Image reading device and image forming device

Abstract

To facilitate specification of an optical element to which a foreign substance is attached, of a plurality of optical elements installed in an optical path.SOLUTION: An image reading device is provided with: a light source 401 that radiates light toward a document D; a plurality of mirrors 402-406 (optical elements) that are installed in an optical path where reflected light reflected on the document D reaches an imaging unit 407; the imaging unit 407 in which the reflected light is formed into an image; and a moving mechanism 500 that can move the imaging unit 407 in a reading depth direction from a reference position. The image reading device specifies a mirror to which a foreign substance is attached, of the plurality of mirrors 402-406, based on first reading data of a white reference plate 40 (body to be read) read when the imaging unit 407 is located at the reference position, and second reading data of the white reference plate 40 read when the imaging unit 407 is located at a separation position where the imaging unit is moved by the moving mechanism 500 by a predetermined distance z in the reading depth direction from the reference position.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an image reading device that reads image information from a document, and to an image forming apparatus that includes the image reading device, such as a copying machine, a printer, a facsimile machine, or a combination machine thereof or a printing machine. [Background technology]

[0002] BACKGROUND ART Conventionally, image forming apparatuses such as copying machines, printers, and printing machines that are provided with an image reading device that reads image information of an original placed on a contact glass have been widely used (see, for example, Patent Document 1).

[0003] Meanwhile, Patent Document 1 discloses a technology for detecting whether or not dust (foreign matter) is attached to the contact glass. Specifically, a reading roller serving as a reference member is moved relative to the reading unit, and whether or not dust is attached to the contact glass is determined from the read data before and after the movement. Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional image reading devices are unable to identify which of the multiple optical elements installed in the optical path has dust or other foreign matter attached to it, making it difficult to remove the foreign matter and preventing image reading problems caused by the attachment of foreign matter from being efficiently resolved.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide an image reading device and an image forming device that make it easy to identify an optical element to which foreign matter has adhered, among multiple optical elements installed in an optical path. [Means for solving the problem]

[0006] The image reading device of this invention is an image reading device that reads image information of a document, and is equipped with a light source that irradiates light toward the document, a plurality of optical elements installed in an optical path along which the reflected light reflected from the document reaches an imaging unit, the imaging unit on which the reflected light forms an image, and a moving mechanism that can move the imaging unit from a reference position in the reading depth direction, and is configured to identify an optical element among the plurality of optical elements to which foreign matter has adhered based on first reading data of the object to be read that is read when the imaging unit is located at the reference position, and second reading data of the object to be read that is read when the imaging unit is located at a separated position moved a predetermined distance in the reading depth direction by the moving mechanism from the reference position. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an image reading device and an image forming device that can easily identify an optical element to which foreign matter has adhered, among a plurality of optical elements installed in an optical path. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram illustrating a configuration of a document transport device. [Figure 3] FIG. 1 is a perspective view showing an image reading device. [Figure 4] FIG. 2 is a perspective view showing the image reading device with a cover member removed. [Figure 5] FIG. 2 is a diagram illustrating the configuration of an image reading unit. [Figure 6] FIG. 2 is a simplified diagram showing a linear optical path from the contact glass to the reading sensor. [Figure 7] 10 is a graph showing the output of the reading sensor when foreign matter adheres to the optical element. [Figure 8] 10A and 10B are diagrams illustrating the operation of the image reading unit when identifying an optical element to which foreign matter is attached. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming apparatus 1 will be described with reference to FIG. In Figure 1, 1 indicates a copier as an image forming device, 2 indicates an image reading device that optically reads image information from an original D, 3 indicates an exposure unit that irradiates exposure light L onto a photosensitive drum 5 based on image information read by the image reading device 2 or a second image reading unit 80, 4 indicates an image creating unit that forms a toner image (image) on the photosensitive drum 5, and 7 indicates a transfer unit (image forming unit) that transfers the toner image formed on the photosensitive drum 5 to paper P (sheet). Also, 10 indicates a document transport device that transports the document D set on the document loading section 61 to the second contact glass 43 or the second image reading section 80 of the image reading device 2 and discharges it to the document discharge section 62, 12 to 14 indicate a paper feed section in which paper P is stored, and 17 indicates a registration roller (timing roller) that transports paper P toward the transfer section 7. Also, 20 denotes a fixing device that fixes the toner image (unfixed image) carried on the paper P, 21 denotes a fixing roller installed in the fixing device 20, 22 denotes a pressure roller installed in the fixing device 20, 31 denotes a paper output tray on which the paper P discharged from the image forming device main body 1 is loaded, and 80 denotes a second image reading unit that optically reads image information on the back side of the document D transported by the document transport device 10. An operation display panel 110 (operation display unit) is provided on the exterior of the image forming apparatus 1 to display various information about the image forming apparatus 1 and to input various commands.

[0011] The document transport device 10 is installed so as to cover the top surface of the image reading device 2. The document transport device 10 is configured so as to be able to expose or cover the top surface of the image reading device 2 (on which the first contact glass 44 and the second contact glass 43 are installed) by rotating about a hinge (not shown). Furthermore, a pressure plate 39 for pressing down the document D on the first contact glass 44 is provided on the bottom surface of the document transport device 10 (the surface facing the first contact glass 44).

[0012] With reference to FIG. 1, the operation of the image forming apparatus main body 1 during normal image formation will be described. Depending on the user's selection, the document D is placed on the document placement section 61 of the document transport device 10, or is placed on the first contact glass 44 by opening and closing (rotating) the document transport device 10. When an original D is placed on the original placement section 61 of the original transport device 10, the original D is transported (fed) from the original placement section 61 in the original transport device 10 and passes the position of the second contact glass 43 of the image reading device 2. At this time, in the image reading device 2, image information on the front side of the original D passing above the second contact glass 43 is optically read by a CIS (contact image sensor) (not shown) fixedly installed below the second contact glass 43. The optical image information read by the CIS at the position of the second contact glass 43 is then converted into an electrical signal and transmitted to the exposure unit 3 (writing unit). Then, exposure light L, such as a laser beam, based on the image information of the electrical signal is emitted from the exposure unit 3 toward the photosensitive drum 5 of the imaging unit 4.

[0013] When the document transport device 10 is opened and closed (rotated) and the document D is placed on the first contact glass 44 (between the first contact glass 44 and the pressure plate 39), an image reading unit 45 (see FIGS. 4, 5, etc.) built into the image reading device 2 moves (travels) in a predetermined direction (the left-right direction in FIG. 1) to optically read the image information of the document D placed on the first contact glass 44. The optical image information read by the image reading unit 45 at the position of the first contact glass 44 is then converted into an electrical signal and transmitted to the exposure unit 3 (writing unit). The exposure unit 3 then emits exposure light L, such as a laser beam, based on the image information of the electrical signal toward the photosensitive drum 5 of the imaging unit 4.

[0014] Meanwhile, in the image creating unit 4, the photosensitive drum 5 rotates clockwise in the figure, and after going through a predetermined image creating process (charging process, exposure process, and development process), an image (toner image) corresponding to the image information is formed on the photosensitive drum 5. Thereafter, the image formed on the photosensitive drum 5 is transferred onto the paper P conveyed by the registration rollers 17 at the transfer section 7 .

[0015] On the other hand, the paper P being transported to the transfer unit 7 (image forming unit) operates as follows. First, one of the paper feed units 12-14 of the image forming apparatus main body 1 is automatically or manually selected (for example, assume that the topmost paper feed unit 12 in the apparatus main body 1 is selected). Then, the topmost sheet of paper P stored in paper feed unit 12 is fed by paper feed mechanism 52 (comprised of a feed roller, a pickup roller, a backup roller, etc.) and conveyed toward the conveyance path. Thereafter, paper P passes through the conveyance path on which multiple conveyance rollers are arranged, and reaches the position of registration rollers 17.

[0016] The paper P that has reached the position of the registration rollers 17 is conveyed toward the transfer unit 7 (image forming unit) in time to be aligned with the image formed on the photosensitive drum 5. After the transfer process, the paper P passes through the transfer unit 7, then travels through a transport path and reaches the fixing device 20. The paper P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, where the toner image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22 (the fixing process). After the fixing process, the paper P with the fixed toner image is sent out from between the fixing roller 21 and the pressure roller 22 (the fixing nip), and then discharged from the image forming apparatus main body 1 and stacked on the paper output tray 31 as an output image. In this way, a series of image forming processes is completed.

[0017] When the original D is placed on the original placement unit 61 of the original transport device 10 and an image is to be formed based on the image on the back side of the original D in addition to the image on the front side, when the original D passes through the position of the second contact glass 43 and the position of the second image reading unit 80 (which is a CIS) in the original transport device 10, the image information on the back side of the original D passing underneath is optically read by the second image reading unit 80. Then, similar to the image formation process based on the image on the front side, the optical image information read by the second image reading unit 80 is sent to the exposure unit 3, and the image formation process is performed based on that information.

[0018] Next, the document transport device 10 will be briefly described with reference to FIG. As shown in Figure 2, the document transport device 10 is composed of a document loading section 61 (document table), a second image reading section 80, a contact member 90, a document discharge section 62 (paper discharge tray), a pickup roller 63, a separation transport roller pair 64 (paper feed roller and separation roller), multiple transport roller pairs 65 to 68, a discharge roller pair 69 (paper discharge roller pair), a transport upper guide plate 71, a first transport lower guide plate 72, a second transport lower guide plate 73, etc.

[0019] Here, the document placement section 61 has an open space formed at the top, and is configured so that the user can place the document D from above with the front side facing upward (it is configured so that a stack of multiple documents D can be stacked). The document discharge section 62 is installed below the document loading section 61, and is configured so that the document D is discharged and loaded after the image has been read by the image reading device 2 or the second image reading section 80 (it is configured so that multiple documents D can be stacked).

[0020] Further, on the transport path from the document placing section 61 to the document discharge section 62, there are provided, in order from the upstream side in the transport direction, a pickup roller 63, a separation transport roller pair 64, a first transport roller pair 65 (abutment roller pair), a second transport roller pair 66 (reading entrance roller pair), a third transport roller pair 67 (first reading exit roller pair), a fourth transport roller pair 68 (second reading exit roller pair) as a downstream transport roller pair, and a discharge roller pair 69. These roller members 63 to 69 function as transport means that transport the document D placed on the document placing section 61 toward the second contact glass 43 (image reading device 2) or the second image reading section 80, and transport the document D toward the document discharge section 62 after image reading.

[0021] Next, the configuration and operation of the image reading device 2 will be described with reference to FIGS. As previously described with reference to FIG. 1 and the like, the image reading device 2 is disposed below the document transport device 10. 3 and 4, the image reading device 2 has a cover member 42 fixed to a housing 41 (frame) by screw fastening or the like, and components such as an image reading unit 45, a guide rod 46 (guide member), a rail 47, and a moving device (not shown) are installed in the substantially sealed space inside. Two substantially rectangular openings are formed in the cover member 42, and a first contact glass 44 (contact glass) and a second contact glass 43 are installed to fit into the respective openings. In addition, a white reference plate 40, at least the reading surface of which is white, is installed near the first contact glass 44 (or on the first contact glass 44). Both the housing 41 and the cover member 42 are made of a resin material or the like that has high mechanical strength. The second contact glass 43 is a member made of a light-transmitting material such as transparent glass, and its surface functions as an image reading surface (document transport surface). That is, as previously described with reference to Figures 1 and 2, light is irradiated from a light-emitting section of the CIS (not shown) through the second contact glass 43 onto the document D transported along the image reading surface (document transport surface) by the document transport device 10, and the light reflected from the document D is received by a light-receiving section of the CIS through the second contact glass 43, whereby the image information of the document D is read by the CIS.

[0022] The first contact glass 44 serving as the contact glass is a member formed of a light-transmitting material such as transparent glass, and its surface functions as a placement section (document placement surface) for the document D. Then, image information of the document D placed on the first contact glass 44 by the user is optically read by the image reading unit 45, which moves in a predetermined direction (the direction of the arrow in FIG. 4, which is the sub-scanning direction). 5, the image reading unit 45 includes a light source 401, a plurality of mirrors 402 to 406 (a plurality of optical elements), and an imaging unit 407. The imaging unit 407 includes a plurality of imaging lenses 408 and 409, a reading sensor 410, a receiving base 412, an adjustment bracket 413, a lens band 414, and the like.

[0023] In detail, referring to Figure 5, by operating a moving device (not shown), the image reading unit 45 moves (travels) in a predetermined direction (sub-scanning direction) toward the original D placed on the first contact glass 44, and light is irradiated from the light source 401 through the first contact glass 44 in the main scanning direction (a direction perpendicular to the sub-scanning direction, which is a direction perpendicular to the paper surface of Figure 5), and the light reflected by the original D is received by a reading sensor 410 (image sensor) such as a CCD or CMOS mounted on a substrate 411 via the first contact glass 44, multiple mirrors 402 to 406 (multiple optical elements), and imaging lenses 408 and 409, and the image information of the original D is read by the reading sensor 410. In this embodiment, the substrate 411 on which the reading sensor 410 is mounted is fixed to an adjustment bracket 413 placed on a receiving stand 412, and is configured so that its position can be adjusted by adjusting the position of the adjustment bracket 413. Also, the first imaging lens 408 is fixed on the receiving stand 412 via a lens band 414, and the second imaging lens 409 is fixed on the receiving stand 412 via a bracket.

[0024] 4, guide rod 46 (axial member) as a guide member is made of a metal material or the like, and is fitted into image reading unit 45 to extend in a predetermined direction (the direction of the arrow in FIG. 4, the left-right direction in FIG. 5, which is the sub-scanning direction) so as to guide the movement of image reading unit 45 in that direction. In this embodiment, both ends of guide rod 46 in the sub-scanning direction (predetermined direction) are supported (both ends are supported) by housing 41 on one end side in the main scanning direction. Also, referring to FIG. 4, rail 47 is formed of a thick metal plate having a relatively high mechanical strength, and extends in the sub-scanning direction so as to slidably hold image reading unit 45 when the other end side of image reading unit 45 in the main scanning direction is placed on it. Although not shown in the figure, the image reading unit 45 is connected to a known moving device using a wire mechanism, a feed screw mechanism, a motor drive, etc., and is configured to be able to move back and forth in the sub-scanning direction by the moving device controlled by the control unit 100 (see Figure 1).

[0025] The characteristic configuration and operation of the image reading device 2 according to this embodiment will be described in detail below with reference to FIGS. 5 to 8. As explained above, the image reading device 2 in this embodiment reads image information of an original D, and in particular, is provided with an image reading unit 45 that reads image information of an original D placed on a first contact glass 44 serving as a contact glass while moving in a predetermined direction (the left-right direction in Figure 5). The image reading unit 45 is also provided with a light source 401, mirrors 402 to 406 as a plurality of optical elements, an imaging unit 407, and the like. Further, a white reference plate 40 serving as an object to be read is placed near the end of the first contact glass 44 in the sub-scanning direction (or on the first contact glass 44).

[0026] Referring to FIG. 5, the light source 401 emits light (irradiation light) toward the document D (or the white reference plate 40) placed on the first contact glass 44. The multiple mirrors 402 to 406 are multiple optical elements installed on the optical path along which light emitted from the light source 401 and reflected by the original D (or the white reference plate 40) reaches the imaging unit 407, and are arranged at positions spaced apart from each other along the optical path as shown in Figures 5, 6, etc. The imaging unit 407 forms an image of light reflected from the original D (or the white reference plate 40), and is made up of a plurality of imaging lenses 408 and 409, a reading sensor 410, and the like. In this embodiment, only the mirrors 402 to 406 are used as the optical elements to be placed in the optical path, but other optical elements such as lenses and slitters can also be placed in the optical path.

[0027] Here, the image reading device 2 in this embodiment is provided with a moving mechanism 500 that can move the imaging unit 407 from a reference position (the position shown in Figures 5 and 8(A)) in the reading depth direction (the direction of the double arrow in Figure 5, the up and down direction in Figure 8, which is the direction along the optical path). Specifically, the moving mechanism 500 is configured to be able to move the imaging unit 407 between the position shown in Figures 5 and 8(A) (which is the reference position when performing normal reading operations) and the position shown in Figure 8(B) (which is the separated position described below) under the control of the control unit 100 (see Figure 1). A rack and pinion mechanism, for example, can be used as such a moving mechanism 500. Furthermore, all or part of the moving mechanism 500 can be provided in the imaging unit 407. The moving mechanism 500 is configured to be able to move the imaging unit 407 in the reading depth direction regardless of the position of the image reading device 2 in the sub-scanning direction.

[0028] Here, the image reading device 2 in this embodiment identifies a mirror (optical element) among the multiple mirrors 402 to 406 (optical elements) that has foreign matter such as dust attached thereto, based on first reading data (sensor output data obtained by reading the white reading surface with the reading sensor 410) of the white reference plate 40 (object to be read) read when the imaging unit 407 is located at the reference position shown in Figure 8 (A) (and Figure 5), and second reading data (sensor output data obtained by reading the white reading surface with the reading sensor 410) of the white reference plate 40 (object to be read) read when the imaging unit 407 is located at a separated position (the position shown in Figure 8 (B)) moved by the moving mechanism 500 a predetermined distance z from the reference position in the reading depth direction. In detail, when the image reading unit 45 is moved to a position where it can read the white reference plate 40 (a position where the light source 401 faces the white reference plate 40) by the operation of a moving device not shown, the mirror (optical element) to which foreign matter is attached is identified based on the first reading data of the white reference plate 40 read by the image reading unit 45 when the imaging unit 407 is located at the reference position shown in Figure 8(A) and the second reading data of the white reference plate 40 read by the image reading unit 45 when the imaging unit 407 is located at the separated position shown in Figure 8(B).

[0029] The reason for performing such control will be explained below with reference to FIGS. As shown in FIG. 5 (a schematic diagram of the reading image line of the reduction optical system), if a foreign substance R (dust) adheres to a part of the mirrors 402-406, the reflected light from the contact glass 44 (original D or white reference plate 40) will be blocked by the part where the foreign substance R adheres. Therefore, as shown in FIG. 7, the sensor output (distribution graph S in the main scanning direction) of the reading sensor 410 drops in sensor output (image output) at position A in the main scanning direction corresponding to the part where the foreign substance R adheres (the parts S1 and S2 in graph S). 6, comparing the case where a foreign substance R1 adheres to the first mirror 402 with the case where a foreign substance R2 adheres to the fourth mirror 405 on the same read image line Q, the degree of drop in the sensor output (image output) differs due to the effect of focus misalignment of the imaging lenses 408 and 409, as shown by S1 and S2 in graph S in Fig. 7, but the center of the drop coincides with the main scanning position (position in the main scanning direction) on the read image. The difference in the degree of drop in the sensor output (image output) as shown by S1 and S2 in graph S varies depending on the size and light blocking level of the foreign substances R1 and R2 themselves, in addition to focus misalignment of the imaging lenses 408 and 409, making it difficult to determine from the degree of drop whether the mirror to which the foreign substance adheres is the first mirror 402 or the fourth mirror 405. Therefore, in this embodiment, the mirror on which the foreign matter is attached is identified based on the read data before and after the imaging unit 407 is moved in the reading depth direction. This makes it easier to remove the foreign matter R from the mirror to which it has adhered, and image reading problems caused by the adhesion of the foreign matter R can be efficiently resolved.

[0030] In detail, referring to FIG. 8, the mirror 404 to which the foreign substance R is attached is identified by calculating the distance M in the optical path (the optical path at the center of the optical path (center of the lens) indicated by the dashed line) from the mirror to which the foreign substance R is attached (the third mirror 404 in the example of FIG. 8) to the imaging lenses 408, 409 (imaging unit 407) using the position of the foreign substance R in the main scanning direction obtained from the first read data (the read data at the reference position in FIG. 8(A)), the position of the foreign substance R in the main scanning direction obtained from the second read data (the read data at the separated position in FIG. 8(B)), and a predetermined distance z (the movement distance of the imaging unit 407). More specifically, when the distance in the main scanning direction from the center of the optical path of the foreign substance R (center of the lens) obtained from the first read data is A (see FIG. 8A), the distance in the main scanning direction from the center of the optical path of the foreign substance R obtained from the second read data is A' (see FIG. 8B), and the predetermined distance is z, the distance M in the optical path from the mirror 404 to which the foreign substance R is attached to the imaging lenses 408 and 409 (imaging unit 407) is M=z×A´ / (A´-A) It can be calculated using the following formula: The distance (M) in the optical path from each of the mirrors 402 to 406 to the imaging lenses 408 and 409 (imaging unit 407) is stored in advance as data in the memory unit of the control unit 100. As described above, the distance M in the optical path from the mirror 404 to which the foreign matter R is attached to the imaging lenses 408 and 409 is calculated, and the distance M is compared with the data in the memory unit (control unit 100) to identify the optical mirror 404 to which the foreign matter R is attached.

[0031] The validity of the above formula for calculating the distance M will be explained in more detail below. 8(A), the third mirror 404 to which the foreign substance R is attached is located at a distance M (stored as data in a storage unit) from the imaging lenses 408 and 409. The foreign substance R is also assumed to be attached at a distance a from the center of the optical path (center of the lens). In this case, as shown in FIG. 7, in the reading sensor 410, the sensor output (reading image output) at a position separated from the optical path center by a distance A will decrease. Then, as described above using FIGS. 6 and 7, such a decrease in the sensor output at the distance A also occurs when foreign matter R' adheres to the same reading imaging line Q in other mirrors (in the example of FIG. 8, the first and fifth mirrors 402 and 406). Just by grasping the position and magnitude where the sensor output decreases, it is impossible to specify that the mirror to which the foreign matter adheres is not the first and fifth mirrors 402 and 406, but the third mirror 403. Therefore, in the present embodiment, as shown in FIG. 8(B), the imaging unit 407 is moved by a predetermined distance z along the optical path center (lens center) by the moving mechanism 500, and the displacement amount of the position where the sensor output of the reading sensor 410 decreases is observed. As shown in FIG.8(B), when the imaging unit 407 is moved by a predetermined distance z, although the distance (M - z) from the third mirror 404 to the imaging lenses 408 and 409 changes, the distance H from the imaging lenses to the reading sensor 410 does not change. Therefore, the position of the foreign matter R read by the reading sensor 410 changes from the optical path center (lens center) to a distance A' (<A) due to the change in the imaging magnification. On the other hand, even when foreign matter R' adheres to the same reading imaging line Q in other mirrors (in the example of FIG. 8, the first and fifth mirrors 402 and, 406), when the imaging unit 407 is moved by a predetermined distance z, although the position of the foreign matter R' read by the reading sensor 410 changes from the distance from the optical path center (lens center), the amount of change will be different depending on the position of the mirror (the distance from the imaging lenses 408 and 409). From such circumstances, it becomes possible to specify the mirror 404 to which the foreign matter R adheres from the data before and after moving the imaging unit 407 by a predetermined distance z

[0032] Specifically, let A be the position (distance from the lens center) of foreign substance R read by reading sensor 410 when imaging unit 407 is located at the reference position, A' be the position (distance from the lens center) of foreign substance R read by reading sensor 410 when imaging unit 407 is located at the separated position, z be the movement distance (predetermined distance) of imaging unit 407 (fixed value), M be the distance on the center of the optical path from mirror 404 to which foreign substance R is attached to imaging lenses 408 and 409 (value stored in advance as data in a storage unit), and H be the distance on the center of the optical path from imaging lenses 408 and 409 to reading sensor 410 (fixed value). M:a=H:A (Mz):a´=H:A´ Since M=z×A´ / (A´-A) The formula explained earlier will then hold true.

[0033] In this embodiment, when a mirror (optical element) to which foreign matter R is attached is identified by the method described above, a notification is given that foreign matter R is attached to that mirror. More specifically, in the example of Figure 8, when it is determined that the mirror to which foreign matter R is attached is the third mirror 404, a message is displayed on the operation display panel 110 (see Figure 1) indicating that foreign matter R is attached to the third mirror 404. This makes it easier to remove the foreign matter R from the mirror to which it has adhered.

[0034] More specifically, in the embodiment, when a user complains to a service technician about an abnormal image caused by the adhesion of foreign matter R, the service technician opens and operates a special screen on the operation display panel 110 (see FIG. 1) to execute a control mode that identifies the mirror 404 to be cleaned by acquiring read data before and after the movement of the imaging unit 407, as previously described with reference to FIG. 8. That is, the positions A and A' of the foreign substance R on the image in the main scanning direction before and after movement are determined from shading data read from the white reference plate 40, and the distance M from the mirror 404 to the imaging lenses 408 and 409 is determined from the amount of change in the positions A and A' of the foreign substance R and the amount of movement z (predetermined distance).The distance M thus determined is then compared with the distances (M) of the mirrors 402 to 406 stored in the memory unit of the control unit 100 to identify the mirror to which the foreign substance R is attached.The identified mirror is then cleaned (the foreign substance R is removed), completing the maintenance.

[0035] As described above, the image reading device 2 in this embodiment is an image reading device that reads image information of an original D, and includes a light source 401 that irradiates light toward the original D, multiple mirrors 402-406 (optical elements) installed on an optical path of the light reflected from the original D until it reaches the imaging unit 407, the imaging unit 407 that forms an image with the reflected light, and a movement mechanism 500 that can move the imaging unit 407 from a reference position in the reading depth direction. Then, based on first read data of the white reference plate 40 (object to be read) read when the imaging unit 407 is located at the reference position, and second read data of the white reference plate 40 read when the imaging unit 407 is located at a separated position moved by the movement mechanism 500 a predetermined distance z in the reading depth direction from the reference position, a mirror on which foreign matter has adhered is identified among the multiple mirrors 402-406. This makes it easier to identify the mirror (optical element) to which foreign matter has adhered, from among the multiple mirrors 402 to 406 (optical elements) placed in the optical path.

[0036] In this embodiment, the present invention is applied to an image reading device 2 installed in a monochrome image forming apparatus 1, but the present invention can naturally also be applied to an image reading device installed in a color image forming apparatus. Furthermore, in this embodiment, the present invention is applied to an image reading device 2 installed in an image forming apparatus 1 in which a document transport device 10 is installed, but the present invention can naturally also be applied to an image reading device installed in an image forming apparatus in which a document transport device is not installed. Furthermore, in this embodiment, the present invention is applied to an image reading device 2 in which the image reading unit 45 is configured to be movable in a predetermined direction (sub-scanning direction), but the present invention can also be applied to an image reading device in which the image reading unit is fixed and does not move (for example, a device in which the document table moves in the sub-scanning direction). Furthermore, in this embodiment, the optical element (mirror) to which the foreign matter R is attached is identified based on the first and second read data obtained by reading the white reference plate 40 as the object to be read. However, the object to be read to identify the optical element to which the foreign matter R is attached is not limited to the white reference plate 40, and for example, a white pressure plate 39 (see FIGS. 1 and 5) can also be used as the object to be read. Furthermore, in this embodiment, the present invention is applied to an image reading device 2 installed in an electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and the present invention can also be applied to image reading devices installed in other types of image forming apparatuses (for example, inkjet image forming apparatuses, stencil printing machines, etc.). Even in these cases, the same effects as those of this embodiment can be obtained.

[0037] It is to be noted that the present invention is not limited to the present embodiment, and it is clear that the present embodiment can be appropriately modified within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. of the components can be any number, position, shape, etc. that is suitable for implementing the present invention.

[0038] In this application, the term "original" is defined to include not only originals made of paper but also all originals made of sheet-like materials such as overhead projectors. [Explanation of symbols]

[0039] 1 Image forming apparatus (image forming apparatus main body), 2. Image reading device, 40 White reference plate (object to be read), 44 contact glass (first contact glass), 45 Image reading unit, 100 control unit (storage unit), 401 light source, 402~406 Mirrors (optical elements), 407 imaging unit, 408, 409 Imaging lenses, 410 reading sensor, 500 moving mechanism, D manuscript. [Prior art documents] [Patent documents]

[0040] [Patent Document 1] Patent No. 5182118

Claims

1. An image reading device that reads image information of a document, a light source that irradiates light toward the document; a plurality of optical elements disposed on an optical path along which light reflected from the document reaches an imaging unit; the imaging unit in which the reflected light is imaged; a moving mechanism capable of moving the imaging unit from a reference position in a reading depth direction; Equipped with An image reading device characterized by identifying an optical element among the plurality of optical elements to which foreign matter has adhered based on first reading data of the object to be read that is read when the imaging unit is located at the reference position and second reading data of the object to be read that is read when the imaging unit is located at a separated position moved by the moving mechanism a predetermined distance in the reading depth direction from the reference position.

2. an image reading unit that includes the light source, the plurality of optical elements, and the imaging unit, and that reads image information of the document placed on a contact glass while moving in a predetermined direction; The object to be read is a white reference plate placed on or near the contact glass, 2. The image reading device according to claim 1, wherein, when the image reading unit is moved to a position where it can read the white reference plate, the optical element to which the foreign matter is attached is identified based on the first read data of the white reference plate read by the image reading unit when the imaging unit is located at the reference position and the second read data of the white reference plate read by the image reading unit when the imaging unit is located at the separated position.

3. 3. The image reading device according to claim 1, wherein the optical element to which the foreign matter is attached is identified by calculating the distance in the optical path from the optical element to which the foreign matter is attached to an imaging lens in the imaging unit from the main scanning direction position of the foreign matter obtained from the first read data, the main scanning direction position of the foreign matter obtained from the second read data, and the predetermined distance.

4. When the distance of the foreign substance from the center of the optical path in the main scanning direction obtained from the first read data is A, the distance of the foreign substance from the center of the optical path in the main scanning direction obtained from the second read data is A', and the predetermined distance is z, the distance M in the optical path from the optical element to which the foreign substance is attached to the imaging lens is expressed as follows: M=z×A' / (A'-A) 4. The image reading apparatus according to claim 3, wherein the image reading is determined by the following formula:

5. the plurality of optical elements are a plurality of mirrors arranged at positions spaced apart from one another along the optical path, distances of the plurality of mirrors to the imaging lens in the optical paths are stored in advance as data in a storage unit; 5. The image reading device according to claim 3, wherein the mirror on which the foreign matter is attached is identified by calculating the distance in the optical path from the mirror on which the foreign matter is attached to the imaging lens and comparing the distance with data in the memory unit.

6. 6. The image reading device according to claim 1, wherein when the optical element to which the foreign matter is attached is identified, the image reading device notifies the user that the foreign matter is attached to the optical element.

7. An image forming apparatus comprising the image reading device according to any one of claims 1 to 6.

Images