JP4642486B2 - Abnormality determination apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an abnormality determination device that determines presence / absence of abnormality of a test object based on a detection result by a sound detection unit that detects sound emitted from the test object. Further, the present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or the like provided with such an abnormality determination device.

  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. In order to suppress the occurrence of such problems and reduce downtime, it is desirable to detect and deal with abnormalities in machines and devices at an early stage.

  On the other hand, various abnormality determination devices that determine the presence / absence of an abnormality in a test object based on detection results of sound emitted from a machine or device that is the test object have been proposed (for example, Patent Documents 1 and 2). 3).

Japanese Patent Laid-Open No. 10-1962 JP 2000-216943 A JP 2001-92688 A

  In order to reduce downtime, the present inventors are developing an image forming apparatus in which the presence / absence of an abnormality is determined based on a detection result by a vibration detection unit. In this image forming apparatus, an electrostatic latent image formed on the surface of a photoreceptor as a latent image carrier is developed with toner to form a visible image, and then transferred to a transfer body such as transfer paper from the photoreceptor. An image is formed by a photographic method. In the image forming apparatus having such a configuration, when the transfer residual toner adhering to the surface of the photoreceptor after the transfer process is cleaned by the cleaning blade, the cleaning blade deteriorated due to wear may cause various failures. There is. Therefore, in the image forming apparatus under development, the vibration detection means is fixed to the cleaning blade, and the abnormality of the cleaning blade and its surroundings can be detected early based on the detection result of vibration.

  However, in this image forming apparatus under development, if the fixing state of the vibration detecting means with respect to the cleaning blade varies from apparatus to apparatus due to variations in the thickness of the adhesive for fixing, an error is caused in the vibration detection result. Abnormality determination accuracy is reduced. Further, when an abnormality has occurred at a location relatively far from the fixed location of the vibration detection means, it has been difficult to detect abnormal vibration by the vibration detection means.

  On the other hand, in the above-described abnormality determination device that determines the presence or absence of abnormality based on sound, the variation in the fixed state of the sound detection means is unlikely to affect the detection of the sound, and therefore it is difficult to cause a decrease in determination accuracy due to the variation. Furthermore, even an abnormality occurring at a location relatively distant from the sound detection means can be detected based on the sound detected by the sound detection means.

  However, among various types of sounds emitted from machines and devices, there are those that change their state with changes in temperature, humidity, composition in the air, and the like. For example, when the frictional resistance at the contact portion between the cleaning blade and the photoconductor changes with changes in temperature and humidity, the state of the sound emitted from the contact portion also changes accordingly. Thus, if the state of a sound changes with environmental changes, it will be difficult to accurately determine the presence or absence of an abnormality based on the sound.

  The present invention has been made in view of the above background, and an object of the present invention is to provide the following abnormality determination apparatus and an image forming apparatus including the abnormality determination apparatus. That is, an abnormality that can accurately determine the presence or absence of an abnormality in the subject regardless of variations in the fixed state of the information detection means that detects information from the subject, the fixed position of the information acquisition means, and environmental fluctuations It is a determination device.

In order to achieve the above object, the invention of claim 1 is directed to a sound detection means for detecting a sound emitted from a subject to be examined, an environmental information detection means for detecting environmental information, a detection result by the sound detection means , and based on the detection result by the environment information detecting means, wherein the abnormality determination device and a determination means for determining whether the inspected object abnormal, as the sound detection means, at least, a piezoelectric microphone and an electrostatic microphone And Fourier transform means for Fourier transforming the low frequency component of the sound signal detected by the piezoelectric microphone and Fourier transforming the high frequency component of the sound signal detected by the electrostatic microphone. A result of quantifying the sound intensity for each predetermined frequency for the signal after Fourier transform by the transforming means; Based on the detection result by the information detection means, wherein so as to determine the presence or absence of a subject of abnormal and is characterized by being configured the determination means.
The invention of claim 2 is characterized in that, in the abnormality determination device of claim 1, a temperature detecting means for detecting temperature and a humidity detecting means for detecting humidity are provided as the environmental information detecting means. Is.
According to a third aspect of the present invention, in the abnormality determination device according to the first or second aspect of the present invention, the environmental information detecting means is provided with a means for detecting nitrogen oxides in the air.
According to a fourth aspect of the present invention, there is provided a latent image carrier for carrying a latent image, developing means for developing the latent image on the latent image carrier, and transferring a visible image after development from the latent image carrier. An image forming apparatus comprising: a transfer unit that transfers to a body; a cleaning unit that cleans the latent image carrier after transfer; and an abnormality determination unit that determines whether there is an abnormality. The abnormality determination device according to any one of 3 is used.
According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect , at least the latent image carrier and the cleaning unit are mounted on the main body of the image forming apparatus in the state of one unit supported by a common support. It is configured as a process unit that can be attached to and detached from the process unit, and the sound detection means and the environmental information detection means are arranged in the process unit.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect , the piezoelectric microphone and electrostatic microphone as the sound detecting means and the environmental information detecting means are detachably fixed to the support. It is characterized by this.
According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect , the plurality of process units are provided, and the visible image developed on each latent image carrier in each process unit is transferred. The transfer unit is configured to transfer the image on the body, and the presence or absence of abnormality in each process unit is determined based on the detection results of the sound detection unit and the environmental information detection unit of each process unit. The above-described determination means is configured as described above.

  In these inventions, the presence or absence of abnormality is determined based on the sound emitted from the subject to be tested, unlike the case based on vibration, regardless of the variation in the fixed state and the fixed position of the sound detection means as the information detection means. Therefore, the presence or absence of abnormality can be accurately determined. In addition to the sound emitted from the subject to be examined, it is possible to determine the degree of sound abnormality based on the reference according to the environment by using environmental information such as temperature, humidity, and air components. . Therefore, the presence / absence of an abnormality can be accurately determined regardless of environmental changes.

A first embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter simply referred to as a copying machine) as an image forming apparatus will be described below.
First, the basic configuration of the copier according to the first embodiment will be described. FIG. 1 is a schematic configuration diagram showing the copying machine. 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 this 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 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, and the toner of the two-component developer adhering to the developing sleeve 65 is used as the photosensitive member 4K, Y, M. , C, a developing unit 67 for transferring to C.

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

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

  The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 73 as the developing sleeve 65 rotates, and then conveyed to the developing area facing the photoreceptor 40. Then, due to the potential difference between the developing bias applied to the developing sleeve 65 and the electrostatic latent image on the 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 a transfer sheet as a recording medium. Yes.

  The copying machine includes information acquisition means for acquiring various information related to the state of the components and phenomena occurring inside. This information acquisition means includes the control unit 1, various sensors 2, and the operation display unit 3 shown in FIG. The control unit 1 is a control unit that controls the entire copying machine, and includes a ROM 1c that is an information storage unit that stores a control program, a RAM 1b that is an information storage unit that stores calculation data and control parameters, and a CPU 1a that is a calculation unit. have. The operation display unit 3 includes a display unit 3a composed of a liquid crystal display for displaying character information and the like, an operation unit 3b that receives input information from an operator through a numeric keypad and the like, and sends the input information to the control unit 1c. . In this copying machine, the information acquisition means including the control unit 1, various sensors 2, the operation display part 3 and the like is periodically transmitted from the copying machine and the group information group stored in the information storage means such as the ROM (1c). It also functions as an abnormality determination device that determines the presence / absence of an abnormality in the copying machine to be examined based on the acquired various information.

  Examples of information acquired by the information acquisition unit of the copying machine include sensing information, control parameter information, input information, and image reading information. Hereinafter, these pieces of information will be described in detail.

(A) Sensing information 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, a thermocouple system that extracts the thermoelectromotive force generated at the contact point between dissimilar metals or between metal and semiconductor as a signal, the resistivity of metal or semiconductor changes with temperature Resistivity change element using this, pyroelectric element that generates a potential on the surface due to bias in the arrangement of charges in the crystal due to the rise in temperature in certain crystals, and magnetic characteristics depending on temperature 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 set value by the control unit, such as a charging potential, a developing bias value, a fixing temperature set value,
-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 information in the copying machine will be described.
(1) Temperature This 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, ZrO2-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, a characteristic configuration of the copying machine will be described.
FIG. 5 is a perspective view showing one of the K, Y, M, and C process units described above. Since the process units of the respective colors have the same configuration, the suffixes K, Y, M, and C added to the end of the reference numerals are omitted in FIG. In the figure, the process unit 18 includes a sensor support portion 19 that is detachably supported by the process unit main body at an upper portion in the vertical direction. This sensor support part 19 constitutes a part of the casing of the process unit 18, and when it functions as a part of the casing, that is, when it is attached to the process unit body, Multiple sensors are fixed. Specifically, it has a first sensor array 26 having a plurality of sensors arranged in the axial direction of the photoconductor 40, and a second sensor array 29 arranged in parallel therewith. An electric microphone 54, one piezoelectric microphone 31, and an environment sensor 41 are provided. In each case, an electrostatic microphone 54 is disposed at the extreme end of the sensor row, and an environmental sensor 41 is disposed at the opposite end, and another electrostatic microphone 54 is adjacent to the environmental sensor 41. Is arranged, and the piezoelectric microphone 31 is disposed between the two electrostatic microphones 54.

  As shown in FIG. 6, the sensor support unit 19 to which the plurality of sensors that function as a part of the information acquisition unit is fixed is detachably attached to the process unit 18 main body.

  The electrostatic microphone 54 as sound detecting means for detecting the sound pressure emitted from the process unit 18 to be tested is a sensor suitable for detecting a sound signal in a high frequency region. A microphone that converts a sound pressure into an electrical signal by using a change in capacitance. As shown in FIG. 7, a diaphragm 54a made of an electrode capable of bringing the outer surface into contact with the outside air, and an inner surface thereof On the other hand, it has the back electrode 54b which opposes via the predetermined gap | interval G, the insulating support body 54c which supports these, and the power supply circuit 54d which applies a voltage to the back electrode 54b. When the vibration plate 54a vibrates due to sound pressure transmitted from the outside in a state where a voltage is applied to the back electrode 54b, the distance between the two electrodes changes. And according to it, the electrostatic capacitance between both electrodes changes. By detecting this change in capacitance, it is possible to detect the sound in the high frequency region satisfactorily.

  The piezoelectric microphone 31 as sound detecting means is a microphone that converts a sound pressure into an electric signal using a piezoelectric element by a known technique, and is suitable for detecting a sound in a low frequency region.

The environmental sensor 41 can detect temperature and humidity as environmental information by the well-known technique described above. It is also possible to detect nitrogen oxides (NO _x ) in the air as environmental information. FIG. 8 is a schematic diagram illustrating a nitrogen oxide detection unit of the environment sensor 41. This nitrogen oxide detector is constituted by a constant potential electrolytic sensor. A working electrode 41b, an electrolytic solution 41e, a reference electrode 41c, and a counter electrode 41d are sandwiched between two gas permeable membranes 41a. The working electrode 41b is an electrode for causing a reaction to the nitrogen oxide that has passed through the gas permeable membrane 41a. The reference electrode 41c is an electrode serving as a reference for electrochemical potential. In addition, the counter electrode 41d is an electrode for flowing a current i in a pair with the working electrode 41b opposed via the electrolytic solution 41e. By measuring the value of this current i, nitrogen oxides contained in the air can be quantified.

The copying machine is configured to determine whether each process unit 18 is abnormal based on sound information and environmental information acquired by the microphone and the environment sensor 41 in each process unit 18. More specifically, the Mahalanobis distance according to the MTS method is obtained based on the set information including the sound information and the environment 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 group information group, which is a collection of a plurality of group information acquired from a normal copying machine. It is designed to be performed during driving based on the order. In the present copying machine, the control unit 1 described above functions as a determination unit that determines an abnormality of the copying machine to be examined.

  FIG. 9 is a flowchart showing an outline of data processing performed by the abnormality determination device of the copying machine. After the copying machine is shipped from the factory (step 1: hereinafter, step is denoted as S), when the main power of the copying machine is first turned on under the user (S2), part of the abnormality determination device The above-mentioned CPU (1a) stores the time in the RAM (1b) as the period measurement start timing (S3). The RAM (1b) stores a period elapsed determination parameter necessary for determining that a certain period has elapsed from the period measurement start timing prior to factory shipment. Examples of the period elapsed determination parameter include an elapsed time threshold, an elapsed days threshold, an elapsed months threshold, a print number threshold, and an operation time threshold. The group information group construction process is executed from the above-described period measurement start timing to a lapse of a certain period determined based on these period elapsed determination parameters, that is, until a predetermined period elapses ( N in S4, S5). Within this predetermined period, the usability does not change specially from the viewpoint of the copying machine user, and stable data is accumulated. In the group information group construction process performed during such a predetermined period, group information that is a combination of various types of information that can be acquired by the information acquisition unit is acquired during a print job, and is stored in the RAM 1b as an information storage unit as a part of the group information group. Remembered. When the predetermined period elapses from the above-described period measurement start timing (Y in S4), an abnormality determination process is executed instead of the group information group construction process (S6). In this abnormality determination process, the Mahalanobis distance based on the set information composed of various information acquired by the information acquisition means during the print job after the lapse of the predetermined period and the set information group stored in the RAM (1b). Is required. Then, based on the obtained Mahalanobis distance, it is determined whether or not the copying machine has an abnormality.

Table 1 shown below is an example of an acquired data table constructed in the above-described group information group construction process. This acquisition data table shows an example in which n sets of group information composed of k types of information are acquired to form an inverse matrix.

In the set information group construction process, first, k types of information (y ₁₁ , y ₁₂ ... Y _1k ) constituting the first set of set information are acquired by the information acquisition means. And it is memorize | stored in RAM (1b) as data of the 1st line in a data table. Next, k types of information (y ₂₁ , y ₂₂ ... Y _2k ) constituting the second set of information are respectively acquired by the information acquisition means, and the second row data in the data table is as follows: It is stored in the RAM (1b). Thereafter, group information for the third and subsequent groups is sequentially acquired along with the print job and stored as data in the data table. Then, the n-th set information is acquired immediately before the above-described predetermined period elapses, and stored in the RAM (1b) as the n-th row data in the data table. When a predetermined period elapses, an average and a standard deviation (σ) of n pieces of k types of information constituting each set of information are obtained, and stored in the RAM as data of n + 1 and n + 2 rows, respectively. The

  When such an acquired data table construction process ends after the above-described predetermined period has elapsed, an inverse matrix construction process is performed immediately thereafter. 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 step 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 step is finished, a correlation coefficient calculation step is performed next. In this correlation coefficient calculation step, all combinations ( _k C ₂ types) in which two different types can be established among the k types of normalized data in the n sets of normalized data groups are based on the following equation. Correlation coefficient r _pq (r _qp ) is calculated.

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

When such a correlation coefficient calculation process is completed, a matrix conversion process is then performed. Through this matrix conversion step, the correlation coefficient matrix R expressed by Equation 3 is converted into an inverse matrix A (R ⁻¹ ) expressed by the following equation.

  The copying machine performs the group information group construction process for constructing the acquisition data table which is the group information group shown in Table 1, and then performs the information normalization process as described above prior to performing the abnormality determination process. The inverse matrix A is constructed by a series of processes including a correlation coefficient calculation process and a matrix conversion process. Then, this inverse matrix A is stored in the RAM (1b).

When the inverse matrix A is constructed, an abnormality determination process for determining whether there is an abnormality in the copying machine is executed. In this abnormality determination process, the Mahalanobis distance (hereinafter referred to as the Mahalanobis distance) in the multi-dimensional space by the inverse matrix A is used for the combination information composed of all or part of various information periodically acquired by the information acquisition means for each print job. D (referred to as Mahalanobis distance) is calculated based on the following equation.

  FIG. 10 is a flowchart showing a series of processes from the group information group construction process to the matrix conversion process. In the figure, first, k pieces of information related to the state of the copier are acquired while operating the copier (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).

FIG. 11 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 x ₁ , x ₂ ,..., X _{k in} an arbitrary state are acquired (S2-1). The data types correspond to y ₁₁ , y _{12 ,.} Next, each acquired data is normalized to X ₁ , X ₂ ,..., X _k based on the relational expression ( ₁ ). Then, the square of the Mahalanobis distance D is calculated by the relational expression of the above equation 5 determined using the element a _kk of the inverse matrix A that has already been constructed. “Σ” in the figure represents the sum of the subscripts p and q.

  The control unit (1) compares the Mahalanobis distance D thus determined 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 the failure occurrence caution information is displayed on the operation display unit 3.

  The example in which the inverse matrix A that functions as the normal group data group is stored in the RAM (1b) has been described. However, instead of the inverse matrix A, the following group information group may be stored. That is, the acquired data table constructed by the group information group construction process, the normalized data table obtained during the inverse matrix construction process, the correlation coefficient matrix R, and the like. When any of these normal group data groups is stored instead of the inverse matrix A, the inverse matrix A may be constructed based on the data prior to the determination of abnormality.

  According to the copying machine configured as described above, various types of abnormalities are found over a wide range by determining abnormalities in the acquisition result of the combination information including all or part of various information by the MTS method. be able to. Further, since it is not necessary to monitor the presence or absence of each abnormality, it is possible to avoid complication of control due to such monitoring. Further, even if the copying machine is not trial-run at the factory prior to shipment, it is possible to determine whether there is an abnormality after acquiring a normal data group from the copying machine in a normal state at the shipping destination. In addition, the normal data group used for determination can be obtained from the copying machine itself, not from the standard machine. Therefore, it is possible to avoid both the high cost of acquiring a normal data group for each product prior to shipment and the decrease in determination accuracy due to the adoption of the normal data group acquired from the standard machine for each product. it can.

  The example in which the group information group as the normal data group is constructed in the period from the time when the operation is first started after the factory shipment until the lapse of the predetermined period has been described. A group information group as a normal data group may be constructed during a period from when the operation is started until a predetermined period elapses. In this case, a normal data group suitable for a part or unit exchanged for repair can be constructed.

Next, a description will be given of the copying machine of each example in which a more characteristic configuration is added to the copying machine according to the first embodiment.
[First embodiment]
FIG. 12 is a block diagram showing a part of the electric circuit of the copying machine according to the first embodiment. The control unit 1 serving as a determination unit receives the sound signal output from the electrostatic microphone 54 and the piezoelectric microphone 31 described above, not directly, but via the Fourier transform circuit 4. Based on the Fourier-transformed sound signal, the above acquisition data table is constructed. The Fourier transform makes it possible to analyze sound information with various frequencies mixed for each frequency. In the figure, for convenience, only a microphone for one process unit and the environment sensor 41 are shown, but actually, a microphone for four process units and the environment sensor 41 are connected to the control unit 1. ing.

  FIG. 13 is a graph showing a waveform after Fourier transform of a low-frequency sound signal detected by the piezoelectric microphone 31 in the process unit 18 in a normal state. When there is no abnormality in the process unit 18, as shown in the figure, the waveform has no undulations in which the sound intensity (amplitude) of each frequency in the low frequency region appears with substantially the same value.

  FIG. 14 is a graph showing a waveform after Fourier transform of a high-frequency sound signal detected by the electrostatic microphone 54 in the process unit 18 in a normal state. When there is no abnormality in the process unit 18, as shown in the figure, even in a high frequency region, a waveform having no undulations in which the sound intensity (amplitude) of each frequency appears at substantially the same value.

  FIGS. 15 and 16 are graphs showing waveforms after low-frequency sound signals and high-frequency sound signals detected by the piezoelectric microphone 31 and the electrostatic microphone 54 in the process unit 18 in an abnormal state, respectively. . When there is an abnormality in the process unit 18, the sound intensity (amplitude) of each frequency often varies greatly from frequency to frequency as shown in the figure. However, depending on the structure and characteristics of the process unit 18, even in a characteristic state, only a sound component of a specific frequency may vary greatly depending on time and circumstances. Therefore, just because the sound intensity at a specific frequency fluctuates greatly does not necessarily mean that it is abnormal. Therefore, in this copying machine, the sound intensity of each sound signal output from each microphone and subjected to Fourier transform is digitized for each predetermined frequency and stored in the above-described acquired data table. In this way, the sound intensity for each frequency is digitized and incorporated into the group information group, and the Mahalanobis distance is obtained based on this, thereby determining that there is no abnormality in the waveform variation in a normal state. it can.

  In addition, in this copying machine, in addition to the sound information acquired by each microphone, the temperature, humidity, and nitrogen oxide concentration in the air as environmental information acquired by the environmental sensor 41 are incorporated as part of the group information group. It has become. In such a configuration, even if the temperature, humidity, and nitrogen oxide concentration fluctuate, it is possible to determine the degree of sound abnormality on the basis of the value after the fluctuation. For example, in a high-humidity environment where the frictional resistance between the cleaning blade 75 and the photosensitive member 40 is relatively large, even if the waveform of a sound signal with conspicuous undulations is generated, it is avoided that it is erroneously detected as abnormal. It becomes possible. Therefore, the presence / absence of an abnormality can be accurately determined regardless of environmental changes.

  The example in which the abnormality determination device is mounted in the copying machine main body has been described so far, but the abnormality determination device may be configured separately from the copying machine. In this case, the receiving means of the abnormality determination device that receives various information sent from the copying machine via the communication line, not the various sensors and control units installed in the copying machine, acquires the information of the abnormality determination device. Functions as a means. Then, abnormality determination and diagnosis can be performed at a remote place away from the copying machine. Furthermore, a plurality of copying machines can be centrally managed by one abnormality determination device, and each abnormality can be determined. In addition, if the abnormality determination device is provided with a transmission means for transmitting the determination result to the outside via a communication line, the determination result is transmitted to each copying machine installed at a different remote location to notify the operator. You can also The communication line may be either wired or wireless, and any form such as an electric line or an optical fiber may be used. Moreover, although the example which calculates | requires Mahalanobis distance based only on sound information and environmental information was demonstrated, in addition to those information, it acquires by the specific acquisition method of other acquisition information, for example, the various information demonstrated previously, for example. The Mahalanobis distance may be obtained based on vibration, toner density, photoreceptor potential, coloring area ratio, and the like.

  As described above, in the copying machine according to the embodiment, the Fourier transform circuit 4 serving as the Fourier transform unit that performs Fourier transform on the sound signal detected by the piezoelectric microphone 31 or the electrostatic microphone 54 serving as the sound detection unit is provided and serves as the determination unit. The control unit 1 is made to determine the presence or absence of abnormality of the process unit 18 to be examined based on the signal subjected to Fourier transform. In such a configuration, it is possible to detect various sound changes by analyzing the intensity of the detected sound for each frequency. As a result, a change in sound accompanying the occurrence of an abnormality can be detected with high accuracy.

  In the copying machine according to the embodiment, since a plurality of microphones as sound detection means are provided, it is possible to detect sounds reverberating in various directions in the process unit and use them for abnormality determination.

  In the copying machine according to the embodiment, since the piezoelectric microphone 31 and the electrostatic microphone 54 are provided as the plurality of sound detection means, sound signal components from the low frequency region to the high frequency region can be accurately obtained. Can be detected.

  In the copying machine according to the embodiment, the environmental sensor 41 having the temperature detecting means for detecting the temperature and the humidity detecting means for detecting the humidity is provided as the environmental information detecting means. By reflecting the relationship with the change in sound when determining the abnormality, it is possible to detect the abnormality in the sound regardless of changes in temperature and humidity.

  In the copying machine according to the embodiment, the environmental sensor 41 that detects nitrogen oxides in the air is provided as the environmental information detection unit. Therefore, the relationship between the change in nitrogen oxides and the change in sound is abnormal. Therefore, it is possible to detect a sound abnormality regardless of a change in the nitrogen oxide concentration in the air. As a result, even in an environment with a high nitrogen oxide concentration in which a phenomenon called image flow is likely to occur, it is possible to accurately detect a sound abnormality by capturing a change in sound accompanying the occurrence of image flow.

  Further, in the copying machine according to the embodiment, the photosensitive member 40 as a latent image carrier and the photosensitive member cleaning device 63 as a cleaning unit are supported on a common support member with respect to the image forming apparatus main body. The process unit 18 is configured to be attached and detached. The process unit 18 is provided with various microphones as sound detection means and an environment sensor 41 as environment information detection means. In such a configuration, an abnormality occurring in the process unit 18 can be determined based on a sound generated in the unit.

  Further, in the copying machine according to the embodiment, each microphone as sound detection means and the environment sensor 41 as environment information detection means are detachably fixed to a unit casing as a support. In such a configuration, when the process unit is replaced, only the unit main body is replaced so that each sensor is reused, and each microphone is easily regenerated when the process unit is recycled, so that the cost can be reduced.

  In the copying machine according to the embodiment, a plurality of process units 18 are provided, and a toner image that is a visible image developed on each photoconductor 40 in each process unit 18 is transferred onto a transfer sheet that is a transfer body. Thus, a secondary transfer device 22 as a transfer means is configured. Further, the control unit 1 is configured as a determination unit so as to determine the presence / absence of abnormality in each process unit 18 based on the detection results of the microphones of each process unit and the environment sensor 41. In such a configuration, it is possible to individually determine whether there is an abnormality in each process unit while forming a multicolor image by superimposing the respective color toner images formed in each process unit.

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 the copier. FIG. 2 is a perspective view showing a process unit of the copier. The perspective view which shows the process unit of the state which removed the sensor support part. The schematic diagram which shows the electrostatic microphone of the sensor support part. The schematic diagram which shows the nitrogen oxide detection part of the environmental sensor of the sensor support part. 6 is a flowchart showing an outline of data processing performed by the abnormality determination device of the copier. 6 is a flowchart showing a series of processes from a group information group construction process to a matrix conversion process performed by the copier. The flowchart which shows the procedure which calculates Mahalanobis distance D based on the inverse matrix A and various acquisition data. 1 is a block diagram showing a part of an electric circuit of a copying machine according to a first embodiment. The graph which shows the waveform after the Fourier-transform of the low frequency sound signal detected with the piezoelectric microphone in the process unit of a normal state. The graph which shows the waveform after the Fourier-transform of the high frequency sound signal detected with the electrostatic type microphone in the process unit of a normal state. The graph which shows the waveform after the Fourier-transform of the low frequency sound signal detected with the piezoelectric microphone in the process unit of the abnormal state. The graph which shows the waveform after the Fourier-transform of the high frequency sound signal detected by the electrostatic microphone in the process unit of an abnormal state.

Explanation of symbols

1a CPU (determination means, part of information acquisition means, part of abnormality determination device)
1b RAM (information storage means, part of information acquisition means, part of abnormality determination device)
1c ROM (information storage means, part of information acquisition means, part of abnormality determination device)
2 Various sensors (part of information acquisition means, part of abnormality determination device)
3 Operation display section (part of information acquisition means, part of abnormality determination device)
20 Intermediate transfer belt (part of transfer means)
22 Secondary transfer device (part of transfer means)
31 Piezoelectric microphone (sound detection means)
40K, Y, M, C photoconductor (latent image carrier)
41 Environmental sensor (environmental information detection means)
54 Electrostatic microphone (sound detection means)
61 Development unit (development means)
62 Primary transfer roller (part of transfer means)

Claims (7)

A sound detecting means for detecting the sound emitted from a subject, the environment information detecting means for detecting environmental information, detection result by the sound detection means, and based on the detection result by the environment information detecting means, said subject In an abnormality determination device comprising determination means for determining the presence or absence of an abnormality of a target,
As the sound detection means, at least a piezoelectric microphone and an electrostatic microphone are used,
Fourier transform means for Fourier transforming the low frequency component of the sound signal detected by the piezoelectric microphone and Fourier transforming the high frequency component of the sound signal detected by the electrostatic microphone,
The presence / absence of abnormality of the test object is determined based on the result of digitizing the sound intensity for each predetermined frequency of the signal after Fourier transform by the Fourier transform means and the detection result by the environmental information detection means. Furthermore, the abnormality determination apparatus comprising the determination means. In the abnormality determination device according to claim 1 ,
An abnormality determination apparatus comprising a temperature detection means for detecting temperature and a humidity detection means for detecting humidity as the environmental information detection means. In the abnormality determination device according to claim 1 or 2 ,
An abnormality determination device, characterized in that a means for detecting nitrogen oxides in the air is provided as the environmental information detection means. A latent image carrier for carrying a latent image; a developing means for developing the latent image on the latent image carrier; a transfer means for transferring the developed visible image from the latent image carrier to a transfer body; In an image forming apparatus comprising: a cleaning unit that cleans the latent image carrier later; and an abnormality determination unit that determines whether there is an abnormality.
As the abnormality determining unit, the image forming apparatus characterized by using any one of the abnormality determination apparatus according to claim 1 to 3. The image forming apparatus according to claim 4 .
At least the latent image carrier and the cleaning unit are configured as a process unit that is detachably attached to the image forming apparatus main body in the state of one unit supported by a common support, and the process unit includes: An image forming apparatus comprising the sound detection unit and the environmental information detection unit. The image forming apparatus according to claim 5 .
An image forming apparatus characterized in that the piezoelectric microphone and electrostatic microphone as the sound detection means and the environmental information detection means are detachably fixed to the support. The image forming apparatus according to claim 5 or 6 ,
A plurality of the process units are provided, and the transfer means is configured to transfer the visible image developed on each latent image carrier in each process unit so as to be superimposed on the transfer body. An image forming apparatus comprising: the determination unit configured to determine whether each process unit has an abnormality based on detection results of the sound detection unit and the environment information detection unit of the unit.

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