JP6380266B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

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

  Conventionally, an image reading apparatus that reads an image formed on a document is known. Various techniques for generating white reference data in an image reading apparatus are known.

  For example, an image reading apparatus that generates white reference data a plurality of times is disclosed (see Patent Document 1). In this image reading apparatus, white reference data is collected a plurality of times while rotating the white reference roller. Then, for each pixel, white reference data is generated using the maximum value of the white reference data collected a plurality of times.

  Patent Document 1 describes that even if the white reference roller is partially contaminated, it can be made less susceptible to the influence.

Japanese Patent Laid-Open No. 10-23253

  However, in the image reading apparatus described in Patent Document 1, the white reference data is generated using the maximum value of the white reference data collected a plurality of times regardless of the presence or absence of dirt, so that normal white reference data may not be generated. was there. For example, when white reference data is collected five times while the white reference roller is rotated 180 degrees, white reference data is generated using the maximum value of the white reference data collected five times. Therefore, when the 180 ° range on the side where the white reference data is collected is dirty among the white reference rollers, normal white reference data may not be generated.

  Specifically, when the 180 ° range on the side where the white reference data is collected is partially dirty among the white reference rollers, the white reference data corresponding to the position in the main scanning direction of the dirty portion May become abnormal. Further, when the 180 ° range on the side where the white reference data is collected is totally dirty among the white reference rollers, the white reference data may become abnormal as a whole.

  SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus and an image forming apparatus capable of generating normal white reference data.

  The image reading apparatus of the present invention includes an image sensor, a white reference roller, a white reference generation unit, an abnormality determination unit, and a white reference rotation unit. The image sensor reads an image formed on a document. The white reference roller is disposed at a position facing the image sensor. The white reference generation unit acquires an image of the white reference roller via the image sensor, and generates white reference data. The abnormality determination unit determines whether the white reference data is abnormal each time the white reference data is generated by the white reference generation unit. The white reference rotation unit rotates the white reference roller by a predetermined angle in a preset rotation direction when it is determined that the white reference data is abnormal. The white reference generation unit generates the white reference data when the white reference roller is rotated by the predetermined angle.

  The image forming apparatus of the present invention includes an image forming unit and the image reading device. The image forming unit forms an image on a recording medium.

  According to the image reading apparatus and the image forming apparatus of the present invention, normal white reference data can be generated.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating configurations of an image reading unit and a document transport unit illustrated in FIG. 1. It is a figure which shows the functional structure of the control part shown in FIG. 3 is a graph showing a relationship between a position in a main scanning direction of the image sensor shown in FIG. 2 and a white reference value. It is a flowchart which shows operation | movement of the control part shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 5). In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof is not repeated.

  First, an image forming apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of an image forming apparatus 100 according to the present embodiment. Here, the image forming apparatus 100 is a multifunction peripheral. The image forming apparatus 100 is a scanner, a copier, a printer, a facsimile, or the like. The image forming apparatus 100 includes an image forming unit 1, an image reading unit 2, a document transport unit 3, and an operation panel 4.

  The image forming unit 1 forms an image on a sheet P that is an example of a recording medium. The image reading unit 2 reads an image formed on the surface of the document R. Further, the image reading unit 2 includes a control unit 5. The document transport unit 3 supplies the document R to the image reading unit 2 and reads an image formed on the back surface of the document R. The operation panel 4 includes a touch panel 41 and receives an operation from the user for the image forming apparatus 100. The control unit 5 controls the operation of the image forming apparatus 100.

  The image forming unit 1 includes a paper feed cassette 11, a paper feed roller 12, a transport roller pair 13, a registration roller pair 14, an image forming unit 15, a fixing device 16, a discharge roller pair 17, and a discharge tray 18. The paper feed roller 12 feeds the paper P from the paper feed cassette 11 one by one. The paper P fed out by the paper supply roller 12 is conveyed to the image forming unit 15 by the conveyance roller pair 13 and the registration roller pair 14.

  The image forming unit 15 forms an image on the paper P conveyed from the paper feed cassette 11. The image forming unit 15 includes a photosensitive drum 151, a charging unit 152, an exposure unit 153, a developing unit 154, a transfer roller 155, and a cleaning unit 156. The photosensitive drum 151 is a cylindrical rotating body, and an electrostatic latent image is formed on the peripheral surface thereof. The charging unit 152 charges the photosensitive drum 151 to a predetermined potential. The exposure unit 153 exposes the peripheral surface of the photosensitive drum 151 by irradiating laser light based on the image data. As a result, an electrostatic latent image corresponding to the image data is formed on the peripheral surface of the photosensitive drum 151. As the image data, for example, image data generated by the image reading unit 2 reading the document R, or image data received from an external computer via a communication network (not shown) is used. The paper P on which the image is formed by the image forming unit 15 is conveyed to the fixing device 16.

  The developing unit 154 supplies toner to the electrostatic latent image formed on the peripheral surface of the photoconductive drum 151 and develops it, and forms a toner image on the peripheral surface of the photoconductive drum 151. The transfer roller 155 transfers the toner image on the photosensitive drum 151 onto the paper P. The cleaning unit 156 removes residual toner remaining on the peripheral surface of the photosensitive drum 151 after the transfer.

  The fixing device 16 thermally fixes the image formed on the paper P to the paper P. The paper P on which the image is fixed is discharged to the discharge tray 18 by the discharge roller pair 17.

  Next, the image reading unit 2 and the document transport unit 3 will be described with reference to FIG. FIG. 2 is a diagram showing the configuration of the image reading unit 2 and the document conveying unit 3 shown in FIG.

  As shown in FIG. 2, the image reading unit 2 includes a contact glass 210, an LED (Light Emitting Diode) 22, a first mirror 231, a second mirror 232, a third mirror 233, a first carriage 26, a second carriage 27, An imaging lens 28 and a CCD (Charge Coupled Device) 29 are provided. The LED 22 and the first mirror 231 are supported by the first carriage 26. Further, the second mirror 232 and the third mirror 233 are supported by the second carriage 27. The contact glass 210 has a wide document placing glass 212 and a long and thin document automatic reading glass 211. The automatic document reading glass 211 is located on the left side of the document placement glass 212 in FIG.

  There are two types of image reading methods of the document R by the image reading unit 2, that is, a flat bed reading mode and an ADF (Auto Document Feeder) reading mode. In the flat bed reading mode, the image of the document R placed on the document placement glass 212 is read. In the ADF reading mode, the original R is conveyed by the original conveying unit 3, and when the original R passes the first reading position 211a, an image on the surface of the original R is read. In the following description, a case where the image reading unit 2 reads an image of the document R placed on the document tray 31 in the ADF reading mode will be described.

  Specifically, in the ADF reading mode, the LED 22 irradiates the surface of the original R with light when the original R passes the first reading position 211a. Then, the reflected light from the surface of the document R is reflected by the first mirror 231, the second mirror 232, and the third mirror 233 in order and enters the imaging lens 28. Light incident on the imaging lens 28 is imaged by photoelectric conversion on the light receiving surface of the CCD 29 and output as an image signal. In this way, while the document transport unit 3 moves the document R, the CCD 29 continuously reads the image on the surface of the document R and generates image data.

  The document conveyance unit 3 includes a document tray 31, a pickup roller 32, a paper feed unit 33, a conveyance roller pair 34, a registration roller pair 341, an image reading unit 351, a white reference roller 352, a conveyance roller pair 35, a reading guide 36, and a conveyance roller. A pair 37, a discharge roller pair 38, and a document discharge tray 39 are provided. The document transport unit 3 constitutes an ADF.

  A plurality of documents R (see FIG. 1) are placed on the document tray 31. On the bottom surface of the document tray 31, for example, a lift mechanism for lifting the document R upward is provided. When the document R is placed on the document tray 31, the lift mechanism lifts the document R upward, and the uppermost document R contacts the pickup roller 32.

  The pickup roller 32 comes into contact with the uppermost document R on the document tray 31 and is rotated to feed the uppermost document R one by one toward the paper feeding unit 33. The pickup roller 32 starts feeding the next document R after a predetermined inter-sheet time has elapsed after feeding the trailing edge of the document R.

  The paper feed unit 33 is disposed downstream of the pickup roller 32 in the conveyance direction of the document R. The paper feed unit 33 includes a driven roller 331, a drive roller 332, a tension adjustment roller 333, a paper feed belt 334, and a separation roller 335. The sheet feeding belt 334 is stretched around the driving roller 332 and the driven roller 331. The drive roller 332 drives the paper feed belt 334. The driven roller 331 is driven to rotate as the paper feed belt 334 rotates. The tension adjustment roller 333 adjusts the tension of the paper feed belt 334.

  A paper feed nip portion is formed between the paper feed belt 334 and the separation roller 335. The paper feed belt 334 is driven by a driving roller 332 and transports the document R that has entered the paper feed nip portion to the transport roller pair 34. The separation roller 335 is rotationally driven so as to convey the document R in the direction opposite to the conveyance direction of the document R. For this reason, even if a plurality of documents R are pulled out from the document tray 31, the separation rollers 335 separate the stacked documents R one by one.

  The transport roller pair 34 sends the transported original R one by one toward the registration roller pair 341. The registration roller pair 341 sends the document R conveyed from the conveyance roller pair 34 to the image reading unit 351 at a predetermined timing. The image reading unit 351 is a CIS (Contact Image Sensor) unit including an LED, a contact glass, an imaging lens, and an image sensor 351a, and these members are integrated. The image reading unit 351 reads an image on the back side of the document R conveyed from the registration roller pair 341.

  The white reference roller 352 is disposed at a position facing the image reading unit 351. The white reference roller 352 has a white outer peripheral surface. This is because white reference data used for shading correction is acquired.

  The conveyance roller pair 35 conveys the document R conveyed by the registration roller pair 341 via the image reading unit 351 and the white reference roller 352 to the reading guide 36.

  The reading guide 36 is disposed on the downstream side of the conveyance roller pair 35 in the conveyance direction of the document R. The reading guide 36 is disposed so as to face the contact glass 210 of the image reading unit 2. The reading guide 36 is formed long in the width direction of the document R (the direction perpendicular to the paper surface of FIG. 2). In the ADF reading mode, the image reading unit 2 reads an image formed on the surface of the document R when the document R passes between the reading guide 36 and the automatic document reading glass 211 (first reading position 211a). It is done.

  The conveyance roller pair 37 is arranged downstream of the first reading position 211a in the conveyance direction of the document R. Further, the transport roller pair 37 transports the document R to the discharge roller pair 38. The discharge roller pair 38 discharges the document R conveyed from the conveyance roller pair 37 to the document discharge tray 39.

  An operation in which the image reading unit 2 and the document transport unit 3 read images on both sides of the document R will be described below.

  The pickup roller 32 feeds the uppermost document R on the document tray 31 one by one toward the paper feed unit 33. The paper feed unit 33 feeds the original R one by one toward the conveyance roller pair 34. The transport roller pair 34 transports the document R toward the registration roller pair 341. The registration roller pair 341 sends the document R to the image reading unit 351 at a predetermined timing. The image reading unit 351 reads an image on the back side of the document R. The conveyance roller pair 35 sends the document R sent from the registration roller pair 341 to the first reading position 211a. At the first reading position 211a, the image reading unit 2 reads an image on the surface of the document R. The transport roller pair 37 transports the document R transported from the transport roller pair 35 via the first reading position 211 a to the discharge roller pair 38. The discharge roller pair 38 discharges the document R onto the document discharge tray 39.

  Next, the configuration of the control unit 5 will be described with reference to FIGS. 2 and 3. FIG. 3 is a diagram illustrating a configuration of the control unit 5. The control unit 5 includes a CPU (Central Processing Unit) and a memory. A control program is stored in the memory. The CPU functions as various functional units by executing the control program. Further, the CPU causes the memory to function as various functional units by executing a control program. As a result, the various functional units of the CPU and memory control the operation of the image forming apparatus 100. As shown in FIG. 3, the control unit 5 includes a white reference generation unit 51, an abnormality determination unit 52, a white reference rotation unit 53, an abnormality count unit 54, a count determination unit 55, a notification unit 56, an image reading unit 57, In addition, an image processing unit 58 is provided.

  The white reference generation unit 51 acquires an image indicating the white reference roller 352 via the image sensor 351a disposed in the image reading unit 351, and generates white reference data. Specifically, the white reference generation unit 51 generates white reference data as follows. That is, the white reference generation unit 51 irradiates the LED of the image reading unit 351 with the outer peripheral surface of the white reference roller 352 in a state where the document R is not present at the position of the image reading unit 351. Then, the white reference generation unit 51 causes the image sensor 351a of the image reading unit 351 to acquire the reflected light from the white reference roller 352, and generates white reference data. The white reference data generated by the white reference generation unit 51 is used for shading correction.

  The abnormality determination unit 52 determines whether the white reference data is abnormal every time the white reference data is generated by the white reference generation unit 51. Specifically, the abnormality determination unit 52 determines that the white reference data is abnormal when the lower limit value WV1 of the white reference data is equal to or less than a preset threshold value WVL.

  Next, a determination method by the abnormality determination unit 52 will be described with reference to FIG. FIG. 4 is a graph G1 showing the relationship between the position P of the image sensor 351a in the main scanning direction and the white reference value WV. The horizontal axis indicates the position P of the image sensor 351a in the main scanning direction, and the vertical axis indicates the white reference value WV. The white reference value WV is a pixel value of each pixel constituting the white reference data. As shown in the graph G1, the white reference value WV at the position P1 is the lower limit value WV1. Further, lower limit value WV1 is equal to or less than threshold value WVL. In such a case, the abnormality determination unit 52 determines that the white reference data is abnormal. The threshold value WVL is set to a larger value as the required image quality is higher. Moreover, the specific setting value of the threshold value WVL is set empirically based on experiments, for example.

  Returning to FIG. 3 again, the configuration of the control unit 5 will be described. When the abnormality determination unit 52 determines that the white reference data generated by the white reference generation unit 51 is abnormal, the white reference rotation unit 53 sets the white reference roller 352 in a preset rotation direction in advance. The predetermined angle θ is rotated. The rotation direction is, for example, clockwise as indicated by an arrow RT in the side view of FIG. The predetermined angle θ is an angle that is not a divisor of 360. The predetermined angle θ is, for example, “70 degrees”.

  The abnormality count unit 54 increments the abnormality count value EC by 1 when the abnormality determination unit 52 determines that the white reference data is abnormal continuously for a predetermined number of times NA or more. In other words, a value obtained by adding 1 to the abnormal count value EC is updated as a new abnormal count value EC. As the predetermined number NA is larger, the abnormal count value EC is less likely to increase. In addition, the larger the predetermined number NA, the more times white reference data is generated, so the probability that normal white reference data is generated increases. On the other hand, the larger the predetermined number NA, the longer the time required to generate the white reference data. As a result, the time required for reading the image formed on the document R may be increased. The predetermined number NA is, for example, “twice”.

  The count determination unit 55 determines whether or not the abnormal count value EC is greater than or equal to a predetermined value ECL set in advance. The count determination unit 55 can reduce the frequency of outputting a notification that the white reference roller 352 is cleaned as the predetermined value ECL is larger. In addition, the larger the predetermined value ECL, the greater the number of times that image data that has undergone shading correction based on abnormal white reference data is generated. In other words, the count determination unit 55 increases the number of times image data with poor image quality is generated as the predetermined value ECL is larger. The predetermined value ECL, for example, “4”.

  The notification unit 56 notifies the outside that the white reference roller 352 is to be cleaned when it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL. Specifically, when it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL, the notification unit 56 indicates, for example, “Please clean the white reference roller” on the touch panel 41 illustrated in FIG. Display a message. The notification unit 56 corresponds to an example of a “second notification unit”.

The image reading unit 57 reads an image formed on the document R using the image reading unit 351 and generates image data. Specifically, image data is generated using the image reading unit 351 in any of the following cases.
Case A: When the white reference data is determined not to be abnormal by the abnormality determination unit 52.
Case B: When it is determined that the abnormal count value EC is not greater than or equal to the predetermined value ECL.
Note that when it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL, the image reading unit 57 does not generate image data. When the white reference roller 352 is cleaned, the abnormal count value EC is initialized to “0”. Therefore, thereafter, the image reading unit 57 generates image data until it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL.

  In the case B, the image processing unit 58 performs image processing on the image data generated by the image reading unit 57. The image processing is, for example, smoothing processing.

  Next, the operation of the control unit 5 will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the control unit 5. First, the white reference generation unit 51 acquires an image showing the white reference roller 352 (step S101). Next, the white reference generation unit 51 generates white reference data from the image indicating the white reference roller 352 acquired in step S101 (step S103). Next, the abnormality determination unit 52 determines whether or not the white reference data generated in step S103 is abnormal (step S105). Specifically, the abnormality determination unit 52 determines whether or not the white reference data is abnormal depending on whether or not the lower limit value WV1 of the white reference data is equal to or less than the threshold value WVL.

  If it is determined that the white reference data is not abnormal (“WV1 ≦ WVL” is not satisfied) (NO in step S105), the process proceeds to step S125. If it is determined that the white reference data is abnormal (“WV1 ≦ WVL”) (YES in step S105), the process proceeds to step S107. Then, the white reference rotation unit 53 rotates the white reference roller 352 clockwise by a predetermined angle θ (step S107). The predetermined angle θ is, for example, 70 degrees. Next, the white reference generation unit 51 acquires an image showing the white reference roller 352 (step S109). Next, the white reference generation unit 51 generates white reference data from the image showing the white reference roller 352 acquired in step S109 (step S111). Next, the abnormality determination unit 52 determines whether or not the white reference data generated in step S111 is abnormal (step S113). Specifically, the abnormality determination unit 52 determines whether or not the white reference data is abnormal depending on whether or not the lower limit value WV1 of the white reference data is equal to or less than the threshold value WVL.

  If it is determined that the white reference data is not abnormal (not “WV1 ≦ WVL”) (NO in step S113), the process proceeds to step S125. If it is determined that the white reference data is abnormal (“WV1 ≦ WVL”) (YES in step S113), the process proceeds to step S115. Then, the abnormality count unit 54 increments the abnormality count value EC by 1 (step S115). Next, the count determination unit 55 determines whether or not the abnormal count value EC is equal to or greater than the predetermined value ECL (step S117). If it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL (YES in step S117), the process proceeds to step S119. If it is determined that the abnormal count value EC is not equal to or greater than the predetermined value ECL (NO in step S117), the process proceeds to step S121. Then, the image reading unit 57 reads an image formed on the document R using the image reading unit 351, and generates image data (step S121). Next, the image processing unit 58 performs image processing on the image data generated in step S121 (step S123), and the processing ends (end).

  If NO in step S105 or NO in step S113, the image reading unit 57 reads the image formed on the document R using the image reading unit 351, and generates image data (step S125). The process ends (end). If YES in step S117, the notification unit 56 notifies the outside that the white reference roller 352 is to be cleaned (step S119), and the process ends (end).

  As described with reference to FIGS. 3 to 5, the white reference generation unit 51 acquires an image indicating the white reference roller 352 via the image sensor 351 a of the image reading unit 351, and generates white reference data. Each time the white reference data is generated, the abnormality determination unit 52 determines whether or not the white reference data is abnormal. When it is determined that the white reference data is abnormal, the white reference rotation unit 53 rotates the white reference roller 352 in a predetermined rotation direction (for example, clockwise) in a predetermined angle θ (for example, 70). Rotate. The white reference generation unit 51 generates white reference data again when the white reference roller 352 is rotated by a predetermined angle θ. Therefore, when it is determined that the white reference data is abnormal, the white reference data is generated again after the white reference roller 352 is rotated by a predetermined angle θ. Therefore, the possibility of generating normal white reference data can be increased.

  Further, the abnormality determination unit 52 determines that the white reference data is abnormal when the lower limit value WV1 of the white reference data is equal to or less than a preset threshold value WVL. When the lower limit value WV1 of the white reference data is equal to or less than the threshold value WVL, there is a high possibility that the area corresponding to the white reference data of the white reference roller 352 is dirty. Therefore, it can be appropriately determined that the white reference data is abnormal.

  When the predetermined angle θ is an angle that is a divisor of 360, if the predetermined angle θ is rotated a plurality of times, the cumulative rotation angle becomes 360 degrees. For example, when the predetermined angle θ is 60 degrees, the white reference roller 352 rotates once by rotating the predetermined angle θ six times. In this case, the white reference data generated for the first time and the white reference data generated for the seventh time correspond to the same area of the white reference roller 352.

  Therefore, unless the white reference roller 352 is cleaned, white reference data better than the white reference data generated at the first time is not likely to be generated at the seventh time. On the other hand, when the predetermined angle θ is not a divisor of 360, even if the predetermined angle θ is rotated several times, it does not become 360 degrees. For example, when the predetermined angle θ is 70 degrees, if the predetermined angle θ is rotated five times, the predetermined angle θ is 350 degrees. Also, the white reference data corresponding to the same region of the white reference roller 352 is generated after the white reference roller 352 rotates seven times (2520 degrees). In other words, it is when the rotation of 70 degrees is performed 37 times. Therefore, when the predetermined angle θ is an angle that is not a divisor of 360, it is possible to increase the possibility of generating normal white reference data by effectively using the unstained area of the white reference roller 352.

  In addition, when the abnormality determination unit 52 determines that the white reference data is abnormal continuously for a predetermined number of times NA or more, the abnormality count unit 54 increments the abnormality count value EC. Then, the count determination unit 55 determines whether or not the abnormal count value EC is greater than or equal to a predetermined value ECL set in advance. When it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL, the notification unit 56 notifies the outside that the white reference roller 352 needs to be cleaned.

  Therefore, by setting the predetermined number NA and the predetermined value ECL to appropriate values, a notification that the white reference roller 352 is to be cleaned can be output at an appropriate timing. For example, when the predetermined angle θ is 70 degrees, the predetermined number NA may be set to 36 in order to reduce the frequency of notification that the white reference roller 352 is cleaned. This is because when the rotation of 70 degrees is performed 36 times, the white reference roller 352 rotates 7 times. In other words, the white reference data generated when the 70 ° rotation is performed 37 times and the white reference data generated before the 70 ° rotation correspond to the same region of the white reference roller 352. . In addition, the greater the predetermined value ECL, the lower the frequency of notification that the white reference roller 352 needs to be cleaned.

  If it is determined that the abnormal count value EC is not equal to or greater than the predetermined value ECL, the image reading unit 57 reads an image formed on the document R and generates image data. Then, the image processing unit 58 performs image processing on the generated image data. Therefore, even if it is determined that the white reference data is abnormal, if it is determined that the abnormal count value EC is not equal to or greater than the predetermined value ECL, the image reading unit 57 is formed on the document R. An image is read and image data is generated. In this case, the white reference data is abnormal because the white reference roller 352 is dirty.

  Therefore, the white reference value WV of the white reference data corresponding to the dirt position of the white reference roller 352 is equal to or less than the threshold value WVL. Therefore, the image data has an inappropriate luminance (brightness of luminance) extending linearly along the sub-scanning direction (the conveyance direction of the document R) at the main scanning direction position corresponding to the dirt position of the white reference roller 352. High) image data. The image processing unit 58 performs image processing (for example, smoothing processing) on the image data. Therefore, the image quality can be improved by performing image processing such as smoothing processing on the image data including a pixel group with inappropriate luminance in a linear shape.

  In the present embodiment, the description has been given of the form in which the notification unit 56 notifies the outside that the white reference roller 352 needs to be cleaned when it is determined that the abnormal count value EC is equal to or greater than the predetermined value ECL. It is not limited to this. For example, the notification unit 56 notifies the outside that the white reference roller 352 is to be cleaned when it is determined that the white reference data is abnormal continuously for a predetermined number of times NB. The notification unit 56 in this form corresponds to an example of a “first notification unit”. In this case, by appropriately setting the predetermined number of times NB, a notification that the white reference roller 352 needs to be cleaned can be output at an appropriate timing.

  For example, if the predetermined angle θ is 70 degrees and the user wants to reduce the frequency of notification to clean the white reference roller 352, the predetermined number NA may be set to 36. This is because when the rotation of 70 degrees is performed 36 times, the white reference roller 352 rotates 7 times. In other words, the white reference data generated when the 70 ° rotation is performed 37 times and the white reference data generated before the 70 ° rotation correspond to the same region of the white reference roller 352. White reference data.

  Therefore, when the white reference roller 352 is not cleaned, the white reference data generated when the rotation of 70 degrees is performed 37 times or more is not better than the white reference data generated before that. In other words, when it is determined that the white reference data obtained at that time is 36 times and all the white reference data obtained at that time are abnormal, it is determined that the white reference data is normal thereafter. I can't expect that. Therefore, when it is desired to reduce the frequency of notification that the white reference roller 352 is cleaned, the predetermined number NA may be set to 36 times.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof. In order to facilitate understanding, the drawings schematically show each component as a main component, and the thickness, length, number, and the like of each component shown in the drawings are different from the actual for convenience of drawing. . Moreover, the shape, dimension, etc. of each component shown by said embodiment are an example, Comprising: It does not specifically limit, A various change is possible in the range which does not deviate substantially from the structure of this invention.

  The present invention can be used for an image reading apparatus and an image forming apparatus.

100 Image forming apparatus 1 Image forming unit 2 Image reading unit (part of image reading apparatus)
210 Contact glass 22 Light source 231 First mirror 232 Second mirror 233 Third mirror 26 First carriage 27 Second carriage 28 Imaging lens 29 CCD
3 Document transport unit (part of image reader)
31 Document tray 32 Pickup roller 33 Paper feed unit 335 Separation roller 34 Transport roller pair 341 Registration roller pair 35 Transport roller pair 351 Image reading unit 351a Image sensor 352 White reference roller 36 Reading guide 37 Transport roller pair 38 Discharge roller pair 39 Document discharge Tray 4 Operation panel 41 Touch panel 5 Control unit 51 White reference generation unit 52 Abnormality determination unit 53 White reference rotation unit 54 Abnormality count unit 55 Count determination unit 56 Notification unit 57 Image reading unit 58 Image processing unit

Claims (4)

An image sensor that reads an image formed on a document;
A white reference roller disposed at a position facing the image sensor;
A white reference generation unit that acquires an image showing the white reference roller through the image sensor and generates white reference data;
An abnormality determination unit that determines whether the white reference data is abnormal each time the white reference data is generated by the white reference generation unit;
A white reference rotation unit that rotates the white reference roller in a predetermined rotation direction in a predetermined angle when it is determined that the white reference data is abnormal,
The white reference generating unit, when the white reference roller is the predetermined angle, generates the white reference data,
The abnormality determination unit determines that the white reference data is abnormal when a lower limit value of the white reference data is equal to or less than a preset threshold value,
The predetermined angle is an angle that is not a divisor of 360 degrees;
An abnormality count unit that increments an abnormal count value when it is determined by the abnormality determination unit that the white reference data is abnormal continuously for a predetermined number of times set in advance;
A count determination unit that determines whether or not the abnormal count value is greater than or equal to a predetermined value set in advance;
A second notification unit that outputs a notification that the white reference roller is to be cleaned to the outside when it is determined that the abnormal count value is equal to or greater than the predetermined value;
An image reading unit that reads an image formed on the document via the image sensor and generates image data;
An image processing unit for performing image processing on the image data;
With
When it is determined that the abnormal count value is not greater than or equal to the predetermined value,
The image reading unit reads an image formed on the document, generates image data,
The image processing unit performs image processing on the image data,
White reference data generated when the white reference roller is rotated at the predetermined angle for the predetermined number of times and white reference data generated before the white reference roller is rotated at the predetermined angle are the white reference data. The image reading device , wherein the predetermined number of times is determined so as to correspond to the same region of the reference roller . An image sensor that reads an image formed on a document;
A white reference roller disposed at a position facing the image sensor;
A white reference generation unit that acquires an image showing the white reference roller through the image sensor and generates white reference data;
An abnormality determination unit that determines whether the white reference data is abnormal each time the white reference data is generated by the white reference generation unit;
A white reference rotation unit that rotates the white reference roller in a predetermined rotation direction in a predetermined angle when it is determined that the white reference data is abnormal,
The white reference generating unit, when the white reference roller is the predetermined angle, generates the white reference data,
The predetermined angle is an angle that is not a divisor of 360 degrees;
A first notification unit that outputs a notification that the white reference roller is to be cleaned to the outside when the white reference data is determined to be abnormal continuously by a predetermined number of times set in advance by the abnormality determination unit. With
White reference data generated when the white reference roller is rotated the predetermined angle for the predetermined number of times and white reference data generated before the white reference roller is rotated for the predetermined angle are the white reference data. The image reading device , wherein the predetermined number of times is determined so as to correspond to the same region of the reference roller . The image reading apparatus according to claim 2 , wherein the abnormality determination unit determines that the white reference data is abnormal when a lower limit value of the white reference data is equal to or less than a preset threshold value. An image forming unit for forming an image on a recording medium;
And an image reading apparatus according to any one of claims 1 to 3, the image forming apparatus.

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