationship between the size of paper and the frequency of use, the relationship between the type of output image and the frequency of output, etc. are reflected in the above-mentioned three individual abnormality threshold values. Each individual abnormality can be detected with accuracy according to the individual user.

As a method of reflecting user information in the threshold, there is a method of multiplying the standard threshold by a coefficient corresponding to the user information. The standard threshold value is a threshold value determined based on a general user (a user who has a general skill level or the like). Table 7 shown below shows an example of standard threshold values relating to three individual abnormality threshold values of a paper jam system, a photoreceptor deterioration system, and an image density fluctuation system.

  The standard threshold values shown in Table 7 are merely examples, and the values that are actually set are not limited to these. Further, although an example has been shown in which the standard threshold value increases in the order of the photoreceptor deterioration system, the paper jam system, and the image density fluctuation system, the invention is not limited to this order.

Table 8 shown below shows an example of the relationship between the proficiency level that is user information and the threshold coefficient.

  In Table 8, as the proficiency level becomes low, medium, and high, the threshold coefficient increases to “0.9”, “1.0”, and “1.2”. This is for the reason explained below. That is, the degree of abnormality increases as the value of Mahalanobis distance D increases. For this reason, an abnormality is detected more sensitively as the individual abnormality threshold compared with the Mahalanobis distance D becomes smaller. On the other hand, even with the same degree of abnormality, the higher the user's proficiency level, the less likely a repair request will be generated. Then, in order to obtain the abnormality detection accuracy suitable for each user, it is necessary to increase the individual abnormality threshold value and make it difficult to detect the abnormality as the user's proficiency level increases. Therefore, as the proficiency level becomes low, medium, and high, the threshold coefficient for multiplying the individual abnormality threshold is increased to “0.9”, “1.0”, and “1.2”. is there.

Table 9 shown below shows an example of the relationship between the failure detection degree, which is user information, and the threshold coefficient.

  In Table 9, the threshold coefficients are decreased to “1.2”, “1.0”, and “0.8” as the failure detection degree becomes low, medium, and high. This is for the reason explained below. That is, as described above, the abnormality is detected more sensitively as the individual abnormality threshold compared with the Mahalanobis distance D becomes smaller. On the other hand, even if the degree of abnormality is the same, a repair request is more likely to occur as the user's degree of failure detection increases. Then, in order to obtain an abnormality detection accuracy suitable for each user, it is necessary to make the individual abnormality threshold smaller as the user's degree of failure detection becomes higher so that the abnormality can be easily detected. Therefore, as the failure detection level becomes higher, lower, middle, and higher, the threshold coefficient for multiplying the individual abnormality threshold is lowered to “1.2”, “1.0”, and “0.8”. It is.

Table 10 shown below shows the relationship between the user's business type, department, and threshold coefficient.

  If the user's business category is related to printing and the user's department is related to production, there is a high possibility that the purpose of use of the copier is book production. There is a high possibility that the user will be sensitively aware of a decrease in image quality and an increase in the frequency of paper jams. Therefore, in Table 10, the threshold coefficient is set to the smallest value “0.8”.

Table 11 shown below shows the relationship between the type of output image, the output frequency, and the threshold coefficient.

  In general, an abnormality in image quality (for example, an image density variation system) is likely to be detected in the order of a text document, a drawing, an advertisement flyer, and a photograph, regardless of individual differences in the degree of user perception. For this reason, regardless of individual differences, a user who outputs a text document more frequently than other types of images is less likely to detect an abnormality in image quality. On the other hand, a user who outputs a photograph more frequently than other types of images can easily detect an abnormality in image quality. Therefore, in the example shown in Table 11, the threshold coefficient is set in consideration of the order of the output frequencies of the four types of images, ie, the text document, the drawing, the advertisement flyer, and the photo, and the order of the ease of detection. is doing. For example, regardless of individual differences, an image quality abnormality is most difficult to be detected when a printout is performed in which the output frequency decreases in the order of a text document, a drawing, an advertisement flyer, and a photograph. Therefore, if the order is such, “1.00”, which is the smallest value in each order, is used as the threshold coefficient. On the other hand, regardless of individual differences, image quality abnormalities are most easily detected when a printout is performed in which the output frequency decreases in the order of photos, advertising flyers, drawings, and text documents. . Therefore, in the case of such an order, “1.50” which is the largest value in each order is used as the threshold coefficient.

  As described above, if the user information is reflected in each individual abnormality threshold (paper jamming system, photoreceptor deterioration system, and image density fluctuation system), each individual abnormality is detected with accuracy according to each user. be able to.

  In addition to user information, it is desirable to reflect environmental information in which the copier is installed in each individual abnormality threshold (paper jamming system, photoreceptor deterioration system, and image density fluctuation system). This is for the reason explained below. That is, even if the calculation result of the Mahalanobis distance D is the same value, there may be an abnormality in which the degree of detection varies depending on the environment regardless of individual differences. For example, even if the calculation result of the Mahalanobis distance D is the same value, more or less paper jams may occur depending on the humidity at which the copier is used. In such a case, if each individual abnormality threshold value is set according to the environment information in which the copier is set, the abnormality occurrence notification time due to the change in the degree of abnormality detection regardless of individual differences depending on the environment. Can be prevented from becoming inappropriate.

  When replacing the old and new copiers for some reason such as the end of their service life, the threshold values for individual abnormalities (paper jam, photoreceptor deterioration, and image density fluctuation) in the new copier are It is desirable to initially set each individual abnormality threshold value that has been used to the same value. This is for the reason explained below. In other words, the initial setting of each individual abnormality threshold value is rarely a value that perfectly suits the user, and gradually becomes more suitable according to repeated abnormality detection and the degree of sensitivity to the user's abnormality at that time. It is desirable to update to a value. When such an update has been made, each individual abnormality threshold used in the old copier is updated to a value more suitable for the user than the initial setting due to the replacement of the old and new ones. It is highly possible that the value is very close to. Nevertheless, if the values that reflect the user's information in general are adopted as the individual abnormality thresholds without adopting these individual abnormality thresholds for the new copier, those values will be changed. It will keep away from the user's request. Therefore, each individual abnormality threshold value is initially set to the same value as that used in the old copier. In this way, it is possible to avoid deterioration of abnormality detection accuracy due to initial setting of a value that generally reflects user information as each individual abnormality threshold for the new copier.

  Further, it is desirable to update each individual abnormality threshold value (paper jam system, photoreceptor deterioration system, image density fluctuation system) according to the repair request history information of the user based on the occurrence of the abnormality. This is because by performing such an update, each individual abnormality threshold value can be gradually changed from the initial setting to a value according to the user's request.

  Depending on the relationship between the determination result of the general abnormality and the inspection result of the copier, it is desirable to update the normal group data group stored in the information storage unit 503. Specifically, if any abnormality is found during inspection of the copier even though the overall abnormality is determined to be “none”, the abnormal group information is included in the normal group data group. It is included. By including such group information, the normal space range in the Mahalanobis space becomes wider than the original, and as a result, an abnormality cannot be detected. Therefore, the group information that is not normal is deleted from the normal group data group, and the normal group data group is updated. New normal group information may be added and updated by the amount deleted. By deleting the group information that is not normal, it is possible to avoid erroneous determination due to the group information being included in the normal group data group. It should be noted that the group information that is not normal can be identified by searching for the one with a large standard deviation from the normalized data table described above.

  In this abnormality determination device, the information acquisition unit 501 and the abnormality determination unit change the acquisition frequency of various types of information and the determination frequency of the presence or absence of the general abnormality according to the Mahalanobis distance D that is the calculation result of the general abnormality. 502 is comprised. Specifically, when the Mahalanobis distance D for the general abnormality approaches the general abnormality threshold to some extent, the acquisition frequency and determination frequency of various information are made higher than before. The reason for this will be described with reference to FIGS. 41, 42 and 43. FIG.

  FIG. 41 is a graph showing an example of the relationship between Mahalanobis distance D and total elapsed time (operating time) for a general abnormality in the copier. In the figure, the abnormality detection threshold is a total abnormality threshold used for determining the presence or absence of a general abnormality. The failure occurrence threshold is the same value as the Mahalanobis distance D when the individual abnormality is advanced until the failure occurs in the copier. When the Mahalanobis distance D increases to the failure occurrence threshold, a failure occurs in the copier. Depending on the type of individual abnormality included in the general abnormality, as shown in the figure, the rate of increase may suddenly increase from the time when the Mahalanobis distance D approaches the failure occurrence threshold to some extent. In such a case, there is a possibility that the detection of the general abnormality is greatly delayed.

  Specifically, FIG. 42 is a graph showing the relationship between Mahalanobis distance D and elapsed time when a total abnormality is determined at a time interval of 4 t in the same copier having the characteristics as shown in FIG. In the drawing, the failure occurs between the time point 32t and the time point 36t. However, since the Mahalanobis distance D has not yet reached the abnormality detection threshold at the time point 32t, the total abnormality is not detected. The determination of the general abnormality is performed at the time 36t next to the time 32t. However, since the abnormality rapidly progresses during this time, the general abnormality occurs earlier than the arrival of the time 36t. For this reason, in the example shown in the figure, a general abnormality is detected after a failure occurs, and the occurrence of the general abnormality cannot be predicted.

  FIG. 43 is a graph showing an example of the relationship between the Mahalanobis distance D and the elapsed time when the Mahalanobis distance D for the total abnormality has approached the abnormality detection threshold to a certain extent and the determination frequency of the general abnormality is further increased. . In the figure, the determination frequency change threshold is a threshold for determining whether or not to change the determination frequency of the overall abnormality, and is set to a value smaller than the abnormality detection threshold. In the example shown in the figure, the Mahalanobis distance D gradually increases with time, and the rate of increase (amount of increase / unit time) of the Mahalanobis distance D starts to increase from around time 24t. Then, the Mahalanobis distance D reaches the determination frequency change threshold at a slightly earlier stage than the time point 28t, and the abnormality determination unit 502 recognizes this at the time point 28t and increases the determination frequency of the total abnormality from the 4t interval to the 1t interval. Thereafter, at 32.5 t, the Mahalanobis distance D reaches the abnormality detection value. A failure occurs at a time point 34t after a general abnormality is detected by the abnormality determination unit 502 at a time point 33t slightly delayed. Since the determination frequency is increased at the time point 28t, a general abnormality is detected at an earlier stage than the occurrence of the failure. Therefore, by configuring the abnormality determination unit 502 so as to change the determination frequency of the presence or absence of a general abnormality according to the Mahalanobis distance D that is the calculation result, the following can be performed. That is, it is possible to suppress a situation in which the occurrence of a general abnormality cannot be predicted due to the rapid increase in the Mahalanobis distance D.

  Depending on the determination result, it is desirable to change the image forming conditions or limit a part of the image forming operation. Specifically, correspondence listed in the following (a) to (c) can be considered.

(A) Stop the device When the Mahalanobis distance D becomes abnormal in threshold value or the rate of increase over time of the Mahalanobis distance D increases, the device cannot be forced to operate and maintenance is performed for the user. Request.

(B) Limit the image forming operation or change the control parameter (b-1) Change the color mode (b-2) Change the recording speed (b-3) The number of lines in the halftone part of the image Change (b-4) Change of halftone processing method (b-5) Restriction of paper type to be used (b-6) Parameter change of resist control (b-7) Parameters of image forming process (uniform charging potential, exposure) Amount, development bias, transfer bias, etc.)

(C) Supply and replacement of consumables and parts Based on the calculation result of Mahalanobis distance D, supply and replacement are automatically performed.

  Depending on the type of individual abnormality that has occurred, even if a failure occurs due to its progress, the function of the copier may be restricted to enable operation for a period until repair preparation is completed. For example, it is assumed that a large damage has occurred near the end of the drum shaft of the drum-shaped photoconductor for some reason. Then, when a printout is performed on a large size paper that uses almost the entire area of the photosensitive member in the axial direction, significant image quality deterioration or smearing occurs near the edge of the paper. However, when the printout is performed with a small size paper that does not require use of the damaged area of the photoconductor, image quality deterioration and smearing do not occur. Therefore, even if a large damage occurs near the drum shaft end of the drum-shaped photoconductor, the function is restricted so that the use of large-size paper is prohibited. The machine can be operated to print out. In view of this, the abnormality determination apparatus is provided with function restriction means for restricting the function of the copier according to the occurrence of each individual abnormality. FIG. 44 is a schematic diagram showing a display screen example of the operation display unit of the copier when the function restriction is performed by the function restriction unit. This is an example of a display screen in a case where image quality deterioration and dirt do not occur if a paper smaller than A4 size is used.

Next, a description will be given of a fourth embodiment of the abnormality determination device to which the present invention is applied.
FIG. 45 is a block diagram illustrating a main part of an electric circuit in the abnormality determination device according to the fourth embodiment. Comparing the figure with FIG. 35 shown above, the configuration of the electric circuit of the abnormality determination device is substantially the same as that of the abnormality determination device according to the third embodiment, but the following points are different. In other words, the data display unit 506 is included, and the abnormality determination unit 502, the information storage unit 503, the data input unit 504, and the data display unit 506 constitute a threshold setting unit 507 serving as a threshold setting unit.

  The information acquisition unit 501 in the abnormality determination apparatus also acquires the above-described information (1) to (12) from the same copier as the test target. The abnormality determination unit 502 is configured to detect the general abnormality or the paper included in the abnormality based on the various data stored in the information storage unit and the information (1) to (12) acquired by the information acquisition unit 501. The presence / absence of three individual abnormalities of a clogging system, a photoreceptor deterioration system, and an image density fluctuation system is determined. Each abnormality is determined by comparing the Mahalanobis distance D with a dedicated individual abnormality threshold, as in the third embodiment. Also, the presence / absence of three individual abnormalities is determined only when it is determined that there is a general abnormality. The data display unit 506 is composed of a liquid crystal display or the like, and displays an image based on the image signal sent from the abnormality determination unit 502.

  The threshold value setting unit 507 configured by the abnormality determination unit 502, the information storage unit 503, the data input unit 504, and the data display unit 506 is used for general abnormality, paper jamming system, and photoconductor stored in the information storage unit 503. Individual abnormality threshold values are set for the degradation system and the image density abnormality system, respectively. The specific method of setting is as follows. That is, the information storage unit 503 stores a question execution program for asking a user a predetermined question in order to obtain user information. The abnormality determination unit 502 causes the data display unit 506 to display various types of question information based on the question execution program. For example, questions such as “Can you investigate the cause when paper jams occur frequently?” Or “Can you replace the photoconductor yourself?”. When the user inputs answer data for these questions to the data input unit 504, the abnormality determination unit 502 stores the input answer data in the information storage unit 503 as user information.

  When such a question execution program ends, a plurality of pieces of user information are stored in the information storage unit 503. The abnormality determination unit 502 performs three individual abnormalities for the paper jam system, the photoconductor deterioration system, and the image density fluctuation system based on the user information and various data stored in the information storage unit 503. Initialize the threshold for use. The various data used at this time are, for example, the data shown in Table 7, Table 8, Table 9, Table 10, and Table 11 above. By such initial settings, the user's information is reflected in the three individual abnormality threshold values for the paper jam system, the photoreceptor deterioration system, and the image density fluctuation system, and the judgment accuracy of each individual abnormality is commensurate with the user. It becomes a thing.

  In the abnormality determination device having such a configuration, the data input to the data input unit 504 is not the individual abnormality threshold value itself but the user information, which is greatly different from the abnormality determination device according to the third embodiment. ing. Instead of allowing the user to input the individual abnormality threshold value, the user information is input in an answer format. In most cases, the user is not familiar with the abnormality determination method. If such a user is allowed to calculate and input individual abnormality threshold values for a paper jam system, a photoreceptor deterioration system, and an image density fluctuation system while referring to a manual or the like, it is inconvenient. It can be. However, if the user information is input in an answer format and the individual abnormality thresholds are set based on the information, as in the abnormality determination device, it is possible to avoid a situation in which the above inconvenience is given. it can. In addition, it is possible to avoid a situation in which the user performs complicated calculations to determine the individual abnormality thresholds.

  The threshold setting unit 507 not only initially sets the individual abnormality thresholds for the paper jam system, the photoreceptor deterioration system, and the image density fluctuation system based on the user information, but also changes them as necessary. It is configured. Specifically, as described above, the initial setting of the individual abnormality thresholds is unlikely to be a value that perfectly meets the user. Most of them will not be complete unless the individual abnormality thresholds are adjusted little by little based on actual experience. Therefore, it is desirable to gradually update the individual abnormality threshold corresponding to each individual abnormality according to the detection accuracy of each individual abnormality. Therefore, in the abnormality determination device, the individual abnormality threshold values for the paper jam system, the photoreceptor deterioration system, and the image density fluctuation system are set based on predetermined data input to the data input unit 504 by the user. The threshold setting unit 507 is configured so as to be changed. About this predetermined data, it is good to have a user input as follows, for example. That is, the threshold update program is stored in the information storage unit 503 in advance. In addition, the user is informed in advance that the threshold update program is started by performing a predetermined operation on the data input 504 by a manual or the like. When the threshold update program is activated by the user's operation, the data display unit 506 displays “How did you feel the abnormality notification timing? Press the key with the appropriate number. 1: Notification is too early. It is displayed as “too late”. Then, when the user presses the corresponding key, the following message is displayed: “What is the type of abnormality? Press the key with the appropriate number: 1: Paper jam, 2: Photoconductor degradation, 3: Image density fluctuation” I do. When the user presses the corresponding key, the individual abnormality threshold for the abnormality is changed based on the information that “notification is too early” or “notification is too late”. This information is the predetermined data described above. If “notification is too early”, the individual abnormality threshold value may be made larger than before. If “notification is too late”, the individual abnormality threshold value may be made smaller than before.

  Further, the threshold setting unit 507 is configured to change the above-described total abnormality threshold according to the change rate of the Mahalanobis distance D, which is a calculation result of the general abnormality. The reason for this configuration is as follows. That is, FIG. 46 is a graph showing an example of the relationship between the Mahalanobis distance D and the elapsed time for the total abnormality in the copier, with an extension line that makes it easy to understand the change in the Mahalanobis distance D. In the figure, the bar graph in the period from the time point 12t to the time point 24t is a substantially straight upward diagonal line, indicating that the rate of change of the Mahalanobis distance D per unit time is substantially the same. Yes. However, after the time point 24t, the rate of change per unit time starts to increase every hour, so that the line graph is obtained. The dotted line a in the figure indicates the Mahalanobis distance D when the rate of change from the time point 24t to the time point 28t is the same as from the time point 20t to the time point 24t, but the actual graph increases at a steeper angle than this. You can see that The same applies from time 28t to time 32t and from time 32t to time 36t. In the example shown in the figure, as in FIG. 42 described above, a general abnormality cannot be detected at the time point 32t where “Mahalanobis distance D <abnormality detection threshold”, and before the general abnormality is detected at a subsequent time point 36t. May break down. Therefore, the threshold value setting unit 507 of the abnormality determination apparatus changes the abnormality detection threshold value so as to be smaller than before when the change rate continuously increases in two consecutive periods. . Then, since the abnormality detection threshold value used at the time point 32t is a value after a small change, a general abnormality is detected at the time point 32t. And this detection can suppress the situation where it becomes impossible to predict the occurrence of the general abnormality due to the rapid increase in the Mahalanobis distance D.

  Instead of changing the overall abnormality threshold according to the rate of change of the Mahalanobis distance D, a general abnormality occurs when the Mahalanobis distance D approaches the overall abnormality threshold to some extent, as in the abnormality determination device according to the third embodiment. The frequency of determination of the presence or absence of may be increased. In the abnormality determination device, the operation display unit 3 of the copying machine shown in FIG. 34 may be used as the data input unit 504 and the data display unit 506 of the abnormality determination device shown in FIG. Also in the abnormality determination device, the determination result is output to the data display unit 506 as in the abnormality determination device according to the third embodiment. FIG. 47 shows an example of an image output to the data display unit 506 in accordance with detection of abnormality in the photoreceptor deterioration system. Also in this abnormality determination device, the same function limiting means as that in the abnormality determination device according to the third embodiment is provided.

  As described above, in the abnormality determination device according to the first embodiment, the modification device thereof, or each example, the information storage unit 503 serving as information storage means has a plurality of normal set data groups having different values as normal index information. Of the plurality of normal set data groups used for determining the presence / absence of an abnormality in the copying machine to be tested is stored at a predetermined timing. It is something to switch with. In such a configuration, as described above, it is possible to avoid erroneous determination due to the normal value of the information acquired by the information acquisition unit 501 being different depending on the content of specific information such as operation mode setting.

  In the printer according to the second embodiment, a plurality of inverse matrices A having different contents are obtained on the basis of a plurality of acquisition results for various types of information including a plurality of types of information acquired by a plurality of information acquisition units. A CPU (900a) as a normal index information construction means to be constructed is provided. In such a configuration, for the reason described above, avoiding a decrease in determination accuracy due to a component error for each product in the printer, and avoiding an increase in cost due to a trial run for constructing each inverse matrix before shipping for each product. be able to.

  Further, in the printer and the modification apparatus according to the second embodiment, the inverse matrix A of the data group is used as each of the plurality of normal index information, and the control unit (900) serving as a determination unit is based on the inverse matrix A. The Mahalanobis distance D is calculated and used for abnormality determination. In such a configuration, unlike a conventional image forming apparatus that determines abnormality by simply comparing standard data and acquired data, it is possible to predict the occurrence of a failure whose cause is not clearly specified using the MST method.

  Moreover, in Example 1 and Example 2 of the deformation | transformation apparatus which concerns on 2nd Embodiment, what has the structure of a modification apparatus is used as an abnormality determination apparatus. And in the printer which concerns on deformation | transformation apparatus Example 1, the temporary inverse matrix which is several temporary normal parameter | index information from which the content differs mutually is memorize | stored in ROM (900c) which is a memory | storage means. Further, when at least one of a plurality of inverse matrices A cannot be constructed due to failure to satisfy predetermined conditions within a predetermined period, a process for compensating for them with a provisional inverse matrix The control unit (900), which is normal index information construction means, is configured to perform the above. In such a configuration, it is possible to avoid the deterioration of the abnormality determination accuracy due to the fact that the predetermined condition is not satisfied at the shipping destination for the reason described above.

  Further, the printer according to Example 2 of the deformation apparatus according to the second embodiment includes an operation display unit (808) as data receiving means for receiving data from the outside. Furthermore, if at least one of the plurality of inverse matrices A cannot be constructed because the predetermined condition is not satisfied within the predetermined period at the shipping destination, the data receiving means The control unit (900), which is normal index information construction means, is configured so as to perform the process of filling with the inverse matrix A accepted by the above. Even in such a configuration, it is possible to avoid the deterioration of the abnormality determination accuracy due to the fact that the predetermined condition is not satisfied at the shipping destination for the reason described above.

  Further, in the printer according to the second embodiment and the modified example thereof, at least one of the information acquisition means uses a device that acquires temperature information, humidity information, or an operation mode setting value, and a plurality of inverse matrices. A is configured to use different contents depending on temperature, humidity, or operation mode set value. In such a configuration, it is possible to avoid erroneous determination due to the normal value of the acquired information being different depending on the temperature, humidity, or operation mode setting value as the specific information.

  As described above, in the abnormality determination device according to the third embodiment, at least the individual abnormality threshold values for the paper jamming system, the photoreceptor deterioration system, and the image density fluctuation system that are individually used in the individual abnormality determination step. If one is initially set according to the environment information where the copier to be tested is installed, that is, if the environment information is reflected in the individual abnormality threshold value, the following becomes possible. That is, for the reason described above, it is possible to suppress inappropriate occurrence notification of abnormality occurrence due to a change in the degree of abnormality detection regardless of individual differences depending on the environment.

  Further, in the abnormality determination device according to the third embodiment, at least one of the three individual abnormality threshold values is obtained from the frequency information of the maintenance inspection operator's visit to the installation location of the copier or from the maintenance inspection service providing organization. If the initial setting is made in accordance with the distance information to the installation location, the following can be performed. In other words, it is possible to suppress a situation in which an abnormality detection timing is delayed from an appropriate timing due to a time lag until a service person actually visits the user from a repair request from the user to the service organization. Can do.

  In the abnormality determination apparatus according to the third embodiment, the above three individual abnormality threshold values used for determining whether there is an abnormality in the new copying machine when the same copying machine is replaced with an old one are used as the old copying machine. If each of the three individual abnormality threshold values is initially set to the same value, the following becomes possible. That is, for the reason described above, it is possible to avoid deterioration of abnormality detection accuracy due to initial setting of a value that generally reflects user information as the individual abnormality threshold for the new copier.

  Further, in the abnormality determination device according to the third embodiment, if at least one of the above-described three individual abnormality thresholds is updated according to the repair request history information of the user based on the occurrence of the abnormality, the following is possible. become. That is, by performing such an update, each individual abnormality threshold value can be gradually changed from the initial setting to a value according to the user's request.

  In addition, based on the normal set data group stored in the information storage unit 503 as the information storage unit and the acquired information by the information acquisition unit 501 as the information acquisition unit in the calculation step of the step of determining the overall abnormality, In the abnormality determination device according to the third embodiment or the fourth embodiment for obtaining the Mahalanobis distance as the calculation result, if the normal data group is updated based on the presence / absence of the comprehensive abnormality determination and the inspection result of the copier The following becomes possible. That is, for the reason described above, it is possible to avoid erroneous determination due to the fact that the abnormal group information is included in the normal group data group.

  In addition, in the abnormality determination device according to the third embodiment, if a data input unit 504 serving as a data input unit that accepts data input of each individual abnormality threshold value sent via a communication line is used, it can be remotely located. It is possible to make a user input data of the threshold value for individual abnormality to the abnormality determination device.

  In addition, in the abnormality determination device according to the fourth embodiment, by providing the threshold value setting unit 507 serving as a threshold value setting unit, it is possible for the user to input user information instead of the individual abnormality threshold value itself. become. Thus, it is possible to avoid a situation in which the user performs complicated calculations to determine the individual abnormality thresholds.

  In the abnormality determination device according to the fourth embodiment, the threshold setting unit 507 performs a predetermined question to the user, and the user information based on the answer data input to the data input unit 504 by the user. To get to. In this way, the user can naturally extract the information from the user and initialize it to a value suitable for the user without making the user need to adjust the accuracy of abnormality determination. Can do.

  In the abnormality determination device according to the fourth embodiment, three individual abnormality threshold values for paper jamming system, photoreceptor deterioration system, and image density adjustment respectively used for determination of the presence or absence of each individual abnormality are set for the user. The threshold value setting unit 507 is configured to change based on predetermined data input to the data input unit 504. In such a configuration, for the reasons described above, these three individual abnormality threshold values can be adjusted little by little based on the actual experience of the user, and gradually approached to a value perfectly suited to the user.

  Further, in the abnormality determination device according to the fourth embodiment, the total abnormality threshold value used for determining the presence or absence of the general abnormality is changed according to the change rate of the Mahalanobis distance D that is a calculation result of the general abnormality. The threshold setting unit 507 is configured. With this configuration, it is possible to suppress a situation in which the occurrence of a general abnormality cannot be predicted due to the rapid increase in the increase rate of the Mahalanobis distance D for the reason described above.

  Further, in the abnormality determination device according to the third embodiment or the fourth embodiment, the Mahalanobis distance D is obtained based on the normal group data group stored in the information storage unit 503 and the acquisition result by the information acquisition unit 501, The abnormality determination unit 502 serving as a determination unit is configured to determine the presence / absence of a general abnormality based on the comparison result between and the general abnormality threshold. By such determination, it is possible to easily detect a general abnormality including a plurality of individual abnormalities.

  In the abnormality determination device according to the third embodiment, the abnormality determination unit 502 is configured to change the determination frequency of the presence or absence of the general abnormality according to the Mahalanobis distance D that is a calculation result of the general abnormality. ing. With such a configuration, as described above, it is possible to suppress a situation in which the occurrence of a general abnormality cannot be predicted due to the rapid increase in the Mahalanobis distance D.

  In addition, in the abnormality determination device according to the third embodiment or the fourth embodiment, the preparation for repair is completed by providing function restriction means for restricting the function of the copying machine according to the type of each individual abnormality that has occurred. During this period, the copier can be operated and printed out.

1 control unit (part of information acquisition means)
2 Various sensors (part of information acquisition means)
3 Operation display section (part of information acquisition means)
600 Copying machine (subject to be examined)
500 Abnormality determination device 501 Information acquisition unit (information acquisition means)
502 Abnormality determination unit (determination means)
503 Information storage unit (information storage means)
504 Data input means (data input means)
507 Threshold setting unit (threshold setting means)
801 Y, M, C, KY, M, C, K process unit (visible image forming means)
803a Paper feed roller (recording member conveying means)
804 Registration roller pair (recording member conveying means)
805 Paper transport unit (recording material transport means)
806 Fixing unit (recording member conveying means)
807 In-machine temperature sensor (information acquisition means)
808 operation display section (information acquisition means, data reception means)
809Y, M, C, KY Optical sensors for M, C, K (information acquisition means)
816Y, M, C, KY Current detection sensor for M, C, K (information acquisition means)
855 Optical Sensor for Belt (Information Acquisition Unit)
900 Control unit (information acquisition means, determination means, normal index information acquisition means)
900b RAM (storage means)
900c ROM (storage means)

Japanese Patent Laid-Open No. 5-281809 JP-A-8-30152

Publication Committee Chairman Genichi Taguchi, “Technology Development in MT System” published by Japanese Standards Association

Claims (39)

In the abnormality determination method for determining the presence or absence of abnormality of the subject to be examined based on the normal indicator information that is an indicator of the normal state of the subject to be examined and the information acquired by the information obtaining unit that obtains each of a plurality of types of information.
As the normal index information, a plurality of items having different values are prepared, and among the plurality of normal index information, information used for determining the presence or absence of abnormality in the subject to be tested is switched at a predetermined timing. An abnormality determination method characterized by the above. In the abnormality determination method of claim 1,
An abnormality determination method, characterized in that, as the normal index information, a normal data group, which is a collection of normal data acquired from the subject to be examined in a normal state, is switched at the predetermined timing. In the abnormality determination method of claim 1,
An abnormality determination method, characterized in that, as the normal index information, a threshold for comparison with a predetermined calculation result is switched at the predetermined timing. Information storage means for storing normal index information which is an index of the normal state of the test object;
Information acquisition means for acquiring a plurality of types of information,
An abnormality determination apparatus comprising: determination means for determining presence or absence of abnormality of the subject to be tested based on the normal index information stored in the information storage means and information acquired by the information acquisition means;
The information storage means stores a plurality of items having different values as the normal index information, and the determination means includes an abnormality in the test subject among the plurality of normal index information. What is used for determining the presence or absence of an abnormality is switched at a predetermined timing. In the abnormality determination device according to claim 4,
As the normal index information, the determination means is configured to switch a normal data group, which is a collection of normal data acquired from the test subject in a normal state, at the predetermined timing. Abnormality judgment device. In the abnormality determination device according to claim 4,
An abnormality determination device, wherein the determination means is configured to switch a threshold for comparison with a predetermined calculation result as the normal index information at the predetermined timing. In the abnormality determination device according to claim 4, 5 or 6,
As the information storage means, using a threshold value for comparison with a predetermined calculation result and a normal data group that is a collection of normal data acquired from the test subject in a normal state,
Further, the Mahalanobis distance is calculated based on the normal data group and the information acquired by the information acquisition means, and the presence or absence of abnormality of the subject to be examined is determined based on a comparison between the calculation result and the threshold value. Furthermore, the abnormality determination apparatus characterized by comprising the determination means. In the abnormality determination device according to any one of claims 4 to 7,
An abnormality determination device, wherein the determination means is configured to switch the normal index information in accordance with an installation environment of the subject to be examined. In the abnormality determination device according to claim 8,
An abnormality determination device comprising: an environment detection unit that detects humidity, temperature, or atmospheric pressure, and the determination unit configured to switch the normal index information according to a detection result of the environment detection unit. In the abnormality determination device according to any one of claims 4 to 7,
The information acquisition unit is configured to acquire the operation mode information of the subject to be examined as one of the plurality of types of information, and the normal index information is set according to the acquisition result of the operation mode information by the information acquisition unit. An abnormality determination device characterized in that the determination means is configured to be switched. In the abnormality determination device according to any one of claims 4 to 7,
The information acquisition unit is configured to acquire user operation history information for the subject to be examined as one of the plurality of types of information, and the normal index information is set according to the operation history information by the information acquisition unit. An abnormality determination device characterized in that the determination means is configured to be switched. In the abnormality determination device according to any one of claims 4 to 7,
The information acquisition unit is configured to acquire environment history information at the installation location of the subject to be examined as one of the plurality of types of information, and the normal index information is set according to the environment history information by the information acquisition unit. An abnormality determination device characterized in that the determination means is configured to be switched. An information storage step for storing normal index information, which is an indicator of the normal state of the subject to be examined, in the information storage unit, an information acquisition step for acquiring information on things by the information acquisition unit, normal index information in the storage unit, and An abnormality determination method for performing a determination step of determining an abnormality of a test object based on an acquisition result by the information acquisition means,
As the information acquisition means, using a plurality of different types of information that acquire different types of information,
As the normal index information, according to the content of the specific information that is at least any one of a plurality of types of information individually acquired by the plurality of information acquisition means, a plurality of items having different contents are used.
In addition, in the determination step, an abnormality determination characterized in that among the plurality of normal index information, the information corresponding to the acquisition result of the specific information by the information acquisition unit is specified and used for the determination of abnormality. Method. Information storage means for storing normal index information that is an indicator of the normal state of the subject to be examined, information acquisition means for acquiring information about things, normal index information in the storage means, and acquisition results by the information acquisition means An abnormality determination device comprising a determination means for determining abnormality of a subject to be tested based on:
As said information acquisition means, it comprises a plurality of items that acquire different types of information from each other,
As the normal index information, according to the content of the specific information that is at least any one of a plurality of types of information individually acquired by the plurality of information acquisition means, a plurality of items having different contents are used.
In addition, the determination unit is characterized in that among the plurality of normal index information, the one corresponding to the acquisition result of the specific information by the information acquisition unit is specified and used for the determination of abnormality. Abnormality judgment device. In the abnormality determination device according to claim 14,
An abnormality determination apparatus, comprising: normal index information construction means for constructing a plurality of normal index information having different contents based on a plurality of acquisition results of various types of information including the plurality of types of information. The abnormality determination device according to claim 14 or 15,
An abnormality determination characterized in that an inverse matrix of a data group is used as each of the plurality of normal index information, and the determination means calculates Mahalanobis distance based on the inverse matrix and uses it to determine an abnormality. apparatus. The abnormality determination device according to claim 16,
Based on a plurality of acquisition results for various types of information consisting of a plurality of types of information, a normal index information construction means for constructing a plurality of normal index information having different contents from each other is provided.
As the information storage means, a plurality of temporary normal index information having different contents are stored,
In addition, when at least one of the plurality of normal index information cannot be constructed because the predetermined condition is not satisfied within a predetermined period, the temporary normal index information is used as the temporary normal index information. An abnormality determination device characterized in that the normal index construction means is configured to perform a compensation process. The abnormality determination device according to claim 16,
Normal index information construction means for constructing a plurality of normal index information different in content from each other based on a plurality of acquisition results for various types of information composed of the plurality of types of information;
A data receiving means for receiving data from outside,
In addition, when at least one of the plurality of normal index information cannot be constructed because a predetermined condition is not satisfied within a predetermined period, it is accepted by the data receiving means. An abnormality determination device characterized in that the normal index information construction means is configured to perform a process of compensating with the normal index information. A recording medium conveying means for conveying the recording medium, a visible image forming means for forming a visible image on the recording medium conveyed by the recording medium conveying means, and an abnormality determination device for judging abnormality of the whole apparatus or a part thereof. In an image forming apparatus comprising:
An image forming apparatus according to any one of claims 14 to 18, wherein the abnormality determination means is any one of claims 14 to 18. The image forming apparatus according to claim 19, comprising:
As one of the plurality of information acquisition means, one that acquires temperature information, humidity information, or an operation mode set value is used, and as the plurality of normal index information, contents are mutually included according to the temperature, humidity, or operation mode set value. An image forming apparatus characterized by using different ones. An information acquisition step of acquiring information on an object by the information acquisition unit, a determination step of determining the presence or absence of abnormality of the test object based on the acquisition information by the information acquisition unit, and in the determination step, A calculation step for performing a predetermined calculation based on the information acquired by the information acquisition means, and a comparison step for comparing the calculation result in the calculation step with a predetermined threshold value are performed. In the abnormality determination method for determining the presence or absence of abnormality when the threshold value is reached, when the threshold value is exceeded or when the threshold value is exceeded,
Comprehensive abnormality determination step of determining the presence or absence of a general abnormality that can include a plurality of types of abnormality by comparing the calculation result based on a plurality of types of the acquired information and a threshold for general abnormality
Only when it is determined that the comprehensive abnormality is present in the comprehensive abnormality determination step, the presence / absence of individual abnormality that is each of a plurality of types of abnormality that can be included in the comprehensive abnormality is acquired for each individual abnormality. An individual abnormality determination step for sequentially determining the calculation result based on at least one of the information and the individual abnormality threshold is performed in the determination step, and the total abnormality threshold and each individual abnormality are determined. An abnormality determination method, comprising: initializing at least one of a plurality of individual abnormality threshold values individually corresponding to information on a user who uses the test object. The abnormality determination method according to claim 21, wherein
An abnormality determination method comprising: initializing each of the plurality of individual abnormality thresholds according to the user information. In the abnormality determination method according to claim 21 or 22,
An abnormality determination method comprising: initializing at least one of the overall abnormality threshold and the plurality of individual abnormality thresholds according to environmental information in which the test target is installed. The abnormality determination method according to claim 21, 22 or 23,
At least one of the total abnormality threshold and the plurality of individual abnormality thresholds is set as information on the frequency of visits of maintenance inspection workers to the installation location of the subject to be inspected, or from the maintenance inspection service providing organization to the installation location. An abnormality determination method, characterized by initial setting according to distance information. The abnormality determination method according to any one of claims 21 to 24,
When the test object is replaced with a new one, the total abnormality threshold value and the plurality of individual abnormality threshold values used in the determination of the presence or absence of abnormality of the new test object are respectively set as the presence or absence of abnormality of the old test object. An abnormality determination method characterized by initial setting to the same value as that used in each individual abnormality determination step in determination. The abnormality determination method according to any one of claims 21 to 25,
An abnormality determination method, wherein at least one of the plurality of individual abnormality thresholds is updated according to user repair request history information based on occurrence of abnormality. The abnormality determination method according to any one of claims 21 to 26,
Based on the normal data group stored in the information storage unit in the calculation step of the comprehensive abnormality determination step and the acquired information by the information acquisition unit, the Mahalanobis distance is obtained as the calculation result, and An abnormality determination method, wherein the normal data group is updated based on the presence / absence of the general abnormality in the comprehensive abnormality determination step and the inspection result of the test object. An information acquisition unit that acquires information on a thing, and a predetermined calculation is performed based on the acquired information by the information acquisition unit, and the calculation result reaches a predetermined threshold, exceeds the threshold, or the threshold In an abnormality determination device comprising determination means for determining the presence or absence of abnormality of the test object when
Whether or not there is a general abnormality that can include multiple types of abnormalities is determined by comparing the calculation results based on the multiple types of acquired information with a threshold for general abnormalities, and only when it is determined that the general abnormalities are present The presence or absence of individual abnormalities that are each of a plurality of types of abnormalities that can be included in the total abnormalities, for each individual abnormality, the calculation result based on at least one of the plurality of types of acquired information and the threshold for individual abnormality The determination means is configured to sequentially determine by comparison, and at least one data input of the overall abnormality threshold and a plurality of individual abnormality thresholds individually corresponding to each individual abnormality is received and stored. An abnormality determination device characterized by comprising data input means for storing in the means. The abnormality determination device according to claim 28,
An abnormality determination device characterized in that the data input means is configured to accept each of the plurality of individual abnormality threshold values. The abnormality determination device according to claim 28 or 29,
An abnormality determination apparatus using the data input means that receives data input of the overall abnormality threshold value or the individual abnormality threshold value sent via a communication line. An information acquisition unit that acquires information on a thing, and a predetermined calculation is performed based on the acquired information by the information acquisition unit, and the calculation result reaches a predetermined threshold, exceeds the threshold, or the threshold In an abnormality determination device comprising determination means for determining the presence or absence of abnormality of the test object when
Whether or not there is a general abnormality that can include multiple types of abnormalities is determined by comparing the calculation results based on the multiple types of acquired information with a threshold for general abnormalities, and only when it is determined that the general abnormalities are present The presence or absence of individual abnormalities that are each of a plurality of types of abnormalities that can be included in the total abnormalities, for each individual abnormality, the calculation result based on at least one of the plurality of types of acquired information and the threshold for individual abnormality The determination means is configured to sequentially determine by comparison, and threshold setting means for setting at least one of the overall abnormality threshold and a plurality of individual abnormality thresholds individually corresponding to each individual abnormality An abnormality determination device characterized by being provided. The abnormality determination device according to claim 31,
An abnormality determination device, wherein the threshold setting means is configured to set each of the plurality of individual abnormality thresholds. In the abnormality determination device according to claim 31 or 32,
The threshold setting means performs a predetermined question on the user, and acquires the user information based on answer data to the question input by the user to the data input means. An abnormality determination device. The abnormality determination device according to claim 33,
To change at least one of the overall abnormality threshold and a plurality of individual abnormality thresholds individually corresponding to each individual abnormality based on predetermined data input to the data input means by the user, An abnormality determination device comprising the threshold value setting means. The abnormality determination device according to any one of claims 31 to 34,
An abnormality determination device, characterized in that the threshold setting means is configured to change the overall abnormality threshold according to a change rate of the calculation result for the overall abnormality. 36. The abnormality determination device according to any one of claims 31 to 35, wherein:
Based on the normal data group stored in the information storage means and the acquisition result by the information acquisition means, the Mahalanobis distance as the calculation result is obtained, and based on the comparison result between the Mahalanobis distance and the total abnormality threshold value. An abnormality determination device characterized in that the determination means is configured to determine the presence or absence of the general abnormality. The abnormality determination device according to any one of claims 31 to 36,
An abnormality determination device, wherein the determination means is configured to change the determination frequency of the presence or absence of the general abnormality according to the calculation result for the general abnormality. The abnormality determination device according to any one of claims 31 to 36,
An abnormality determination apparatus, comprising: function restriction means for restricting the function of the object to be examined according to the type of any individual abnormality. In an image forming apparatus comprising: a visible image forming unit that forms a visible image on a recording medium; and an abnormality determination unit that determines abnormality of the device.
An abnormality determination device using the abnormality determination device according to any one of claims 4 to 12, any one of claims 14 to 18, or any one of claims 28 to 38 as the abnormality determination means.

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