Recording material conveyance system, image forming system, and control program

Abstract

To provide a recording material conveyance system capable of determining an optical sensor deteriorated in a machine of a recording material conveyance system without being affected by paper powder and dirt in the machine of the recording material conveyance system.SOLUTION: A recording material conveyance system 40 comprises conveyance units 20 and 50 for conveying a recording material, a light-emitting unit for irradiating a conveyed recording material with light, and a light-receiving unit for receiving reflected light from the recording material, and further comprises an optical sensor (for example, paper sheet detection sensors 46 and 47) outputting a detection result corresponding to the reflected light, and a control unit 41 for determining deterioration of the optical sensor based on the detection result output from the optical sensor by irradiating the recording material on which a density patch image is formed with light.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a recording material conveyance system, an image forming system, and a control program.

Background Art

[0002] Conventionally, in a conveyance path within a recording material conveyance device, an optical sensor has been employed to detect the arrival timing of a sheet, the leading edge or trailing edge of the sheet. Optical sensors generally deteriorate over time and the amount of light emitted decreases. Also, in image forming apparatuses, the use of white toner and the like has increased, and colored papers such as black paper have come to be used. Originally, the amount of reflected light from black paper is less than that from white paper. Therefore, with an optical sensor that has advanced deterioration, it has been difficult to ensure detection accuracy for colored papers such as black paper, and there has been a problem that jams and problems in image formation occur.

[0003] Therefore, Patent Document 1 discloses a technique for irradiating a member facing an optical sensor with light and detecting deterioration of the optical sensor based on the output level of the optical sensor when no sheet is present.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique described in Patent Document 1, since the member facing the optical sensor is on the recording material conveyance path, there are changes in the output of the optical sensor due to a plurality of factors such as paper dust, soiling of the member, and external light. Therefore, it has sometimes been difficult to judge deterioration of the optical sensor. Also, the sensor output level when no sheet is present may not be detectable or there may be a concern about a decrease in detection accuracy depending on the member facing the optical sensor on the recording material conveyance path. Therefore, the technique described in Patent Document 1 is restricted in its configuration.

[0006] Under the above circumstances, there has been a demand for a method capable of determining the deterioration of an optical sensor without being affected by paper dust or dirt in the recording material conveyance system.

Means for Solving the Problems

[0007] In order to solve the above problems, a recording material conveyance system according to an aspect of the present invention includes a conveyance unit that conveys a recording material, a light emitting unit that irradiates light onto a surface on which a density patch image of the conveyed recording material is formed, and a light receiving unit that receives reflected light from the recording material, an optical sensor that outputs a detection result according to the reflected light, and a control unit that determines the deterioration of the optical sensor based on a result of comparing the detection result output from the optical sensor with a preset threshold value.

Effects of the Invention

[0008] According to at least one aspect of the present invention, it is possible to determine the deterioration of the optical sensor in the recording material conveyance system without being affected by paper dust or dirt in the recording material conveyance system.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 10

Mode for Carrying Out the Invention

[0010] Hereinafter, with reference to the accompanying drawings, examples of modes for carrying out the present invention (hereinafter referred to as "embodiments") will be described.

[0011] In this specification and the accompanying drawings, the same reference numerals are given to the same or similar components, and redundant descriptions may be omitted, or only descriptions centered on the differences may be made. Also, when there are a plurality of the same or similar components, they may be described with different subscripts attached to the same reference numeral. In addition, when it is not necessary to distinguish these plurality of components, the subscripts may be omitted in the description. The number of each component may be singular or plural unless otherwise specified.

[0012] <First Embodiment> [Configuration of Image Forming System] FIG. 1 is a schematic cross-sectional view schematically showing the configuration of an image forming system according to a first embodiment of the present invention. The image forming system 100 includes a recording material conveyance system 40 (see FIG. 2).

[0013] The image forming system 100 is composed of an image forming apparatus 2 and an image reading apparatus 3. A paper feeding apparatus 1 is provided upstream of the image forming apparatus 2. A paper discharging apparatus 4 is provided downstream of the image reading apparatus 3. Note that the paper feeding apparatus 1 and the paper discharging apparatus 4 do not necessarily have to be provided.

[0014] [Image forming apparatus] The image forming apparatus 2 forms an image by, for example, an electrophotographic method. The image forming apparatus 2 is a so-called tandem type color image forming apparatus that forms a full-color image by arranging a plurality of photosensitive drums 11Y, 11M, 11C, and 11K facing a single intermediate transfer belt 15 in the vertical direction. The image forming apparatus 2 includes an original reading apparatus SC, four sets of image forming units 10Y, 10M, 10C, and 10K, and a fixing apparatus 30.

[0015] The original reading apparatus SC scans and exposes the image of the original by the optical system of the scanning exposure apparatus, reads the reflected light by a line image sensor, and obtains an image signal. The image signal is input as a read value of the image after being subjected to processes such as A / D conversion, shading correction, and compression. Note that the input image data is not limited to that read by the original reading apparatus SC. For example, the image data may be received from a personal computer connected to the image forming apparatus 2, another image forming apparatus, or read from a portable recording medium such as a semiconductor memory.

[0016] The four sets of image forming units 10Y, 10M, 10C, and 10K are composed of an image forming unit 10Y, an image forming unit 10M, an image forming unit 10C, and an image forming unit 10K. The image forming unit 10Y forms a yellow (Y) image. The image forming unit 10M forms a magenta (M) image. The image forming unit 10C forms a cyan (C) image. The image forming unit 10K forms a black (K) image. Each of the individual image forming units 10Y, 10M, 10C, and 10K is composed of a photosensitive drum 11Y, 11M, 11C, 11K, a charging unit arranged around it, an optical writing unit, a developing device, and a drum cleaner.

[0017] The photosensitive drums 11Y, 11M, 11C, and 11K have their surfaces uniformly charged by a charging unit, and a latent image is formed by scanning exposure by an optical writing unit. The developing device develops the latent image on the photosensitive drums 11Y, 11M, 11C, and 11K by using toner. As a result, a predetermined color image (toner image) corresponding to any one of yellow, magenta, cyan, and black is formed on the photosensitive drums 11Y, 11M, 11C, and 11K.

[0018] The image formed on the photosensitive drums 11Y, 11M, 11C, and 11K is sequentially transferred to a predetermined position on the rotating intermediate transfer belt 15 by a primary transfer roller. Note that yellow (Y), magenta (M), cyan (C), and black (K) correspond to the "respective colors of CMYK" of the present invention.

[0019] In addition to the four sets of image forming units 10Y, 10M, 10C, and 10K, the image forming apparatus 2 may include an image forming unit for forming a white (W) image. That is, the image forming unit for forming a white (W) image and the photosensitive drum for white may be provided on the downstream side of the drum cleaner and on the upstream side of the image forming unit 10Y for yellow and the photosensitive drum. When using a colored paper with a high density such as black paper, the image forming apparatus 2 may preferably include an image forming unit for white and a photosensitive drum.

[0020] The image transferred onto the intermediate transfer belt 15 is transferred to a sheet P (an example of a recording material) conveyed at a predetermined timing by a sheet conveying unit 20 by a secondary transfer roller 16. The secondary transfer roller 16 forms a secondary transfer nip by being disposed in pressure contact with the intermediate transfer belt 15.

[0021] The sheet conveying unit 20 conveys the sheet P fed from a sheet feeding unit 21 along a conveyance path. In the sheet feeding unit 21, the sheet P is stacked on a sheet tray. The sheet P stacked on the sheet tray is taken in by a sheet feeding section 22 and sent out to the conveyance path.

[0022] The conveyance path (paper conveyance path 29) is provided with a plurality of paper conveyance means for conveying the paper P. Each conveyance means is composed of a pair of rollers pressed against each other, and at least one of the rollers is rotationally driven through an electric motor which is a driving means. Note that, in addition to being composed of a pair of rollers, a configuration composed of a pair of rotating members can be widely adopted as the conveyance means. Examples of the configuration composed of a pair of rotating members include a combination of belts, a combination of a belt and a roller, and the like.

[0023] A paper detection sensor 25, a skew detection sensor 26, and a media sensor 27 are provided on the conveyance path. The paper detection sensor 25 is an optical sensor used for the purpose of detecting the paper P on the conveyance path. In FIG. 1, the paper detection sensor 25 is arranged between when the paper P is fed and when an image is transferred to the paper P, but it is not limited to this example. The skew detection sensor 26 is a line-shaped image sensor (CIS: Contact Image Sensor) for detecting the skew and posture of the paper P on the conveyance path. The skew detection sensor 26 is provided immediately before the position of the secondary transfer nip on the conveyance path.

[0024] The media sensor 27 acquires the physical property values of the paper P. In FIG. 1, the media sensor 27 is arranged on the downstream side of the confluence point of the conveyance path connected to the three paper feed units 21, but it is not particularly limited as long as it is on the conveyance path. By arranging the media sensor 27 upstream of the transfer position, the image forming conditions can be set according to the physical property values detected by the media sensor 27. Further, for example, the media sensor 27 may be arranged downstream of the fixing device 30.

[0025] The media sensor 27 detects, as physical property values of the sheet P, for example, smoothness, stiffness, and thickness, which are physical property values unique to the sheet P. Further, the media sensor 27 detects the charge amount, moisture content, and grain direction (the angle of the fiber direction of the sheet P) of the sheet P that vary depending on the surrounding environment and usage method. The charge amount is generated when the recording material is affected by the external environment and friction with the conveyance path. The moisture content changes not only due to the external environment but also due to the fixing process of the image forming apparatus 2.

[0026] The media sensor 27 preferably detects at least one or more of the above physical property values. Note that the media sensor 27 may acquire physical property values of recording materials other than the above. The configuration of the media sensor 27 is not particularly limited. As long as it is possible to acquire the physical property values of the above recording materials, a conventionally known detection device can be used without particular limitation.

[0027] The fixing device 30 is a device that performs a fixing process on the sheet P on which an image has been transferred. The fixing device 30 includes, for example, a pair of fixing rollers that are pressed against each other to form a fixing nip, and a heater that heats one or both of the fixing rollers. The fixing device 30 fixes the transferred image to the sheet P through the action of pressure by the pair of fixing rollers and the heat of the fixing rollers. The sheet P on which the fixing process has been performed by the fixing device 30 is discharged outside the machine (outside the image forming apparatus 2) by the paper discharge roller 23.

[0028] When image formation is also performed on the back surface of the sheet P, the sheet P on which image formation on the front surface has been completed is conveyed to the re-feed conveyance path by the switching gate 24. In the re-feed conveyance path, after the rear end of the conveyed sheet P is clamped by the reverse roller, the front and back of the sheet P are reversed by reverse conveyance. The sheet P with the front and back reversed is conveyed by a plurality of conveyance rollers and merged into the conveyance path upstream of the transfer position for image formation on the back surface.

[0029] The operation panel 110 is a touch panel type input unit capable of inputting information according to the information displayed on a display (not shown). The user can set information regarding the sheet P through operations on the operation panel 110. Specifically, the information regarding the sheet P includes, for example, the density or magnification of an image, the paper tray serving as the paper supply source, and the like. Further, when controlled, the operation panel 110 also functions as a display unit that displays various information to the user via the operation panel 110.

[0030] [Image reading device] The image reading device 3 is disposed on the downstream side of the image forming device 2 in the conveyance direction of the sheet P. The image reading device 3 is provided with a sheet conveyance unit 50. The sheet conveyance unit 50 has a conveyance path for conveying the sheet P fed from the image forming device 2 and discharging it outside the machine.

[0031] In the image reading device 3, a first scanner 60a (first image reading unit), a second scanner 60b (second image reading unit), a spectral colorimeter 70, and the like are provided from the upstream side to the downstream side in the conveyance direction of the sheet P. The first scanner 60a, the second scanner 60b, and the spectral colorimeter 70 only need to be disposed on the downstream side of the transfer position, and are not limited to this position and order.

[0032] At a position facing the first scanner 60a, a first backing 80a (background member, first backing unit) is provided in order to accurately read the image on the sheet P by the first scanner 60a. The first backing 80a faces the first scanner 60a through the conveyance path along which the sheet P is conveyed, and constitutes a first opposing surface having a black (background color).

[0033] At a position facing the second scanner 60b, a second backing 80b (background member, second backing unit) is provided in order to accurately read the image on the sheet P by the second scanner 60b. The second backing 80b faces the second scanner 60b through the conveyance path along which the sheet P is conveyed, and constitutes a second opposing surface having a white (background color).

[0034] At a position facing the spectrophotometer 70, a third backing 80c (background member) is provided in order to accurately measure the color of the image on the paper P in the spectrophotometer 70. The third backing 80c faces the spectrophotometer 70 through the transport path along which the paper P is transported, and constitutes a third facing surface having white (background color).

[0035] When the image reading device 3 receives the paper P supplied from the image forming device 2, it detects the image formed on the paper P. The first scanner 60a and the second scanner 60b are respectively arranged so as to face the paper P transported along the transport path, and read the image formed on the paper P.

[0036] Specifically, the first scanner 60a reads the image formed on the paper P from the back surface (first surface) side of the paper P. The first scanner 60a is used, for example, for reading operations of patch images (corresponding to the "density patch images" of the present invention) formed on the paper P, checking for front-back misalignment of the images formed on the paper P, checking for the presence of unexpected images, etc.

[0037] The second scanner 60b reads the image formed on the paper P from the front surface (second surface opposite to the first surface) side of the paper P. The second scanner 60b is used for reading operations of patch images and the like formed on the paper P. When the first scanner 60a and the second scanner 60b are collectively referred to, they are hereinafter referred to as the scanner 60.

[0038] The scanner 60 and the spectrophotometer 70 will be further described. The scanner 60 is provided on the upstream side of the spectrophotometer 70 in the transport direction of the paper P, and includes a light source that irradiates light onto the paper P passing through the reading position, and a line image sensor in which a plurality of imaging elements that perform photoelectric conversion for each pixel are arranged in a one-dimensional manner in the paper width direction.

[0039] Here, the image sensor is specifically a CCD (Charge Coupled Device). The CCD is an optical sensor that reads the image on the paper P at the reading position. The CCD functions as a color line sensor that can read the entire width range in the width direction of the paper P by being arranged in a row. Note that the image sensor may be a CMOS (Complementary MOS).

[0040] Specifically, when actually performing the reading operation, in addition to the image sensor, an optical system (not shown) and a light source of an LED (Light Emitting Diode) that illuminates the reading position operate in cooperation. The optical system is for guiding the image at the reading position to the CCD and includes a plurality of mirrors and a plurality of lenses. Note that the above line image sensor can be realized by a CCD line sensor.

[0041] The reading range of the scanner 60 is set to cover the maximum width of the paper P that can be supplied from the image forming apparatus 2. The scanner 60 repeatedly performs the reading operation of an image for one line extending in the paper width direction in accordance with the conveyance operation of the paper P passing through the reading position. By doing so, the scanner 60 reads the image formed on the paper P as a two-dimensional image. The read image is generated as measurement values (RGB values) of the image.

[0042] That is, the scanner 60 has a line image sensor that reads the paper P along the width direction of the paper P. Then, the scanner 60 can acquire the image of the entire surface of the paper P by reading the width of the paper P as one line in the conveyance direction of the paper P. Further, when the spectrocolorimeter 70 and the scanner 60 are collectively referred to as a reading device 55, the image reading device 3 feeds back the result of the reading of the paper P by the reading device 55 to the image forming apparatus 2. That is, the image forming apparatus 2 performs calibration processing for creating a calibration table for each color of the image to be formed on the paper P based on the reading result of the paper P by the image reading device 3.

[0043] The spectral colorimeter 70 (an example of a color measurement unit) is arranged to face the paper P conveyed along the conveyance path, and is disposed on the downstream side of the scanner 60 in the conveyance direction of the paper P. The spectral colorimeter 70 measures the color of an image formed on the paper P, specifically, a patch image or the like.

[0044] The spectral colorimeter 70 irradiates a visible light source from a light source toward a patch image or the like formed on the paper P, acquires the spectral spectrum of the reflected light of the visible light source by a spectral imaging unit, and executes an operation to a predetermined color system. Thereby, color information (chromaticity, lightness, and saturation) of the patch image or the like formed on the paper P is derived.

[0045] The color measurement range of the spectral colorimeter 70, that is, the viewing angle, is set narrower than the reading range of the scanner 60 and narrower than the width of the patch image along the paper width direction. In this way, since the spectral colorimeter 70 performs color measurement limited to a certain viewing angle range, color information can be acquired with higher accuracy than the scanner 60.

[0046] As shown in FIG. 1, the image forming apparatus 2 has a configuration provided on the upstream side of the image reading apparatus 3 in the conveyance direction of the paper P. The image reading apparatus 3 operates in either an in-line method or an off-line method.

[0047] The in-line method is configured to directly feed the image-formed paper P discharged from the image forming apparatus 2 to the image reading apparatus 3. On the other hand, the off-line method is not configured to directly feed the image-formed paper P discharged from the image forming apparatus 2 to the image reading apparatus 3. The off-line method is a method in which the image forming apparatus 2 and the image reading apparatus 3 are each independently configured. Here, the following description will be made on the premise of the in-line method, but the image reading apparatus 3 may operate in the off-line method.

[0048] [Configuration of the Recording Medium Conveying System] Next, the recording medium conveying system 40 according to the present embodiment will be described with reference to FIG. 2. FIG. 2 is a diagram showing a configuration example of a recording material conveyance system 40 according to the present embodiment.

[0049] In the image forming system 100, a paper detection sensor 46, a paper detection sensor 47, and a spectrocolorimeter 70 are arranged on a paper conveyance path 29 (an example of a conveyance path). The paper conveyance path 29 is a path for conveying a sheet of paper P in the paper feeding device 1, the image forming device 2, the image reading device 3, and the paper discharging device 4.

[0050] The paper detection sensors 46 and 47 can detect the arrival timing of the sheet of paper P and the leading edge and trailing edge of the sheet of paper P from the detection result of the sheet of paper P. A reflection type optical sensor is used for the paper detection sensors 46 and 47. The reflection type optical sensor includes a light emitting unit (a light emitting element such as an LED) that irradiates the sheet of paper P with light, and a light receiving unit that receives the reflected light from the sheet of paper P. The light emitting unit irradiates light onto the surface of the conveyed sheet of paper P on which the density patch is formed. For example, the paper detection sensor (optical sensor) irradiates the sheet of paper P with light emitted by a constant current type LED. Then, the reflected light from the sheet of paper is received by a phototransistor, photoelectrically converted, the obtained voltage is amplified by an amplifier circuit, and the output is turned ON / OFF (only binary output) by a comparator.

[0051] In the present invention, the deterioration of the sheet of paper P is determined based on the reflected light from the sheet of paper P on which the patch image is formed. However, the positions of the paper detection sensors 46 and 47 are not limited to the downstream side of the position of the secondary transfer nip on the paper conveyance path 29. For example, assume a configuration in which the sheet of paper P that has completed image formation is conveyed to a refeeding conveyance path as in the image forming device 2, and the sheet of paper P is merged into a conveyance path upstream of the transfer position in order to form an image on the back surface. In this case, the optical sensor for which deterioration is to be determined may be upstream of the transfer position. Further, it may be configured to determine the deterioration of the optical sensor using a sheet of paper on which a patch image is formed and that is fed from the manual feed tray, the paper feeding unit 21, or the paper feeding device 1. By adopting this configuration, the position of the optical sensor for which deterioration is to be determined is not limited to the downstream side or the upstream side of the transfer position.

[0052] The configuration and functions of the spectrocolorimeter 70 are as described above. The spectrocolorimeter 70 measures the color of an image (e.g., a patch image) formed on the paper P and sends the color measurement result to the control unit 41. Note that the scanner 60 and the spectrocolorimeter 70 are one of the optical sensors. Therefore, it is also possible to use the scanner 60 and the spectrocolorimeter 70 as a paper detection sensor. Also, the deviation detection sensor 26 can be used as the paper detection sensor.

[0053] The image forming system 100 mainly includes a control unit 41, a paper conveyance unit 20, 50, an image forming unit 42, and a storage unit 43. The functional configuration of the image forming system 100, particularly the control unit 41 and the storage unit 43, can be realized using a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface (not shown). Various programs and data are stored in the ROM. The RAM temporarily stores programs (control programs) and data necessary when the CPU controls the image forming system 100. The CPU reads programs and data from the ROM to control the image forming system 100. By executing the read program, the deterioration determination of the optical sensor according to the present invention is realized.

[0054] Normally, the image forming system 100 is provided with a non-volatile memory having a relatively large storage capacity. For example, the storage unit 43 is composed of a ROM, a RAM, and a non-volatile memory. Programs may be stored in the non-volatile memory.

[0055] The non-volatile memory consists of, for example, a hard disk, an SSD (Solid State Drive), etc., and stores the image data acquired by the original document reading device SC or the image reading device 3, as well as the image data acquired from the outside via the network. Further, the non-volatile memory stores the image formation conditions set in the image formation job. For example, the non-volatile memory stores the image formation conditions input by the user via the operation panel 110 and the conditions set in advance for the recording material to be used. The non-volatile memory stores, as the image formation conditions set for the recording material used in the image formation job, conditions such as, for example, the basis weight, size, type, printing surface, and coverage of the recording material.

[0056] Each of the image forming apparatus 2, the image reading apparatus 3, the paper feeding apparatus 1, and the paper discharging apparatus 4 may be provided with a microcomputer for realizing the intended function.

[0057] The control unit 41 (an example of a control unit) comprehensively controls the image forming system 100. For example, the functions of the control unit 41 are realized by the CPU executing a program. When each apparatus constituting the image forming system 100 is provided with a microcomputer, the control unit 41 communicates with other apparatuses and controls the image forming apparatus 2 in cooperation with other apparatuses. For example, the control unit 41 controls the operations of the paper conveyance units 20, 50 and the image forming unit 42. Further, the control unit 41 receives the output data of the paper detection sensors 46, 47 (and the spectrocolorimeter 70) and determines the deterioration of the paper detection sensors 46, 47 (and the spectrocolorimeter 70) based on the output data.

[0058] The paper conveyance units 20, 50 include conveyance means such as a plurality of conveyance rollers and registration rollers, and a conveyance path (for example, the paper conveyance path 29). The paper conveyance units 20, 50 convey the paper P in accordance with the control by the control unit 41. Note that the paper feeding apparatus 1 and the paper discharging apparatus 4 also each include a paper conveyance unit (not shown) and convey the paper P in accordance with the control by the control unit 41.

[0059] The image forming unit 42 is a mechanism that forms an image on the paper P, and is composed of four sets of image forming units 10Y, 10M, 10C, 10K, an intermediate transfer belt 15, a primary transfer roller, and a secondary transfer roller 16. The image forming unit 42 forms an image on the paper P according to the control by the control unit 41. On the paper P, an image instructed by an image forming job, a patch image for determining the deterioration of the optical sensor, and the like are formed. Note that the fixing device 30 also performs a fixing process based on the control by the control unit 41, but is not shown in FIG. 2.

[0060] The patch image is formed outside the area where the image by the image forming job is formed on the paper P (outside the image forming area), or at an unnecessary portion (cutting area) that is cut in a post-processing step (not shown) of the paper P. Thereby, the patch image does not interfere with the image formed by the image forming job according to the user's instruction.

[0061] [Sensor received light voltage and paper detection determination result (when the optical sensor is normal)] FIG. 3 is a diagram showing an example of the waveform of the sensor received light voltage and the paper detection determination result when the optical sensor according to the present embodiment is normal. In FIG. 3 and the following drawings, the patch image is also described as a "density patch". In FIG. 3, an example of the received light voltage of the optical sensor to be determined for deterioration, the result of the paper detection determination, the presence or absence of the density patch on the paper, and the integration time of the state where the paper overlaps the optical sensor is shown in a timing chart.

[0062] The image forming apparatus 2 forms a density patch on the paper and conveys the paper (state (1)). The density patch is preferably formed with a density and color that reduce the amount of reflected light. By being reflected by the density patch, the reflected light is reduced (state (2)), and the received light voltage detected by the optical sensor drops to voltage V1. When the optical sensor is not deteriorated, a voltage V1 equal to or higher than the threshold value Vth for determining the presence or absence of the paper can be obtained from the reflected light, and the control unit 41 determines that "paper is present" (state (3)).

[0063] In the figure, time T1 is the timing when the leading edge of the sheet enters the detection range of the optical sensor. Time T2 is the timing when the leading edge of the density patch passes through the detection range of the optical sensor. Time T3 is the timing when the trailing edge of the density patch passes through the detection range of the optical sensor. Time T4 is the timing when the trailing edge of the sheet exits the detection range of the optical sensor.

[0064] [Sensor received light voltage and paper detection determination result (when the optical sensor deteriorates)] FIG. 4 is a diagram showing an example of the waveform of the sensor received light voltage and the paper detection determination result when the optical sensor deteriorates according to the present embodiment. In FIG. 4, an example of the received light voltage of the optical sensor to be determined for deterioration, the result of the paper detection determination, the presence or absence of the density patch on the paper, and the integration time of the state where the paper overlaps the optical sensor is shown in a timing chart.

[0065] The image forming apparatus 2 forms a density patch on the paper and conveys the paper (state (1)). The reflected light is reduced by being reflected by the density patch. Here, when the optical sensor is deteriorated, the reflected light decreases more than when the optical sensor is normal (state (2)). Therefore, the received light voltage detected by the optical sensor becomes a voltage V2 smaller than the voltage V1 when the optical sensor is normal. When the optical sensor is deteriorated, since a voltage equal to or higher than the threshold value Vth for determining the presence or absence of the paper cannot be obtained from the reflected light, the control unit 41 determines that "there is no paper" (state (3)). Therefore, the control unit 41 determines that the optical sensor is at "the end of its life".

[0066] [Sensor deterioration determination process] Next, the procedure of the sensor deterioration determination process of the recording material conveyance system according to the present embodiment will be described with reference to FIG. 5. FIG. 5 is a flowchart showing an example of the procedure of the sensor deterioration determination process of the recording material conveyance system according to the present embodiment.

[0067] When the control unit 41 (Fig. 2) receives a start command for the sensor deterioration determination process, it starts the paper passing for the optical sensor deterioration determination by the paper conveyance units 20, 50, etc. (S1). Next, the control unit 41 generates a density patch on the paper P and forms the density patch on the paper P (S2). When feeding the paper P on which the density patch is formed from the manual feed tray or the paper feeding unit 21, etc., the processing step of density patch generation can be omitted.

[0068] Next, the control unit 41 determines whether the time T1 has elapsed, that is, whether it has detected the timing when the leading edge of the paper P has entered the detection range of the target optical sensor (for example, the paper detection sensor 46 or 47) (S3). If it is determined that the leading edge of the paper P has not entered the detection range of the optical sensor (NO determination in S3), the control unit 41 re-executes the determination process in step S3 after a predetermined time has elapsed.

[0069] On the other hand, if it is determined that the leading edge of the paper P has entered the detection range of the optical sensor (YES determination in S3), the control unit 41 acquires the sensor output data in the state where the optical sensor has read the density patch (S4). Here, the state where the optical sensor has read the density patch means a state where the optical sensor irradiates light on the area including the density patch of the paper P being conveyed and receives the reflected light from the paper P.

[0070] Next, the control unit 41 determines the deterioration of the optical sensor based on the sensor output data (detection result) output from the optical sensor by irradiating light on the paper P on which the density patch is formed. As an example, the control unit 41 compares the sensor output data, that is, the light-receiving voltage of the optical sensor, with a threshold value Vth (Figs. 3 and 4), and determines whether the paper P has been detected (S5). When the light-receiving voltage of the optical sensor is greater than the threshold value Vth, the control unit 41 determines that the paper P has been detected (YES determination in S5) and proceeds to step S7.

[0071] On the other hand, when the received light voltage of the optical sensor is equal to or lower than the threshold value Vth, the control unit 41 determines that the paper P has not been detected (NO determination in S5), and stores the sensor output data (the value of the received light voltage) in the storage unit 43 (S6). By storing the sensor output data in the storage unit 43, the sensor output data can be used for analyzing the cause of deterioration of the optical sensor.

[0072] In the case of a YES determination in step S5, or after the processing of step S6, the control unit 41 ends the paper passage for optical sensor deterioration determination by the paper conveyance units 20, 50, etc. (S7).

[0073] Next, the control unit 41 performs deterioration determination of the optical sensor (S8). In step S8, when the control unit 41 detects the paper P in the determination process of step S5, it determines that the optical sensor is deteriorated. When the control unit 41 determines that the optical sensor is deteriorated, for example, it notifies the operation panel 110 or the terminal device used by the administrator of the image forming system 100 that the optical sensor is deteriorated. After the processing of step S8, the control unit 41 ends the sensor deterioration determination process.

[0074] As described above, the recording material conveyance system 40 (image forming system 100) according to the first embodiment can determine an optical sensor deteriorated in the machine of the recording material conveyance system without being affected by paper dust or dirt in the machine of the recording material conveyance system. In this embodiment, since it is possible to determine an optical sensor deteriorated in the recording material conveyance system, it is possible to determine whether replacement is necessary or the replacement timing, and plan an efficient replacement operation. Therefore, it is possible to prevent a decrease in the productivity / operation rate of the machine. Further, in this embodiment, it is also possible to perform deterioration determination on an optical sensor for which deterioration determination has been difficult due to the configuration of the recording material conveyance system, such as an optical sensor (transmission type optical sensor) that uses a facing member.

[0075] Furthermore, according to this embodiment, since there is no need for a facing member used for the purpose of detecting a detection object with an optical sensor in the machine of the recording material conveyance system, it is more advantageous than the conventional in terms of cost and arrangement space.

[0076] <Second Embodiment> The second embodiment is an example in which, when performing the deterioration determination process of the optical sensor in the first embodiment, the color measurement result of the spectrocolorimeter 70 is taken into consideration. The configuration of the recording material conveyance system (image forming system) according to this embodiment is basically the same as the recording material conveyance system 40 (image forming system 100) shown in FIG. 2 (FIG. 1).

[0077] FIG. 6 is a flowchart showing an example of the procedure of the sensor deterioration determination process of the recording material conveyance system according to the second embodiment of the present invention. The main difference between the flowchart shown in FIG. 6 and the flowchart shown in FIG. 5 is that steps S17 and S19 are added. Hereinafter, the flowchart shown in FIG. 6 will be described centering on the differences from the flowchart shown in FIG. 5.

[0078] When receiving the start command of the sensor deterioration determination process, the control unit 41 (FIG. 2) performs the processes of steps S11 to S16. Since the processes of steps S11 to S16 are the same as the processes of steps S1 to S6 in FIG. 5, detailed description thereof is omitted.

[0079] In the case of a YES determination in step S15, or after the process of step S16, the control unit 41 performs color measurement of the density patch of the paper P by the spectrocolorimeter 70 (S17). The spectrocolorimeter 70 measures all or part of the density patch and sends the color measurement result (color information) to the control unit 41.

[0080] Next, the control unit 41 ends the paper passage for optical sensor deterioration determination by the paper conveyance units 20, 50, etc. (S18).

[0081] Next, the control unit 41 compares the colorimetric result (color information) of the density patch by the spectrocolorimeter 70 with the original data of the density patch, and determines whether the colorimetric result of the density patch is within a preset range (S19). The control unit 41 compares the color information of the density patch formed on the paper P with the corresponding parts of the original data of the density patch. For example, the saturation and / or lightness are compared. Chromaticity may be included in the comparison target.

[0082] When the colorimetric result of the density patch is not within the preset range (NO determination in S19), the control unit 41 ends the sensor deterioration determination process. That is, the control unit 41 determines that the colorimetric result of the density patch is not good and the accuracy of the sensor deterioration determination is not guaranteed, and does not perform the deterioration determination of the optical sensor. Since the control unit 41 does not perform the deterioration determination even if it acquires the sensor output data, it can also be said that the sensor output data is invalidated. The control unit 41 performs the sensor deterioration determination only when the density and color of the density patch formed on the paper P are as intended.

[0083] On the other hand, when the colorimetric result of the density patch is within the preset range (YES determination in S19), the control unit 41 performs the deterioration determination of the optical sensor in the same manner as step S8 in FIG. 5 (S20). After the process of step S20, the control unit 41 ends the sensor deterioration determination process.

[0084] As described above, the recording material conveyance system 40 (image forming system 100) according to the second embodiment has the following effects in addition to the effects of the first embodiment. In this embodiment, since the deterioration determination of the optical sensor using the density patch is performed when the density patch is formed well, it is possible to prevent the accuracy of the deterioration determination from decreasing. Therefore, this embodiment can prevent misjudgment in the deterioration determination of the optical sensor.

[0085] <Third Embodiment> The third embodiment is an example in which, when determining the deterioration of the optical sensor in the first and second embodiments, the deterioration state is determined using density patches including at least two different densities. The configuration of the recording material conveyance system (image forming system) according to this embodiment is basically the same as that of the recording material conveyance system 40 (image forming system 100) shown in FIG. 2 (FIG. 1).

[0086] [Overview of Sensor Deterioration Judgment] FIG. 7 is a diagram for explaining the overview of sensor deterioration determination in the recording material conveyance system according to the third embodiment of the present invention. In this embodiment, density patches composed of images with two different densities are formed on the paper P, and the read information of these density patches is used. The control unit 41 determines the deterioration of the optical sensor based on the detection results of the optical sensor for the images with two different densities included in the density patch.

[0087] The density patch Pd has two images Ima and Imb with different densities. The images Ima and Imb are arranged along the conveyance direction of the paper P indicated by the arrow. The density of the image Ima is "A", and the density of the image Imb is "B". The density B of the image Imb is higher than the density A of the image Ima. The first density A is a density for determining that the optical sensor is approaching the end of its life. The second density B is a density for prompting replacement assuming that the optical sensor has reached the end of its life.

[0088] When it is determined that "paper is present" based on the output data of the optical sensor that has read the image Ima with density A, and it is determined that "paper is absent" based on the output data of the optical sensor that has read the image Imb with density B, the optical sensor is in a state approaching the end of its life. Also, when it is determined that "paper is absent" based on the output data of the optical sensor that has read the image Ima with density A, and it is determined that "paper is absent" based on the output data of the optical sensor that has read the image Imb with density B, the optical sensor has reached the end of its life.

[0089] In this example, the density patch Pd is composed of images Ima and Imb with different densities, but it may also be composed of images with three or more different densities. For example, when the density patch is composed of three images, the density of each image is set as density A, density B, and density C. For example, in descending order of density, let density B > density C > density A. By using such a density patch having three density images, the degree of deterioration of the optical sensor can be determined more finely than in the example of FIG. 7. In this example, it is possible to determine the quality of the sensitivity of the optical sensor with respect to density C, which is an intermediate density between density B and density A.

[0090] Also, a density patch may be configured using three or more images including at least two densities. For example, when the density patch is composed of three images, two of the three images are set to density A (light), and the remaining one image is set to density B (dark). Alternatively, one of the three images may be set to density A, and two images may be set to density B. In the case of such a density patch, sheet detection such as in step S35 or S38 is performed three or more times. By including two or more images of the same density in the density patch, sheet detection based on the corresponding density can be performed twice to accurately determine. Therefore, the determination accuracy of the sensor deterioration state (degree of deterioration) can be improved by the combination of sheet detection determinations for each density.

[0091] [Sensor Deterioration Determination Process] Next, the procedure of the sensor deterioration determination process of the recording material conveyance system according to the present embodiment will be described with reference to FIG. 8. FIG. 8 is a flowchart showing an example of the procedure of the sensor deterioration determination process of the recording material conveyance system according to the present embodiment.

[0092] When the control unit 41 (FIG. 2) receives a start command for the sensor deterioration determination process, it starts paper passage for optical sensor deterioration determination by the paper conveyance units 20, 50, etc. (S31). Next, the control unit 41 generates a density patch Pd having a plurality of densities (density A, density B) on the paper P, and forms the density patch Pd on the paper P (S32).

[0093] Next, the control unit 41 determines whether the time T1 has elapsed, that is, whether it has detected the timing when the leading edge of the sheet P has entered the detection range of the target optical sensor (for example, the sheet detection sensors 46 or 47) (S33). If it is determined that the leading edge of the sheet P has not entered the detection range of the optical sensor (NO determination in S33), the control unit 41 re-executes the determination process in step S33 after a predetermined time has elapsed.

[0094] On the other hand, if it is determined that the leading edge of the sheet P has entered the detection range of the optical sensor (YES determination in S33), the control unit 41 acquires the sensor output data in the state where the optical sensor has read the image Ima with density A (S34).

[0095] Next, the control unit 41 determines whether the sheet P has been detected from the sensor output data for density A as in step S5 (S35). If the control unit 41 has detected the sheet P (YES determination in S35), it proceeds to step S37.

[0096] On the other hand, if the control unit 41 has not detected the sheet P (NO determination in S35), it determines that the optical sensor has reached the end of its life (S36), and stores the sensor output data in the storage unit 43. The control unit 41 notifies the operation panel 110 or the terminal device used by the administrator of the image forming system 100 that the optical sensor has reached the end of its life. Further, the control unit 41 outputs a message prompting the replacement of the optical sensor to the operation panel 110 or the administrator's terminal device.

[0097] In the case of a YES determination in step S35, or after the process in step S36, the control unit 41 acquires the sensor output data in the state where the optical sensor has read the image Imb with density B (S37).

[0098] Next, the control unit 41 determines whether the sheet P has been detected from the sensor output data for density B as in step S5 (S38). When the control unit 41 detects the sheet P (YES determination in S38), it proceeds to step S40. After determining the deterioration of the optical sensor using the image Ima with a low density of the density patch Pd, the control unit 41 determines the deterioration of the optical sensor taking into account the image Imb with a higher density.

[0099] On the other hand, when the control unit 41 does not detect the sheet P (NO determination in S38), it determines that the optical sensor is approaching the end of its life (S39), and stores the sensor output data in the storage unit 43. The control unit 41 notifies the operation panel 110 or the terminal device used by the administrator of the image forming system 100 that the optical sensor is approaching the end of its life. Even if the sheet is detected with the density patch of density A in step S35 (YES determination in S35), when the sheet cannot be detected with the density patch of the higher density B, it is determined that the optical sensor is deteriorated and approaching the end of its life. When the sheet cannot be detected with the density patch of density A in step S35 (NO determination in S35), it is not assumed that the sheet will be detected with the density patch of density B in step S38 (YES determination in S38).

[0100] In the case of a YES determination in step S38, or after the process of step S39, the control unit 41 ends the paper passage for optical sensor deterioration determination by the paper conveyance units 20, 50, etc. (S40). After the process of step S40, the control unit 41 ends the sensor deterioration determination process.

[0101] As described above, in the recording material conveyance system 40 (image forming system 100) according to the third embodiment, the density patch has images with at least two different densities. The control unit 41 first determines the deterioration of the optical sensor from the result of comparing the detection result of the optical sensor for the image with a lower density (image Ima with density A) with the threshold value (first comparison result). Here, it is determined whether the optical sensor has reached the end of its life. Next, the control unit 41 determines the deterioration of the optical sensor based on the result of comparing the detection result of the optical sensor for the image with a higher density (image Imb with density B) with the threshold value (second comparison result) and the first comparison result. Here, it is determined whether the optical sensor is approaching the end of its life. Thus, in this embodiment, the state of deterioration (degree of deterioration) of the optical sensor can be determined based on the detection results of the optical sensor for different densities.

[0102] Also, in this embodiment, the images of each density included in the density patch are arranged along the conveyance direction of the paper P. By arranging the images of each density included in the density patch in the conveyance direction and forming them on the paper P in this way, this embodiment can acquire the detection results of the optical sensor step by step for each density. Then, in this embodiment, the deterioration of the optical sensor can be determined step by step using the images of different densities of the density patch.

[0103] <Fourth Embodiment> The fourth embodiment is an example of predicting the life of an optical sensor based on time-series sensor output data. The configuration of the recording material conveyance system (image forming system) according to this embodiment is basically the same as the recording material conveyance system 40 (image forming system 100) shown in FIG. 2 (FIG. 1).

[0104] FIG. 9 is a diagram showing an overview of sensor deterioration determination in the recording material conveyance system according to the fourth embodiment of the present invention. In FIG. 9, the horizontal axis represents the energization time of the optical sensor, and the vertical axis represents the sensor light-receiving voltage (sensor output data) at the time of detecting the density patch. The energization time may be considered to be the same as the time when the power supply of the image forming system 100 is on. In FIG. 9, the broken line is a function calculated from the time-series sensor output data 90.

[0105] In this embodiment, the control unit 41 accumulates the time-series sensor output data of the target optical sensor in the storage unit 43. Although the sensor output data when the sheet P was not detected in FIGS. 5 and 6 and the like was stored in the storage unit 43, in this embodiment, the sensor output data when the sheet P is detected is also stored in the storage unit 43.

[0106] In FIG. 9, the sensor output data 90 represents the temporal change of the sensor received light voltage, and the broken line is a function calculated from the sensor output data 90. Based on this function, from a certain time t1, the time t2 when the sensor received light voltage drops below the threshold value Vth at which paper detection becomes impossible can be estimated. The time Tpre from time t1 to time t2 is the time from time t1 until the optical sensor reaches the end of its life, that is, the remaining life.

[0107] As described above, in the recording material conveyance system 40 (image forming system 100) according to the fourth embodiment, the timing when the optical sensor reaches the end of its life (paper detection impossible) can be predicted from the current sensor output data (received light voltage value) and the sensor output data accumulated in the storage unit 43.

[0108] <Fifth Embodiment> The fifth embodiment is an embodiment characterized by the accumulation of time-series sensor output data and the deterioration determination timing of the optical sensor. The configuration of the recording material conveyance system (image forming system) according to this embodiment is basically the same as the recording material conveyance system 40 (image forming system 100) shown in FIG. 2 (FIG. 1).

[0109] FIG. 10 is a flowchart showing an example of the procedure of the sensor deterioration determination process of the recording material conveyance system according to the fifth embodiment of the present invention. When the control unit 41 (Fig. 2) receives a start command for the sensor deterioration determination process, it performs the processes of steps S51 to S57. Since the processes of steps S51 to S57 are the same as the processes of steps S1 to S7 in Fig. 5, detailed descriptions thereof are omitted. However, in order to calculate the most recent paper detection rate, the control unit 41 stores the sensor output data in the storage unit 43 even when the paper P is detected in the determination process of step S55 (YES determination in step S55).

[0110] After the process of step S57, the control unit 41 determines whether or not the most recent paper detection rate of the sensor output data (received light voltage) is equal to or less than a preset value (for example, 80%) (S58). When the most recent paper detection rate is equal to or less than the predetermined value (YES determination in S58), the control unit 41 determines that the optical sensor has reached the end of its life (S59), and stores the sensor output data in the storage unit 43. Then, the control unit 41 notifies the operation panel 110 or the terminal device used by the administrator of the image forming system 100 that the optical sensor has reached the end of its life, and outputs a message prompting replacement of the optical sensor (S60).

[0111] If the most recent paper detection rate exceeds 80% in step S58 (NO determination in S58), or after the process of step S60, the control unit 41 ends the sensor deterioration determination process.

[0112] As described above, the recording material conveyance system 40 (image forming system 100) according to the fifth embodiment determines the deterioration of the optical sensor from the most recent multiple paper detection results (paper detection rate). Thereby, in this embodiment, it is possible to determine the deterioration of the optical sensor while suppressing the influence of disturbances such as noise.

[0113] <Sixth Embodiment> The sixth embodiment is an example of determining whether to perform deterioration determination of the optical sensor or correcting information related to the deterioration determination based on the type of recording material and the physical property values of the media sensor. The configuration of the recording material conveyance system (image forming system) according to this embodiment is basically the same as that of the recording material conveyance system 40 (image forming system 100) shown in FIG. 2 (FIG. 1). Hereinafter, the first to third examples of the recording material conveyance system according to this embodiment will be described.

[0114] (First example) When the control unit 41 determines that the recording material is not of a type suitable for determining the deterioration of the optical sensor using the density patch, the control unit 41 does not perform the deterioration determination of the optical sensor. That is, when the type of the recording material is not suitable for the deterioration determination of the optical sensor, the deterioration determination of the optical sensor is not performed.

[0115] For example, the image forming job acquired by the image forming system 100 includes information on the recording material. Examples of the information on the recording material include the basis weight, size, type, etc. of the recording material. The control unit 41 compares the type of the recording material in the recording material information with the type of the recording material registered in advance as a recording material not suitable for the deterioration determination, and if they match, the deterioration determination is not performed. When passing the paper with the density patch formed through the manual feed tray, the user may input the type of paper used for the deterioration determination from the operation panel 110. Note that the control unit 41 may determine the type of the recording material from the physical property values acquired by the media sensor 27.

[0116] Recording materials that are inappropriate for determining the deterioration of an optical sensor are, for example, black paper, silver paper, clear sheets, etc. With these recording materials, even if the optical sensor has not deteriorated, it is highly likely that a light-receiving voltage (e.g., a voltage value within a predetermined range) suitable for detecting the paper cannot be obtained. For example, in the case of black paper, the light-receiving voltage required for detecting the paper may not be obtained, and there is a possibility that the density patch cannot be detected correctly. Also, since silver paper has a high reflectivity, the light-receiving voltage value may saturate, and there is a possibility that the density patch cannot be detected correctly. Furthermore, in the case of a clear sheet, due to its high transparency and the possibility that a density patch cannot be formed properly, there is a possibility that the density patch cannot be detected correctly. Black paper and silver paper are also one of the recording materials that cannot form a density patch properly.

[0117] In this example, when the type of recording material is not suitable for determining the deterioration of the optical sensor, the determination of the deterioration of the optical sensor is not performed. Thereby, this example can prevent misjudgment in the determination of the deterioration of the optical sensor and can correctly perform the determination of the deterioration of the optical sensor.

[0118] (Second example) When the physical property value of the recording material acquired by the media sensor 27 (Fig. 1) exceeds a preset range, the control unit 41 executes control to not form a density patch on the recording material or to invalidate the sensor output data (an example of a detection result) of the optical sensor. When the physical property value of the recording material is not within the set range, it can be said that the conditions for correctly determining the deterioration of the optical sensor are not met. Examples of the physical property values of the recording material obtained by the media sensor 27 include humidity and reflectivity.

[0119] In this example, when the physical property value of the recording material is not within the appropriate range, the determination of the deterioration of the optical sensor is not performed. Thereby, this example can prevent misjudgment in the determination of the deterioration of the optical sensor and can correctly perform the determination of the deterioration of the optical sensor.

[0120] (Third example) The control unit 41 corrects information related to the deterioration determination of the optical sensor based on the type of recording material or the physical property value of the recording material acquired by the media sensor 27 (FIG. 1), and determines the deterioration of the optical sensor using the corrected information related to the deterioration determination.

[0121] Examples of information related to the deterioration determination of the optical sensor include the received light voltage detected by the optical sensor and the threshold value for paper detection. The control unit 41 performs correction (adjustment) to increase or decrease the received light voltage value or the threshold value detected by the optical sensor based on the physical property value of the recording material.

[0122] In this example, the received light voltage value or the threshold value detected by the optical sensor is corrected based on the physical property value of the recording material obtained by the media sensor. Therefore, in this example, it is possible to correctly perform the deterioration determination of the optical sensor according to the state of the recording material on which the density patch is formed. In addition, since this example corrects the received light voltage value or the threshold value of the optical sensor, there is also an effect of preventing misjudgment of optical sensor deterioration.

[0123] As described above, the recording material conveyance system 40 (image forming system 100) according to the sixth embodiment can prevent misjudgment of optical sensor deterioration and correctly perform the deterioration determination of the optical sensor according to the type of recording material or information on the physical property value of the recording material.

[0124] As described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various other modifications and application examples can be adopted without departing from the gist of the invention described in the claims. For example, the above-described embodiments have described the configuration in detail and specifically in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configured components described. Also, it is possible to replace a part of the configuration of one embodiment with the configured components of another embodiment. It is also possible to add the configured components of another embodiment to the configuration of one embodiment. It is also possible to add, replace, or delete other configured components to a part of the configuration of each embodiment.

[0125] Further, some or all of the above functions, processing units, etc. may be realized in hardware, for example, by designing them using an integrated circuit. As the hardware, a processor device in a broad sense such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) may be used.

Description of Reference Numerals

[0126] 1... Paper feeding device, 2... Image forming device, 3... Image reading device, 4... Paper discharging device, 10C, 10K, 10M, 10Y, 42... Image forming unit, 20, 50... Paper conveyance unit, 25, 46, 47... Paper detection sensor, 27... Media sensor, 29... Paper conveyance path, 40... Recording material conveyance system, 41... Control unit, 43... Storage unit, 70... Spectrophotometer, 90... Sensor output data, 100... Image forming system, 110... Operation panel, V1, V2... Voltage, Vth... Threshold value

Claims

1. A conveying unit that conveys a recording material, a light emitting unit that irradiates light onto the recording material to be conveyed, and a light receiving unit that receives reflected light from the recording material, an optical sensor that outputs a detection result according to the reflected light, a control unit that determines deterioration of the optical sensor based on the detection result output from the optical sensor by irradiating light onto the recording material on which a density patch image is formed, A recording material conveyance system.

2. The density patch image is formed with a density and color that reduce the amount of the reflected light The recording material conveyance system according to Claim 1.

3. The density patch image has images of at least two different densities, The control unit determines deterioration of the optical sensor based on the detection result of the optical sensor with respect to the images of the different densities The recording material conveyance system according to Claim 2.

4. The control unit determines deterioration of the optical sensor based on a result of comparing the detection result with a preset threshold value The recording material conveyance system according to Claim 1.

5. Images of each density included in the density patch image are arranged along the conveyance direction of the recording material, After the control unit determines deterioration of the optical sensor using an image with a lower density of the density patch image, the control unit determines deterioration of the optical sensor using an image with a higher density The recording material conveyance system according to Claim 3.

6. A storage unit that stores the detection result of the optical sensor in time series, The control unit predicts deterioration of the optical sensor using the detection result in time series stored in the storage unit The recording material conveyance system according to Claim 2.

7. A color measurement unit that measures the density patch image formed on the recording material, The control unit compares the color measurement result of the density patch image by the color measurement unit with the original data of the density patch image, and when it is determined that the color measurement result of the density patch image is not within a preset range, the control unit does not determine deterioration of the optical sensor The recording material conveyance system according to Claim 2.

8. When the control unit determines that the recording material is not of an appropriate type for determining deterioration of the optical sensor using the density patch image, the control unit does not determine deterioration of the optical sensor The recording material conveyance system according to Claim 2.

9. A media sensor that acquires physical property values of the recording material, When the physical property value of the recording material acquired by the media sensor exceeds a preset range, the control unit does not form the density patch image on the recording material or executes control to invalidate the detection result of the optical sensor. The recording material conveyance system according to claim 2.

10. Comprising a media sensor that acquires the physical property value of the recording material, Based on the type of the recording material or the physical property value of the recording material acquired by the media sensor, the control unit corrects information related to the deterioration determination of the optical sensor and determines the deterioration of the optical sensor using the corrected information related to the deterioration determination. The recording material conveyance system according to claim 2.

11. The control unit corrects the detection result of the optical sensor as information related to the deterioration determination of the optical sensor. The recording material conveyance system according to claim 10.

12. The optical sensor is disposed on a conveyance path for conveying the recording material. The recording material conveyance system according to claim 1.

13. A conveyance unit that conveys a recording material, An image forming unit that forms a density patch image on the recording material, A light emitting unit that irradiates light on the conveyed recording material and a light receiving unit that receives reflected light from the recording material, and an optical sensor that outputs a detection result according to the reflected light, A control unit that determines the deterioration of the optical sensor based on the detection result output from the optical sensor by irradiating light on the recording material on which the density patch image is formed. An image forming system.

14. A control program for determining the deterioration of an optical sensor provided with a light emitting unit that irradiates light on a recording material conveyed by a conveyance unit and a light receiving unit that receives reflected light from the recording material, the optical sensor being disposed in the conveyance unit, An acquisition step of acquiring a detection result corresponding to the reflected light from the optical sensor by irradiating light on the recording material on which the density patch image is formed, A determination step of determining the deterioration of the optical sensor based on the acquired detection result, A control program comprising the above.

Images