JP4922564B2 - Abnormality determination apparatus and image forming apparatus - Google Patents

Description

  The present invention provides a group information group including a plurality of sets of information consisting of a plurality of different types of information acquired from the subject to be examined or the same specification as that of the subject, and a plurality of types of information acquired from the subject to be tested itself. The present invention relates to an abnormality determination device that determines the presence / absence of abnormality of a subject to be examined.

  Conventionally, in various machines and devices on the market, when a failure occurs, it cannot be used until the completion of repair depending on the content of the failure, which may inconvenience the user. For this reason, it is desired to predict the occurrence of a failure in advance and deal with it before the occurrence.

  On the other hand, conventionally, when the test object is normal, a plurality of types of information are acquired from the test object to construct a normal data group, and then the acquired information from the test object and the normal data group Based on the above, various methods for measuring the normality of the subject to be examined are known. For example, the MTS (Maharanobis Taguchi System) method described in Non-Patent Document 1 is one of them. In the MTS method, first, set information composed of a plurality of types of information is acquired from a test subject in a normal state. A large number of pieces of group information are collected to construct a normal data group as a group information group. Thereafter, when it is desired to check the normality of the subject to be examined, various information is acquired from the subject to be examined. Then, for those pieces of information, the Mahalanobis distance indicating the relative positional relationship in the multidimensional space based on the normal data group constructed in advance is obtained, and the normality of the test subject is determined based on the result. Weigh in and out. By using such an MTS method, it is possible to detect a minor abnormality of a machine or device as a test target and predict the occurrence of a failure in advance. Then, by preparing parts in advance or exchanging the parts, the downtime of the test object can be reduced.

"Technology development in MT system" Publication Committee Chairman Genichi Taguchi Published by Japanese Standards Association

  In the course of developing an abnormality determination device that determines the presence or absence of an abnormality in an image forming apparatus using the MTS method, the present inventors have made it possible for a normal data group to make an accurate determination. I found out that it might not be appropriate.

  For example, there is information acquired from the image forming apparatus in which normal values are different between summer when the humidity is high and winter when the humidity is low. When such information is incorporated as a part of the normal data group, the normal data group is not suitable for determining an abnormality in summer or winter depending on the acquisition time of the information. Moreover, although the cause is not certain, there is information in which normal values differ among a plurality of test objects having different production lots. When such information is incorporated as a part of the normal data group, the normal data group is included in the determination of abnormality in an image forming apparatus of a production lot different from the image forming apparatus from which the information was acquired. This is not suitable for the image forming apparatus to be inspected.

  The present invention has been made in view of the above background, and an object of the present invention is to provide an abnormality that can accurately determine the presence or absence of an abnormality in a test subject regardless of the season or the production lot of the test subject. It is to provide a determination device.

In order to achieve the above object, the invention of claim 1 stores a group information group including a plurality of group information composed of a plurality of different types of information obtained from the subject to be examined or the same specification as the subject. Based on information storage means, information acquisition means for acquiring set information from the subject to be examined, the set information group stored in the information storage means, and set information acquired by the information acquisition means, In an abnormality determination device comprising determination means for determining the presence or absence of abnormality of a subject to be examined, a plurality of group information groups associated with different selection information are stored in the information storage means, and the selection information is determined by an operator an information input means for inputting by an operator provided, and, among these sets information group, and corresponds to the selection information input to the information input unit by the operator, the information acquisition hand Calculating the Mahalanobis distance based on the obtained plurality kinds of information by, based on the calculation result so as to perform the process of determining the presence or absence of the above test object abnormalities, that constitute the determining means It is characterized by .
Also, the invention of claim 2, image forming means for forming an image on a recording material, the image forming apparatus and an abnormality determination means for determining the presence or absence of an abnormality, as the abnormality determining means, according to claim 1 abnormality The determination device is used.

In these inventions , when a plurality of group information groups are stored in the information storage unit, the determination unit uses the selection information input to the information input unit as the selection information. It is possible to select an appropriate one and use it to determine abnormality. Therefore, the presence or absence of abnormality in the test object can be accurately determined regardless of the season and the production lot of the test object .

Hereinafter, a first embodiment of a copying machine that forms an image by an electrophotographic process will be described as an image forming apparatus to which the present invention is applied.
FIG. 1 is a schematic configuration diagram showing a copying machine according to the first embodiment. The copier includes an image forming unit including a printer unit 100 and a paper feeding unit 200, a scanner unit 300, and a document conveying unit 400. The scanner unit 300 is mounted on the printer unit 100, and a document transport unit 400 including an automatic document transport device (ADF) is mounted on the scanner unit 300.

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

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

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

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

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

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

  On the other hand, the paper feed unit 200 operates any one of the three paper feed rollers to feed the transfer paper having a size corresponding to the image information, and feeds the transfer paper to the paper feed path of the printer unit 100. Lead to 48. After the transfer paper that has entered the paper feed path 48 is sandwiched between the registration roller pair 49 and temporarily stopped, the intermediate transfer belt 10 and the secondary transfer roller 23 of the secondary transfer device 22 come into contact with each other at the appropriate timing. To the secondary transfer nip, which is a part. Then, in the secondary transfer nip, the four-color superimposed toner image on the intermediate transfer belt 10 and the transfer paper are brought into close contact in synchronization. Then, the four-color superimposed toner image is secondarily transferred onto the transfer paper due to the influence of the transfer electric field formed at the nip, the nip pressure, etc., and becomes a full color image combined with the white color of the paper.

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

  FIG. 2 is an enlarged configuration diagram illustrating the printer unit 100. The printer unit 100 includes a belt unit, four process units 18K, Y, M, and C that form toner images of respective colors, a secondary transfer device 22, a belt cleaning device 17, a fixing device 25, and the like.

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

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

  FIG. 3 is a partially enlarged view showing a part of the tandem unit 20 including the four process units 18K, Y, M, and C. Since the four process units 18K, Y, M, and C have substantially the same configuration except that the colors of the toners to be used are different, K, Y, M, and C attached to the respective reference numerals in FIG. The subscript is omitted. As shown in the figure, the process unit 18 includes a charging device 60 as a charging unit, a developing device 61, a primary transfer roller 62 as a primary transfer unit, a photoconductor cleaning device 63, a charge eliminating device around the photoconductor 40. A device 64 or the like is provided.

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

  The developing device 61 develops a latent image using a two-component developer containing a magnetic carrier and a nonmagnetic toner. An agitating unit 66 that conveys the two-component developer accommodated in the inside while stirring and supplies the developer sleeve 65 to the developing sleeve 65; , C, a developing unit 67 for transferring to C.

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

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

  The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 73 as the developing sleeve 65 rotates, and then conveyed to the developing area facing the photoreceptor 40. Then, due to the potential difference between the developing bias applied to the developing sleeve 65 and the electrostatic latent image on the photoreceptor 40, it is transferred onto the electrostatic latent image and contributes to development. Further, as the developing sleeve 65 rotates, the developing sleeve 65 returns to the developing portion 67 again, and after being separated from the sleeve surface due to the influence of the repulsive magnetic field between the magnetic poles of the magnet roller 72, the developing sleeve 65 is returned to the stirring portion 66. In the stirring unit 66, an appropriate amount of toner is supplied to the two-component developer based on the detection result by the toner density sensor 71. The developing device 61 may employ a one-component developer that does not include a magnetic carrier, instead of the one that uses a two-component developer.

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

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

  The static eliminator 64 includes a static elimination lamp or the like, and removes the surface potential of the photoreceptor 40 by irradiating light. The surface of the photoreceptor 40 thus neutralized is uniformly charged by the charging device 60 and then subjected to optical writing processing.

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

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

  The belt cleaning device 17 has two fur brushes 90 and 91. By rotating a plurality of raised brushes in contact with the intermediate transfer belt 10 in a counter direction with respect to the flocking direction, the transfer residual toner on the belt is mechanically scraped off. In addition, a cleaning bias is applied by a power source (not shown) to electrostatically attract and recover the scraped transfer residual toner.

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

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

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

  In general, the registration roller pair 49 is often used while being grounded. However, a bias can be applied to remove the paper dust of the transfer paper P.

  Under the secondary transfer device 22 and the fixing device 25, a transfer paper reversing device 28 (see FIG. 1) is provided so as to extend in parallel with the tandem portion 20 described above. As a result, the transfer paper that has undergone the image fixing process on one side is switched by the switching claw to the transfer paper path to the transfer paper reversing device side, where it is reversed and enters the secondary transfer transfer nip again. Then, after the secondary transfer process and the fixing process of the image are performed on the other side, the sheet is discharged onto a discharge tray.

  In the copying machine configured as described above, each process unit 18K, Y, M, C, secondary transfer device 22, exposure device 21 and the like constitute image forming means for forming an image on transfer paper as a recording medium. .

  In the copying machine according to the first embodiment, various information such as sensing information, control parameter information, input information, and image reading information can be acquired by an information acquisition unit such as a sensor. Hereinafter, an example of information that can be acquired will be described.

(A) Sensing information Sensing information is considered to be a target for acquiring drive relationships, various characteristics of recording media, developer characteristics, photoreceptor characteristics, various electrophotographic process states, environmental conditions, various characteristics of recorded materials, etc. . The outline of the sensing information is as follows.

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

(A-2) Paper transport status • The position of the leading or trailing edge of the transported paper is read using a transmissive or reflective optical sensor or contact type sensor to detect that a paper jam has occurred. Reads deviations in the passage timing of the leading and trailing edges of the paper and fluctuations in the direction perpendicular to the feeding direction.
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 and 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 information alone in the image forming apparatus. Therefore, it may be 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 Like the developer characteristics, the photoreceptor characteristics are closely related to the function of the electrophotographic process. Information on the photoconductor characteristics includes photoconductor film thickness, surface characteristics (friction coefficient, unevenness), surface potential (before and after each process), surface energy, scattered light, temperature, color, surface position (flare), linear velocity , Potential decay rate, electrical resistance, capacitance, surface moisture content and the like. Among these, the following information can be detected in the image forming apparatus.
・ Detect the current flowing from the charging member to the photoconductor, and simultaneously compare the change in capacitance with the change in film thickness with the voltage-current characteristics with respect to the voltage applied to the charging member and the preset dielectric thickness of the photoconductor. Thus, the film thickness is obtained.
-The surface potential and temperature can be determined by a conventionally known sensor.
-The linear velocity is detected by an encoder attached to the photoconductor rotating shaft.
-Scattered light from the surface of the photoreceptor is detected by an optical sensor.

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

Examples of the method for acquiring various states of the toner image include the following.
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 characteristic, image density and color of the formed toner image are optically detected. Either reflected light or transmitted light may be used. What is necessary is just to select a light projection wavelength according to a 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) Image characteristics obtained by detecting the toner image on the photosensitive member, intermediate transfer member, or recording paper with an area sensor, such as physical characteristics, image flow and image fading of the printed material of the image forming apparatus Is determined by image processing.
The toner dust stain is obtained by taking an image on a recording sheet with a high resolution line sensor or an area sensor and calculating the amount of toner scattered around the pattern portion.
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.
• Curling, undulation and crease of the recording paper 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, the thermocouple method that extracts thermoelectromotive force generated at the contact point between dissimilar metals or between metal and semiconductor as a signal, the resistivity of metal or semiconductor changes with temperature Resistivity change element using this, pyroelectric element that generates a potential on the surface due to bias in the arrangement of charges in the crystal due to the rise in temperature in certain crystals, and magnetic characteristics depending on temperature It is possible to employ a thermomagnetic effect element or the like that detects the change of.
-For humidity detection, there are an optical measurement method for measuring light absorption of H ₂ O or OH group, a humidity sensor for measuring a change in electric resistance value of a material due to adsorption of water vapor, and the like.
・ Various gases are basically detected by measuring changes in the electrical resistance of the oxide semiconductor accompanying gas adsorption.
Although there are optical measurement methods and the like for detection of airflow (direction, flow velocity, gas type), an air bridge type flow sensor that can be made smaller in consideration of mounting on a system is particularly useful.
-There are methods for detecting pressure and pressure, such as using a pressure sensitive material and measuring the mechanical displacement of the membrane. A similar method is used for vibration detection.

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

(B-1) Image Forming Parameters Direct parameters output by the control unit through image processing for image formation include the following examples.
A process condition setting value by the control unit, such as a charging potential, a developing bias value, a fixing temperature setting value, and the like.
-Similarly, setting values for various image processing parameters such as halftone processing and color correction.
Various parameters set by the control unit for the operation of the apparatus, for example, paper conveyance timing, execution time of the preparation mode before image formation, and the like.

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

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

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

(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.) Such.

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

Next, a specific method for acquiring various types of information in the copier will be described.
(1) Temperature The copying machine includes a temperature sensor that acquires temperature information using a variable resistance element that is simple in principle and structure and that can be miniaturized.

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

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

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

(5) Photoconductor uniform charging potential (for 4 colors)
A uniform charged potential is detected for each color photoconductor (40K, Y, M, C). A known surface potential sensor that detects the surface potential of an object can be used.

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

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

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

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

(10) Paper discharge timing The transfer paper after passing through the pair of discharge rollers (56 in FIG. 1) is detected by an optical sensor. In this case as well, the measurement is performed with reference to the time when the paper feed roller drive signal is transmitted.

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

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

  Next, an abnormality determination apparatus mounted on the copying machine according to the first embodiment will be described. In the first embodiment, an example in which the abnormality determination device is mounted on a copying machine that is a test target will be described. However, the abnormality determination device may be provided separately from the test target such as a copying machine. In this case, in the abnormality determination device, receiving means for receiving various information sent from the copying machine functions as information acquisition means for acquiring information. In addition, when the abnormality determination device is disposed in a remote place far from the copying machine, the abnormality determination device is made to perform data communication between the subject to be detected and the reception unit of the abnormality determination device through a communication line. Information can be acquired.

  FIG. 4 is a block diagram showing a part of the electric circuit of the abnormality determination device 600 in the present copying machine. In the figure, an abnormality determination device 600 stores information acquisition means 601 for acquiring a plurality of types of information indicating the state of the copier, set information composed of a combination of a plurality of types of information, and a set information group that is a collection of the information. An information storage unit 602 and the like are included. In addition, a determination unit 603 for determining whether there is an abnormality in the copying machine to be examined based on the group information acquired by the information acquisition unit 601 and the group information group stored in the information storage unit 602 is provided. Yes. In addition, an information input unit 604 including a keyboard or the like for inputting information by an input operation by a user or the like is also provided.

  As shown in the figure, when a control unit including a CPU, a RAM, and the like is provided in the abnormality determination device 600, the RAM of the control unit can function as the information storage unit 602. Further, the control unit can also function as a determination unit 603 that determines whether there is an abnormality.

  FIG. 5 is a block diagram showing an example in which the abnormality determination device 600 is installed in the copying machine 500. In this example, various sensors and operation units mounted on the copier 500 can function as the information acquisition unit 601 of the abnormality determination device 600. Further, the main control unit that controls the entire copying machine 500 can function as the determination unit 603 of the abnormality determination apparatus 600.

  FIG. 6 is a block diagram showing an example in which a personal computer (PC) is connected to the copying machine 500 configured as shown in FIG. In this example, communication means such as a communication port installed in the copying machine 500 to enable communication with a personal computer (PC) is caused to function as the information acquisition means 601 and the information input means 604 of the abnormality determination device 600. It becomes possible. In addition, the operation display unit mounted on the copying machine 500 can function as information input means of the abnormality determination device 600.

  FIG. 7 is a block diagram illustrating an example in which the abnormality determination device 600 is disposed in a remote place far from the installation site of the copying machine 500. In this example, the copier 500 and the abnormality determination device 600 can exchange data via a communication line using wired or wireless communication. In order to enable communication with the copying machine 500, communication means such as a communication port installed in the abnormality determination apparatus 600 can function as the information acquisition means 601 and the information input means 604.

  FIG. 8 shows an example in which an abnormality determination device 600 is connected to a plurality of copiers 500 connected to a plurality of personal computers (PCs) via a network via a communication line. In the case of this example, one abnormality determination device 600 can individually determine the presence or absence of abnormality for a plurality of copying machines 500.

  As shown in FIGS. 5 to 8, the abnormality determination device 600 may be mounted on the subject to be examined or may be configured separately from the subject to be examined. Further, only a part of the abnormality determination device 600 may be mounted in the subject to be examined, and the rest may be separated. In this case, the presence or absence of abnormality can be determined within the subject to be examined, or can be performed separately. As described above, in the first embodiment, an example in which the abnormality determination device 600 is mounted in the copying machine 500 will be described.

  The abnormality determination device 600 is a copying machine that is a subject to be tested based on group information including a plurality of types of information acquired by various sensors, a main control unit, an operation display unit, etc. Determine whether there is any abnormality. More specifically, the Mahalanobis distance by the MTS method is obtained based on the set information, and it is determined whether or not an abnormality has occurred in the apparatus. In order to obtain the Mahalanobis distance, it is necessary to construct a normal data group as a group information group that is a collection of a plurality of group information acquired from a normal copying machine. This is not performed for each machine product, but based on group information acquired from a standard copier in a factory. At the time of shipment, the group information for each product may be acquired and added to the normal data group stored in advance.

Table 1 shown below is an example of an acquired data table for storing group information acquired from a standard machine having the same specifications as each copying machine product itself. This acquisition data table shows an example in which n sets of group information composed of k types of information are acquired to form an inverse matrix.

  When constructing a normal data group, first, k types of information (y11, y12,..., Y1k) constituting the first set of group information are respectively acquired by the information acquisition means of the standard machine described above. The And it is memorize | stored in an information recording means as data of the 1st line in a data table. Next, k types of information (y21, y22,..., Y2k) constituting the second set information are acquired from the standard machine and stored as the second row data in the data table. Thereafter, group information for the third and subsequent groups is sequentially acquired and stored as data in the data table. Then, the n-th set information is acquired and stored as the n-th row data in the data table. When the necessary amount (n sets) of group information is acquired in this way, next, the average and standard deviation (σ) of n pieces of k types of information constituting each group information are obtained, and each n + 1 , N + 2 line data is stored in the acquired data table.

  After the acquisition data table is constructed in this way, next, an inverse matrix construction process for constructing an inverse matrix is performed. In this inverse matrix construction process, an information normalization process, a correlation coefficient calculation process, and an inverse matrix conversion process described below are performed.

In the information normalization process in the inverse matrix construction process, a normalized data table as shown in the following Table 2 is constructed based on the acquired data table shown in Table 1.

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

When the information normalization process is finished, a correlation coefficient calculation process is performed next. In this correlation coefficient calculation step, all combinations (kC2 types) in which two different types of k types of normalized data in each of the n sets of normalized data groups can be established based on the following equations are used. The relation number rpq (rqp) is calculated.

After calculating correlation coefficients rpq (rqp) for all combinations, next, k × k correlation coefficient matrices with diagonal elements as 1 and other elements in p rows and q columns as correlation coefficients rpq Build R. The contents of this correlation coefficient matrix R are shown in the following equation.

After completing the correlation coefficient calculation step in this way, a matrix conversion step is performed next. Through this matrix conversion step, the correlation coefficient matrix R expressed by Equation 3 is converted into an inverse matrix A (R−1) expressed by the following equation.

  FIG. 9 is a flowchart showing a series of processes from the group information group construction process to the matrix conversion process. In the figure, first, n sets of k pieces of information related to the state of the copying machine are acquired from the copying machine (step 1-1: hereinafter, step is denoted as S). Next, for each type of information (j), an average value and a standard deviation σ based on the relational expression 1 are calculated, and a normalized data table is constructed based on the calculation result (S1-2). . Then, after the correlation coefficient matrix R is constructed based on the normalized data table (S1-3), it is converted into an inverse matrix A (S1-4).

When the inverse matrix A is constructed as described above, it is stored in the information storage means 602 of the abnormality determination device 600 of the copying machine. The abnormality determination device 600 executes an abnormality determination process for determining the presence or absence of an abnormality in the copier based on the inverse matrix A that is a group information group stored in the information storage means. In this abnormality determination process, the Mahalanobis distance (hereinafter referred to as the Mahalanobis distance) in the multidimensional original space of the inverse matrix A is obtained for the combination information consisting of all or part of various information acquired by the information acquisition means for each print job. D) is calculated based on the following equation.

  FIG. 10 is a flowchart showing a procedure for calculating the Mahalanobis distance D based on the inverse matrix A and various acquired data. In this procedure, first, k types of data x1, x2,..., Xk are acquired in an arbitrary state (S2-1). Data types correspond to y11, y12,. Next, each acquired data is normalized to X1, X2,..., Xk based on the relational expression (1). Then, the square of the Mahalanobis distance D is calculated by the relational expression of the above formula 5 determined using the element akk of the inverse matrix A that has already been constructed. “Σ” in the figure represents the sum of the subscripts p and q.

  The abnormality determination device 600 compares the Mahalanobis distance D thus obtained with a preset threshold value. When the Mahalanobis distance D is larger than the threshold value, it is determined that the acquired group information is abnormal data that is greatly deviated from the normal distribution, and failure occurrence caution information is displayed on the operation display unit.

Next, a characteristic configuration of the copying machine according to the first embodiment will be described.
This copier is shipped with 10 inverse matrices A stored in the information storage means 602 of the abnormality determination device 600. These inverse matrices A are individually constructed based on the set information acquired from 10 different standard machines, and the correlation coefficients of the information in the set information are slightly different from each other. Although it is confirmed that all the standard machines are in a normal state, it is not clear why the correlation coefficients are slightly different even though they are in the same normal state.

この行列選択テーブルは、情報記憶手段６０２に記憶されている１０個の逆行列Ａのファイル名と、それぞれの逆行列Ａに付されている選択番号とを関連付けるものである。 The information storage unit 602 also stores a matrix selection table shown in Table 3 below.

This matrix selection table associates the file names of the 10 inverse matrices A stored in the information storage means 602 with the selection numbers given to the respective inverse matrices A.

  FIG. 11 is a flowchart showing a control flow of matrix selection variable setting processing performed by the abnormality determination unit 603 of the abnormality determination device 600. When the operator inputs information for starting the selected variable setting process to the information input unit 604, the selected variable setting process is started. When the process is started, a message prompting the operator to input a numerical value of the selected variable is first displayed on a display unit such as a display (not shown) (S1). When the numerical value of the selected variable is input to the information input means 604 according to this message (Y in S2), the numerical value of the selected variable stored so far in the information storage means 604 is updated to the input one ( S3), a series of control flow ends.

  FIG. 12 is a flowchart showing a control flow of the abnormality determination process performed by the determination unit 603 of the abnormality determination device 600. When the abnormality determination process is started, first, after the set information is acquired from the copying machine by the information acquisition means 601 (S1), each information in the set information is normalized (S2). Next, after the value of the selection variable stored in the information storage unit 602 is read (S3), among the 10 inverse matrices A stored in the information storage unit 602, the selection variable read in S3 (Table 3) associated with the selection number having the same value as is specified (S4). Then, after the Mahalanobis distance D is calculated based on the identified inverse matrix A and each information standardized in S2 (S5), the presence or absence of abnormality is determined by comparing it with a threshold value (S6). ).

  In such an abnormality determination process, the determination unit 603 selects the same selection variable as the information input to the information input unit 602 out of the 10 inverse matrices A stored in the information storage unit 602. It will be used to determine abnormality. In such a configuration, the operator can empirically find out which of the 10 inverse matrixes A is suitable for the copier he owns, or can be provided with information from the manufacturer. By setting the corresponding selection variable, it is possible to accurately determine whether there is an abnormality regardless of the production lot of the copying machine.

Next, the copying machine of the first reference form will be described. Unless otherwise specified below, the basic configuration of the copying machine according to the first reference embodiment is the same as the basic configuration of the copying machine according to the first embodiment.

  This copying machine is shipped in a state in which information for spring / summer and that for autumn / winter are stored as the inverse matrix A in the information storage means 602 of the abnormality determination device 600. The spring / summer inverse matrix A is constructed based on group information acquired from a standard machine that is trial-run in spring / summer. Further, the inverse matrix A for autumn / winter is constructed based on group information acquired from a standard machine that is trial run in the fall / winter period.

  FIG. 13 is a flowchart showing a control flow of the abnormality determination process performed by the determination unit 603 of the abnormality determination apparatus 600 of the copying machine. When the abnormality determination process is started, first, after the set information is acquired from the copying machine by the information acquisition means 601 (S1), each information in the set information is normalized (S2). Next, it is determined whether or not the current time is the spring / summer period based on the time measurement result by the clock circuit (S3). If it is spring / summer (Y in S3), the inverse matrix A for spring / summer is selected (S4), whereas if it is not spring / summer (N in S3), it is for fall / winter. Is selected (S5). Next, after the Mahalanobis distance D is calculated based on the selected inverse matrix A and each information standardized in S2 (S6), the presence or absence of abnormality is determined by comparing it with a threshold value (S7). ).

  In such an abnormality determination process, the inverse matrix A suitable for the season at the time of abnormality determination is selected and used for abnormality determination throughout the year, so that the presence or absence of an abnormality in the copying machine can be determined regardless of the season. It can be determined accurately.

Next, a copying machine according to the second reference embodiment will be described. Unless otherwise specified below, the basic configuration of the copier according to the second reference embodiment is the same as the basic configuration of the copier according to the first embodiment.

  The copying machine abnormality determination device 600 includes a modem (not shown) as receiving means for receiving an inverse matrix A sent from a maintenance / inspection service company through a telephone line as a communication line. When the inverse matrix A is received by the modem, the inverse matrix A stored in the information storage unit 602 is replaced with the inverse matrix A received by the modem and stored in the information storage unit 602. Information updating means is also provided.

  In this configuration, the inverse matrix A stored in the information storage unit 602 can be updated according to the season and the production lot of the copying machine. Can be accurately determined.

Next, a copying machine according to the third reference embodiment will be described. Unless noted below, the basic configuration of a copier according to a third reference embodiment is the same as the basic construction of the copying machine of the first embodiment.

  FIG. 14 is a perspective view showing the printer unit (100) of the copying machine. A front door 151 is attached to an exterior cover 150 serving as a casing of the printer unit so as to be freely opened and closed. When the front door 151 is opened, as shown in FIG. 15, the opening on the front side of the exterior cover 150 opens a large opening, and the information storage means 602 such as a hard disk mounted inside is exposed. This information storage means 602 can be attached to and detached from the printer unit through an opening that is opened by opening the front door 151.

  In such a configuration, by replacing the removable information storage unit 602, the inverse matrix A used by the determination unit 603 can be switched according to the season and the production lot of the copying machine. Regardless of this, it is possible to accurately determine whether there is an abnormality in the copying machine.

1 is a schematic configuration diagram showing a copier according to a first embodiment. FIG. 2 is a schematic configuration diagram illustrating a printer unit of the copier. The elements on larger scale which show the tandem part of the copier. FIG. 2 is a block diagram showing a part of an electric circuit of an abnormality determination device in the copier. FIG. 3 is a block diagram showing an example in which the abnormality determination device is installed in the copier. FIG. 2 is a block diagram showing an example in which a personal computer is connected to the copier. FIG. 3 is a block diagram showing an example in which the abnormality determination device is disposed in a remote place far from the installation site of the copier. FIG. 3 is a block diagram showing an example in which the abnormality determination apparatus is connected to a plurality of copying machines connected to a plurality of personal computers via a network via a communication line. The flowchart which shows a series of processes from a group information group construction process to a matrix conversion process. The flowchart which shows the procedure which calculates Mahalanobis distance D based on the inverse matrix A and various acquisition data. The flowchart which shows the control flow of a matrix selection variable setting process. The flowchart which shows the control flow of the abnormality determination process implemented by the determination means of the abnormality determination apparatus. 6 is a flowchart showing a control flow of abnormality determination processing performed by a determination unit of the abnormality determination device for the copying machine according to the first reference embodiment. The perspective view which shows the printer part of the copying machine which concerns on a 3rd reference form. FIG. 3 is a perspective view showing the printer unit with the front cover opened.

Explanation of symbols

100 Printer section (part of image forming means)
200 Paper feed unit (part of image forming means)
600 Abnormality determination device 601 Information acquisition means 602 Information storage means 603 Determination means 604 Information input means

Claims (2)

Information storage means for storing a set information group including a plurality of set information composed of a plurality of different types of information acquired from the test object itself or the same specification as the test object, and acquiring the set information from the test target An information acquisition means; and a determination means for determining the presence / absence of abnormality of the subject to be tested based on the group information group stored in the information storage means and the set information acquired by the information acquisition means In the abnormality determination device,
Storing the plurality of group information groups associated with different selection information in the information storage means;
Providing an information input means for inputting the selection information by an operation by an operator;
In addition, the Mahalanobis distance is calculated based on the group information group corresponding to the selection information input to the information input unit by the operator and the plurality of types of information acquired by the information acquisition unit. An abnormality determination device, characterized in that the determination means is configured to execute a process of calculating and determining the presence or absence of abnormality of the test object based on the calculation result . In an image forming apparatus comprising: an image forming unit that forms an image on a recording medium; and an abnormality determination unit that determines whether there is an abnormality.
An image forming apparatus using the abnormality determination device according to claim 1 as the abnormality determination means.

Images