JP2015122594A - Image reading device, image forming apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device, an image forming apparatus, and a program, which include simple failure diagnosis means capable of identifying a failure spot.SOLUTION: An image reading device includes: a color reference part colored with plural reference colors to be used for proofing; illumination means for emitting illumination light for illuminating the color reference part; and reading-means for reading the color reference part by separating into individual colors of plural colors that form a predetermined color space, the color reference part illuminated by the illumination means, and outputting a set of spectral intensities consisting of spectral intensities for each of the plural colors of each of plural reference colors. Further, the device performs at least one of a first detection and a second detection, where, in the former, presence of a lighting failure of the illumination means is detected on the basis of the set of spectral intensities of each of the plural reference colors, and in the latter, at least one of presence of a characteristic change of the illumination means and presence of characteristic change of at least one reference color is detected on the basis of a chromaticity difference of a reference color calculated based on the chromaticity of each of plural reference colors within a color space represented by a set of spectral intensities.

Description

  The present invention relates to an image reading apparatus, an image forming apparatus, and a program.

Patent Document 1 discloses a photoelectric conversion unit configured to emit illumination light, photoelectrically convert a light source divided into blocks and light corresponding to an original image illuminated by the light source, and divided into blocks. The photoelectric conversion unit is configured to photoelectrically convert light corresponding to the document image by dividing the block, and a shading correction unit that corrects shading of image information output from the photoelectric conversion unit, and the shading An abnormality determination processing unit that determines which block of the photoelectric conversion unit is abnormal based on reference plate data obtained by reading a shading correction reference plate obtained by the correction unit, and the abnormality The judgment processing unit
Based on the reference plate data obtained by the shading correction unit, the average value data of the photoelectric conversion blocks corresponding to the blocks constituting the photoelectric conversion unit is obtained, and the average value data of the other photoelectric conversion blocks is unique. It is determined that one block of the photoelectric conversion unit having a value is abnormal, and the light source is configured to divide a plurality of point light sources into blocks and illuminate the light amount control unit for each of the blocks, The abnormality determination processing unit obtains the average value data of the block of the point light source that is different from the data collection range of the photoelectric conversion block and corresponds to the block corresponding to the light amount control unit based on the reference plate data, It is determined which block of one of the light sources having a singular value with respect to the average value data of the block of the point light source is abnormal. The abnormality determination processing unit includes all of the pixel data of one block of the photoelectric conversion unit across a plurality of blocks of the light source for a block indicating a data singular value among average values corresponding to each block of the photoelectric conversion block. If it is abnormal, it is determined that there is no abnormality in the block of the light source and that one block of the photoelectric conversion unit is abnormal, and pixel data of one block of the photoelectric conversion unit straddling a plurality of blocks of the light source An image reading apparatus is disclosed in which, when only average value data corresponding to one position of a block of the light source exhibits specificity, the block of the light source is determined to be abnormal. Has been.

Japanese Patent No. 4894247

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading apparatus, an image forming apparatus, and a program that are capable of specifying a failure location and that include a simple failure diagnosis image means.

  In order to achieve the above object, an image reading apparatus according to claim 1, a color reference unit in which a plurality of reference colors used for calibration are colored, and an illumination unit that emits illumination light that illuminates the color reference unit. The color reference portion illuminated by the illuminating means is spectrally read into each of a plurality of colors forming a predetermined color space, and each of the plurality of reference colors is composed of spectral intensities for the plurality of colors. Based on a reading unit that outputs a set of intensities, a first detection that detects the presence or absence of lighting failure of the illumination unit based on a set of spectral intensities of each of a plurality of reference colors, and a set of the spectral intensities. Presence or absence of a change in the characteristics of the illumination means based on a chromaticity difference between the reference colors calculated based on the chromaticity of each of the plurality of reference colors in the color space, and characteristics of at least one reference color Detect at least one of changes Detecting means for performing at least one of the detection of the second detection, it is intended to include.

  According to a second aspect of the invention, there is provided the invention according to the first aspect, wherein the detection means selects two of the total spectral intensities obtained for each set of spectral intensities for a plurality of reference colors. Each of the ratios of the total spectral intensities is compared with a threshold value to detect the presence or absence of lighting failure of the illumination means.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the detection means is formed by connecting points in the color space representing each of the chromaticity differences. The ratio of the length of each side to the center of the figure and the total length of each side of the figure is obtained for each side, and the amount of deviation from the predetermined position of the center of gravity is determined in advance. When there are two ratios that exceed the predetermined amount and exceed the predetermined reference value, there is a change in the characteristics of the reference color common to the sides corresponding to the two ratios. Is detected.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the detection means is formed by connecting points in the color space representing each of the chromaticity differences. The ratio of the length of each side to the center of the figure and the total length of each side of the figure is obtained for each side, and the amount of deviation from the predetermined position of the center of gravity is determined in advance. When there is no ratio exceeding the predetermined reference value exceeding the predetermined reference value, it is detected that there is a change in the characteristics of the illumination means.

  Further, in order to achieve the above object, an image forming apparatus according to a fifth aspect includes an image reading apparatus according to any one of the first to fourth aspects and an image on a recording medium based on image information. The image forming means for forming the image, and when the detection by the detection means does not detect the presence or absence of the lighting failure or the characteristic change, the recording medium is inspected based on predetermined image information for inspection. Determining means for determining whether or not there is a failure in the image forming means based on a difference between the image information obtained by forming the image for inspection and the image information obtained by reading the inspection image with the image reading device; Is included.

  On the other hand, in order to achieve the above object, the program according to claim 6 includes a color reference portion in which a plurality of reference colors used for calibration are colored, and illumination means for irradiating illumination light for illuminating the color reference portion. The color reference portion illuminated by the illuminating means is spectrally read into each of a plurality of colors forming a predetermined color space, and each of the plurality of reference colors is composed of spectral intensities for the plurality of colors. A program for controlling an image reading apparatus including a reading unit that outputs a set of intensities, wherein the computer is configured to detect a lighting failure of the lighting unit based on a set of spectral intensities of a plurality of reference colors. Based on the first detection for detecting presence / absence, and the chromaticity difference of the reference color calculated based on the chromaticity of each of the plurality of reference colors in the color space represented by the set of the spectral intensities , The characteristic change of the illumination means No, and it is intended to function as at least one detecting means for performing at least one of the detection of the second detection for detecting at least one of the presence or absence of the reference color characteristic change.

  According to the first and sixth aspects of the present invention, there is provided an image reading apparatus and program that can specify a fault location and includes a simple fault diagnosis image means, as compared with a case where the present invention is not applied. The effect of being provided is obtained.

  According to the second aspect of the present invention, it is possible to obtain an effect that the lighting failure of the illumination means is easily detected as compared with the case where the present invention is not applied.

  According to the third aspect of the present invention, it is possible to obtain an effect that the characteristic change of the color reference portion is easily detected as compared with the case where the present invention is not applied.

  According to the invention described in claim 4, it is possible to obtain an effect that the characteristic change of the illumination means is easily detected as compared with the case where the present invention is not applied.

  According to the fifth aspect of the present invention, it is possible to obtain an effect that the presence or absence of a failure of the image forming unit is determined as compared with the case where the present invention is not applied.

1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to an embodiment. 1 is a schematic configuration diagram illustrating an example of a configuration of a built-in image sensor provided in an image forming apparatus according to an embodiment. It is a perspective view of the reference | standard roll which concerns on embodiment. 1 is a perspective view showing a part of a built-in image sensor provided in an image forming apparatus according to an embodiment. It is a schematic diagram for demonstrating the arrangement | positioning relationship between the lamp | ramp which concerns on embodiment, and each color reference plane. 1 is a block diagram illustrating an example of a main configuration of an electric system in an image forming apparatus according to an embodiment. It is a block diagram which shows an example of a structure of the read signal processing part which concerns on embodiment. It is a graph which shows the reading value corresponding to the reading position of the 1st white reference plane concerning an embodiment. It is a graph which shows the state which plotted the reading value of each color reference plane which concerns on embodiment in RGB color space. It is a part of flowchart which shows an example of the flow of a process of the failure diagnosis processing program which concerns on 1st Embodiment. It is a part of flowchart which shows an example of the flow of a process of the failure diagnosis processing program which concerns on 1st Embodiment. It is a schematic diagram which shows an example of the display on the display of the failure diagnosis result which concerns on 1st Embodiment. It is a flowchart which shows an example of the flow of a process of the failure diagnosis processing program which concerns on 2nd Embodiment. 6 is a schematic diagram illustrating an example of an inspection image to be read by a built-in image sensor provided in an image forming apparatus according to a second embodiment. FIG.

[First Embodiment]
Hereinafter, an example of an embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a diagram of a built-in image sensor 200 provided in the image forming apparatus 10 according to the embodiment of the present invention. It is a figure which shows an example.

(overall structure)
The image forming apparatus 10 according to the present embodiment selectively forms a full-color image and a black-and-white image, and is connected to the first housing 10A and the first housing 10A as shown in FIG. A second housing 10B. An image signal processing unit 13 that performs image processing on image data supplied from an external device such as a computer is provided on the upper portion of the second housing 10B. On the other hand, the first special color (V), second special color (W), yellow (Y), magenta (M), cyan (C), and black (K) toners are provided on the upper portion of the first housing 10A. Toner cartridges 14V, 14W, 14Y, 14M, 14C, and 14K are provided.

  Note that examples of the first special color and the second special color include colors other than yellow, magenta, cyan, and black (including transparency). In the following description, the first special color (V), the second special color (W), yellow (Y), magenta (M), cyan (C), and black (K) are distinguished for each component. Is described with a letter as a symbol followed by any letter of V, W, Y, M, C, or K. The first special color (V), second special color (W), yellow (Y ), Magenta (M), cyan (C), and black (K) are not distinguished, V, W, Y, M, C, and K are omitted.

  Under the toner cartridge 14, six image forming units 16 corresponding to the toners of the respective colors are provided so as to correspond to the toner cartridges 14.

  An exposure device 40 (40V, 40W, 40Y, 40M, 40C, 40K) provided for each image forming unit 16 receives image data subjected to image processing by the image signal processing unit 13 from the image signal processing unit 13. The image carrier 18 (18V, 18W, 18Y, 18M, 18C, 18K), which will be described later, is irradiated with a light beam L received and modulated according to the image data.

  Each image forming unit 16 includes an image carrier 18 that is rotationally driven in one direction. By irradiating each image carrier 18 with the light beam L from each exposure device 40, an electrostatic latent image is formed on each image carrier 18.

Around each image carrier 18, a corona discharge (non-contact charging) scorotron charger that charges the image carrier 18 and an electrostatic latent image formed on the image carrier 18 by the exposure device 40 are developed. A developing device that develops with toner, which is an example of an agent, a blade that removes the developer remaining on the image carrier 18 after transfer, and a static eliminator that performs static elimination by irradiating the image carrier 18 after transfer with light. Is provided. The scorotron charger, developing device, blade, and static eliminator are
Opposite the surface of the image carrier 18, the image carrier 18 is arranged in this order from the upstream side to the downstream side in the rotation direction.

  A transfer unit 32 is provided below each image forming unit 16. The transfer unit 32 includes an annular intermediate transfer belt 34 that is in contact with each image carrier 18 and a primary transfer roll 36 that multi-transfers the toner image formed on each image carrier 18 to the intermediate transfer belt 34. Has been.

  The intermediate transfer belt 34 includes a drive roll 38 that is driven by a motor (not shown), a tension applying roll 41 that applies tension to the intermediate transfer belt 34, an opposing roll 42 that faces a secondary transfer roll 62 described below, It is wound around a plurality of winding rolls 44 and is circulated and moved in one direction (counterclockwise direction in FIG. 1) by a drive roll 38.

  Each primary transfer roll 36 is disposed opposite to the image carrier 18 of each image forming unit 16 with the intermediate transfer belt 34 interposed therebetween. The primary transfer roll 36 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power supply unit (not shown). With this configuration, the toner image formed on the image carrier 18 is transferred to the intermediate transfer belt 34.

  On the opposite side of the drive roll 38 across the intermediate transfer belt 34, there is provided a removing device 46 that removes residual toner, paper dust and the like on the intermediate transfer belt 34 by bringing the blade into contact with the intermediate transfer belt 34. .

  Below the transfer unit 32, a plurality of recording medium storage units 48 that store a recording medium P as an example of a medium such as paper are provided. Each of the recording medium accommodating portions 48 can be pulled out from the first housing 10A. A delivery roll 52 that feeds the recording medium P from each recording medium container 48 to the transport path 60 is provided above one end side (right side in front view in FIG. 1) of each recording medium container 48.

  In each recording medium accommodating portion 48, a bottom plate 50 on which the recording medium P is placed is provided. The bottom plate 50 is lowered by an instruction from a control means (not shown) when the recording medium accommodating portion 48 is pulled out from the first housing 10A. When the bottom plate 50 is lowered, a space in which the user replenishes the recording medium P is formed in the recording medium accommodating portion 48.

When the recording medium accommodating portion 48 pulled out from the first housing 10A is attached to the first housing 10A,
The bottom plate 50 is raised by an instruction from the control means. As the bottom plate 50 moves up, the uppermost recording medium P placed on the bottom plate 50 and the delivery roll 52 come into contact with each other.

  On the downstream side in the recording medium conveyance direction of the delivery roll 52 (hereinafter sometimes simply referred to as “downstream side”), a separation roll 56 that separates the recording media P delivered from the recording medium accommodating portion 48 one by one. Is provided. A plurality of transport rolls 54 that transport the recording medium P downstream in the transport direction are provided on the downstream side of the separation roll 56.

  A conveyance path 60 provided between the recording medium storage unit 48 and the transfer unit 32 folds the recording medium P sent out from the recording medium storage unit 48 to the left side as viewed from the front in FIG. The second folding portion 60B extends to the transfer position T between the secondary transfer roll 62 and the counter roll 42 so as to be folded back to the right in the front view in FIG.

  The secondary transfer roll 62 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power feeding unit (not shown). With this configuration, the toner images of each color that have been multiplex-transferred onto the intermediate transfer belt 34 are secondarily transferred onto the recording medium P that has been transported along the transport path 60 by the secondary transfer roll 62.

  A preliminary path 66 extending from the side surface of the first housing 10 </ b> A is provided so as to join the second folding portion 60 </ b> B of the transport path 60. The recording medium P sent out from another recording medium accommodation unit (not shown) arranged adjacent to the first housing 10 </ b> A can enter the conveyance path 60 through the spare path 66.

  On the downstream side of the transfer position T, a plurality of conveying belts 70 that convey the recording medium P on which the toner image has been transferred toward the second casing 10B are provided in the first casing 10A, and are conveyed to the conveying belt 70. A transport belt 80 that transports the recording medium P to the downstream side is provided in the second housing 10B.

  Each of the plurality of conveyor belts 70 and the conveyor belt 80 is formed in an annular shape and is wound around a pair of winding rolls 72. The pair of winding rolls 72 are respectively arranged on the upstream side and the downstream side in the conveyance direction of the recording medium P, and when one of them is driven to rotate, the conveyance belt 70 (conveyance belt 80) moves in one direction (in FIG. 1). Cycle in the clockwise direction.

  A fixing unit 82 for fixing the toner image transferred onto the surface of the recording medium P to the recording medium P with heat and pressure is provided on the downstream side of the conveyance belt 80.

  The fixing unit 82 includes a fixing belt 84 and a pressure roll 88 disposed so as to contact the fixing belt 84 from below. A fixing unit N is formed between the fixing belt 84 and the pressure roll 88 to fix the toner image by pressurizing and heating the recording medium P.

The fixing belt 84 is formed in an annular shape and is wound around the drive roll 89 and the driven roll 90. The drive roll 89 faces the pressure roll 88 from above,
The driven roll 90 is disposed above the drive roll 89.

  Each of the driving roll 89 and the driven roll 90 includes a heating unit such as a halogen heater. As a result, the fixing belt 84 is heated.

  As shown in FIG. 1, a conveyance belt 108 is provided on the downstream side of the fixing unit 82 to convey the recording medium P sent from the fixing unit 82 to the downstream side.

  A cooling unit 110 that cools the recording medium P heated by the fixing unit 82 is provided on the downstream side of the conveyance belt 108.

  The cooling unit 110 includes an absorption device 112 that absorbs the heat of the recording medium P, and a pressing device 114 that presses the recording medium P against the absorption device 112. The absorption device 112 is disposed on one side (upper side in FIG. 1) with respect to the conveyance path 60, and the pressing device 114 is disposed on the other side (lower side in FIG. 1).

  The absorption device 112 includes an annular absorption belt 116 that contacts the recording medium P and absorbs the heat of the recording medium P. The absorption belt 116 is wound around a driving roll 120 that transmits a driving force to the absorption belt 116 and a plurality of winding rolls 118.

  A heat sink 122 made of, for example, an aluminum material is provided on the inner peripheral side of the absorption belt 116 to dissipate the heat absorbed by the absorption belt 116 in contact with the absorption belt 116 in a planar shape.

  Further, a fan 128 for removing heat from the heat sink 122 and discharging hot air to the outside is disposed on the back side of the second housing 10B (the back side of the paper surface shown in FIG. 1).

  The pressing device 114 that presses the recording medium P against the absorbing device 112 includes an annular pressing belt 130 that conveys the recording medium P while pressing the recording medium P against the absorbing belt 116. The pressing belt 130 is wound around a plurality of winding rolls 132.

  On the downstream side of the cooling unit 110, there is provided a correction device 140 that conveys the recording medium P and corrects the curl of the recording medium P.

On the downstream side of the correction device 140, a toner density defect of the toner image fixed on the recording medium P,
A built-in image sensor 200 that detects image defects, image position defects, and the like is provided. Details of the built-in image sensor 200 will be described later.

  On the downstream side of the built-in image sensor 200, a discharge roll 198 that discharges the recording medium P having an image formed on one side thereof to a discharge unit 196 attached to the side surface of the second housing 10B is provided.

  On the other hand, when images are formed on both sides, the recording medium P sent from the built-in image sensor 200 is conveyed to a reversing path 194 provided on the downstream side of the built-in image sensor 200.

  The reversing path 194 includes a branch path 194A that branches from the transport path 60, a paper transport path 194B that transports the recording medium P transported along the branch path 194A toward the first housing 10A, and a paper transport path. A reversing path 194C is provided for turning the recording medium P conveyed along 194B in the reverse direction to switch back and reversing it.

  With this configuration, the recording medium P that is switched back and conveyed by the reverse path 194C is conveyed toward the first housing 10A, and further enters the conveyance path 60 provided above the recording medium container 48, and is transferred to the transfer position. It is sent to T again.

  Next, an image forming process of the image forming apparatus 10 will be described.

The image data that has been subjected to image processing by the image signal processing unit 13 is sent to each exposure device 40.
In each exposure device 40, each light beam L is emitted according to image data, and is exposed to each image carrier 18 charged by a scorotron charger, thereby forming an electrostatic latent image.

  The electrostatic latent image formed on the image carrier 18 is developed by the developing device, and the first special color (V), the second special color (W), yellow (Y), magenta (M), and cyan (C). A toner image of each color of black (K) is formed.

  As shown in FIG. 1, each color toner image formed on the image carrier 18 of each of the image forming units 16V, 16W, 16Y, 16M, 16C, and 16K is composed of six primary transfer rolls 36V, 36W, 36Y, and 36M. , 36C, and 36K, multiple transfer is sequentially performed on the intermediate transfer belt.

  The toner images of the respective colors that have been multiplex-transferred onto the intermediate transfer belt 34 are secondarily transferred onto the recording medium P conveyed from the recording medium accommodating portion 48 by the secondary transfer roll 62. The recording medium P onto which the toner image has been transferred is transported toward the fixing unit 82 provided inside the second housing 10B by the transport belt 70.

  The toner images of the respective colors on the recording medium P are fixed on the recording medium P by being heated and pressurized by the fixing unit 82. Further, the recording medium P on which the toner image is fixed is cooled by passing through the cooling unit 110 and then sent to the correction device 140 to correct the curvature generated in the recording medium P.

  The recording medium P whose curvature is corrected is discharged to the discharge unit 196 by the discharge roll 198 after an image defect or the like is detected by the built-in image sensor 200.

  On the other hand, when an image is formed on a non-image surface where no image is formed (in the case of double-sided printing), after passing through the built-in image sensor 200, the recording medium P is inverted by the inversion path 194, and A toner image is formed on the back surface in the above-described procedure.

  In the image forming apparatus 10 according to the present embodiment, components for forming images of the first special color and the second special color (image forming units 16V and 16W, exposure devices 40V and 40W, toner cartridges 14V and 14W). The primary transfer rolls 36V and 36W) are configured to be attachable to the first housing 10A as additional parts according to the user's selection. Therefore, the image forming apparatus 10 does not have a component for forming the first special color and second special color images, and the image of any one of the first special color and the second special color. It is good also as a structure which has only the components for forming.

  Next, the built-in image sensor 200 will be described.

  In the following description, the length direction of the image forming apparatus 10 (sub-scanning direction that is the conveyance direction of the recording medium P) is the X direction, the height direction of the apparatus is the Y direction, and the depth direction of the apparatus (main scanning direction) is Z. The direction is assumed (see FIGS. 2 and 4).

  The built-in image sensor 200 according to the present embodiment is used, for example, for detecting whether or not there is an abnormality in the image formed on the recording medium P by the image forming unit 16, and in this case The built-in image sensor 200 has a function as a means for measuring gradation reproducibility and color reproducibility of the image forming unit 16. In addition, in order to maintain the function as the measurement unit normally, the built-in image sensor 200 may be calibrated regularly or irregularly.

(Basic configuration and function of built-in image sensor)
As shown in FIG. 2, the built-in image sensor 200, which is an example of an image reading device, includes an illumination unit 202 that emits light toward a recording medium P on which an image is recorded, and a recording medium that is irradiated from the illumination unit 202. An imaging unit 208 having an imaging optical system 206 that forms an image of light reflected by P on a CCD sensor 204 as an example of a reading unit, and various standards and the like when using the built-in image sensor 200 or during calibration. And a setting unit 210 provided. The CCD sensor 204 in the present embodiment includes a red image sensor configured to include a plurality of light receiving elements (for example, photodiodes) arranged along a direction corresponding to the main scanning direction.
A green image sensor and a blue image sensor. Each color image sensor is provided with a filter that transmits light of each color component on the light receiving surface of the light receiving element. Each color image sensor outputs, as a signal, the electric charge accumulated according to the amount of each color component of the light received by the light receiving element.

  The illumination unit 202 is disposed above the conveyance path 60 of the recording medium P, and has a pair of a first lamp 212A and a second lamp 212B (hereinafter referred to as a first lamp 212A) that are elongated in the Z direction (main scanning direction). And the second lamp 212B may be simply referred to as “lamp 212”). As the lamp 212, for example, a fluorescent lamp, a xenon lamp, or a plurality of white LEDs arranged along the main scanning direction is used. As shown in FIG. Used. Further, in this embodiment, the lamp 212 is configured by arranging a plurality of LED substrates 302 on which one or more white LEDs 304 are mounted in the main scanning direction. Of course, the substrate on which the plurality of white LEDs 304 are mounted may be a single substrate. The details of the configuration including the LED substrate 302 of the lamp 212 will be described later.

  Further, the length of the irradiation range of the lamp 212 is set larger than the width of the maximum recording medium P to be conveyed. The lamp 212 is arranged symmetrically with respect to the optical axis OA (designed optical axis) that is reflected by the recording medium P and travels toward the image forming unit 208. More specifically, the lamps 212 are arranged symmetrically with respect to the optical axis OA so that the irradiation angle to the recording medium P is, for example, not less than 45 ° and not more than 50 °.

Specifically, the pair of lamps 212 are arranged along the conveyance path 60 of the recording medium P, and are recorded on the first lamp 212A and the first lamp 212A arranged on the upstream side in the conveyance direction of the recording medium P. And a second lamp 212B disposed on the downstream side in the conveyance direction of the medium P.
Then, the light irradiated from the first lamp 212A and the second lamp 212B is irradiated with the transparent window glass 286 (see also FIG. 4) on the conveyance path 60 between the first lamp 212A and the second lamp 212B. D is irradiated.

  The imaging optical system 206 also reflects the light guided along the optical axis OA in the X direction (in the present embodiment, downstream in the transport direction of the recording medium P), and the first mirror 214. The second mirror 216 that reflects the light reflected by the second mirror 216 upward, the third mirror 218 that reflects the light reflected by the second mirror 216 upstream in the transport direction of the recording medium P, and the light reflected by the third mirror 218 A lens 220 that focuses (images) the CCD sensor 204 is configured as a main part. The CCD sensor 204 is arranged on the upstream side in the transport direction of the recording medium P with respect to the optical axis OA.

  The length of the first mirror 214 in the Z direction is larger than the width of the maximum recording medium P. The first mirror 214, the second mirror 216, and the third mirror 218 squeeze (condensate) the reflected light of the recording medium P incident on the imaging optical system 206 in the Z direction (main scanning direction). It is designed to reflect. Thus, the reflected light from each part in the width direction of the recording medium P is incident on the substantially cylindrical lens 220.

  The built-in image sensor 200 is configured such that the CCD sensor 204 outputs (feeds back) the imaged light, that is, a signal corresponding to the image density, to the control device 20 (see FIGS. 1 and 6) of the image forming apparatus 10. Has been. The control device 20 performs processing for correcting an image formed in the image forming unit 16 based on a signal input from the built-in image sensor 200. As an example of the process of correcting the image, correction of the intensity of irradiation light by the exposure apparatus 40 based on a signal input from the built-in image sensor 200, the image formation position, and the like can be given.

  In addition, a light amount diaphragm unit 224 (224L, 224S, 224U)) is provided between the third mirror 218 and the lens 220 in the imaging optical system 206. The light amount diaphragm unit 224 narrows the light amount of light that forms an image on the CCD sensor 204 across the optical path in the Z direction in the Y direction (direction intersecting with the main scanning direction), and adjusts the amount of light diaphragm by operating from the outside. It is configured freely. The amount of light reduced by the light amount restrictor 224 is adjusted so that the amount of light imaged on the CCD sensor 204 is equal to or greater than a predetermined amount even if the light emission amount of the lamp 212 changes over time.

  The built-in image sensor 200 includes a control circuit 100 provided with a circuit board 262 for controlling a reference roll rotation motor 22 (see FIG. 6) that is a motor for rotating the reference roll 226.

  The setting unit 210 includes a reference roll 226 that is long in the Z direction. The reference roll 226 is formed in a polygonal cylindrical shape in which a predetermined number of surfaces are formed in the circumferential direction. As shown in FIG. 3, in the present embodiment, the reference roll 226 is a polygonal cylindrical shape having 10 surfaces. Has been.

  The reference roll 226 is directed toward the conveyance path 60 when the image detection of the recording medium P is not performed, and the detection reference surface 228 directed toward the conveyance path 60 when the image detection of the recording medium P is performed. A retraction surface 230, a first white reference surface 232, a yellow reference surface 234, and a composite inspection surface 236 on which a plurality of inspection patterns are formed are provided.

  The reference roll 226 is configured to switch the surface to be directed to the conveyance path 60 side by rotating around the rotation shaft 226A. The surface of the reference roll 226 is switched by the control circuit 100 provided on the circuit board 262. Further, the reference roll 226 is formed in a decagonal cylindrical shape, so that a difference in distance from the rotation center between the center in the circumferential direction of each surface and the corner portion between the surfaces is suppressed. Thus, the corners between the surfaces of the reference roll 226 do not interfere with the illumination unit 202 while keeping the distance between each surface of the reference roll 226 and the irradiation position (window glass 286) of the lamp 212 small.

  The detection reference surface 228 has a circumferential width smaller than the other surfaces, and the surfaces on both sides in the circumferential direction are guide surfaces 238 that do not have the above-described functions as the respective references. The detection reference surface 228 is a position reference surface that positions the detected (read) surface of the conveyed recording medium P at the irradiation position by the lamp 212.

The retracting surface 230 has a circumferential width larger than that of other surfaces. The retraction surface 230 is a guide surface that guides the recording medium P when the built-in image sensor 200 does not detect the image of the recording medium P, and the distance from the axis of the rotation shaft 226A is more than the detection reference surface 228. It is considered small. Thereby, when the image detection of the recording medium P by the built-in image sensor 200 is not performed, the image detection of the recording medium P by the built-in image sensor 200 is performed, compared with
A conveyance path having a wide interval with the illumination unit 202 (window glass 286) is formed.

  The composite inspection surface 236 is formed by arranging a position adjustment pattern for correcting the position in the rotation direction of the reference roll 226 (the conveyance direction of the recording medium P), a focus detection pattern, and a depth detection pattern on the same surface. ing.

  The first white reference surface 232 is a reference surface for correcting lightness unevenness in the main scanning direction caused by the lamp 212 or the CCD sensor 204, that is, so-called shading correction, and is configured by adhering a white film, for example. ing. When irradiation light from the lamp 212 is applied to the first white reference surface 232, the reflected light reflected by the first white reference surface 232 is input to the CCD sensor 204 via the imaging optical system 206 as a read signal. It has become.

  The yellow reference surface 234 is a reference surface (color sample) for correcting hue / saturation unevenness in the main scanning direction caused by the lamp 212 or the CCD sensor 204. For example, the yellow reference surface 234 is configured by attaching a yellow film. ing. When the irradiation light from the lamp 212 is applied to the yellow reference surface 234, the reflected light reflected by the yellow reference surface 234 is input to the CCD sensor 204 via the imaging optical system 206 as a read signal. . In the present embodiment, the reason why the yellow color sample is used is that the lamp 212 according to the present embodiment includes a white LED including a blue LED chip and a yellow fluorescent material. is there.

That is, the white LED used in the lamp 212 according to the present embodiment is configured by laminating a blue LED chip and a transparent resin containing a yellow fluorescent material. The yellow fluorescent material around the chip is excited by the blue light emitted from the blue LED chip to generate yellow fluorescence. As a result, the blue and yellow, which are complementary colors, are added together (combined)
Generate white light. Therefore, for example, when manufacturing a white LED, when the blue LED chip has a variation in blue color, or a variation in the characteristics, addition amount, dispersion state, etc. of the yellow fluorescent material, the color temperature of the light generated by the white LED is This is because it may change in the yellow direction or the blue direction.

  In addition, white LED is not restricted to the combination of said blue LED chip and yellow fluorescent substance, The combination of the LED chip of another color and fluorescent substance may be sufficient. In this case, the color of the reference surface may be changed according to the configuration and color of the white LED.

FIG. 4 is a perspective view showing the configuration of the illumination unit 202 and its surroundings according to the present embodiment.
As shown in FIG. 4, the illumination unit 202 includes a window glass 286 that transmits light from the lamp 212 (the first lamp 212A and the second lamp 212B) toward the recording medium P. The window glass 286 has a second white reference surface (side reference) 286 </ b> A that is a white reference provided separately from the reference roll 226. The second white reference plane 286A is
This is a reference surface for correcting variations in brightness for each recording medium P when a plurality of recording media P are read continuously, and is configured, for example, by adhering a white film. Hereinafter, when the first white reference surface 232, the second white reference surface 286A, and the yellow reference surface 234 are not distinguished, they may be simply referred to as “color reference surfaces”.

  In the window glass 286, the irradiation area irradiated with light from the lamp 212 is an area that overlaps the area through which the image forming area of the recording medium P passes on the setting unit 210, and is formed on the recording medium P on the conveyance path 60. A region (image reading region) predetermined as a region where the obtained image is read by the CCD sensor 204 and a region (second white reference surface region) where the second white reference surface 286A is arranged are configured. ing. The second white reference plane area is adjacent to the image reading area in the main scanning direction (Z direction) and is a reading target area by the CCD sensor 204. Accordingly, reading with respect to the second white reference surface 286A is also performed in conjunction with the time when reading of the image reading area by the CCD sensor 204 is performed. Further, since the second white reference plane area exists at a position that does not overlap with the image (image forming area) formed on the recording medium P, the second white reference plane area is included in the image while the recording medium P passes through the built-in image sensor 200. Toner adhesion is suppressed. Therefore, even if the second white reference surface 286A is a light-transmitting white plate, the occurrence of a situation in which the light reflectance decreases due to the toner adhering to the second white reference surface 286A is suppressed. .

Here, the positional relationship between the lamp 212 and each color reference plane will be described with reference to FIG.
Each of the lamps 212 (the first lamp 212A and the second lamp 212B) is configured by arranging a plurality of LED substrates 302 each having a plurality of white LEDs 304 arranged in one or a plurality of rows. The length of the lamp 212 in the main scanning direction is longer than the lengths of the first white reference surface 232 and the yellow reference surface 234 in the main scanning direction (the first white reference surface 232 and the yellow reference surface 234 have substantially the same length). And extending to a region facing the second white reference surface 286A. In the built-in image sensor 200 according to the present embodiment, the first white reference surface 232 and the yellow reference surface 234 are mainly opposed to the first white reference surface 232 and the yellow reference surface 234 as shown in FIG. Irradiation light from the first light source unit 306 is irradiated. Further, as shown in FIG. 5, the second white reference surface 286A is mainly irradiated with the irradiation light from the second light source unit 308 facing the second white reference surface 286A. Hereinafter, when the first light source unit 306 and the second light source unit 308 are not distinguished, they may be simply referred to as “light source unit”.

(Schematic configuration of control device)
FIG. 6 is a block diagram showing a main configuration of the electrical system in the image forming apparatus 10 according to the embodiment of the present invention.

As described above, the control device 20 is based on the signal from the built-in image sensor 200.
A function of correcting an image formed in the image forming unit 16 is provided. The control device 20 also has a function of controlling calibration of the built-in image sensor 200 (for example, calibration of the CCD sensor 204 described above).

  More specifically, as shown in FIG. 6, the control device 20 includes a CPU (Central Processing Unit) 20A, a ROM (Read Only Memory) 20B, a RAM (Random Access Memory) 20C, and an input / output port 20D. These are connected to each other via a bus 20E such as an address bus, a data bus, and a control bus.

  Various programs are stored in the ROM 20B, and various controls are performed by the CPU 20A expanding and executing the programs in the RAM 20C.

A user interface (UI) panel 30, a lamp 212, a control circuit 100, and a read signal processing unit 350 are connected to the input / output port 20D. The UI panel 30
As an example, it is composed of a touch panel display or the like in which a transmissive touch panel is superimposed on a display, and various types of information are displayed on the display surface of the display, and information and instructions are received when the user touches the touch panel. In this embodiment,
Although the present invention has been described with reference to a form example to which the UI panel 30 is applied, the present invention is not limited thereto, and a form in which a display unit such as a liquid crystal display and an operation unit provided with a numeric keypad or operation buttons are provided separately. Good.

  As described above, the lamp 212 reads the image formed on the recording medium P by the built-in image sensor 200 or each color reference plane (the first white reference plane 232, the second white reference plane 286A, and the yellow reference plane 234). The light for performing is irradiated, and the controller 20 controls on / off (light irradiation or non-irradiation).

  Further, as described above, the control circuit 100 controls each surface of the reference roll 226 (the detection reference surface 228, the retraction surface 230, the composite inspection surface 236, the guide surface 248, the first white reference surface 232, and the yellow reference surface 234). The switching is controlled, and the driving of the reference roll rotation motor 22 connected to the control circuit 100 is controlled based on an instruction from the control device 20.

  On the other hand, the read signal processing unit 350 performs various calibrations of the built-in image sensor 200 and detects a failure of a later-described lamp 212 or each color reference plane in accordance with instructions from the control device 20. As calibration of the built-in image sensor 200, for example, offset and gain correction for correcting the output upper and lower limit values of the CCD sensor 204, and the profile of the read image on the first white reference plane 232 in the main scanning direction of the read image. A shading correction for correcting the lightness distribution can be given. In addition, hue / saturation unevenness correction in the main scanning direction with respect to the read image performed based on the profile of the read image on each color reference surface (yellow reference surface 234 in the present embodiment), and the profile of the read image on the second white reference surface 286A. Correction of brightness variation among the recording media P when continuously reading images formed on the recording media P based on the above.

  FIG. 7 shows an example of the configuration of the read signal processing unit 350. As shown in FIG. 7, the read signal processing unit 350 includes an S & H (sample and hold) unit 352, an amplification unit 354, an A / D conversion unit 356, a shading correction unit 358, a color conversion unit 360, and a failure determination unit 362. It is configured to include.

S & H unit 352, the read signal _{S R} of the analog to red (R) color transferred from the CCD sensor 204, green (G) color analog read signal _{S G} of the analog read signal _{S B} of the blue (B) In addition to sampling (sampling), sampling hold for holding (holding) for a certain period is performed.

The amplifying unit 354 includes the read signals S _R , S _G , sampled and held by the S & H unit 352.
Amplifying the S _B. Between the S & H unit 352 and the amplifying unit 354, the black output level of the read image (hereinafter, also referred to as “read image”) with respect to the read and held signals S _R , S _G , and S _B. In some cases, a black level adjustment circuit for performing a correction process is provided so as to achieve a predetermined black level (zero level).

The A / D conversion unit 356 performs A / D (analog / digital) conversion on the read signals S _R , S _G , and S _B amplified by the amplifying unit 354, and image data (R, G, B) that is digital data. Get.

  The shading correction unit 358 corrects unevenness in brightness of the read output of the image caused by the lamp 212 and the CCD sensor 204 with respect to the image data (R, G, B) converted into a digital signal by the A / D conversion unit 356. At the same time, correction is performed so that the white level of the read image matches the white level in image formation by the image forming unit 16.

The color conversion unit 360 uses the color conversion coefficient group (color conversion parameter) to convert the image data (R, G, B) in the RGB color space (device-dependent color space) to L ^* a ^* b which is a luminance color difference color space. ^* Convert into image data (L ^* , a ^* , b ^* ) in color space (device-independent color space). In the image forming apparatus 10 according to the present embodiment, the image data (L ^* , a ^* , b ^* ) subjected to color conversion processing by the color conversion unit 360 is, for example, an image processing unit (illustrated) connected to the input / output port 20D. The color conversion processing to the image data (C, M, Y, K) of the CMYK color space (device-dependent color space) that is the output color space is performed.

In the present embodiment, an example in which the L ^* a ^* b ^* color space is applied as the luminance color difference color space for converting the image data (R, G, B) has been described. However, the present invention is not limited to this. For example, a form in which a YCbCr color space, which is another luminance color difference color space, is applied may be employed.

  Next, referring to FIG. 7, failure determination section 362 uses the image data (R, G, B) converted into a digital signal by A / D conversion section 356, and relates to the embodiment described below. A failure in the built-in image sensor 200 is determined, and the determination result is output as a failure determination result.

  Each unit constituting the read signal processing unit 350 according to the present embodiment is controlled by a control signal from the CPU 20A input via the input / output port 20D.

  By the way, in order to accurately perform various calibrations using the first white reference surface 232, the second white reference surface 286A, and the yellow reference surface 234 described above as calibration means, the image forming apparatus 10 may be initially (for example, shipped). ), It is desired that the color characteristics (reflectance, chromaticity) of each color reference plane are maintained constant, that is, the color characteristics are not changed over time (discoloration, etc.). In addition, regarding the lamp 212 composed of the white LEDs 304, in addition to the fact that the color characteristics (chromaticity) do not change with time as in the case of each color reference plane, some of the white LEDs 304 are not lit properly (not lit or unlit). It is desirable that no extreme reduction in light intensity or the like occurs. Hereinafter, a change in color characteristics with time will be described by taking a typical color change as an example.

  Therefore, in the built-in image sensor 200 of the image forming apparatus 10 according to the present embodiment, the ratio of the reading values by the CCD sensor 204 of each color reference surface of the first white reference surface 232, the second white reference surface 286A, and the yellow reference surface 234. Based on the above, failure diagnosis processing for diagnosing whether or not a lighting failure has occurred in the lamp 212 is executed. Further, based on the color difference calculated from the read value of each color reference surface, a failure diagnosis process for diagnosing whether or not discoloration has occurred on the lamp 212 and each color reference surface is executed. That is, in the built-in image sensor 200 according to the present embodiment, a failure diagnosis process is executed by detecting temporal changes in the hue and saturation of the lamp 212 or each color reference surface.

  Hereinafter, a failure diagnosis method in the failure diagnosis process according to the present embodiment will be described. In the failure diagnosis method according to the present embodiment, first, irradiation light from the lamp 212 is applied to each color reference surface of the first white reference surface 232, the yellow reference surface 234, and the second white reference surface 286A of the reference roll 226. . Then, the reflected light from each color reference plane is read by the CCD sensor 204 of the built-in image sensor 200 to acquire each read value, and a fault diagnosis is performed by executing arithmetic processing on the read value.

More specifically, the irradiation light is emitted from the lamp 212 toward the conveyance path 60 while switching the first white reference surface 232 and the yellow reference surface 234 of the reference roll 226. In this case, the light from the first light source unit 306 shown in FIG. Then, the reflected light from the first white reference surface 232 is read by the CCD sensor 204, and read values (R _w1 , G _w1 , B _w1 ) represented by the respective components (R, G, B) are obtained. Further, the reflected light from the yellow reference surface 234 is read by the CCD sensor 204, and read values (R _y , G _y , B _y ) represented by the respective components (R, G, B) are acquired.

Further, the lamp 212 irradiates the irradiation light toward the second white reference surface 286A. In this case, the light from the second light source unit 308 shown in FIG.
Then, the CCD sensor 204 reads the reflected light from the second white reference surface 286A, and obtains read values (R _w2 , G _w2 , B _w2 ) represented by the respective components (R, G, B).
In the built-in image sensor 200 according to the present embodiment, each read value uses the output of the A / D conversion unit 356 in the read signal processing unit 350 shown in FIG.

Next, a method for acquiring each reading value will be described more specifically.
FIG. 8 shows reading of each component of (R, G, B) of the first white reference surface 232 with respect to the position in the main scanning direction, which is obtained by irradiating the irradiation light mainly from the first light source unit 306 of the lamp 212. Indicates a profile of values. The horizontal axis of FIG. 8 shows the position of the main scanning direction, in the example of FIG. 8, the image reading one end P _S region as a reference, to the other end P _E of the image reading area, + Z direction (FIG. 4 It is represented by the number of pixels toward In addition, the vertical axis indicates a read value represented by a 16-bit gradation as an example. Therefore, the maximum value Nmax on the vertical axis shown in FIG. 8 is Nmax = 65535. The profile of the reading value shown in FIG. 8 is a profile including characteristics such as aberration of the lens 220, and the curves shown by R, G, and B in FIG. 8 are reduced at the left and right shoulders. This is due to 220 characteristics.

The yellow reference surface 234 is also irradiated with the irradiation light mainly from the first light source unit 306 of the lamp 212, and the reading value profiles of the respective components (R, G, B) similar to those in FIG. 8 are acquired.
Further, although the width of the horizontal axis is narrower than that in FIG. 8, the reading light profile of the second white reference surface 286 </ b> A is acquired by irradiating the irradiation light mainly from the second light source unit 308 of the lamp 212.

Then, in this embodiment, reading of the first white reference surface 232 a _{(R w1, G w1, B} w1), and to read near the middle of the image reading region indicated by the position _{P R} reading 8 ing. The same applies to the position where the reading values (R _y , G _y , B _y ) of the yellow reference surface 234 are read. In addition, the position where the read values (R _w2 , G _w2 , B _w2 ) of the second white reference surface 286A are read is near the center of the second white reference surface region. The read value of each color reference surface is not limited to reading near the center of each color reference surface, and for example, an average value of read values over the entire image reading area may be used.

In the built-in image sensor 200 according to the present embodiment, the read values (R _w1 , G _w1 , B _w1 ), (R _w2 , G _w2 , B _w2 ), and (R _y , G _y , B _y ) are obtained. The following arithmetic processing is used to determine the presence or absence of each failure due to lighting failure of the lamp 212 (first light source unit 306 and second light source unit 308), discoloration of the lamp 212, and discoloration of each color reference plane. To do. Hereinafter, a specific calculation method for determining (separating) each failure will be described.

(Fault diagnosis of lighting failure)
First, according to the following equation (1), the read value obtained by summing up the components of (R, G, B) for each color reference surface from the read values of each color reference surface (hereinafter referred to as “total read value”) It _is) calculates the _{P w1, P w2, P y} .

In the failure diagnosis processing according to the present embodiment, the lamp 212 (the first light source unit 306 and the second light source unit 308) of the illumination unit 202 is normally turned on when the condition shown in the following formula (2) is satisfied. It is determined that In the failure diagnosis processing according to the present embodiment, the lighting failure of the first light source unit 306 and the second light source unit 308 is determined by the ratio between the total read values P _w1 , P _w2 , and P _{y of} each reference plane. Here, th ₁ to th ₆ in the equation (2) are threshold values for a ratio of a predetermined total reading value. These threshold values are stored in a storage unit such as the ROM 20B, with values obtained in advance by simulation or evaluation using an actual machine, or values obtained by inspection at the time of shipment of the image forming apparatus 10 as standard values. Also good.

In the failure diagnosis process according to the present embodiment, it is determined that a lighting failure has occurred in the first light source unit 306 when the condition shown in the following equation (3) is satisfied. As described above, the first light source unit 306 is a part that faces the first white reference surface 232 or the yellow reference surface 234 of the lamp 212, and is a light source unit that mainly irradiates these color reference surfaces with irradiation light. If the first light source unit 306 is not lit, P _w1 or P _y becomes zero. Further, since if the amount of light reduction occurs in the first light source unit 306 _{P w1} or _{P y} is smaller than the initial _value, it becomes greater than P w2 _{/ P w1} threshold th _2, from P w2 / _{P y} is the threshold th ₄ Since it becomes larger, it is determined that a lighting failure has occurred in the first light source unit 306.

In the failure diagnosis processing according to the present embodiment, it is determined that a lighting failure has occurred in the second light source unit 308 when the condition shown in the following equation (4) is satisfied. As described above, the second light source unit 308 is a part facing the second white reference surface 286A of the lamp 212, and is a light source unit that mainly irradiates the color reference surface with irradiation light. If the second light source unit 308 is not lit, _Pw2 becomes zero. Further, since _{the P w2} if light amount drop occurs in the second light source unit 308 is smaller than the initial value _becomes smaller than P w2 _{/ P w1} threshold th _1, since P w2 / _{P y} is smaller than the threshold th ₃ Then, it is determined that a lighting failure has occurred in the second light source unit 308.

(Failure diagnosis for discoloration)
Next, failure diagnosis relating to discoloration of the lamp 212 and each color reference surface will be described.
First, the read values (R _w1 , G _w1 , B _w1 ) of the first white reference plane 232 are normalized by the following formula (5), and the coordinates in the RGB color space (hereinafter referred to as “RGB chromaticity coordinates”) W ₁ (r _w1 , g _w1 , b _w1 ), RGB chromaticity coordinates w ₂ (r _w2 , g _w2 , b) of the read values (R _w2 , G _w2 , B _w2 ) of the second white reference plane 286A _w2 ) and the RGB chromaticity coordinates y (r _y , g _y , b _y ) of the reading values (R _y , G _y , B _y ) of the yellow reference plane 234 are calculated.

Next, the length l of each side of the triangle composed of the points w ₁ , w ₂ , and y in the RGB color space is calculated from the following equation (6). In the formula _{(6), l} w1_w2 the length of the side connecting the point _{w 1} and the point _{w 2} (i.e., the point _{w 1} - Distance between the points _{w 2) are, l W1_y} is the point _{w 1} and the point y Is the length of the side connecting the points y ₁ (ie, the distance between the points w ₁ and y), and _{ly_w2} is the length of the side connecting the points y and w ₂ (ie, the distance between the points y and w _2). ). Length _{l w1_w2, l w1_y,} each l _{Y_w2} are that _{w 1} in the RGB color space, the point _{w 2,} represents the color difference of the point y cross.

Further, from the following equation (7), the ratio k of the length of each side to the total value of the lengths of each side of the triangle (the total circumference: l _w1 — _w2 + l _w1 — _y + l _y — _w2 ) is calculated. In the formula _{(7), k w1_w2} is the ratio of _{l W1_w2} to the total circumferential length of the _{triangle, k w1_y} is the ratio of _{l W1_y} to the total circumferential length of the _{triangle, k w2_y's l W2_y} to the total circumferential length of the triangle Is the ratio. Hereinafter, this ratio k may be referred to as a distance ratio.

Further, the coordinates ν (ν _r , ν _g , ν _b ) of the center of gravity ν of the triangle are obtained from the following equation (8).

Here, the initial value of the distance ratio k is k _{0, w1_w2} , k _{0, w1_y} , k _{0, w2_y, respectively,} and the initial value of the coordinates of the center of gravity ν is ν ₀ (ν _0r , ν _0g , ν _0b ). . These initial values may be acquired in advance at the time of shipping inspection, for example, and the results may be stored in storage means such as the ROM 20B, or may be preset as standard values and stored in storage means such as the ROM 20B. You may keep it.

Also, since prior to use of the user, for example, the value of the respective distance ratio k obtained in the calibration, etc. of the internal image sensor 200 to be executed regularly or irregularly _{k t, w1_w2, k t,} w1_y, k t _{, w2_y,} and similarly, the coordinates of the center of gravity ν acquired in the calibration or the like are ν _t (ν _tr , ν _tg , ν _tb ).

  Based on the above calculation result, the center-of-gravity evaluation value dν shown in the following equation (9) is calculated. dν indicates how much the center of gravity ν at the time of calibration varies from the initial value.

Further, based on the above calculation result, each distance evaluation value dk shown in the following equation (10) is calculated.
Each dk indicates how much the distance ratio k at the time of calibration varies from the initial value.

  In the fault diagnosis processing according to the present embodiment, fault diagnosis relating to discoloration is performed by calculation based on the following equations using the center-of-gravity evaluation value dν and each distance evaluation value dk obtained by the above calculation.

In the failure diagnosis processing according to the present embodiment, it is determined that no discoloration has occurred in the lamp 212 and each reference surface when the condition shown in the following equation (11) is satisfied. In equation (11), Th _ν is a predetermined threshold for the centroid evaluation value dν, and Th _{w1_w2} , Th _{w1_y} , and Th _{w2__y} are predetermined thresholds for the distance evaluation value dk. Since both the center-of-gravity evaluation value dν and each distance evaluation value dk are equal to or less than a predetermined threshold value, it is determined that the variation in the color characteristics (chromaticity) of the lamp 212 and each color reference surface is within the allowable range. Each threshold value may be stored in advance in a storage unit such as the ROM 20B.

In the failure diagnosis processing according to the present embodiment, it is determined that the lamp 212 has discolored when the condition shown in the following equation (12) is satisfied. Since each distance evaluation value dk is equal to or less than the threshold value, there is no great change in the shape of the triangle w ₁ -w ₂ -y (although it changes in a similar manner), and therefore there is no discoloration or discoloration in each color reference plane. Is determined to be within the allowable variation. On the other hand, since the center-of-gravity evaluation value ν fluctuates more than the threshold value, the center of gravity of the triangle w ₁ -w ₂ -y has moved beyond the allowable variation amount, and the lamp 212 that is irradiated under the same conditions to each color reference plane is applied. This is because it is determined that discoloration has occurred.

In the failure diagnosis processing according to the present embodiment, it is determined that discoloration has occurred on the first white reference surface 232 when the condition shown in the following equation (13) is satisfied. Centroid evaluation value dν varies more than the threshold value, and the point _{w 1} - Distance evaluation value _{dk W1_w2} between the points _{w 2,} and the point _{w 1} - Distance evaluation value _{dk W1_y} between points y fluctuates above threshold This is because it is considered that the coordinates of the point w ₁ common to both distance evaluation values have changed.

In the failure diagnosis processing according to the present embodiment, it is determined that discoloration has occurred in the second white reference plane 286A when the condition shown in the following equation (14) is satisfied. Centroid evaluation value dν varies more than the threshold value, and the point _{w 1} - Distance evaluation value _{dk W1_w2} between the points _{w 2,} and the point _{w 2} - Distance evaluation value _{dk W2_y} between points y fluctuates above threshold since, because variations in the coordinates of w ₂ features common to both the distance evaluation value is thought to be occurring.

In the failure diagnosis processing according to the present embodiment, it is determined that discoloration has occurred on the yellow reference plane 234 when the condition shown in the following equation (15) is satisfied. Centroid evaluation value dν varies more than the threshold value, and the point _{w 1} - Distance evaluation value _{dk W1_y} between points y, and the point _{w 2} - the distance evaluation value _{dk W2_y} between points y fluctuates above threshold This is because it is considered that the coordinates of the point y common to both distance evaluation values have changed.

<Numerical example>
Next, the failure diagnosis method based on calculation will be described more specifically using numerical values. The following numerical examples are examples when a lighting failure occurs in the second light source unit 308 and when discoloration occurs in the first white reference surface 232.

(Numerical example when detecting lighting failure of second light source unit 308)
First, the reading value of the first white reference surface 232, the reading value of the second white reference surface 286A, and the reading value of the yellow reference surface 234 in the normal state are assumed as follows.
_{(R w1, G w1, B} w1) = (53429,55509,55864)
(R _w2 , G _w2 , B _w2 ) = (39912, 44120, 44585)
_{(R y, G y, B} y) = (44424,37838,6783)

Further, it is assumed that the threshold values Th ₁ to Th ₆ when detecting a lighting failure of the light source unit are as follows.
Th ₁ = 0.73
Th ₂ = 0.83
Th ₃ = 1.34
Th ₄ = 1.54
Th ₅ = 0.49
Th ₆ = 0.59

At this time, the reading values of the respective color reference planes are substituted into the equation (1), and the values of the total reading values P _w1 , P _w2 , P _y are as follows.
P _w1 = 164802
P _w2 = 128617
P _y = 89045

In this case, since the following inequality shown in Expression (2) is established, it is determined that the light source unit is normally lit.
0.73 = Th ₁ <P _w2 / P _w1 ≈0.78 <Th ₂ = 0.83
1.34 = Th ₃ <P _w2 / P _y ≈1.44 <Th ₄ = 1.54
0.49 = Th ₅ <P _y / P _w1 ≈0.54 <Th ₆ = 0.59
P _w1 = 164802> P _w2 = 128617> P _y = 89045> 0

Next, it is assumed that a new read value is acquired in the calibration or the like of the built-in image sensor 200. In this numerical example, it is assumed that the reading value of the second white reference surface 286A changes as follows, and the reading value of the first white reference surface 232 and the reading value of the yellow reference surface 234 do not change.
(R _w1 ′, G _w1 ′, B _w1 ′) = (53429, 55509, 55864)
(R _w2 ′, G _w2 ′, B _w2 ′) = (33296, 35296, 35222)
(R _y ′, G _y ′, B _y ′) = (44424, 37838, 6783)

At this time, the values of the total reading values P _w1 ′, P _w2 ′, and P _y ′ change as follows.
P _w1 '= 164802
P _w2 '= 103814
P _y ′ = 89045

In this case, the following inequality shown in Expression (4) holds.
_{0.62 ≒ P w2 '/ P w1} '<Th 1 = 0.73
1.16≈P _w2 ′ / P _y ′ <Th ₃ = 1.34
0.49 = Th ₅ <P _y ′ / P _w1 ′ ≈0.54 <Th ₆ = 0.59
Therefore, it is determined that a lighting failure has occurred in the second light source unit 308.

(Numerical example when detecting discoloration of first white reference surface 232)
First, the reading value of the first white reference surface 232, the reading value of the second white reference surface 286A, and the reading value of the yellow reference surface 234 in the normal state are assumed as follows.
_{(R w1, G w1, B} w1) = (53429,55509,55864)
(R _w2 , G _w2 , B _w2 ) = (39912, 44120, 44585)
_{(R y, G y, B} y) = (44424,37838,6783)

At this time, each RGB chromaticity coordinate is as follows from the equation (5).
w ₁ (r _w1 , g _w1 , b _w1 ) = (0.3242, 0.3368, 0.3390)
w ₂ (r _w2 , g _w2 , b _w2 ) = (0.3103, 0.3430, 0.3466)
y (r _y , g _y , b _y ) = (0.4989, 0.4249, 0.0762)

Also, from equation (6), the length of each side is as follows.
l _{w1_w2} = 0.01701
l _{w1_y} = 0.3276
l _{y_w2} = 0.3397

Further, the initial value of each distance ratio k is as follows from the equation (7).
k _{0, w1_w2} = 0.02486
k _{0, w1_y} = 0.4786
k _{0, w2_y} = 0.4964

On the other hand, the initial value ν _{0 of the} center of gravity is as follows from the equation (8).
ν ₀ = (ν _r0 , ν _g0 , ν _b0 ) = (0.3778, 0.3682, 0.2539)

FIG. 9A shows a state where the above w ₁ , w ₂ , y, and ν ₀ are plotted in the RGB color space.

Next, it is assumed that a new read value is acquired in the calibration or the like of the built-in image sensor 200. In this numerical example, it is assumed that the first white reference surface 232 is discolored and the read value of the first white reference surface 232 changes as follows, the read value of the second white reference surface 286A, and the yellow reference Assume that the reading on surface 234 has not changed.
(R _w1 ′, G _w1 ′, B _w1 ′) = (53429, 55509, 49160)
(R _w2 ′, G _w2 ′, B _w2 ′) = (39912, 44120, 44585)
(R _y ′, G _y ′, B _y ′) = (44424, 37838, 6783)

Further, it is assumed that the threshold value for color characteristic abnormality determination is as follows.
Th _{w1_w2} = 0.5
Th _{w1_y} = 0.05
Th _{w2_y} = 0.01
Th _ν = 0.01

At this time, each RGB chromaticity coordinate is as follows from the equation (5).
w ₁ ′ (r _w1 ′, g _w1 ′, b _w1 ′) = (0.3379, 0.3511, 0.3109)
w ₂ ′ (r _w2 ′, g _w2 ′, b _w2 ′) = (0.3103, 0.3430, 0.3466)
y ′ (r _y ′, g _y ′, b _y ′) = (0.4989, 0.4249, 0.0762)

Also, from equation (6), the length of each side is as follows.
l ′ _{w1_w2} = 0.04585
l ′ _{w1_y} = 0.2940
l ′ _y — w2 = 0.3397

Further, from the equation (7), the value of each distance ratio k is as follows.
k _{t, w1_w2} = 0.06746
k _{t, w1_y} = 0.4327
k _{t, w2_y} = 0.4999

On the other hand, the center of gravity ν _t is as follows from the equation (8).
ν _t (ν _rt , ν _gt , ν _bt ) = (0.3824, 0.3730, 0.2446)
FIG. 9B shows a state in which the above w ₁ ′, w ₂ ′, y ′, and ν _t are plotted in the RGB color space.

K _{0, w1_w2} , k _{0, w1_y} , k _{0, w2_y} , ν ₀ (ν _r0 , ν _g0 , ν _b0 ), k _{t, w1_w 2} , k _{t, w1_y} , _kt , _{w2_y} , obtained _{by the above procedure} Using ν _t (ν _rt , ν _gt , ν _bt ), the center-of-gravity evaluation value dν is calculated from equation (9), and each distance evaluation value dk _{w1_w2} , dk _{w1_y} , dk _{w2_y} is calculated from equation (10), and the threshold Th _{w1_w2} is calculated. , Th _{w1 — y} , Th _{w2 — y} , and Th _ν are as follows.
0.01146≈dν> Th _ν = 0.01
1.714≈dk _{w1_w2} > Th _{w1_w2} = 0.5
0.09628 ≒ dk _{w1_y} > Th _{w1_y} = 0.05
0.007028 ≒ dk _{w2_y} <Th _{w2_y} = 0.01
Therefore, since Expression (13) is established, it is determined that a color characteristic abnormality has occurred on the first white reference plane 232.

  Next, with reference to FIG. 10 and FIG. 11, a failure diagnosis process executed by the image forming apparatus 10 according to the present embodiment will be described. 10 and 11 are flowcharts showing the flow of processing of the failure diagnosis processing program according to the present embodiment. FIG. 10 is a flowchart of a failure diagnosis process related to a lighting failure of the light source unit (the first light source unit 306 and the second light source unit 308) in the failure diagnosis process according to the present embodiment, and FIG. The flowchart of the fault diagnosis process regarding the discoloration of a surface is shown, respectively.

  In the image forming apparatus 10 according to the present embodiment, the processing illustrated in FIGS. 10 and 11 is stored in the storage unit such as the ROM 20B by the CPU 20A when the user instructs the start of the failure diagnosis via the UI panel 30 or the like. This is done by reading and executing the fault diagnosis processing program. Note that the processing shown in FIGS. 10 and 11 is not limited to execution according to a user instruction, and may be automatically executed periodically or irregularly, for example. In the present embodiment, when the failure diagnosis process of the lamp or the light source unit is executed, both the first lamp 212A and the second lamp 212B may be turned on, and which one has a failure? When it is desired to divide, one of them may be lit and executed.

  In this embodiment, an example in which the fault diagnosis processing program is stored in advance in a storage unit such as the ROM 20B will be described as an example. However, the present invention is not limited to this, and the fault diagnosis processing program can be read by a computer. A form provided in a state of being stored in a portable storage medium, a form distributed via wired or wireless communication means, and the like may be applied.

  Furthermore, in the present embodiment, the fault diagnosis process is realized by a software configuration using a computer by executing a program, but the present invention is not limited to this. For example, you may implement | achieve by the hardware structure which employ | adopted ASIC (Application Specific Integrated Circuit), or the combination of a hardware structure and a software structure.

  As shown in FIG. 10, first, in step S100, initialization is performed by substituting 0 into flags F1 and F2. The flag F1 is a flag for identifying a case where there is no abnormality in the first light source unit 306 and the second light source unit 308, and the flag F2 is for identifying a case where there is no discoloration in the lamp 212 and each color reference plane. Flag.

In the next step S102, the irradiation light from the lamp 212 (the first light source unit 306 and the second light source unit 308) is applied to the reference surfaces of the first white reference surface 232, the second white reference surface 286A, and the yellow reference surface 234. The lamp 212 is controlled to irradiate, the reflected light from each color reference plane is read by the CCD sensor 204, the read values (R _w1 , G _w1 , B _w1 ) of the first white reference plane 232, the second white reference plane A reading value (R _w2 , G _w2 , B _w2 ) of 286A and a reading value (R _y , G _y , B _y ) of the yellow reference plane 234 are acquired. The read value may be stored in a storage unit such as the RAM 20C.

In the next step S104, threshold _values th ₁ to th ₆ for diagnosis of lighting failure of each light source unit, and threshold _values Th _ν , Th _{w1_w2} , Th _{w1_y} , and Th for diagnosis of discoloration of the lamp and each color reference plane are _obtained . _{w2_y} is read from storage means such as the ROM 20B.

In the next step S106, the initial value k ₀ of the distance ratio k previously _{described, w1_w2, k 0, ROM20B w1_y} , k 0, w2_y, coordinates of the initial value [nu ₀ of the center of gravity _{ν (ν 0r, ν 0g,} ν 0b) the Read from the storage means.

In the next step S108, the total reading values P _w1 , P _{w2, and} P _y are calculated by substituting the reading values for each color reference plane acquired in step S102 into the equation (1).
In the next step S110, it determines that the threshold value th ₁ to th ₆ read in step S104, whether the total readings _{P w1, P w2,} formula based on _{P y} calculated in step S108 (2) is satisfied .

If a negative determination is made in step S110, the process proceeds to step S116,
When it becomes affirmation determination, it transfers to step S112 and alert | reports that each light source part (lamp 212) is lighting normally. The notification may be displayed on, for example, a display of the UI panel 30, or may be notified by voice from a speaker (not shown), or an image is formed (printed) on the recording medium P by the image forming apparatus 10. May be notified. In this embodiment,
The form displayed on the display of the UI panel 30 is applied, and FIG. 12 shows an example of the display. In the display example of Fig. 12, along with the OK button, "The lamp is lit normally.
Is displayed.
In the next step S114, 1 is assigned to the flag F1, and the process proceeds to step S126.

On the other hand, in step S116, it is determined whether Expression (3) is satisfied.
If a negative determination is made in step S116, the process proceeds to step S120. If an affirmative determination is made, the process proceeds to step S118 to notify the first light source unit 306 that a lighting failure has occurred. The notification may be displayed on the display of the UI panel 30 according to FIG.

In the next step S120, it is determined whether or not the formula (4) is satisfied. If the determination is negative, the process proceeds to step S122 and an error is displayed. The process proceeds to step S124 to notify the second light source unit that a lighting failure has occurred.
The notification may be displayed on the display of the UI panel 30 according to FIG. Note that the reason why an error is displayed in step S122 is that, although it is determined in step S110 that any one of the light source units is abnormal, it does not correspond to the failure determination of any light source unit in the subsequent processing. is there.

As shown in FIG. 11, in the next step S126, the reading value of each color reference surface acquired in step S102, that is, the reading value (R _w1 , G _w1 , B _w1 ) of the first white reference surface 232, the second white color. The reading value (R _w2 , G _w2 , B _w2 ) of the reference surface 286A, the reading value of the yellow reference surface 234 (R _y , G _y , B _y ), and the initial value k _0, of the distance ratio k read in step S106 _{. Based on} the initial value ν ₀ (ν _0r , ν _0g , ν _0b ) of the coordinates of w _{1 —w 2} , k _{0, w 1 —y} , k _{0, w 2 —y} and the center of gravity ν, the center of gravity is evaluated using Equation (5) to Equation (10). A value dν and each distance evaluation value dk are calculated.

In the next step S128, the threshold value Th _[nu read in step _{S104, Th} w1_w2, using _{Th w1_y} ,, _{Th w2_y,} and the center of gravity evaluation value dν calculated in step S126, the respective distances evaluation value dk, formula (11) It is determined whether or not is established. If the determination in step S128 is negative, the process proceeds to step S134. If the determination is affirmative, the process proceeds to step S130 to notify that the color characteristics of the lamp and each color reference surface are normal. The notification may be displayed on the display of the UI panel 30 according to FIG.
In the next step S132, after substituting 1 for the flag F2, the present fault diagnosis processing program is terminated.

  In step S134, it is determined whether Formula (12) is materialized. If the determination is negative, the process proceeds to step S138. If the determination is affirmative, the process proceeds to step S136 to notify that an abnormality has occurred in the color characteristics of the lamp 212. The notification may be displayed on the display of the UI panel 30 according to FIG.

  In step S138, it is determined whether or not Expression (13) is established. If the determination is negative, the process proceeds to step S142. If the determination is affirmative, the process proceeds to step S140, and an abnormality has occurred in the color characteristics of the first white reference surface 232. Inform. The notification may be displayed on the display of the UI panel 30 according to FIG.

In step S142, it is determined whether Formula (14) is materialized. If the determination is negative, the process proceeds to step S146. If the determination is affirmative, the process proceeds to step S144, and an abnormality has occurred in the color characteristics of the second white reference surface 286A. Inform.
The notification may be displayed on the display of the UI panel 30 according to FIG.

  In step S146, it is determined whether Formula (15) is materialized. If the determination is negative, the process proceeds to step S148 to display an error, and then the failure diagnosis processing program is terminated. On the other hand, if the determination is affirmative, the process proceeds to step S150 to notify that there is an abnormality in the color characteristics of the yellow reference surface 234, and then the present failure diagnosis processing program is terminated. The notification may be displayed on the display of the UI panel 30 according to FIG.

  As is clear from the above description, according to the image reading apparatus and the image forming apparatus according to the present embodiment, it is not necessary to use an inspection image or add a dedicated device in failure diagnosis. Are provided, and an image reading apparatus and an image forming apparatus provided with a simple failure diagnosis image means are provided.

  In the above-described embodiment, an example has been described in which it is determined whether the expressions (2) to (4) and the expressions (11) to (15) are established in this order. However, the present invention is not limited to this. However, it may be performed in any order.

Moreover, in the said embodiment, the failure diagnosis process regarding the lighting failure of the light source part shown in FIG.
Although the embodiment of executing both the lamp and the failure diagnosis process related to the color change of each color reference plane illustrated in FIG. 11 is described as an example, the present invention is not limited to this, and only one of them may be executed.

[Second Embodiment]
In the present embodiment, in the failure diagnosis process according to the first embodiment, it is determined that the built-in image sensor 200 is normal (no lamp lighting failure or color characteristic failure has occurred in the lamp and each color reference). In this case, the failure diagnosis of the image forming apparatus 10 (mainly the image forming unit 16) is continued.

  In an image forming apparatus having a built-in image sensor, for example, when a defect occurs in an image formed on the recording medium P, whether the defect is caused by a failure of the built-in image sensor or caused by an image forming unit Sometimes it may be necessary to isolate it.

  In the image forming apparatus 10 according to the present embodiment, as described in the failure diagnosis process of the first embodiment, failure diagnosis of the built-in image sensor 200 is performed regardless of image formation. Therefore, when the failure diagnosis processing according to the first embodiment is executed and it is determined that the built-in image sensor 200 is normal as a result of the failure diagnosis processing, the failure diagnosis processing of the image forming unit 16 is continued. By executing, it is determined whether there is an abnormality in the image forming unit 16. In addition, when a failure is detected in the built-in image sensor 200 as a result of executing the failure diagnosis processing according to the first embodiment, after performing maintenance (maintenance) on the failure and removing the failure The failure diagnosis process according to the present embodiment may be executed.

  In the failure diagnosis process according to the present embodiment, an inspection image is formed on the recording medium P by the image forming process, and the image is formed by the image forming process based on the result of reading the inspection image by the CCD sensor 204. Whether or not there is an abnormality in the image forming unit 16 is determined by determining whether or not there is an abnormality in the density of the generated image. Note that the image data of the inspection image may be stored in a storage unit such as the ROM 20B in advance.

  With reference to FIG. 13, a failure diagnosis process executed by image forming apparatus 10 according to the present exemplary embodiment will be described. FIG. 13 is a flowchart showing a processing flow of the failure diagnosis processing program according to the present embodiment. The failure diagnosis processing program shown in FIG. 13 is a program that is executed subsequent to step S150 in the failure diagnosis processing program shown in FIGS.

  Also in the failure diagnosis processing according to the present embodiment, it is assumed that the user has already instructed the start of failure diagnosis via the UI panel 30 or the like as in the first embodiment. Further, the failure diagnosis processing according to the present embodiment is also performed by the CPU 20A reading and executing a failure diagnosis processing program stored in the storage means such as the ROM 20B. Note that the processing shown in FIG. 13 is not limited to execution by a user instruction, and may be automatically executed, for example, regularly or irregularly.

  As shown in FIG. 13, first, in step S200, it is determined whether or not flags F1 and F2 (see FIGS. 10 and 11) are both 1. If the determination result is affirmative, the process proceeds to step S202. If the determination is negative, the failure diagnosis processing program is terminated. This is because when the built-in image sensor 200 detects a lighting failure of the light source unit or a color characteristic failure of the lamp 212 or each color reference surface, the failure diagnosis processing program is out of scope.

  In step S202, the image data of the inspection image (inspection image data) is read from storage means such as the ROM 20B. FIG. 14 shows an example of the inspection image data. The inspection image in the present embodiment is, for example, an inspection image for image density, and is an image in which color image regions with different image densities are arranged for each color as shown in FIG.

In the next step S204, the image forming apparatus 10 is controlled so as to form (print) the inspection image.
In the next step S206, the built-in image sensor 200 is controlled so as to read the printed inspection image.

  In the next step S208, the difference between the image data obtained by reading the printed inspection image with the built-in image sensor 200 and the image data of the reference image corresponding to the printed inspection image is extracted. The image data of the reference image may be the inspection image data read in step S202.

  In the next step S210, it is determined whether or not there is a density abnormality in the print image. This determination may be determined as abnormal when the difference extracted in step S208 is larger than a predetermined size.

  If a negative determination is made in step S210, the process proceeds to step S212 to notify that the image forming operation in the image forming apparatus 10 is normal. On the other hand, if the determination in step S210 is affirmative, the process proceeds to step S214 to notify that there is an abnormality in the image forming operation in the image forming apparatus 10. The notification may be displayed on the display of the UI panel 30 according to FIG.

As is apparent from the above description, the image reading apparatus and the image forming apparatus according to the present embodiment can also identify a fault location and include a simple fault diagnosis image unit,
An image forming apparatus is provided. According to the image forming apparatus according to the present embodiment, in particular, failure diagnosis processing of both the image reading apparatus and the image forming unit is executed.

  In each of the above-described embodiments, the failure diagnosis in which the built-in image sensor has two white reference surfaces and a yellow reference surface has been described as an example. However, the present invention is not limited to this, and for example, a plurality of built-in image sensors include a plurality of built-in image sensors. You may apply to the failure diagnosis of the form which has a chromatic color reference plane.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 10A 1st housing | casing 10B 2nd housing | casing 13 Image signal processing part 14 Toner cartridge 16 Image forming unit 18 Image holding body 20 Control apparatus 20A CPU
20B ROM
20C RAM
20D I / O port 20E Bus 22 Reference roll rotation motor 30 UI panel 32 Transfer section 34 Intermediate transfer belt 36 Primary transfer roll 38 Drive roll 40 Exposure apparatus 41 Tension applying roll 42 Opposing roll 44 Winding roll 46 Removal apparatus 48 Recording medium storage section 50 Bottom plate 52 Sending roll 54 Conveying roll 56 Separating roll 60 Conveying path 60A First folding section 60B Second folding section 62 Secondary transfer roll 66 Preliminary paths 70 and 80 Conveying belt 72 Winding roll 82 Fixing unit 84 Fixing belt 88 Pressure Roll 89 Drive roll 90 Drive roll 100 Control circuit 108 Conveying belt 110 Cooling unit 112 Absorber 114 Press device 116 Absorber belt 118 Wrap roll 120 Drive roll 122 Heat sink 128 Fan 130 Press belt 132 Wrap roll 140 Positive device 194 Reverse path 194A Branch path 194B Paper transport path 194C Reverse path 196 Discharge unit 198 Discharge roll 200 Built-in image sensor 202 Illumination unit 204 CCD sensor 206 Imaging optical system 208 Imaging unit 210 Setting unit 212 Lamp 212A First lamp 212B Second lamp 214 First mirror 216 Second mirror 218 Third mirror 220 Lens 224 Light quantity diaphragm 226 Reference roll 226A Rotating shaft 228 Detection reference surface 230 Retraction surface 232 First white reference surface 234 Yellow reference surface 236 Compound inspection surface 238 Guide Surface 262 Circuit board 286 Window glass 286A Second white reference surface (side reference)
302 LED board 304 White LED
306 First light source unit 308 Second light source unit 350 Read signal processing unit 352 S & H unit 354 Amplifying unit 356 A / D conversion unit 358 Shading correction unit 360 Color conversion unit 362 Failure determination unit L Light beam N Fixing unit OA Optical axis P Recording Media T Transfer position

In this case, the following inequality shown in Expression (4) holds.
_{0.62 ≒ P w2 '/ P w1} '<Th 1 = 0.73
1.1 7 ≒ P _w2 '/ P _y '<Th ₃ = 1.34
0.49 = Th ₅ <P _y ′ / P _w1 ′ ≈0.54 <Th ₆ = 0.59
Therefore, it is determined that a lighting failure has occurred in the second light source unit 308.

In the next step S120, it is determined whether or not the formula (4) is satisfied. If the determination is negative, the process proceeds to step S122 and an error is displayed. The process proceeds to step S124 to notify the second light source unit that a lighting failure has occurred.
The notification may be displayed on the display of the UI panel 30 according to FIG. Note that the reason why an error is displayed in step S122 is that, although it is determined in step S110 that any one of the light source units is abnormal, it does not correspond to the failure determination of any light source unit in the subsequent processing. is there. The error display in step S122 may be displayed on the display of the UI panel 30 according to FIG. 12, for example, “Please let the service engineer check the lighting state of the light source”. The cause of the negative determination in step S120 is, for example, a case where an abnormality occurs in the lighting circuit that controls the lighting of the lamp, and a lighting abnormality occurs simultaneously in both the first light source unit 306 and the second light source unit 308. It is done. In such a case, the image forming apparatus 10 according to the present embodiment prompts the user to request maintenance from a maintenance person (service engineer).

In step S146, it is determined whether Formula (15) is materialized. If the determination is negative, the process proceeds to step S148 to display an error, and then the failure diagnosis processing program is terminated. On the other hand, if the determination is affirmative, the process proceeds to step S150 to notify that there is an abnormality in the color characteristics of the yellow reference surface 234, and then the present failure diagnosis processing program is terminated. The notification may be displayed on the display of the UI panel 30 according to FIG. The error display in step S148 may be displayed on the display of the UI panel 30 according to FIG. 12, for example, “Please let the service engineer check the color change of the light source and each color reference plate”. The cause of the negative determination in step S146 is, for example, that the toner flies inside the image forming apparatus 10 as dust, and each color reference plane (in this embodiment, the first white reference plane 232, the yellow reference plane 234, and For example, when a plurality of color reference surfaces of the second white reference surface 286A) are stained simultaneously. In such a case, the image forming apparatus 10 according to the present embodiment prompts the user to request maintenance from a maintenance person (service engineer).

In the next step S208, the average value of the image data (R, G, B) obtained by reading the printed inspection image with the built-in image sensor 200 and the image data of the reference image corresponding to the printed inspection image. The difference is extracted by comparing with the average value of (R, G, B) . The image data of the reference image may be the inspection image data read in step S202.

Claims (6)

A color reference portion in which a plurality of reference colors used for calibration are colored, and
Illuminating means for illuminating illumination light for illuminating the color reference portion;
The color reference portion illuminated by the illumination means is spectrally read into each of a plurality of colors forming a predetermined color space, and a spectral intensity comprising a spectral intensity for each of the plurality of colors for each of the plurality of reference colors. Reading means for outputting a set of
Based on a set of spectral intensities of each of a plurality of reference colors, a first detection for detecting the presence or absence of lighting failure of the illumination means, and the plurality of the plurality of colors in the color space represented by the set of spectral intensities Based on the chromaticity difference between the reference colors calculated based on the chromaticities of the reference colors, at least one of the presence / absence of the characteristic change of the illumination unit and the presence / absence of the characteristic change of at least one reference color is detected. Detection means for detecting at least one of the second detections;
An image reading apparatus. The detection unit compares each of the ratios of the total spectral intensities obtained by selecting two from the total spectral intensities obtained for each set of spectral intensities for a plurality of reference colors, and turns on the illumination unit. The image reading apparatus according to claim 1, wherein presence / absence of a defect is detected. The detecting means includes a gravity center of a graphic formed by connecting points in the color space representing each of the chromaticity differences, and a ratio of the length of each side to the total value of the lengths of the respective sides of the graphic. For each side, the amount of deviation from a predetermined position of the center of gravity exceeds a predetermined amount, and the amount of change from a predetermined reference value exceeds a predetermined amount 3. The image reading apparatus according to claim 1, wherein when there are two, a change in the characteristic of the reference color common to the sides corresponding to the two ratios is detected. The detecting means includes a gravity center of a graphic formed by connecting points in the color space representing each of the chromaticity differences, and a ratio of the length of each side to the total value of the lengths of the respective sides of the graphic. For each side, the amount of deviation from a predetermined position of the center of gravity exceeds a predetermined amount, and the amount of change from a predetermined reference value exceeds a predetermined amount 3. The image reading apparatus according to claim 1, wherein when there is no image, it is detected that there is a change in characteristics of the illumination unit. An image reading apparatus according to any one of claims 1 to 4,
Image forming means for forming an image on a recording medium based on image information;
As a result of detection by the detection means, if the presence or absence of the lighting failure and the presence or absence of the characteristic change are not detected, an inspection image is formed on a recording medium based on predetermined inspection image information, and the inspection A determination unit that determines the presence or absence of a failure of the image forming unit based on a difference between the image information obtained by reading the image for image with the image reading device and the image information for inspection;
An image forming apparatus including: A color reference portion in which a plurality of reference colors used for calibration are colored, and
Illuminating means for illuminating illumination light for illuminating the color reference portion;
The color reference portion illuminated by the illumination means is spectrally read into each of a plurality of colors forming a predetermined color space, and a spectral intensity comprising a spectral intensity for each of the plurality of colors for each of the plurality of reference colors. Reading means for outputting a set of
A program for controlling an image reading apparatus including:
Computer
Based on a set of spectral intensities of each of a plurality of reference colors, a first detection for detecting the presence or absence of lighting failure of the illumination means, and the plurality of the plurality of colors in the color space represented by the set of spectral intensities Based on the chromaticity difference between the reference colors calculated based on the chromaticities of the reference colors, at least one of the presence / absence of the characteristic change of the illumination unit and the presence / absence of the characteristic change of at least one reference color is detected. A program for functioning as detection means for detecting at least one of the second detections.