JP2005266380A - State judging apparatus, image forming apparatus, external information processor, image quality detecting apparatus and state judging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine calculation parameters in optional timing after various kinds of pieces of information are continuously obtained in a market. <P>SOLUTION: Various pieces of input information, such as sensing information, control parameter information, and input image information, are obtained (S501), and the state of the image forming apparatus when the these pieces of data are obtained is judged (S502). The judgement is manually made by an operator or automatically made by a sensor. When the machine is judged to be normal as the result of the above judgment (S502-Y), the input data information is stored as normal data (S503), and when the machine is judged to be abnormal, the machine is repaired (S504) and information is collected again. When the state of the machine is normal, the pieces of normal data are gradually accumulated. When the number of pieces of data exceeds a given number or a data collection period elapses (S505-Y), the calculation parameters are derived (S506) and the calculation parameters are thus determined. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a state determination device that predicts in advance the occurrence of an abnormal state from information related to an operation, an image forming device that includes the state determination device, forms an image on a recording medium such as paper, and a plurality of the image forming devices are connected. The present invention relates to an external information processing apparatus, an image quality detection apparatus detachably provided in the image forming apparatus, and a state processing method.

As this type of technology, for example, the inventions disclosed in Patent Documents 1-4 are known.
For example, Patent Document 1 includes a plurality of driving elements and a single driving source that drives these driving elements, and a copying machine that performs a copying operation by driving each driving element in a predetermined order. First storage means for storing, for each driving element, a reference value of the driving load of the driving source when each of the driving elements is driven alternatively, and selecting each driving element before executing the copying operation. A unit for driving the driving source; a unit for detecting a driving load of the driving source when the driving element is driven by the unit; and a driving of the driving source when driving the driving element detected by the unit A means for comparing a load with a reference value stored in the first storage means; a means for diagnosing the quality of the operating state of each drive element based on the comparison result of the means; and the copying operation At different timings Second storage means for storing a reference value of the drive load of the drive source at each timing, means for detecting the drive load of the drive source at each timing during execution of the copying operation, and detected by the means Means for comparing the drive load of the drive source at each timing with the reference value stored in the second storage means, and means for diagnosing the quality of the operating state of each drive element based on the comparison result of the means A copying machine characterized by comprising: is disclosed.

  Patent Document 2 includes a charging device that charges the image carrier, an exposure unit that exposes the image carrier to form an electrostatic latent image, and a developing device that develops the electrostatic latent image. The image forming apparatus includes: a potential detection unit that detects a potential of the electrostatic latent image; and a life prediction unit that determines a remaining life of the image carrier based on an output of the potential detection unit. An image forming apparatus is disclosed.

  In Patent Document 3, an abnormality detection device for an electrostatic recording type image forming apparatus that forms a toner image on a photosensitive drum and transfers the toner image onto a sheet by a transfer roller before the image recording is started. Check pattern forming means for forming a check pattern by a toner image on a photosensitive drum; and check pattern detection means for detecting the check pattern by the toner image by irradiating light to the check pattern by the toner image and obtaining reflected light thereof; An abnormality determination means for determining whether the toner image is abnormal by comparing the output of the check pattern detection means and the check pattern to be formed by the check pattern forming means; and when the abnormality determination means determines that the abnormality is abnormal And a stop signal output means for outputting a signal for stopping the normal recording operation. Anomaly detector of the electrostatic recording type image forming apparatus is disclosed that.

  Further, in Patent Document 4, in an image quality detection apparatus that detects image quality based on a predetermined image pattern formed on an image carrier, the image pattern and the image carrier on which the pattern image is formed are disclosed. A light emitting means for irradiating spot light; a scanning means for scanning the image pattern with the spot light; and a light quantity reflected or transmitted through the image pattern and the image carrier in the scanning process by the scanning means. There is disclosed an image quality detecting device comprising a light receiving means, wherein a diameter dimension in the scanning direction of the spot light is set to be equal to or less than a reciprocal of a spatial frequency that maximizes human visual sensitivity.

Patent application 0302950 “Abnormality Prediction Method, State Determination Device, and Image Forming Device” (Ricoh)
An abnormality occurrence prediction method for predicting occurrence of an abnormal state of an image forming apparatus, the step of acquiring a plurality of types of information related to the state of the image forming apparatus, and a step of calculating an index value from the plurality of types of information And a step of determining a subsequent change in the state of the image forming apparatus based on the time change data of the index value.
JP 05-281809 A Japanese Patent Laid-Open No. 05-1000051 Japanese Patent Laid-Open No. 08-137344 Patent application 0204742

  Since the image forming apparatus has consumables such as ink or toner and a photoconductor, and also has various driving parts, continuous maintenance and failure repair are required. Once the machine goes down due to a failure or part life, it will not be possible to print at all until repairs or parts replacement. To avoid this, efforts have been made to detect failures and component life in advance.

  In the invention described in Patent Document 1, the load state of the drive source is monitored to diagnose whether the operation state of the drive component is good, that is, the possibility of failure. In the invention described in Patent Document 2, the lifetime of the photoconductor is predicted by monitoring the potential state of the photoconductor. The purpose of these inventions is to predict failure / lifetime of limited locations in the system that monitors the information.

  This is important, but with this method, it is possible to determine the abnormality of the part being monitored, but it is impossible to predict a device trouble caused by multiple factors. In particular, an electrophotographic image forming apparatus balances the entire apparatus by controlling process parameters in conjunction with process control as a whole, so whether or not it is abnormal just by monitoring a single piece of information. There is a problem that cannot be judged.

  In the invention described in Patent Document 3, the state of the image forming apparatus is determined by detecting whether or not the image is normal by detecting a check pattern on the photoreceptor. With this method, there is an advantage that abnormality on the upstream side of the image forming operation including the photosensitive member can be determined in a complex manner, but abnormality on the downstream side cannot be determined at all.

  On the other hand, a plurality of types of information representing the state of the image forming apparatus are acquired, one index value is calculated from the plurality of types of information, and a state change of the image forming apparatus is determined based on time change data of the index value. It is also possible. With this method, if the information on each part of the apparatus is acquired as a plurality of types of information, the overall operation state of the apparatus can always be monitored. Further, when a plurality of types of information change in conjunction with each other, it is determined that the information is normal if the information is linked with a normal balance, and is abnormal if the information is not synchronized. An important point in this state determination method is that “a calculation parameter for calculating an index value is obtained using only a plurality of types of data collected when the image forming apparatus is in a normal state”. This calculation parameter is a standard representing the normal state, and the index value calculated using instantaneous data over time (or average data for a certain period) after the calculation parameter is determined is the distance between the image forming apparatus and the normal state. There is a characteristic that it grows larger as it falls. Thereby, it can be determined that somewhere in the image forming apparatus is approaching an abnormality.

  At that time, the problem is "when will the calculation parameters be determined?" In such a determination, it is considered that a normal data group acquired in, for example, a factory environment before shipment will be insufficient. This is because the actual usage environment in the market seems to be different from the factory environment, and calculation parameters that match the actual usage conditions of the customer are required only by incorporating many normal data groups in the actual usage environment. It is. Indispensable at this time is an apparatus or a system that determines whether or not the state of the image forming apparatus is normal. Originally, the calculated parameter is defined to determine the state of the apparatus, but it is necessary to guarantee the normal state of the apparatus by another means until the calculated parameter is determined.

  The present invention has been made in view of such a background, and the purpose thereof is to continue to acquire multiple types of information over time in the market, and then determine calculation parameters at an arbitrary timing and approach elements that are abnormal Is to be able to determine.

  In order to achieve the object, the first means includes an information acquisition means for acquiring a plurality of types of information related to the operation of the target device, and an index value calculation means for calculating a single index value from the plurality of acquired information. Determination means for determining the state of the image forming apparatus based on the calculated index value, and calculating parameters for calculating the index value based on the plurality of types of information acquired during normal operation of the target device. In the state determination device to be obtained, the information acquisition unit continuously collects a plurality of types of information that is operating normally for the calculation parameter derivation in a state in which the target device is shipped and operated in the market. And

  A second means is characterized in that, in the first means, the target device is an image forming apparatus.

  According to a third means, in the image forming apparatus for forming a visible image on the recording medium based on the input image information, an information acquiring means for acquiring a plurality of types of information relating to the operation of the image forming apparatus; Index value calculating means for calculating a single index value from the information of the information, and determining means for determining the state of the image forming apparatus based on the calculated index value, the image forming apparatus being shipped to the market and operating In order to calculate the index value based on the plurality of types of information acquired during normal operation of the image forming apparatus. And a state determination device for obtaining a calculation parameter of

  The fourth means is characterized in that in the third means, there is provided image quality detection means for detecting the image quality of the output image in order to determine whether or not the image forming apparatus is operating normally in the market.

  The fifth means includes storage means for preliminarily storing the user's image quality allowance information as a threshold value as a reference for determining whether or not the calculated image quality is normal in the fourth means. It is characterized by being.

  The sixth means is that in the third to fifth means, the information acquisition means continues to acquire a plurality of types of information for deriving a calculation parameter with reference to a threshold value of image quality allowance information determined for each user. It is characterized by.

  The seventh means is characterized in that, in the fourth to sixth means, the image quality detecting means is detachably provided separately from the main body of the image forming apparatus.

  According to an eighth means, in the fourth to seventh means, the plurality of types of information acquired by the information acquisition means and the image quality detection means detected by the image quality detection means and the calculated image quality information are stored in an external information processing apparatus. A communication means for transmitting is provided.

  According to a ninth means, in the eighth means, the external information processing apparatus uses the two types of information collected from a plurality of image forming apparatuses through the communication means to the external information processing apparatus as a reference for an arbitrary image quality allowable value. The calculation parameters as an image forming apparatus aggregate are derived as follows.

  The tenth means is an image quality detection apparatus that is detachably provided in the image forming apparatus and detects the image quality of the image by introducing the image-formed paper ejected from the image forming apparatus. A paper discharge tray for stacking paper sheets, a stacking unit for stacking papers whose image quality has been detected, a switching means for switching the paper transport direction to the paper discharge tray or the stacking unit, and introduced to the stacking unit side. And image quality detecting means for detecting the image quality of the image formed on the sheet.

  The eleventh means includes an information acquisition means for acquiring a plurality of types of information related to the operation of the target device, an index value calculation means for calculating a single index value from the acquired plurality of information, and a calculated index value. A state determination method for determining a calculation parameter for calculating the index value based on the plurality of types of information acquired during normal operation of the target device. In order to determine whether or not the image forming apparatus is operating normally, an image quality detecting means for detecting the image quality of the output image is detachably provided separately from the image forming apparatus main body, and a preset period has elapsed. The image quality detecting means is sometimes removed from the image forming apparatus.

  A twelfth means is characterized in that, in the eleventh means, the period is after the calculation parameter is determined.

  A thirteenth means is characterized in that, in the eleventh or twelfth means, the period is determined by the number of output sheets.

  A fourteenth means is characterized in that, in the eleventh or twelfth means, the period is determined by a rotational speed integrated value of the photosensitive member.

  A fifteenth means is characterized in that, in the eleventh or twelfth means, the period is determined by the number of operating days of the image forming apparatus.

  A sixteenth means is characterized in that, in the eleventh or twelfth means, the period is a period in which at least four seasons have passed.

  A seventeenth means is characterized in that, in the eleventh or thirteenth means, the period is a period until the number of data used for the calculation parameter reaches an arbitrary value.

  According to the present invention, it is determined whether the operation of the image forming apparatus is normal by detecting the image quality on the final output paper by the image quality sensor. Therefore, after continuously acquiring multiple types of information over time in the market, Calculation parameters can be determined at an arbitrary timing. This makes it possible to determine an element that is approaching an abnormality.

  When acquiring a plurality of types of information representing the state of the image forming apparatus, calculating one index value from the plurality of types of information, and determining a state change of the image forming apparatus based on time change data of the index value, If information on various parts of the device is acquired as a plurality of types of information, the overall operating state of the device can be monitored at all times. Further, when a plurality of types of information change in conjunction with each other, it is determined that the information is normal if the information is linked with a normal balance, and is abnormal if the information is not synchronized. An important point in this state determination method is that “a calculation parameter for calculating an index value is obtained using only a plurality of types of data collected when the image forming apparatus is in a normal state”. This calculation parameter is a standard representing the normal state, and the index value calculated using instantaneous data over time (or average data for a certain period) after the calculation parameter is determined is the distance between the image forming apparatus and the normal state. There is a characteristic that it grows larger as it falls. Thereby, it can be determined that somewhere in the image forming apparatus is approaching an abnormality.

  Thus, the question is “When will the calculated parameters be finalized?”. For example, the normal data group acquired in the factory environment before shipment is considered to be insufficient. This is because the actual use environment in the market is different from the factory environment, and calculation parameters adapted to the actual use state of the customer are required only by incorporating many normal data groups in the actual use environment. Indispensable at this time is an apparatus or a system that determines whether or not the state of the image forming apparatus is normal. Originally, the calculated parameter is defined to determine the state of the apparatus, but it is necessary to guarantee the normal state of the apparatus by another means until the calculated parameter is determined. Therefore, in the present invention, this state determination is performed based on the image quality detected by the image quality sensor. That is, by detecting the image quality on the final output paper by the image quality sensor, it is determined whether or not the operation of the image forming apparatus is normal. As a result, it is possible to determine the calculation parameter at an arbitrary timing after continuously acquiring plural types of information with time in the market.

  Hereinafter, examples of the present invention will be described in accordance with the above-described purpose.

  FIG. 1 is a block diagram showing a basic configuration of an abnormality occurrence prediction system including a state determination device according to the present invention. The state determination device 1 includes an information acquisition unit 2 as an information acquisition unit, an index value calculation unit 3 as an index value calculation unit, and a determination unit 4 as a state change determination unit. The information acquisition unit 2 acquires a plurality of types of information related to the image forming operation of the image forming apparatus. The index value calculation unit 3 calculates a single index value based on a plurality of types of information acquired by the information acquisition unit 2. The determination unit 4 determines a subsequent change in the state of the image forming apparatus based on the time-change data of the index value calculated by the index value calculation unit 3. The index value time change data calculated by the index value calculation unit 3 and the determination result data determined by the determination unit 4 are used as control means for controlling each device in the image forming system 6 as image forming means. It can be used in the control unit 5 or output to a display means such as a display or an external device.

The information acquisition unit 2 acquires various types of information to be described later, and includes various sensors for detecting various types of sensing information, a control unit 5 and a communication interface for data transmission / reception with an image data processing unit (not shown). Has been. The information acquisition unit 2 transmits a data acquisition request to various sensors, the control unit 5 and the image data processing unit. And various sensing information data can be received from various sensors, control parameter information data can be received from the control unit 5, and input image information data can be received from the image data processing unit. , RAM, ROM, and I / O interface unit. The index value calculation unit 3 and the determination unit 4 may be provided separately from the control unit 5 as a device constituted by a dedicated LSI or the like, or may also be used as hardware resources such as a CPU constituting the control unit 5. It may be configured.

  Information acquired by the information acquisition unit 2 and input to the index value calculation unit is information such as sensing information (a), control parameter information (b), and input image information (c). The sensing information is information including data obtained by various sensors provided in or around the image forming apparatus. The sensing information includes the dimensions of each part of the apparatus, the speed of the moving body in the apparatus, time (timing), weight, current value, potential, vibration, sound, magnetic force, light quantity, temperature, humidity, and the like.

  The control parameter information is generally information stored as a result of device control. The control parameter information includes user operation history, power consumption, toner consumption, various image forming condition setting history, warning history, and the like.

  The input image information is obtained from information input to the image forming system 6 as image data. The input image information includes the 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, and document with borders. , Character type (size, font), etc.

  The state determination device includes an information acquisition unit, an index value calculation unit, and a determination unit. The information acquisition unit acquires a plurality of types of information as shown in the input information, and the index value calculation unit uses the information as a single item. The index value is calculated, and the determination unit determines whether or not the apparatus is normal based on the index value. If the apparatus is in an abnormal state, it is necessary to take corrective actions such as correction control of the image forming system or notification / display to the outside through the control unit. However, in the present invention, the operation after the control unit is not referred to, and the range up to the calculation of the index value and the state determination is only claimed. In this flow of “information acquisition → index value calculation → state determination”, information on normal data groups collected in advance is required for index value calculation. This normal data group information is used in the calculation of an index value in the form of a matrix. This matrix is referred to as a “calculation parameter” here, and the following description will proceed. This calculation parameter corresponds to the “reference space” in the MT method (Mahalanobis-Taguchi method). This calculation parameter derivation method is performed as follows.

  FIG. 2 is a flowchart showing the basic operation of the abnormality occurrence prediction system having the above configuration. The above-described plurality of types of information that are predicted to be related to the state of the image forming apparatus are input to the state determination device 1 of the abnormality occurrence prediction system (step 1-1). The plurality of types of information is acquired at a necessary timing by the information acquisition unit 2, and the index value calculation unit 3 calculates a single index value by a calculation method determined in advance based on the acquired information (step 1-2). The calculated index value temporal change data is used to determine whether an abnormality such as a failure of the image forming apparatus has occurred, or is output to a display or an external device (step 1-3).

  Here, prior to the calculation of the index value, it is necessary to determine a calculation method (calculation formula) of the index value. In this embodiment, a multidimensional space in which different coordinate axes are set for each of a plurality of pieces of input information is defined, and an index value is calculated as a distance in the multidimensional space. For this purpose, a plurality of sets of a plurality of pieces of information acquired in FIG. 1 are obtained while the image forming apparatus is operating normally.

  FIG. 3 is a flowchart showing a procedure for determining the index value calculation method (calculation formula).

  First, k sets of information that are considered to be related to the state of the image forming apparatus are acquired while operating the image forming apparatus (step 2-1). Information acquisition is as described above, and a specific example thereof will be described later.

Table 1 shows the data structure of the acquired information. K data is obtained under the first condition (for example, the first day or the first vehicle). These are y11, y12,..., Y1k. Similarly, data obtained under the following conditions (such as the second day or the second vehicle) are y21, y22,..., Y2k, etc., and n sets of data are obtained.

Next, for each type of information (j), the raw data (for example, yij) is normalized by the average value (yj) and the standard deviation (σj) using Expression (1) (step 2-2). Table 2 shows the result of normalizing the data shown in Table 1 using the equation shown in Equation 1.

Next, all the correlation coefficients rpq (= rqp) between two sets of data among the k types are obtained using the equation shown in Equation 2, and these are represented by the matrix R as shown in Equation 3 (Step 2-3). ). Further, an inverse matrix of the correlation coefficient matrix R is obtained, and the result is represented by the matrix A as shown in Equation 4 (step 2-4). In addition, “Σ” in the expression shown in Equation 2 represents the sum total regarding the subscript i.

  As described above, the value of the calculation parameter in the calculation formula used when calculating the single index value is determined. Since the data group handled here represents a normal state, it is considered that there is a certain correlation between the various pieces of information captured. When an abnormality such as a failure is likely to occur away from the normal state, these correlations are disturbed, and the “distance” from the origin (average of the steady state) in the multidimensional space defined above increases. This “distance” is an index value.

FIG. 4 is a flowchart of the procedure for calculating the index value in step 1-2 in FIG. The index value at an arbitrary timing is obtained as follows. First, k types of data x1, x2,..., Xk in an arbitrary state are acquired (step 3-1). The data type corresponds to y11, y12,. Next, the data of the acquired information is normalized using the formula shown in Equation 5 (step 3-2). Here, the normalized data is assumed to be X1, X2,. Next, the index value D2 is calculated by the calculation formula shown in Expression 6 determined using the element akk of the inverse matrix A that has already been obtained. The square root of this index value is called “Mahalanobis distance”. In addition, “Σ” in the expression shown in Equation 6 represents the sum total regarding the subscripts p and q.

  The process for determining the index value calculation method, that is, the process for determining the index value calculation formula and the process for calculating and updating the index value D using the calculation formula, operate the image forming system 6. You may make it perform continuously in the state. The flowchart of the process in this case is a combination of the process steps of FIG. 2 and the process steps of FIG. 3 as shown in FIG.

  Next, a configuration example and operation of an image forming apparatus to which the present invention can be applied will be described.

  FIG. 6 is a configuration diagram of a color copying machine which is an image forming apparatus using an electrophotographic system according to the present embodiment. An image forming system 6 as an image forming unit of the color copying machine includes a printer unit 100, a paper feeding unit 200, a scanner unit 300, and a document conveying unit 400, which are copying machine main bodies. The scanner unit 300 is mounted on the copying apparatus main body 100, and a document transport unit 400 including an automatic document transport device (ADF) is mounted on the scanner unit 300. Also provided is a control unit 5 (see FIG. 1) as a control means for controlling the operation of each apparatus in the color copying machine. As described above, the control unit 5 includes a CPU, a RAM, a ROM, an I / O interface unit, and the like.

  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 the control unit. Based on the image information received from the scanner unit 300, the control unit controls a laser, an LED, and the like (not shown) disposed in the exposure device 21 of the printer unit 100 to face the photosensitive drums 40Bk, 40Y, 40M, and 40C. Then, the laser writing light L is irradiated. By this irradiation, electrostatic latent images are formed on the surfaces of the photosensitive drums 40Bk, 40Y, 40M, and 40C, and the latent images are developed into toner images through a predetermined development process.

  In addition to the exposure device 21, the printer unit 100 includes a primary transfer device 62, 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. The development process will be described in detail later.

  The paper feeding unit 200 separates the fed paper cassettes 44 provided in multiple stages in the paper bank 43, the paper feeding rollers 42 for feeding transfer paper as a recording medium from the paper feeding cassettes, and the fed transfer paper P to the paper feeding path 46. A separation roller 45, a conveyance roller 47 that conveys the transfer paper P to the paper feed path 48 of the printer unit 100, and the like are provided. In the apparatus of this embodiment, manual paper feeding is possible in addition to the paper feeding unit, and the manual feed tray 51 for manual feeding and the transfer paper P on the manual tray are directed toward the manual paper feed path 53. A separation roller 52 for separating the sheets one by one is also provided on the side of the apparatus. The registration roller 49 discharges only one sheet of transfer paper P placed on the paper feed cassette 44 or the manual feed tray 51, and is positioned between the intermediate transfer belt 10 as the intermediate transfer member and the secondary transfer device 22. To the secondary transfer nip.

  In the above configuration, when copying a color image, the document is set on the document table 30 of the document conveying unit 400 or the document conveying unit 400 is opened and the document is set on the contact glass 32 of the scanner unit 300. The document feeder 400 is closed and the document is pressed. When a start switch (not shown) is pressed, the original is conveyed onto the contact glass 32 when the original is set on the original conveying unit 400, and immediately after the original is set on the other contact glass 32, the scanner unit 300 is driven to travel on the first traveling body 33 and the second traveling body 34.

  Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34, and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. It puts in the reading sensor 36 and reads image information. When image information is received from the scanner unit, a laser image as described above or a development process described later is performed to form a toner image on the photosensitive drums 40Bk, 40Y, 40M, and 40C, and in accordance with the image information. One of the four registration rollers is operated to feed the transfer paper P having a different size.

Along with this, one of the support rollers 14, 15, 16 is rotated by a drive motor (not shown), the other two support rollers are driven to rotate, and the intermediate transfer belt 10 is rotated and conveyed. At the same time, the photosensitive drums 40Bk, 40Y, 40M, and 40C are rotated by the individual image forming units 18 so that black, yellow, magenta, and cyan single-color images are respectively formed on the photosensitive drums 40Bk, 40Y, 40M, and 40C. Form. Then, along with the conveyance of the intermediate transfer belt 10, the monochrome images are sequentially transferred to form a composite color image on the intermediate transfer belt 10.

  On the other hand, one of the paper feed rollers 42 of the paper feed unit 200 is selectively rotated, the transfer paper P is fed out from one of the paper feed cassettes 44, separated one by one by the separation roller 45, and put into the paper feed path 46. The transfer roller 47 is guided to a paper feed path 48 in the copying machine main body 100, and the transfer paper P is abutted against the registration roller 49 and stopped. Alternatively, the sheet feeding roller 50 is rotated to feed the transfer paper P on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual sheet feed path 53, and abutted against the registration roller 49 and stopped. Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 10, and the transfer paper P is sent to the secondary transfer nip portion where the intermediate transfer belt and the secondary transfer roller 23 are in contact with each other. The color image is secondarily transferred by the influence of the transfer electric field formed in the nip, the contact pressure, and the like, and the color image is recorded on the transfer paper P.

  After the image transfer, the transfer paper P is fed to the fixing device 25 by the transport belt 24 of the secondary transfer device, and after fixing the toner image by applying pressure and heat by the pressure roller 27 by the fixing device 25, it is discharged. The paper is discharged onto a paper discharge tray 57 by a roller 56.

  Next, details of the printer unit 100 in the color copying machine of this embodiment will be described.

  FIG. 7 is an enlarged view of a main part of the printer unit 100. The printer unit 100 is provided side by side with an intermediate transfer belt 10 instructed by three support rollers 14, 15, and 16 as an intermediate transfer belt so as to face the intermediate transfer belt, and has black, yellow, magenta, and cyan on the surface. Four photosensitive drums 40Bk, 40Y, 40M, and 40C as latent image carriers each carrying one of the color toner images, and a developing unit 61Bk as developing means for forming a toner image on the surface of the photosensitive drum. , 61Y, 61M, 61C. Further, photoconductor cleaning devices 63Bk, 63Y, 63M, and 63C are provided for removing toner remaining after the primary transfer from the surface of the photoconductor drum. The four photosensitive drums 40Bk, 40Y, 40M, and 40C, the developing units 18Bk, 18Y, 18M, and 18C, and the four image forming units 18Bk, 18Y, 18M, and the photosensitive member cleaning devices 63Bk, 63Y, 63M, and 63C, A tandem image forming apparatus 20 is configured by 18C. A belt cleaning device 17 is provided on the left side of the support roller 15 to remove residual toner remaining on the intermediate transfer belt 10 after the toner image is transferred onto the transfer paper.

The cleaning device 17 is provided with two fur brushes 90 and 91 as cleaning members. The fur brushes 90 and 91 are φ20 mm, acrylic carbon, 6.25 D / F, 100,000 pieces / inch ² , 1 × 10 ⁷ Ω, and contact the intermediate transfer belt 10 to rotate in the counter direction. Provide to do. Then, biases having different polarities are applied to the fur brushes 90 and 91 from a power source (not shown). The fur brushes 90 and 91 are respectively provided with metal rollers 92 and 93 so as to be rotatable in the forward or reverse direction with respect to the fur brush.

  In this embodiment, a (−) voltage is applied from the power source 94 to the metal roller 92 on the upstream side in the rotation direction of the intermediate transfer belt 10, and a (+) voltage is applied from the power source 95 to the metal roller 93 on the downstream side. The tips of the blades 96 and 97 are pressed against the metal rollers 92 and 93, respectively. Then, along with the rotation of the intermediate transfer belt 10 in the direction of the arrow, the surface of the intermediate transfer belt 10 is cleaned by applying a bias (−), for example, using the fur brush 90 on the upstream side. If -700V is applied to the metal roller 92, the fur brush 90 becomes -400V, and the (+) toner on the intermediate transfer belt 10 can be transferred to the fur brush 90 side. 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 scraped off by the blade 96.

  As described above, 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. Those toners are charged (−) by a (−) 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 (+) 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). These toners may be returned to the developing device 61 using a toner recycling device described later.

  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 to (+) by the (+) bias applied to the fur brush 91 as described above. The toner charged to (+) is transferred to the photosensitive drums 40Bk, 40Y, 40M, and 40C by the transfer electric field applied at the primary transfer position, and can be collected by the photosensitive member cleaning device 63.

  A secondary transfer device 22 is provided on the opposite side of the intermediate transfer belt 10 from the tandem image forming device 20. In the present embodiment, the secondary transfer device 22 is configured such that a secondary transfer belt 24 is stretched between two rollers 23 and pressed against the third support roller 16 via the intermediate transfer belt 10. Then, a secondary transfer nip portion is formed, and the color toner image on the intermediate transfer belt 10 is secondarily transferred onto the transfer paper. The intermediate transfer belt 10 after the secondary transfer is removed from the residual toner remaining on the intermediate transfer belt 10 after image transfer by the belt cleaning device 17, and is prepared for re-image formation by the tandem image forming device 20.

  The secondary transfer device 22 described above is also provided with a transfer paper P transport function for transporting the transfer paper P after image transfer to the fixing device 25. Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device 22, and in such a case, it is difficult to provide this transfer paper P conveyance function together.

  In general, the registration roller 49 is often used while being grounded, but it is also possible to apply a bias for removing 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 thickness of 1 mm is used. The electrical resistance is about 10 × 10 9 Ω · cm as the volume resistance of the rubber material, and the applied voltage is about −800 V on the toner transfer side (front side). Further, 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 photosensitive drum, 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 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 49.

  In this embodiment, the transfer paper P is transferred under the secondary transfer device 22 and the fixing device 25 so as to invert the transfer paper P so as to record images on both sides of the transfer paper P in parallel with the tandem image forming device 20 described above. A paper reversing device 28 (see FIG. 6) is provided. As a result, after the image is fixed on one side of the transfer paper, the path of the transfer paper is switched to the transfer paper reversing device side with the switching claw, and the toner image is transferred again at the maintenance transfer nip after being reversed, and then onto the paper discharge tray. The paper may be discharged.

  Next, the tandem image forming apparatus 20 will be described.

  FIG. 8 is a partially enlarged view of the tandem image forming apparatus 20. Since the four image forming units 18Bk, 18Y, 18M, and 18C have the same configuration, the details of the configuration of one unit will be described with the four color symbols Bk, Y, M, and C omitted. As shown in FIG. 14, the image forming unit includes a charging device 60 as a charging unit, a developing device 61, a primary transfer device 62 as a primary transfer unit, and a photosensitive member around the photosensitive drums 40Bk, 40Y, 40M, and 40C. A body cleaning device 63, a charge removal device 64, and the like are provided. In the illustrated example, the photosensitive drums 40Bk, 40Y, 40M, and 40C have a drum shape in which a photosensitive organic photosensitive material is applied to a base tube such as aluminum to form a photosensitive layer. There may be.

  Although not shown, at least the photosensitive drums 40Bk, 40Y, 40M, and 40C are provided, and a process cartridge is formed by all or a part of the parts forming the image forming unit 18, and the copier main body 100 is collectively. Then, it may be detachable to improve maintenance. In addition, among the parts constituting the image forming unit 18, the charging device 60 is formed in a roller shape in the illustrated example, and contacts the photosensitive drums 40Bk, 40Y, 40M, and 40C to apply a voltage to the photosensitive drum. 40Bk, 40Y, 40M, and 40C are charged. Of course, charging can also be performed with a non-contact scorotron charger.

  The developing device 61 may use a one-component developer, but in the illustrated example, a two-component developer composed of a magnetic carrier and a non-magnetic toner is used. The agitation unit 66 conveys the two-component developer while stirring and supplies and adheres the two-component developer to the developing sleeve 65, and the toner of the two-component developer attached to the developing sleeve 65 is transferred to the photosensitive drum. 40Bk, 40Y, 40M, and 40C are provided, and the stirring unit 66 is positioned lower than the developing unit 67.

  The stirring unit 66 is provided with two parallel screws 68, and the two screws 68 are partitioned by a partition plate 69 except for both ends. Further, a toner density sensor 71 is provided in the developing case 70.

  The developing portion 67 is provided with a developing sleeve 65 facing the photosensitive drums 40Bk, 40Y, 40M, and 40C through the opening of the developing case 70, and a magnet 72 is fixedly provided in the developing sleeve 65. Further, a doctor blade 73 is provided with the tip approaching the developing sleeve 65. In the illustrated example, the distance at the closest portion between the doctor blade 73 and the developing sleeve 65 is set to 500 μm.

  The developing sleeve 65 has a non-magnetic rotatable sleeve shape, and a plurality of magnets 72 are disposed therein. Since the magnet 72 is fixed, a magnetic force can be applied when the developer passes through a predetermined place. In the illustrated example, the diameter of the developing sleeve 65 is 18 mm, and the surface is subjected to sandblasting or a process of forming a plurality of grooves having a depth of 1 to several mm, and the surface roughness (Rz) falls within the range of 10 to 30 μm. It is formed as follows.

  The magnet 72 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. The developer forms a magnetic brush by the magnet 72 and is carried on the developing sleeve 65. The developing sleeve 65 is disposed in a region on the S1 side of the magnet 72 that forms a developer magnetic brush so as to face the photosensitive drums 40Bk, 40Y, 40M, and 40C.

  With the above configuration, the two-component developer is conveyed and circulated while being stirred by the two screws 68 and supplied to the developing sleeve 65. The developer supplied to the developing sleeve 65 is pumped and held by the magnet 72 to form a magnetic brush on the developing sleeve 65. The magnetic brush is trimmed to an appropriate amount by the doctor blade 73 as the developing sleeve 65 rotates. The developer that has been cut off is returned to the stirring unit 66.

  Of the developer carried on the developing sleeve 65, the toner is transferred to the photosensitive drums 40Bk, 40Y, 40M, and 40C by the developing bias voltage applied to the developing sleeve 65, and the photosensitive drums 40Bk, 40Y, 40M, The electrostatic latent image on 40C is visualized. After the visualization, the developer remaining on the developing sleeve 65 leaves the developing sleeve 65 and returns to the stirring unit 66 where there is no magnetic force of the magnet 72. When the toner concentration in the stirring unit 66 becomes light by this repetition, it is detected by the toner concentration sensor 71 and the stirring unit 66 is replenished with toner.

  In the apparatus of this embodiment, the setting of each unit is such that the linear speed of the photosensitive drums 40Bk, 40Y, 40M, and 40C is 200 mm / s, the linear speed of the developing sleeve 65 is 240 mm / s, and the photosensitive drums 40Bk, 40Y, and 40C. The developing process is performed with the diameter of 40M and 40C being 50 mm and the diameter of the developing sleeve 65 being 18 mm. 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 GP, which is the gap between the photosensitive drums 40Bk, 40Y, 40M, and 40C and the development sleeve 65, can be set in the range of 0.8 mm to 0.4 mm as in the conventional case, and the development efficiency is improved by reducing the value. Can be achieved. Further, the thickness of the photoreceptor 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 developing process is performed with the charging (before exposure) potential VO of the photosensitive drum 40 being −700 V, the after-exposure potential VL being −120 V, and the developing bias voltage being −470 V, that is, the developing potential 350 V.

  The primary transfer device 62 is constituted by a roller-shaped primary transfer roller 62 and is provided by being pressed against the photosensitive drum 40 with the intermediate transfer belt 10 interposed therebetween. A conductive roller 74 is provided between the primary transfer rollers 62 in contact with the base layer 11 side of the intermediate transfer belt 10. The conductive roller 74 prevents the bias applied by each primary transfer roller 62 during transfer from flowing into the adjacent image forming units 18 via the intermediate resistance base layer 11.

  The photoconductor cleaning device 63 uses, for example, a cleaning blade 75 made of polyurethane rubber, and the front end thereof is pressed against the photoconductor drum 40. Further, in this embodiment, a contact conductive fur brush 76 whose outer periphery is in contact with the photosensitive drum 40 is rotatably provided in the direction of the arrow in order to improve the cleaning performance. Further, a metal electric field roller 77 for applying a bias to the fur brush 76 is rotatably provided in the direction of the arrow, and the tip of the scraper 78 is pressed against the electric field roller 77.

  Further, a collection screw 79 for collecting the removed toner is also provided.

  Residual toner on the photosensitive drum 40 is removed with the fur brush 76 that rotates in the counter direction with respect to the photosensitive drum 40 by the photosensitive member cleaning device 63 configured as described above. 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 collected by the photoconductor cleaning device 63 is brought to one side of the photoconductor cleaning device 63 by the collection screw 79 and returned to the developing device 61 by the toner recycling device 80 for reuse.

The static eliminator 64 uses a static elimination lamp, and irradiates light to initialize the surface potential of the photosensitive drum 40.

  The image forming process in the tandem image forming apparatus 20 configured as described above is performed as follows. As the photosensitive drum 40 rotates, the surface of the photosensitive drum 40 is first uniformly charged by the charging device 60, and the writing light L is irradiated to form an electrostatic latent image on the photosensitive drum 40. Thereafter, development is performed by attaching toner to the electrostatic latent image by the developing device 61 to form a toner image, and the toner image is primarily transferred onto the intermediate transfer belt 10 by the primary transfer roller 62. Residual toner is removed from the surface of the photoconductive drum 40 after the image transfer by the photoconductive cleaning device 63, and the charge is removed by the static eliminating device 64 to prepare for image formation again. On the other hand, the residual toner removed from the surface of the photosensitive drum is used again for development by a toner recycling device described later. Here, the order of colors for forming an image is not limited to the above, but varies depending on the aim and characteristics of the image forming apparatus.

  Next, the type of information to be acquired and the acquisition method for predicting the occurrence of an abnormality in the color copying machine having the above configuration will be specifically described.

(A) Sensing information The sensing information includes information related to driving characteristics, various characteristics of recording media, developer characteristics, photoreceptor characteristics, various electrophotographic process states, environmental conditions, various characteristics of recorded matter, and the like. Conceivable. 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-The transmission / reflection optical sensor or contact type sensor reads the position of the leading and trailing edges of the transported paper and detects 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.

  It is usually difficult to detect such items alone in the image forming apparatus. 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 Photoreceptor characteristics are closely related to the functions of the electrophotographic process, as are the developer characteristics. The photoconductor characteristics information 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. To obtain the film thickness.

・ Surface potential and temperature can be obtained 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.

-Generated sound due to charging-Exposure intensity-Exposure light wavelength 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, blur, etc. 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 obtained. 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 a thermoelectromotive force generated at a contact point between dissimilar metals or a metal and a semiconductor as a signal, and the resistivity of the metal or semiconductor changes depending on the temperature. Resistivity change elements that use this, pyroelectric elements that generate a potential on the surface due to a bias in the arrangement of charges in the crystal due to the rise in temperature, and magnetic properties due to 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 H2O 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 the electrical resistance of the oxide semiconductor accompanying the 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 formation parameters The 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. (B-2) User operation history / number of colors, number of sheets, image quality instruction, etc., selected by the user, for example, paper transport timing, preparation mode execution time before image formation, etc. -Frequency of the paper size selected by the user (b-3) Power consumption-Total power consumption or its distribution, change amount (differentiation) of the whole period or specific period unit (1 day, 1 week, 1 month, etc.), Cumulative value (integration)
(B-4) Consumables consumption information-Amount of toner, photoconductor, paper used or distribution, change amount (differentiation), cumulative value (for 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 obtained from image information sent directly as data from the host computer, or image information obtained after image processing 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.

  From the various information as described above, the above-described index value D is calculated, and based on the index value, the possibility of occurrence of an abnormality such as a failure is determined, and the occurrence of an abnormality such as a failure is predicted. Basically, if the magnitude of the index value D calculated from a plurality of types of information is larger than a predetermined threshold as described above, it is assumed that the possibility of failure is high. This threshold is generally determined by prior experiments. Alternatively, the initial value may be set to an appropriate value (for example, 10) and updated as data accumulates.

  The index value D represents a scale by which the correlation between the incorporated information is deviated from the normal state. Since it is determined that the deviation from the normal state is larger as the index value is larger, it is possible to foresee the possibility of failure even when the failure mechanism is unknown.

  Next, a description will be given of a treatment method after calculating the index value D and then determining the state of the image forming apparatus based on the index value D to predict the occurrence of an abnormality. After calculating the index value or predicting the occurrence of an abnormality, the following treatments (d) to (j) can be performed.

(D) A calculation result, a state determination result, and an abnormality occurrence prediction result are output.

The contents to be output include a calculation result of the index value D or a numerical value reflecting the index value, a determination result of a change in the state of the image forming apparatus, a failure such as a warning for notifying the user that the failure is near, a life span, etc. The prediction result of the occurrence of abnormality can be given. The index value D or the numerical change data reflecting the time may be output as a graph. Examples of the output method include the following methods.

(D-1) Numerical data and message display on display means such as a liquid crystal display on the operation panel or the like (d-2) Notification or warning consisting of sound or specific pattern sound from sound output means such as a speaker (d- 3) Recording on a recording medium (transfer paper) The output of the result of (d) above is output to a display means or a sound output means provided in the corresponding image forming apparatus, or recorded on a recording medium (transfer paper). Output. Apart from this, there is also a method of transferring these to a printer server connected via a network or a monitoring center connected via a communication line and monitoring the status of each device by communication means.

(E) The calculation result, state determination result, and abnormality occurrence prediction result are transferred.

  The same contents as in the case of (d) are transferred to the printer server or the monitoring center.

(F) A calculation result, a state determination result, and an abnormality occurrence prediction result are stored.

The same contents as in the case of (d) above are stored in a storage device (memory) provided in each image forming apparatus, printer server, and monitoring center apparatus. Further, the contents stored in the storage device can be read and controlled.

(G) Stop the device.

When the calculation result of the index value D exceeds a predetermined reference value or when the increase rate becomes large, the image forming apparatus cannot be forcibly operated and maintenance is requested.

(H) Limit the operation and change the control.

From both the calculation result of the index value D and each information source, a related portion is estimated, and control changes such as limiting operations related thereto are performed. Examples of the control change include the following.

(H-1) Color mode change (h-2) Recording speed change (h-3) Halftone line number change (h-4) Halftone processing method change (h-5) Paper type restriction (H-6) Parameter change for resist control (h-7) Parameter change for image forming process (for example, in an electrophotographic image forming apparatus, charging potential, exposure amount, developing bias, transfer bias, etc.)
(I) Supply / replacement of consumables and parts Replenishment and replacement are automatically performed based on the calculation result of the index value D.

(J) Automatic repair When an abnormality of a specific part is found from both the index value D and each information source, a mode for repairing the target part is executed.

  Next, an example showing a more specific information acquisition method in the image forming apparatus of this embodiment will be described. Note that the types of information used to determine the state of the image forming apparatus and the acquisition method thereof are not limited to those described below, and various types and forms of information described above and acquisition methods thereof can be employed.

  In this embodiment, using the image forming apparatus shown in FIGS. 6 to 8, individual or common index values are obtained before product shipment, and the index values are monitored online after shipment and increased. Sometimes maintenance is done. The types of information to be acquired and the specific contents of the acquisition method are as follows.

(1) Temperature In this embodiment, as an information acquisition means for acquiring temperature information, a means using a resistance change element that has the simplest principle and structure and can be miniaturized is employed.

FIG. 9 is a perspective view of a thin film type resistance change element used in this example. This variable resistance element can be manufactured as follows. First, an insulating film 502 is formed on a substrate 501, and a thin film sensing portion 503 made of a metal or a semiconductor material is provided thereon. Further, pad electrodes 504 are provided at both ends of the sensing unit 503, and finally a lead wire 505 is connected. In this resistance change element, when the ambient temperature changes, the electrical resistance of the sensing unit 503 changes accordingly. Therefore, the change may be extracted as a voltage or current change. Since the sensing unit 503 is a thin film, the entire element can be made small and easy to incorporate in the system.

FIG. 10 shows another variable resistance element used in this embodiment. 9 differs from the resistance change element of FIG. 9 in that a thin film sensing unit 503 is installed on a thin film bridge 507 that is suspended from a substrate 501 via a spacer 506. With such a structure, heat dissipation from the sensing unit 503 is prevented, and the temperature response of the sensing unit 503 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 sensor that can reduce the humidity is useful. The basic principle is that when water vapor is adsorbed to 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, ZrO2-MgO-based, etc. are used.

FIG. 11 is a perspective view of the humidity sensor used in this example. Comb electrodes 512 are provided on an insulating substrate 511, and terminals 513 are connected to both ends thereof. Further, a moisture-sensitive layer 514 (generally moisture-sensitive ceramics) is provided and the whole is covered with a case 515. When water vapor is adsorbed to the moisture-sensitive ceramics via the case 515, 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 motion 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. 12 is a cross-sectional view of the vibration sensor used in this example. A counter electrode 522 is provided over the insulating substrate 521. Next, a thin diaphragm 524 and a vibrator 525 are provided on the silicon substrate 523, and further, a step portion 52 that maintains a distance from the counter electrode 522.
6 is bonded to the substrate 521 having the counter electrode 522 previously prepared. When vibration or pressure is applied from the surroundings in this state, the vibrator 525 vibrates accordingly, and this may be measured as a change in capacitance with the counter electrode 522.

(4) Toner density The toner density is detected for each color. A conventionally known method can be used as the toner concentration sensor. 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. 13 is a schematic configuration diagram of the toner concentration detection unit. For example, a reference coil 533 is differentially connected to a detection coil 532 disposed in the vicinity of a developer 531 formed by mixing a magnetic carrier and nonmagnetic toner. The inductance of the detection coil 532 fluctuates with respect to the magnetic permeability change due to the increase / decrease of the toner concentration (directly magnetic carrier), whereas the inductance of the reference coil 533 is not affected by the change of the toner concentration. It has become. An AC drive source 534 that oscillates and drives at, for example, 500 kHz is connected to the series circuit of the two coils 532 and 533 so as to drive both the coils 532 and 533. A differential output is taken out from the connection point between the coils 532 and 533, and the output is connected to the phase comparator 535. One output of the AC drive source 534 is separately connected to the phase comparator 535. The phase of the voltage from the drive source 534 and the differential output voltage are compared.

  In the illustrated example, a sensitivity setting resistor 536 (R1) is connected in parallel to at least one of the two coils, that is, the detection coil 532 and the reference coil 533. Sensitivity characteristics can be controlled by slowing down the sensitivity to changes. FIG. 14 shows an assembly diagram of both the coils. The coils 532 and 533 are wound around a cylindrical coil support 537 in the vertical direction in the figure, and are close to the developer 531. Is provided with a detection coil 532 for detecting a change in permeability, and a reference coil 533 is disposed on the far side so that the permeability does not change even if the toner concentration changes.

(5) Charging potential The charging potential is detected for each color.

  FIG. 15 is a schematic configuration diagram of a potential measurement system that detects a charging potential used in this embodiment. In FIG. 15, reference numeral 541 indicates a sensor unit substrate that is attached to face an object (not shown). Reference numeral 542 denotes a signal processing unit substrate that sends a drive signal to the sensor unit substrate 1 and receives a sensor output. In the sensor substrate 1, a sound 543 that is chopping means and a piezoelectric element 544 are provided. The piezoelectric element 544 is driven by a drive signal from the signal processing unit substrate 542. This potential measurement system uses a self-excited oscillation method by a loop in which when one piezoelectric element 544 is driven, the vibration caused thereby is transmitted to the other piezoelectric element 544a through the sound 543 and returned to the drive source. Reference numeral 545 denotes a measurement electrode (hereinafter referred to as an electrode) that receives the lines of electric force from the object. Reference numeral 546 represents an amplifier that amplifies the amount of time change of the electric lines of force S received by the electrode 545. In the signal processing unit substrate 542, a piezoelectric element drive circuit 547, a filter 548, and a piezoelectric element drive circuit 549 are provided. Filter 548 shapes the waveform. The phase shift circuit 549 has a purpose of shifting 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 550 has a role of adjusting the magnitude of the phase-adjusted correction signal. The adding circuit 551 adds the correction signal and the sensor output. A processing circuit 552 processes the final signal output to determine the potential of the object. Reference numerals 553 and 554 denote adjustment volumes for the phase shift circuit and the attenuator, respectively.

  In the configuration as described above, by adjusting and optimizing the phase shift amount and the attenuator gain, it is possible to add a signal having the opposite phase and the same level as the correction signal to the mixed signal based on the drive signal. Only the sensor output based on the true object can be detected. Further, by providing the adjusting means, it is possible to cope with a characteristic change accompanying the secular change by the adjustment, and the reliability as the sensor is improved.

(6) LD drive current A drive current value of an LD (semiconductor laser) that performs image exposure is monitored on a drive circuit for each color and used.

(7) Total counter (cumulative print screen by color)
Accumulated data obtained by counting the number of print screens for each color is used. For example, when one sheet is formed in the full color mode, Y, M, C, and Bk are each increased by one count, and when one sheet is formed in the monochrome (black) mode, only Bk is increased by one count, and in the Y and M modes, Y is increased. Only M increases by 1 count. Such data is stored in the storage element, and the result is used.

(8) Development γ value A stepwise latent image potential is formed on the photoconductor in the test mode, and developed under specific conditions to form a stepwise density pattern. This is read by a reflection density sensor, and the relationship between the potential (potential difference) and the developed reflection density is obtained. Let the slope be the γ value. This value is obtained for each color and used.

(9) Development start voltage In the same manner as described above, the relationship between the potential and the developed reflection density in the test mode is obtained, and the potential at which development becomes 0 is obtained by extrapolation. This is the development start voltage. This value is obtained for each color and used.

(10) Colored area ratio 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 is used.

In this example, the following tests were performed. A printer prototype is prepared and running tests are simulated in the laboratory assuming various usage patterns. At that time, the above 10 items and 30 kinds of data are collected several times every day. A part of the collected data is shown in Table 3.

  In fact, 50 sets of data were collected, but during that time it worked without any problems.

Based on this data, calculation using the mathematical formulas shown in the above-mentioned formulas 1 to 5 was performed, and calculation parameters in the calculation formula shown in formula 6 were obtained. Using this result, the average value of 50 sets of D during normal operation is about 1. Thus, the calculation method (calculation formula) of the index value D was defined.

Next, after the product based on the prototype was released, it was continuously monitored in the market. The data to be acquired is the same item as the previous test.

  FIG. 16 is a graph showing the movement (time change) of the index value D calculated in this embodiment. In FIG. 16, the timing at which a problem (abnormal state) occurs in the image forming apparatus is indicated by an arrow. The problem that occurred here was toner filming on the photosensitive drum. Prior to the occurrence of this abnormality, the index value D increases. From this result, there is a strong correlation between the increase of the index value D and the occurrence of an abnormality, and the occurrence of the above problem (toner filming) can be predicted in advance by tracking the data of the index value D over time. I understand. That is, by determining a subsequent change in the printer state based on a change in time when the index value D increases, the index value D becomes the above problem (toner filming) after a certain period of time has passed. Since it can be seen whether the value is generated, it is possible to predict not only the occurrence of the problem (toner filming) but also the occurrence time of the problem (toner filming).

In this embodiment, the image forming apparatus is connected to the monitoring system via a communication line, and the index value D is constantly transmitted to the monitoring system. The monitoring system is set to monitor the change of the index value D, and to issue an alarm when the specific value exceeds the specific value. The alarmed condition is considered a potential failure and a service person is dispatched for maintenance. The service person directly checks the state of the image forming apparatus and performs necessary measures such as replacement of parts and electrical / mechanical adjustment. After the treatment, after confirming that the index value D is within the normal range, the maintenance is finished. In addition, the value of the index value D or a comment corresponding to the index value D can be displayed at all times, and the user can be informed of the state and urged for prior maintenance.

  As described above, by using this calculation parameter defined only by the normal data group, the index value can be calculated from the input information data group obtained thereafter, and the obtained index value is calculated. When the input information data group used is different from the tendency of the normal data group of the calculation parameter, the value is increased. In other words, since the index value increases as the device is separated from the normal state, the state determination can be performed with this. This index value corresponds to the Mahalanobis distance in the MT method, and is a value around 1 in the normal state and increases in the abnormal state. Usually, about 3 seems to be a normal / abnormal threshold.

  FIG. 17 shows a flowchart for calculating parameters described above, and FIG. 18 shows a flowchart for index value calculation and state determination.

  In the calculation parameter derivation method shown in FIG. 17, first, various input information is acquired (step S501). This input information is sensing information (a), control parameter information (b), input image information (c), etc. as shown in FIG. Next, the state of the image forming apparatus at the time of data acquisition is separately determined by some means (step S502). As this determination means, manual determination by an operator or automatic determination by a sensor is adopted. If it is determined that the machine is normal (step S502-Y), the input data information is stored as normal data (step S503). If the machine is determined abnormal, the machine is repaired (step S504). The collection will be redone. If the state of the machine is normal, normal data is gradually accumulated. However, when a certain number of data or a data collection period has elapsed (step S505-Y), calculation parameters are derived ( Step S506), with this, the calculation parameter is determined. Note that there is a minimum limit to the certain number of data, and assuming that there are k types of input information data types, k + 1 sets of data are required. This is an indispensable condition from the method of obtaining calculation parameters as an inverse matrix.

  In the index value calculation / state determination method shown in FIG. 18, first, various pieces of input information are acquired as in FIG. 17 (step S601). This input information type needs to be exactly the same as the input information type at the time of calculation parameter derivation. If the number of types is different, the calculation of the index value cannot be performed normally, and even if the number of types is the same, the input parameters of the different types will lose the meaning of the calculation parameter, and it will not be possible to determine the status with the calculated index value. Because it will end up. In the case of index value calculation, the index value is calculated for each information input (step S602).

  The information input timing is determined, for example, at a fixed number of sheets, once a day, what time, etc. When calculating the index value, the calculation parameters derived in FIG. 17 are used, and it is determined whether the state of the apparatus is normal or not based on the obtained index value (step S603). The threshold value of the index value at the time of determination is generally set to about 3 as described above, but the threshold value may be set independently depending on the applied system, the type of input information, and the level of user request. Absent. If it is below this threshold value, it is determined that the entire machine is normal (step S604), and if it exceeds the threshold value, it is determined that an abnormal state is approaching (step S605). If the threshold value is greatly exceeded (a two-digit or three-digit number), a definite abnormal state is determined. The state determination method described above performs the state determination in the flow shown in FIGS. In the case of predicting the occurrence of an abnormality, the time series fluctuation of the index value is monitored to predict when a definite abnormality will occur, so the basic state determination shown in FIGS. It is the same as the method.

In such an image forming apparatus, the plural types of information to be acquired are as described above.
a) Sensing information Developer information (toner concentration, fluidity, bulk density, electrical resistance, consumption, remaining amount, etc.), photoreceptor information (surface potential, color, unevenness, friction coefficient, electrical resistance value, etc.), paper Conveyance information (deviation of conveyance timing, sliding sound during conveyance, etc.), paper information (stiffness, thickness, surface condition, moisture content, etc.), drive information (rotation speed, drive current, drive sound, etc.), output image information ( Density, γ characteristics, halftone reproducibility, etc.), environmental information (temperature, humidity, airflow, atmospheric components, etc.), etc. b) control parameter information image formation parameters (various bias values, light quantity, linear speed, fixing temperature, etc.), user Scan history, power consumption, consumption of consumables, etc. c) Input image information The number of pixels, character ratio, halftone portion ratio, color ratio, font information, and the like.

  Such information is continuously collected during normal operation in a state where the image forming apparatus is shipped to the market and is in operation, thereby improving the accuracy of the calculation parameters. Since the calculated parameter is an index that represents the normal state of the apparatus, it is ideal that it includes data of all combinations that are determined to be normal. If there is a combination of normal data that is not included in the calculated parameters, the index value calculated for the normal data combination becomes large, and it is determined that there is an abnormality. In order to avoid this, the normal data group for derivation of the calculation parameter requires a certain combination of normal data groups, but it is impossible to align them before shipping the device. This is because there are many different kinds of environments where users are placed and how they are used. Considering this point, the normal data group is continuously collected at the user after the device is shipped, and the calculation parameters are derived and determined after the data amount is sufficient.

  What is necessary to realize the continuous collection of the normal data group is a means for determining whether or not the image forming apparatus is normal. According to another aspect of the present invention, image quality detection means for detecting the image quality of the output image is provided in order to determine whether or not the image forming apparatus is operating normally. There are two types of image quality detection means: a line shape such as a CCD and a spot shape such as a P sensor. In order to measure the image quality of the entire output image, a line shape like a CCD is indispensable, but since the amount of data is large, image quality calculation processing becomes heavy. ing. However, a line sensor such as a CCD may be applicable to an application such as the present invention that does not require speed. These image quality detecting means are installed so as to detect on the medium on which the toner image is formed. Specifically, the image quality detecting means may be on the photosensitive member, on the intermediate transfer member, on the recording paper or the like. The final output medium is the most appropriate for checking the operation state of the entire apparatus. That is, if the image quality on the recording paper is detected, the state of the entire apparatus can be grasped. However, there may be a method in which an image quality sensor is provided on the intermediate transfer member or the photosensitive member, and an event downstream thereof is checked by an individual sensor.

(11) Image quality detection Here, the concept of the image quality detection sensor will be described.

1. Outline of Image Quality Detection First, an outline of image quality detection will be described with reference to FIGS.

1.1 Overall Configuration The schematic configuration of the entire image forming apparatus that is the target of image quality detection is as shown in FIG. 6, and the main part of the image forming unit is as shown in FIG.

  In FIG. 6, a four-tandem intermediate transfer type full-color machine is shown as an example of the image forming apparatus according to the present invention, but this is only drawn as a representative example of the image forming apparatus, which will be described later. As described above, the present invention may be applied to a full-color machine such as a 4-drum tandem direct transfer system or a 1-drum intermediate transfer system, a direct transfer monochrome machine, or an image forming apparatus of another system.

1.2 Image Quality FIGS. 19 and 20 show halftone images formed on the recording paper by the image forming apparatus of FIGS. 6 and 7 having a 600 dpi writing system (the size of one halftone dot is “2 pixels × 2 pixels”). )) Of enlarged images (for convenience of description, binarization processing is performed for photography), FIG. 19 shows an initial image PT1, and FIG. 20 shows printing for a very long time under certain conditions. The image PT2 after performing is shown. As shown in FIG. 20, the halftone image PT1 that was initially uniform as shown in FIG. 19 has a rough halftone image as shown in FIG. 20 due to various factors such as the deterioration of the developer and the photoreceptor in the long-term image forming process. It has become the tone image PT2. Such a feeling of roughness can be quantified as a spatial frequency characteristic of fine density unevenness, and is expressed as a characteristic value such as “granularity”, for example.

That is, an image with a high degree of granularity (poor graininess) shows an image with a large roughness, and an image with a low degree of granularity (good graininess) shows a uniform image with little feeling of roughness. However, not all of the density unevenness gives a sense of roughness that appeals to the eye, and the image quality of the printed image need not be felt when a human visually observes it. FIG. 21 shows visual spatial frequency characteristics of an average subject regarding density unevenness. As described above, the spatial frequency at which density unevenness is perceived by human vision is about 0 [cycle / mm] to about 10 [cycle / mm] with a peak of about 1 [cycle / mm] as described above.
It is known that it is limited to the spatial frequency region of the range.

1.3 Image Quality Detection Device FIG. 22 is a diagram showing a schematic configuration of an image quality detection device that measures minute density unevenness of an image. In the figure, an image quality detection apparatus 600 is based on a light reflection type sensor (photo reflector) 610, an amplification circuit 620 that amplifies an electric signal from the light reflection type sensor 610, and a signal amplified by the amplification circuit 120. And an arithmetic circuit 630 as arithmetic means for performing predetermined arithmetic processing, and a signal generation circuit 640 as signal generation means for generating a signal for optical writing control based on the arithmetic output from the arithmetic circuit 630. The light reflection type sensor 610 includes an LED (light emitting diode-light emitting element) 601 as a light source, a condensing lens 602 that condenses light emitted from the LED 601 into a light beam having a predetermined beam diameter, and an image carrier 650. The photoelectric conversion element (light receiving element) 603 that receives the reflected light from the image pattern 651 and converts it into an electrical signal, and the imaging for imaging the reflected light from the image pattern 651 on the imaging surface of the photoelectric conversion element 603 Lens 604. As the light reflection type sensor 610, a light reflection type sensor that uses the spot light SP by narrowing the irradiation beam diameter is used as can be seen from the characteristic diagram showing the relationship between the distance (beam diameter) in the scanning direction and the light quantity in FIG.

  The light reflection sensor 610 condenses the irradiation beam from the light source composed of the LED 601 by the condenser lens 602, and the circular beam diameter on the surface of the image pattern 651 formed on the image carrier 650 becomes approximately 400 [μm]. I am doing so. The light reflected from this is detected by a photoelectric conversion element 603 such as a photodiode, and the uneven adhesion of the toner particles 652 in the image pattern 651 can be captured as fluctuations in the amount of light incident on the photoelectric conversion element 603.

  As a method of capturing the light amount fluctuation according to the toner adhesion amount, a method of detecting based on a difference in regular reflection characteristics or irregular reflection characteristics between the toner particles and the surface of the image carrier, or a difference in reflection spectral characteristics between the toner particles and the surface of the image carrier. There are detection methods and the like, and by combining these, detection with higher sensitivity can be performed. When utilizing the difference between regular reflection characteristics or irregular reflection characteristics, since the toner image generally has strong irregular reflection characteristics, the surface of the image carrier 650 is preferably made of a material having high glossiness and strong regular reflection characteristics. Further, when detecting based on a difference in reflection spectral characteristics, it is preferable to use a light source wavelength in which the reflection spectral characteristics of the toner particles 652 and the reflection spectral characteristics of the surface of the image carrier 650 are greatly different. The measurement apparatus of FIG. 22 is an example in which an LED 601 having an emission wavelength of 870 [nm] is used, and a detection method that utilizes the difference in irregular reflection characteristics between the toner particles 652 and the surface of the image carrier 650 is implemented. With respect to the beam diameter, at least the beam diameter (in the scanning direction of the spot light SP (see FIG. 21) so that density unevenness of about 1 [cycle / mm] with the highest sensitivity can be detected in the spatial frequency characteristics of human vision. In FIG. 23, d1) needs to be 1 [mm] or less. This beam diameter d1 is derived from 1 [mm], which is the reciprocal of the value 1 [cycle / mm] at which the spatial frequency in FIG. 22 is maximum. Here, the beam diameter (d1) is approximately 400 [μm]. Yes. The beam diameter d1 is defined here as a distance between points on both sides of the light beam at which the power per unit area of the spot light SP on the beam irradiation surface is reduced to 1 / e of the maximum value.

  19 and 20 described above are diagrams showing an example of the configuration of the image forming process of the image forming apparatus in which the light reflection type sensor (image quality sensor) 610 of FIG. 22 is installed facing the intermediate transfer belt 5 immediately after the developing process. is there. Scanning of the image on the photosensitive member by the spot light SP is performed by rotational driving of the photosensitive member, and when images PT1 and PT2 as shown in FIG. 19 or FIG. 20 are scanned in the paper conveyance direction (longitudinal direction in the drawing) The reflected light output is detected. FIG. 24 shows the state of fluctuation of the amount of light (voltage) of the reflected light from the amplifier circuit 620. The scanning condition of the spot light SP at this time is that the scanning speed is 200 [mm / s], the scanning distance is about 11 [mm], and the data sampling period is 75 [μs], that is, the sampling interval on the image is about The pitch is 15 [μm], and only one scan does not include an average processing step. It is also possible to calculate the average adhesion amount of the toner particles 152 adhering to the pattern by obtaining the average amount of light in FIG.

1.4 Visual noise (image quality)
1.4.1 Calculation of Noise Volume Since the spatial frequency characteristic of the image density unevenness cannot be read in the output state in which the amount of light is output using the time shown in FIG. 24 as a parameter, the spatial frequency characteristic is calculated by the arithmetic circuit 630. To do. In calculating the spatial frequency characteristics, it is preferable in terms of processing speed to apply a known method such as fast Fourier transform (FFT). The conversion result by the fast Fourier transform is shown in FIG. Note that the peak observed at 6 [cycle / mm] in FIG. 25 is due to the repetition frequency of the dot patterns in FIGS.

  As can be seen from FIG. 21, the visual characteristics are very sensitive to density unevenness having a spatial frequency near 1 [cycle / mm]. For example, the noise amount around 1 [cycle / mm] in FIG. 25 is compared. Accordingly, it is possible to know the degree of image quality deterioration of the pattern (image PT2) shown in FIG. 20 with respect to the pattern (image PT1) shown in FIG. When a decrease in image quality is detected as described above, a signal is generated by the signal generation circuit 640 in the measurement apparatus of FIG. 22 so as to prompt control of appropriate image forming conditions. In response to this signal, the image forming conditions are automatically controlled by the control circuit CON of the image forming apparatus MFP shown in FIG. 22, and automatic control is performed so that the image quality can be restored to the normal image quality as much as possible.

  When it is determined that the image quality cannot be restored only by automatic control, the control circuit CON instructs a display device (not shown) to replace parts such as a developer and a photoreceptor, and prompts replacement of the parts. These procedures can maximize the life of the developer and the photoconductor. Further, since the minimum required pattern size is about 1 [mm] × about 10 [mm], the amount of toner consumed by pattern image formation can be suppressed to the minimum level.

1.4.2 Calculation of Visual Noise Amount After obtaining the spatial frequency characteristic of FIG. 25, the arithmetic circuit 630 weights the visual spatial frequency characteristic shown in FIG. Ask for. FIG. 26 is a diagram showing the relationship between the visual noise amount and the spatial frequency, and shows the output state of the visual noise amount of the arithmetic circuit 630. This weighting is performed by multiplying the characteristic of FIG. 25 by the characteristic of FIG. This calculation makes it possible to extract only the spatial frequency characteristics that appeal to the eye, so that the target image quality can be easily detected. Further, since it is possible to remove a signal component due to an image pattern structure that has appeared in the vicinity of 6 [cycle / mm], it is also possible to remove information unrelated to the image quality of interest. If information that is not related to image quality can be removed in this way, the occurrence of false detection can be almost eliminated.

1.4.3 Total Amount of Visual Noise When the visual noise amount shown in FIG. 26 is integrated in the spatial frequency region of 0.2 [cycle / mm] to 4 [cycle / mm] using the arithmetic circuit 630, FIG. As shown, the total amount of visual noise is calculated. With this value, it is possible to know the overall image quality change in almost all spatial frequency regions appealing to the eye.

  Note that an image quality evaluation pattern described later preferably uses a halftone image of about 50%. This is because the graininess is easily noticeable. First, in the case of a monocular sensor as shown in FIG. 22, continuous density fluctuation data in the sub-scanning direction is collected on the image pattern, and in the case of a line sensor, density fluctuation continuous data in the main and sub-scanning directions is collected. In the case of a monochrome sensor, continuous data of only a specific wavelength (color) is collected, and in the case of a color sensor, continuous data of a plurality of wavelengths (colors) is collected.

  The collected continuous data is Fourier transformed as described above to obtain a power spectrum of density fluctuation. The square root (amplitude of fluctuation) of the power spectrum is multiplied by the visual spatial frequency characteristic (VTF), and the density fluctuation is weighted based on the visual characteristic in the frequency domain as described above. The granularity is obtained by integrating the weighted density fluctuation amount. This is a method for obtaining density-based granularity, but recently, granularity of lightness with good linearity with human vision has also been adopted. Therefore, when obtaining the granularity of lightness, it is necessary to first convert density data into lightness data. When obtaining the color granularity, the granularity is calculated by adding the chromaticity information to the lightness information. The above is how to obtain graininess information from density variation data. By applying feedback control based on the graininess information thus obtained, it is possible to continuously output images with stable graininess.

  In addition to the pattern shown in FIG. 19, the pattern for detecting the image quality based on the density unevenness is, for example, a dot having a minimum unit of 600 dpi as one unit of 2 pixels × 2 pixels, and in the scanning direction of the spot light SP. If the dot array repetition period z1 is about 170 [μm] (spatial frequency f1 is about 5.9 [cycle / mm]), scanning is performed with the spot light SP having a beam diameter of about 400 [μm] as described above. When performing the above, a spectrum appears at a spatial frequency near 6 [cycle / mm] as shown in FIG. In order to avoid that the spectrum caused by the image pattern itself overlaps the image quality detection signal detection region, the dot array repetition period z1 in the scanning direction is smaller than 250 [μm], preferably 200 [μm]. It is necessary to make it smaller. Therefore, here, z1 = 170 [μm].

  In any case, as shown in the flowchart of FIG. 29 described later, a procedure for forming an image pattern on the image carrier to detect image quality, a procedure for irradiating the image pattern with spot light, An image quality detection function is realized by a computer program including a procedure for scanning the image pattern with the spot light and detecting a light amount reflected from the image pattern, and a procedure for detecting an image quality based on the detected light amount. Such a computer program is used by being downloaded from a recording medium recorded so as to be readable by a computer, or downloaded from a server or the like via a network.

  This control is executed by the CPU of the control circuit CON of the image forming apparatus MFP based on the output signal from the signal generation circuit 640 of the image quality detection apparatus 600. The CPU executes each process while using a ROM (not shown) as a work area based on a ROM (not shown) or a downloaded program. Program data is downloaded to a storage device such as a hard disk (not shown) from a server via a network (not shown) or from a recording medium such as a CD-ROM or an SD card via a recording medium driving device (not shown) or upgraded. Is called.

  FIG. 28 shows the installation position of the image quality sensor (image quality detection means). The installation position 1 is on the photoreceptor, the installation position 2 is on the intermediate transfer belt, the installation position 3 is an unfixed image on the recording paper, and the installation position 4 is a fixed image on the recording paper. As described above, the installation position 4 is ideal, but in this case, since a patch pattern for image quality detection must be formed on the recording paper, there is a problem of whether it can be accepted by the user. If it is on the photosensitive member or the intermediate transfer member, it is only necessary to clean the formed toner image with a cleaning device on each medium, so it is considered that there is no problem in terms of the burden on the user (recording paper). However, since it cannot be a check of the final output image, for example, when detecting image quality at the sensor installation position 2, it is comprehensive after taking into account individual information such as secondary transfer current value, fixing temperature, and recording paper conditions. Therefore, it is necessary to determine the state of the image forming apparatus.

  FIG. 29 is a flowchart showing the data processing flow of the image quality sensor.

  The light receiving unit output from the CCD sensor 603 or the spot light sensor (step S701) is amplified to a desired value by an amplifier (amplification circuit) 620 (step S702), and converted into digital data by an A / D converter. Thereafter (step S703), the arithmetic circuit 630 performs Fourier transform (FFT operation) (step S704) to obtain frequency band data. This frequency band data is overlaid with VTF, which is human visual characteristics (step S705), weights the frequency domain data that is conspicuous to the human eye, and finally integrates only the frequency band data that is sensitive to the human eye. (Step S707) to obtain an image quality numerical value.

  Although the image quality information is obtained in this manner, the image quality level required by the user is different at present. There is a tendency that high image quality is not required for normal office use, but a high image quality is required for offices related to design. In other words, an image quality threshold value corresponding to the user who desires high image quality must be set, and when the threshold value is exceeded, it must be determined that the machine is abnormal. For this reason, as a criterion for determining whether or not the image quality detected / calculated by the image quality detection means is normal, it is necessary to store the user's image quality allowance information in advance in the apparatus storage means as a threshold (claim 3). It becomes. This image quality allowance information may be specified by, for example, showing the image quality sample to the user when the apparatus is delivered, and then stored in the storage unit of the image forming apparatus by input by a service person or reading the image quality sample with a scanner. Just do it.

  The threshold value of the image quality allowance information in the case where the acquisition of a plurality of types of information for derivation of the calculation parameters is continued based on the threshold value of the image quality allowance information determined for each user may be defined by the method described in the previous stage. . A flowchart when information acquisition is continued with this threshold as a reference is as shown in FIG. In the first conditional branch “Is the machine state normal?” (Step S502), the image quality detected by the image quality detection device 600 is compared with the threshold value of the image quality allowance information for each user previously stored in the storage means. If it is less than or equal to the threshold value, it is judged normal, and if not, it is judged abnormal. The information acquisition is continued only when the apparatus is determined to be normal, and when it is determined to be abnormal, the acquisition is resumed after a separate repair (steps S501 to S503). While normal data is being accumulated, calculation parameters are derived and determined after the data accumulation amount or accumulation period reaches a specified amount (steps S503 to S506). After this is confirmed, it is no longer necessary to collect normal data for the calculated parameters, so that it is not necessary to judge the state of the image forming apparatus MFP by the image quality detection apparatus 600. Therefore, in the present invention, image quality detection apparatus 600 is configured as an additional unit separate from image forming apparatus MFP main body, and is removed from the image forming apparatus main body after calculation parameters are determined after a certain period after operation in the market. To be able to.

  The image quality detection means as the additional unit can be lent to a user from a manufacturer, for example, and the manufacturer can pull it up when it becomes unnecessary. As a merit on the user side, if it is installed for a certain period of time, it can obtain the function of judging the state of the machine and predicting the occurrence of an abnormality. Good, etc. Advantages of the manufacturer include that the image quality detection means can be recycled and used, and that customers do not need to purchase it. It can be said that these merits are stronger in terms of business model merits than technical merits.

FIG. 30 is a diagram showing an example of a specific configuration in the case where the image quality detection apparatus is a separate additional unit 700.
In this example, the additional unit 700 is a combination of a paper discharge tray function and an image quality detection function. A conventional paper discharge tray 720 that discharges paper through a normal paper discharge path 710 is installed at the top of the additional unit 700, and a box-shaped container 730 is disposed below it. The additional unit 700 is attached to the image forming apparatus main body in the same manner as a normal paper discharge tray, and is electrically connected to the image forming apparatus main body side separately. Therefore, communication means are interposed between them. This is for notifying image quality detection information to the image forming apparatus main body. In a normal printing operation, the recording paper is discharged onto the upper paper discharge tray 720. However, during the normal data collection operation for the calculated parameters, the image quality detection mode for determining the state of the image forming apparatus is activated, and the paper discharge path switching means 750 of the additional unit 700 is automatically opened to add The paper discharge path to the inside of the unit 700, that is, the image quality detection paper discharge path 740 is switched.

  A conveyance roller 760 and an image quality sensor 770 are installed at the entrance of the addition unit 700, and recording paper loaded with image quality detection patch patterns discharged from the image forming apparatus is stably added by the conveyance roller 760. After drawing in the unit 700 and reading the patch pattern by the image quality sensor 770 installed in the subsequent stage, the image quality numerical value is calculated and calculated by a calculation unit (not shown). The recording paper that has passed through the image quality sensor 770 is stocked in the image quality detection sample storage unit 780. It is assumed that the capacity of the image quality detection sample storage unit 780 is determined in accordance with a period for collecting a plurality of types of information for calculation parameters, and it is not necessary for the user to take out a sample after detection. When a sufficient number of data has been collected, the additional unit 700 is pulled up together with the image quality detection sample stocked therein, and a normal paper discharge tray 720 is installed.

  Note that the image quality calculation unit may be installed in the vicinity of the image quality sensor, or may use a calculation unit of the image forming apparatus main body. Although not shown in detail, there is also a method in which the additional unit including the image quality sensor can be attached in an easily attachable / detachable form at the image quality sensor installation position shown in FIG. In this case, the function of the additional unit is a function of only the image quality sensor, and it is sufficient that it has a shape that can be easily attached and detached.

  A method of determining a certain period for collecting data for calculation parameters corresponds to the determination in step S505 of “Is data storage sufficient?” Described in the flowchart of FIG. When the period is determined by the number of output sheets, the condition determination “is data storage sufficient?” Is a condition determination “Is X printed?”.

  This method is considered to be the most straightforward method. For example, data is collected at regular intervals while counting the number of sheets by monitoring the output of a paper discharge sensor or a writing start signal, and the data collection is terminated when a certain number of sheets is reached. In this case, the calculated parameter includes the durability deterioration information of the apparatus when the image forming apparatus is driven by a certain number of sheets. The period determined by the accumulated number of rotations of the photoconductor is conceptually similar to the number management.

  The data collection interval is a fixed rotation speed integrated value interval, and data collection ends when a certain rotation speed integrated value is reached. The calculation parameter in this case also includes the durability deterioration information of the apparatus. These methods can be said to be data collection methods based on the operation time of the apparatus, and can include the durability deterioration information of the apparatus to an arbitrary degree. However, the collected data may be affected by environmental changes in which the machine is located. In the data collection method based on the operating time, there is a possibility that the influence from environmental changes may be biased. In this case, when the device is placed in a different environment (or when the environment changes greatly due to a change in season), it may be determined that the device is operating normally but is abnormal. In order to avoid this, a period determined by the number of working days can be used.

  In this case, since it is based on the number of days, the data is collected, for example, how many times a day and what time. In the case of using the working days standard, it is an advantage that the calculation parameters including the influence of environmental fluctuations within the set days period can be used. In particular, if the period determined by the number of working days is set to one year, environmental information for all seasons of spring, summer, autumn and winter can be taken into the calculation parameters, so that it is considered that the calculation parameters are highly reliable against environmental fluctuations. On the other hand, there is a demerit that the period of one year is too long (even as a period until failure prediction is started by confirming the calculation parameters, or as a lending period for image quality detection means), and machine operating time varies. There is also a demerit that the influence of the durability deterioration information varies.

  For users with a small number of prints, there is a possibility that only a narrow range of normal data can be obtained without deteriorating the device. Conversely, for users with a large number of prints, if the machine deteriorates too much and a failure tends to occur, normal data Will be a hindrance to the collection. In addition to this, a period until the number of data reaches an arbitrary value can also be used. In this case, it is necessary to determine the data collection interval in advance (any operating time standard or days standard), but the calculation parameters are derived from the determined number of normal data, so the number of data in the population is insufficient. The fear of Further, since the image quality detection means can be pulled up as soon as the necessary minimum number of data is secured, efficient operation of the image quality detection means becomes possible. This method, which is based on the period of collected data, is considered the most reasonable method.

  As described above, there are various ways of determining the period, but actually, these methods can be used in combination. Basically, there is a minimum number of data for calculation parameters, so collect data while counting the number of data, secure the minimum number of data, and then define the period on the basis of operating hours or the number of days One of the most realistic would be to define a time period by criteria. In some cases, a combination of operating hours and days is also conceivable.

  The external information processing apparatus when transmitting the acquired plural types of information and the detected and calculated image quality information to the external information processing apparatus through a communication line is, for example, a printer server or a manufacturer's monitoring center. is there. The purpose of transmitting the collected data to the external information processing apparatus is to derive calculation parameters as an image forming apparatus aggregate using data of a plurality of image forming apparatuses collected in the external information processing apparatus. . Since information is collected from a plurality of image forming apparatuses in the external information processing apparatus, for example, calculation parameters for each office floor, calculation parameters for each type of industry in which the machine is used, calculation parameters for each geographical area The calculation parameters for each machine model can be obtained.

  Thus, by obtaining the calculation parameters for the image forming apparatus aggregate, the calculation parameters are appropriate for each aggregate, and the reliability of state determination can be increased. Further, since the favorable state of a plurality of image forming apparatuses when a certain level is used as a reference can be grasped, it can be used, for example, when a priority order for a serviceman is given.

  As described above, according to this embodiment, the following effects can be obtained.

1) After the image forming apparatus is shipped to the market, in the usage state in the user environment, various populations affected by the user environment can be obtained by increasing the population of normal data groups used for calculation parameter derivation. Since a normal data group with a proper balance is included in the population, the reliability of the state determination can be improved.

2) In order to collect a data group during normal operation, means for determining whether or not the state of the image forming apparatus is normal is indispensable. By installing image quality detection means as the determination means, an output image can be obtained. Whether or not the device operation is normal can be determined based on the reference. As a result, data collection during normal operation can be continued.

3) The image quality detection means is a means for digitizing the image quality at that time, but whether the image quality is satisfactory depends on the user. Therefore, the image quality level allowed by the user is researched at the time of delivery of the apparatus, and the information is stored in the in-device storage means as a threshold value, so that the normal / abnormal determination of the apparatus state according to the image quality level requested by the user can be performed. You can do it. In addition, by predicting the occurrence of an abnormality corresponding to each user in this way, it is possible to respond and take action before the user feels dissatisfied, so the number of discarded prints due to image quality degradation can be suppressed, and resource saving benefits There is also.

4) A calculation parameter corresponding to the image quality level required by the user by collecting a plurality of types of data only when it is determined that the image forming apparatus is in a normal state with the image quality allowed by the user as a threshold. Therefore, it is possible to determine the state corresponding to each user.

5) The image quality detection means is used for the purpose of deriving the calculation parameter, and is unnecessary after the calculation parameter is determined. For this reason, the image quality detection means can be pulled up by the service person after it becomes unnecessary by making it an external additional device and a separate body from the image forming apparatus main body. By lending the image quality detection means to the user, the user can obtain the advantage of automatically predicting a machine failure after a certain period of time, and installing unnecessary devices in the machine forever. It does not have to be left. In addition, the manufacturer has the advantage that the raised image quality detection means can be reused for new image forming devices that are put on the market, and the environmental load is increased by reusing it without producing more image quality detection means than necessary. There is also a merit of not letting it.

6) By defining the period until the calculated parameter is stabilized by the number of output sheets that reflect the actual operating state of the device and the accumulated value of the photosensitive drum rotation, the device has deteriorated in durability (it has become so bad because it has been used so much). Can be reflected in the calculated parameters.

7) By defining the period until the calculated parameter is stabilized on the basis of the number of days, it is possible to reflect the environmental fluctuation as a disturbance in the calculated parameter. In particular, when the number of days is set to one year, a change in temperature and humidity throughout the year can be reflected in the calculation parameters, and there is an advantage that there is no error in state determination due to the season.

8) Since the data used for the calculation parameter derivation is data while the image quality detection means determines that the image quality is normal, when the period is determined on the basis of the number of output sheets or the number of days, the data population The number cannot be specified. Therefore, the image quality detection means can be reused efficiently by setting the data population for deriving the calculation parameters to a certain period when the data population becomes a certain size.

9) By transmitting plural types of information and image quality information of the image forming apparatus to the external information processing apparatus, it is possible to monitor the status of the plurality of image forming apparatuses by the external information processing apparatus.

10) In the external information processing apparatus, by using the information of a plurality of image forming apparatuses to derive calculation parameters as an image forming apparatus aggregate, for example, the calculation parameters according to the model type, the user industry, the region, etc. Derivation is possible.

It is a block diagram which shows the fundamental structure of the abnormality generation | occurrence | production prediction system containing the state determination apparatus which can implement the abnormality generation | occurrence | production prediction method which concerns on this invention. It is a flowchart which shows the basic operation | movement of an abnormality generation | occurrence | production prediction system. It is a flowchart which shows the procedure which determines the calculation formula used when calculating an index value. It is a flowchart of the procedure of the calculation of the index value in step 1-2 in FIG. It is a flowchart which shows the basic operation | movement of the abnormality generation | occurrence | production prediction system which concerns on a modification. 1 is a diagram illustrating a configuration of a color copying machine according to an embodiment. FIG. 2 is an enlarged view of a main part of a printer unit of the color copying machine. FIG. 2 is a partially enlarged view of a tandem image forming apparatus of the printer unit. It is a perspective view of the thin film type resistance change element used for the Example. It is a perspective view of the resistance change element concerning a modification. It is a perspective view of the humidity sensor used for the Example. It is sectional drawing of the vibration sensor used for the Example. FIG. 3 is a schematic configuration diagram of a toner concentration detection unit used in an example. It is an assembly drawing of the coil in the same toner concentration detection part. It is a schematic block diagram of the electric potential measurement system which detects the charging electric potential used in the Example. It is a graph which shows the motion (time change) of the index value D computed in the Example. It is a flowchart for calculation parameter derivation. It is a flowchart for index value calculation and state determination. FIG. 21 is an enlarged photograph of a halftone dot image formed on the recording paper 20 by the image forming apparatus of FIG. 19 and FIG. 20 having a 600 dpi writing system. It is a figure which shows the initial image PT1. It is a figure which shows image PT2 after printing for a long term on a certain condition. It is a figure which shows schematic structure of the image quality detection apparatus which measures the fine density nonuniformity of an image. It is a characteristic view which shows the relationship between the distance (beam diameter) of a scanning direction, and light quantity. It is a figure which shows the output state which outputs light quantity by setting time as a parameter. It is a figure which shows the conversion result (spatial frequency characteristic) by a fast Fourier transform. It is a figure which shows the amount of visual noises. It is a figure which shows the total amount of the calculated visual noise. It is a figure which shows the installation position of an image quality sensor (image quality detection means). It is a flowchart which shows the flow of a data process of an image quality sensor. It is a figure which shows the specific structural example of an additional unit when an image quality detection means is made into a separate additional unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 State determination apparatus 2 Information acquisition part 3 Index value calculation part 4 Judgment part 5 Control part 6 Image formation system 600 Image quality detection apparatus 610 Light reflection type sensor 620 Amplification circuit 630 Operation circuit 640 Signal generation circuit 650 Image carrier 700 Additional unit 710 Normally, a will path 720, a discharge tray 730, a container 740, a discharge path for image quality detection 750, a discharge path switching means 760, a transport roller 770, an image quality sensor 780, an image quality detection sample storage section

Claims (17)

Information acquisition means for acquiring a plurality of types of information related to the operation of the target device;
Index value calculation means for calculating a single index value from a plurality of pieces of acquired information;
Determination means for determining the state of the target device based on the calculated index value;
In a state determination device for obtaining a calculation parameter for calculating the index value based on the plurality of types of information acquired during normal operation of the target device,
The state determination apparatus, wherein the information acquisition unit continuously collects a plurality of types of information that is operating normally for the calculation parameter derivation in a state where the target device is shipped to the market and is operating.   The state determination apparatus according to claim 1, wherein the target device is an image forming apparatus. In an image forming apparatus that forms a visible image on a recording medium based on input image information,
An information acquisition unit that acquires a plurality of types of information related to the operation of the image forming apparatus, an index value calculation unit that calculates a single index value from the acquired plurality of information, and an image forming apparatus that uses the calculated index value Determination means for determining a state, and continuously collecting a plurality of types of information during normal operation for derivation of the calculation parameter in a state where the image forming apparatus is shipped and operated in the market, and the image formation An image forming apparatus comprising: a state determination device that obtains a calculation parameter for calculating the index value based on the plurality of types of information acquired during normal operation of the device.   4. The image forming apparatus according to claim 3, further comprising image quality detecting means for detecting the image quality of the output image in order to determine whether or not the image forming apparatus is operating normally in the market.   5. The image according to claim 4, further comprising storage means for preliminarily storing a user's image quality allowance information as a threshold as a reference for determining whether or not the image quality detected and calculated by the image quality detection means is normal. Forming equipment.   6. The information acquisition unit according to claim 3, wherein the information acquisition unit continues to acquire a plurality of types of information for deriving a calculation parameter based on a threshold of image quality allowance information determined for each user. The image forming apparatus described in the item.   7. The image forming apparatus according to claim 4, wherein the image quality detection unit is detachably provided separately from the main body of the image forming apparatus.   The information processing device includes a communication unit configured to transmit the plurality of types of information acquired by the information acquisition unit and the image quality information detected and calculated by the image quality detection unit to an external information processing apparatus. The image forming apparatus according to any one of 4 to 7.   9. The calculation parameters as a set of image forming apparatuses based on an arbitrary image quality allowable value using the two types of information collected from a plurality of image forming apparatuses according to claim 8 to an external information processing apparatus through communication means. An external information processing apparatus characterized by being derived. In an image quality detection apparatus that is detachably provided in an image forming apparatus and detects the image quality of the image by introducing an image-formed sheet discharged from the image forming apparatus,
A paper discharge tray for collecting sheets discharged from the image forming apparatus;
A stacking unit for stacking paper whose image quality has been detected;
Switching means for switching the paper transport direction to the paper discharge tray or the stacking unit;
Image quality detecting means for detecting the image quality of the image formed on the paper introduced on the stacking unit side;
An image quality detection device comprising: Information acquisition means for acquiring a plurality of types of information related to the operation of the target device;
Index value calculation means for calculating a single index value from a plurality of pieces of acquired information;
Determination means for determining the state of the image forming apparatus based on the calculated index value;
In a state determination method for obtaining a calculation parameter for calculating the index value based on the plurality of types of information acquired during normal operation of the target device,
In order to determine whether or not the image forming apparatus is operating normally in the market, an image quality detecting means for detecting the image quality of the output image is detachably provided separately from the image forming apparatus main body, and a preset period has elapsed. A state determination method, wherein the image quality detection means is removed from the image forming apparatus when   The state determination method according to claim 11, wherein the period is after the calculation parameter is determined.   The state determination method according to claim 11 or 12, wherein the period is determined by the number of output sheets.   13. The state determination method according to claim 11 or 12, wherein the period is determined by a rotation speed integrated value of the photosensitive member.   The state determination method according to claim 11, wherein the period is determined by the number of operating days of the image forming apparatus.   The state determination method according to claim 11 or 12, wherein the period is a period in which at least four seasons have passed.   The state determination method according to claim 11 or 12, wherein the period is a period until the number of data used for the calculation parameter reaches an arbitrary value.

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