Image forming device

Abstract

To improve accuracy of a reading image.SOLUTION: An image formation device comprises: image formation means arranged on a first conveyance path to form an image on a sheet conveyed through the first conveyance path; reading means arranged on a second conveyance path which is branched from the first conveyance path and through which the sheet is conveyed when an image is formed on a second surface opposite to a first surface of the sheet in which an image is formed on the first surface by the image formation means, to read image formation from the sheet; an opposing member opposed to the reading means across a space which the sheet passes through; and a conveyance roller for conveying the sheet via the space between the reading means and the opposing member. The conveyance roller is rotatably supported by the opposing member.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus for forming an image on a sheet. [Background technology]

[0002] Some image forming apparatuses such as printers, copiers, and multifunction machines are equipped with an image reading device that reads an image from a sheet being transported. For example, in a copier, an image reading device is known that reads an image of a document while the document is being transported by an automatic document feeder (ADF). Patent Document 1 describes a method in which a reading unit is disposed in a double-sided transport path for double-sided printing, and abnormal images are automatically identified using the reading unit following an image forming operation on a recording material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-146487 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an image forming apparatus that reads an image from a sheet being transported after an image is formed on the sheet, the position of the opposing member that faces the reading unit and the position of the transport roller that transports the sheet toward the gap between the reading unit and the opposing member affect the accuracy of the read image. In other words, if the transport roller is not positioned appropriately with respect to the transport space between the reading unit and the opposing member, the sheet cannot pass through the transport space stably, and the accuracy of the read image may decrease.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an image forming apparatus capable of improving the accuracy of read images. [Means for solving the problem]

[0006] One aspect of the present invention is an apparatus main body; and an opening / closing member that is openable and closable relative to the apparatus main body; an image forming means disposed on a first transport path, which forms an image on a sheet transported on the first transport path; and a reading means disposed on a second transport path branched off from the first transport path, along which the sheet is transported when an image is formed on a second surface of the sheet opposite to the first surface on which an image has been formed by the image forming means, which reads image information from the sheet. An opposing member fixed to the opening / closing member by a screw member, The sheet conveying device includes an opposing member that faces the reading means across a space through which the sheet passes, and a conveying roller that conveys the sheet through the space between the reading means and the opposing member, and the conveying roller is rotatably supported by the opposing member. Cage , The opposing member has a support portion that rotatably supports the transport roller. The image forming apparatus is characterized in that

[0007] Another aspect of the present invention is an apparatus main body; and an opening / closing member that is openable and closable relative to the apparatus main body; an image forming means disposed on a first transport path and configured to form an image on a sheet transported on the first transport path; and a reading means disposed on one side of a second transport path branched off from the first transport path and configured to read image information from the sheet fed from the first transport path to the second transport path. An opposing member fixed to the opening / closing member by a screw member, a conveying roller that conveys a sheet through a space between the reading means and the opposing member, the conveying roller being arranged to convey the sheet through the space between the reading means and the opposing member; The opening and closing member and a conveying roller that rotates about a roller shaft supported by a roller support member, and the opposing member is positioned relative to the roller shaft. Effect of the Invention

[0008] According to the present invention, it is possible to provide an image forming apparatus capable of improving the accuracy of read images. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view including a cross section of the reading unit according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view of a white reference plate according to the first embodiment. [Figure 4] FIG. 2 is a perspective view showing the positional relationship between a reading unit and a white reference plate according to the first embodiment. [Diagram 5] FIG. 2 is a perspective view for explaining a method for attaching the reading unit according to the first embodiment. [Figure 6] FIG. 2 is a perspective view showing a white reference unit according to the first embodiment. [Figure 7] FIG. 2 is a perspective view showing a mounting state of a gear according to the first embodiment. [Figure 8] FIG. 4 is a perspective view for explaining an attachment state of a white reference unit according to the first embodiment. [Figure 9] FIG. 4 is a perspective view for explaining a positioning portion of the white reference unit according to the first embodiment. [Figure 10] FIG. 11 is a cross-sectional view showing a reading unit and a white reference unit according to a second embodiment. [Figure 11] FIG. 11 is a perspective view for explaining a support structure of a conveying roller according to a third embodiment. [Figure 12] FIG. 11 is a perspective view for explaining a positioning method of a white reference plate according to a third embodiment. [Figure 13] FIG. 13 is a perspective view showing a white reference unit according to a fourth embodiment. [Figure 14] FIG. 13 is a perspective view of a white reference unit according to a modified example of the first embodiment. [Figure 15] FIG. 13 is a perspective view of a white reference unit according to a modified example of the first embodiment. [Figure 16] FIG. 11 is a cross-sectional view of a white reference unit according to a modified example of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

[0011] Although a number of features are described in the following embodiments, not all of these features are essential, and the features may be combined in any desired manner. Furthermore, in the accompanying drawings, the same or similar configurations are given the same reference numerals, and duplicated descriptions are omitted. Note that the drawings may show three arrows indicating the x-direction, y-direction, and z-direction. This will help to grasp the positions of each member. EXAMPLES

[0012] 1. Image forming device FIG. 1 is a cross-sectional view showing an outline of an image forming apparatus 100 according to a first embodiment. Here, an electrophotographic method is adopted as an image forming method of an image forming means, but an inkjet method may also be adopted. In addition, the present technology is applicable not only to full-color printers but also to monochrome printers. In addition, the image forming apparatus is not limited to a printer that executes printing based on image information input from the outside, but may also be a copying machine having a copying function or a multifunction machine having multiple functions.

[0013] In each drawing, the z direction represents the vertical direction when the image forming apparatus 100 is installed on a horizontal plane, and in particular, the upward direction is represented as the positive z direction and the downward direction is represented as the negative z direction. The y direction is the main scanning direction during image formation, and substantially coincides with the sheet width direction of the sheet transported within the image forming apparatus 100. The y direction is also the main scanning direction of the reading unit 24 described below. The x direction is a direction intersecting the z direction and the y direction, and is preferably a horizontal direction perpendicular to the z direction and the y direction.

[0014] In the image forming apparatus 100 of FIG. 1, a feed cassette 10 is provided at the bottom of the apparatus main body 1A as a storage for storing a large number of sheets S. As the sheet S as a recording material, various sheets of different sizes and materials can be used, such as paper such as plain paper and thick paper, sheet materials with surface treatments such as plastic film, cloth, and coated paper, and sheet materials with special shapes such as envelopes and index paper. A pickup roller 15 as a feeding means picks up the sheet S stored in the feed cassette 10 and passes it to a conveying roller 16 and a separation roller 17. The conveying roller 16 and the separation roller 17 convey the sheet S fed from the pickup roller 15 to the downstream side while separating the sheet S one by one. The downstream side is the downstream side in the conveying direction of the sheet S along the conveying path in the apparatus main body 1A. The registration roller pair 4 corrects the skew of the sheet S and conveys the sheet S to the secondary transfer unit 6 along the first conveying path 22a.

[0015] In parallel with the feeding of the sheet S from the feeding cassette 10, a toner image forming process is performed by the image forming unit 7 as an image forming means. The image forming unit 7 is a tandem type intermediate transfer type electrophotographic unit in which four image forming stations 7Y, 7M, 7C, and 7K are arranged along the intermediate transfer belt 9. The image forming stations 7Y, 7M, 7C, and 7K form toner images of yellow (Y), magenta (M), cyan (C), and black (K) on the surfaces of the photosensitive drums 71, which are image carriers (electrophotographic photosensitive bodies), respectively, and perform primary transfer to the intermediate transfer belt 9. That is, the surfaces of the photosensitive drums 71 are uniformly charged by a charger such as a charging roller, and then exposed to light irradiated from the exposure device 2, and an electrostatic latent image corresponding to a monochrome image of each color is written. This electrostatic latent image is developed by toner supplied from a developing device and visualized as a monochrome toner image, and then transferred to the intermediate transfer belt 9 by the primary transfer roller 72. Any deposits such as residual toner that have not been transferred to the intermediate transfer belt 9 and remain on the surface of the photosensitive drum 71 are removed by a drum cleaner (not shown).

[0016] The single-color toner images formed by the image forming stations 7Y to 7K are primarily transferred onto the intermediate transfer belt 9 so as to be superimposed on each other, forming a full-color toner image on the intermediate transfer belt 9. The intermediate transfer belt 9 is stretched around a secondary transfer inner roller 91 and a tension roller 92, and conveys the toner image toward the secondary transfer unit 6 by being rotated counterclockwise in the figure.

[0017] The secondary transfer unit 6 is a nip portion between the intermediate transfer belt 9, the inner peripheral surface of which is supported by a secondary transfer inner roller 91, and a secondary transfer roller 94 disposed on the outer peripheral side of the intermediate transfer belt 9. The toner image carried on the intermediate transfer belt 9 is secondarily transferred from the intermediate transfer belt 9 to the sheet S in the secondary transfer unit 6 by a mechanical force and an electrostatic bias applied by the secondary transfer roller 94 as a transfer means.

[0018] The sheet S that has passed through the secondary transfer unit 6 is transported to the fixing unit 12. The fixing unit 12 has a pair of rotating bodies consisting of a roller and / or a belt, and a heat source such as a halogen lamp, a ceramic heater, or an induction heating unit that heats the toner image on the sheet S. The fixing unit 12 fixes the toner image on the sheet S by applying heat and pressure to the toner image on the sheet S while nipping and transporting the sheet S in a nip portion of the pair of rotating bodies.

[0019] When the sheet S after image formation is discharged to the outside of the image forming apparatus 100, the sheet S that has passed through the fixing unit 12 is guided to a pair of discharge rollers 11 as a discharge means by a switching member, that is, a switching flap 20. Then, the sheet S is discharged by the pair of discharge rollers 11 to a discharge tray 13 provided on the upper part of the apparatus main body 1A.

[0020] When forming images on both sides of the sheet S, the sheet S having the image transferred and fixed on the first side is guided by the switching flap 20 toward the reversing roller pair 21. The reversing roller pair 21 pulls the sheet S from the first conveying path 22a, and after the rear end of the sheet S passes the switching flap 20, reverses the conveying direction and sends the sheet S to the second conveying path 22b. The second conveying path 22b is a conveying path for forming images on both sides that branches off from the first conveying path 22a where the image forming unit 7 is disposed. The sheet S conveyed again to the first conveying path 22a via the second conveying path 22b passes through the secondary transfer unit 6 and the fixing unit 12, where an image is formed on the second side opposite to the first side, and is then discharged by the discharge roller pair 11 to the discharge tray 13.

[0021] Here, the second conveying path 22b of the image forming apparatus 100 of this embodiment is provided with the reading unit 24, the white reference plate 32, the conveying guide 33, and a plurality of conveying roller pairs. In the illustrated configuration example, three conveying roller pairs 1, 3, and 5 are provided as the plurality of conveying roller pairs. The conveying roller pair 1 is disposed most upstream in the conveying direction of the sheet S in the second conveying path 22b, and receives and conveys the sheet S inverted by the reversing roller pair 21. The conveying roller pair 3 is disposed downstream of the conveying roller pair 1 and upstream of the reading unit 24, and the conveying roller pair 5 is disposed downstream of the reading unit 24. In other words, the conveying roller pairs 3 and 5 are both conveying members that convey the sheet S through the reading position of the reading unit 24 (the position on the second conveying path 22b where the optical image of the sheet S is taken in by the reading unit 24).

[0022] The reading unit 24 is disposed facing a white reference plate 32, which is an opposing member (also called an opposing unit or backing unit), across the second conveying path 22b, and constitutes a reading section consisting of the reading unit 24 and the white reference plate 32. That is, the reading unit 24 is disposed so as to face one side of the sheet S passing through the second conveying path 22b, and the white reference plate 32 is disposed so as to face the other side of the sheet S passing through the second conveying path 22b. Note that, when performing normal double-sided image formation, the reading unit 24 is disposed so as to face a first side of the sheet S passing through the second conveying path 22b, and the white reference plate 32 is disposed so as to face a second side of the sheet S. The first side of the sheet S is the side on which an image is formed first in double-sided image formation, and the second side is the side on which an image is formed later in double-sided image formation.

[0023] The reading unit 24 functions as a reading means for optically scanning the sheet S passing through the second transport path 22b to obtain image data (hereinafter, referred to as a read image) of the sheet S. The reading unit 24 is supported by the internal frame 18 constituting the framework of the apparatus main body 1A so as to be movable in a direction approaching and moving away from the white reference plate 32 (i.e., in the thickness direction of the sheet S in the reading section, in the depth of field direction of the optical system). By reading the white reference plate 32 with the reading unit 24, the control section of the image forming apparatus 100 can create data (data defining a reference white level) for performing shading correction of the read image.

[0024] Here, the housing of the image forming apparatus 100 (excluding the reading unit 24, the white reference plate 32, etc.) is composed of the apparatus main body 1A and a maintenance door 23 which is an opening / closing member that can be opened and closed relative to the apparatus main body 1A. The white reference plate 32 is supported by the maintenance door 23. When the user is notified by the image forming apparatus 100 that a jam of the sheet S has occurred, the user can open the maintenance door 23 and remove the sheet S from the second conveying path 22b.

[0025] Incidentally, the conveying rollers for conveying the sheet S are usually arranged at intervals that allow the sheet to be handed over, in accordance with the sheet having the shortest length in the conveying direction among the various sheets on which the image forming apparatus 100 can perform image formation. In this embodiment, the conveying roller pair 3 on the upstream side of the reading section is arranged close to the reading unit 24 in the sheet conveying direction. This stabilizes the relative position between the nip position of the conveying roller pair 3 and the gap in the reading section. Therefore, the reading unit 24 can read an image from the surface of the sheet S that is stably sent out by the conveying roller pair 3, and it is expected that the accuracy of the image read by the reading unit 24 will be improved.

[0026] The transport roller pair 5 on the downstream side of the reading section is disposed at a position relatively farther from the reading unit 24 than the transport roller pair 3 on the upstream side. This is mainly for the purpose of optimizing the overall configuration of the image forming apparatus 100. However, the downstream transport roller pair 5 may be disposed at a position as close to the reading unit 24 as the upstream transport roller pair 3 to further improve the accuracy of the read image.

[0027] The conveying roller pair 3 upstream of the reading unit has a driving roller 3a that rotates by receiving a driving force from a drive source, and a driven roller 3b that rotates following the conveying roller 3a. The conveying roller 3a is a first roller in this embodiment, and the conveying roller 3b is a second roller in this embodiment that constitutes a roller pair together with the first roller. In this embodiment, the conveying roller 3a on the driving side is supported by the maintenance door 23, and the conveying roller 3b on the driven side is supported by the internal frame 18 of the device main body 1A.

[0028] By disposing the driving-side conveying roller 3a on the maintenance door 23 and the driven-side conveying roller 3b on the apparatus main body 1A, the possibility of damage to the image when the sheet S formed on the first side is conveyed to the conveying roller pair 3 during the double-sided image forming operation can be reduced. That is, the driving-side conveying roller 3a is made of a material (e.g., rubber) that has a large friction against the sheet so that the sheet S can be conveyed more reliably, whereas the driven-side conveying roller 3b is made of a material such as plastic that has a relatively small friction. Therefore, if the driven-side conveying roller 3b is disposed on the maintenance door 23 and the driving-side conveying roller 3a is disposed on the apparatus main body 1A, the driving-side conveying roller 3a may strongly rub against the first side of the sheet S, leaving a friction mark on the image on the first side. In contrast, according to the arrangement of this embodiment, it is the driven-side conveying roller 3b that comes into contact with the first side of the sheet S, so the possibility of leaving a friction mark can be reduced. However, the driving-side conveying roller may be supported by the internal frame 18, and the driven-side conveying roller may be supported by the maintenance door 23. The supporting structure of the transport roller pair 3 on the upstream side of the reading unit will be described in detail later.

[0029] 2. Reading unit FIG. 2 is a perspective view including a cross section of the reading unit 24. The reading unit 24 is a so-called contact type image sensor (CIS) unit, and includes a housing 26, an electric board 27, a rod lens array 28, and a contact glass 29. The housing 26 is a substantially rectangular parallelepiped shape elongated in the y direction, and the contact glass 29 is attached to the housing 26 from one side in the x direction, and the electric board 27 is attached to the housing 26 from the other side in the x direction. The contact glass 29 faces the second transport path 22b and the white reference plate 32. The rod lens array 28 is disposed so as to face the electric board 27 in the x direction, and forms an image of reflected light from the sheet S on the imaging surface of an image sensor (light receiving element, photoelectric conversion element) mounted on the electric board 27. Note that, although a reading unit of a life-size optical system using a rod lens array is exemplified here, a reading unit of a CCD type that forms an image of reflected light from a sheet on a charge-coupled device via a reduction optical system using a plurality of mirrors may also be used.

[0030] The CPU mounted on a control board (not shown) connected to the electric board 27 grasps the print state of the image and executes a fault diagnosis of the image forming apparatus 100 based on the result of reading the sheet S by the reading unit 24 received from the electric board 27. For example, the read image acquired by the reading unit 24 is used for the purpose of notifying the necessity of maintenance by early detection of the occurrence of an abnormal image, or for the purpose of correcting the image forming conditions to maintain the image quality. The image forming conditions are, for example, the setting of the exposure amount by the exposure device 2, and the setting of the voltage values ​​of charging, developing, and transferring in the electrophotographic process. The sheet S to be read may be a sheet on which an image is formed to obtain a print product, or may be a sheet on which a predetermined image pattern (test chart) is formed. The CPU functions as a control means for controlling the operation of the image forming apparatus 100.

[0031] FIG. 3 is a perspective view of the white reference plate 32. In FIG. 3, an arrow Ar1 indicates the sheet transport direction in the reading section. The white reference plate 32 is molded from resin and has a guide shape for transporting a sheet. That is, the white reference plate 32, together with the contact glass 29 of the reading unit 24, forms a sheet transport path in the reading section. In other words, a transport space that is part of the second transport path 22b is formed as a space (gap) between the white reference plate 32 and the contact glass 29 at the reading position of the reading unit 24 in the sheet transport direction (arrow Ar1).

[0032] The white reference plate 32 has a main body portion 320 (guide portion) extending in the y direction (sheet width direction) including a surface (guide surface) on the sheet conveying path side facing the contact glass 29, and side portions 322 provided at both ends of the main body portion 320 in the y direction. The main body portion 320 has a substantially flat plane portion 32b recessed so as to be farther away from the reading unit 24 than the surroundings, and a white sheet 19, which is a resin sheet-like member, is fixed to the plane portion 32b by a means such as pasting with double-sided tape. The white sheet 19 forms a white surface that defines a reference white level when an image is read by the reading unit 24. Instead of pasting a resin sheet as a portion that serves as a color reference, the white reference plate 32 may be molded from a white resin material.

[0033] Furthermore, the main body 320 of the white reference plate 32 is provided with inclined portions 32a and 32c inclined with respect to the flat portion 32b on the upstream and downstream sides of the flat portion 32b. When viewed in the sheet width direction, the inclined portion 32a on the upstream side is inclined with respect to the surface of the contact glass 29 so as to approach the contact glass 29 in the x direction toward the downstream of the sheet conveying direction. The x direction is also the thickness direction of the sheet in the reading section and the depth of field direction of the reading unit 24. The inclined portion 32a having such an inclination has a function of guiding the leading edge of the sheet conveyed on the second conveying path 22b to the gap between the contact glass 29 and the white reference plate 32. When viewed in the sheet width direction, the inclined portion 32c on the downstream side is inclined so as to move away from the reading unit 24 in the x direction toward the downstream of the sheet conveying direction. The inclined portion 32c having such an inclination guides the rear end of the sheet that has slipped out from the relatively narrow gap between the contact glass 29 and the white reference plate 32 into the wider space on the downstream side so that it can be smoothly delivered to the downstream conveyance guide without bouncing. The bouncing of the rear end of the sheet refers to a behavior in which the sheet moves suddenly in the thickness direction and collides with the conveyance guide.

[0034] The guide surface of the main body 320 of the white reference plate 32 on which the white sheet 19 is provided extends in the sheet width direction perpendicular to the sheet conveying direction (arrow Ar1) so as to cover the entire passing area (hereinafter referred to as the paper passing area) through which the sheet can pass. The paper passing area is an area in the sheet width direction in the reading unit, and corresponds to the range through which the sheet passes when the image forming apparatus conveys a sheet of the maximum width on which an image can be formed. Elements such as the abutment portion 321, side portion 322, and bearing support portion 323 in the figure will be described later.

[0035] 4 is a perspective view for explaining the positional relationship between the reading unit 24 and the white reference plate 32 when they are installed in the image forming apparatus 100, and shows the opposing reading unit 24 and the white reference plate 32 as viewed from the rear side of the reading unit 24. In Fig. 4, an arrow Ar1 indicates the sheet transport direction in the reading section, and an arrow Ar3 indicates the movable direction of the reading unit 24.

[0036] The housing 26 of the reading unit 24 has a protrusion 241 provided on each of the side walls 261 on both sides in the y direction. Each protrusion 241 engages with a recess 183 of the internal frame 18, which will be described later, to restrict the movement of the reading unit 24 relative to the internal frame 18 to a predetermined direction (arrow Ar3).

[0037] Furthermore, the reading unit 24 is provided with abutment sections 243 on both outer sides of the sheet passing area of ​​the reading unit 24 in the y direction (sheet width direction). The sheet passing area refers to an area in the y direction through which a sheet may pass in a normal conveying operation when sheets of various sizes that can be used in the image forming apparatus 100 are conveyed through the reading unit. The contact glass 29 is provided over the entire sheet passing area in the y direction. Furthermore, the abutment sections 243 in this embodiment are provided on the side walls 261 on both sides of the housing 26 in the y direction.

[0038] The white reference plate 32 also has an abutment portion 321 (see also FIG. 3) so as to face the abutment portion 243 of the reading unit 24. The abutment portion 243 of the reading unit 24 protrudes toward the white reference plate 32 further than the contact glass 29. Similarly, the abutment portion 321 of the white reference plate 32 also protrudes further than the white surface of the white reference plate 32. With this configuration, the abutment portion 243 and the abutment portion 321 abut against each other, thereby ensuring a gap of a preset size between the contact glass 29 and the white surface of the white reference plate 32. The size of the gap is set, for example, in the range of 0.3 mm to 0.5 mm.

[0039] Since the sheet transported through the second transport path 22b is transported through this gap, fluctuations in the sheet position in the depth of field direction are suppressed, and the reflected light from the sheet is easily focused on the image sensor. Even in a configuration in which either the abutment portion 243 of the reading unit 24 or the abutment portion 321 of the white reference plate 32 is omitted, it is possible to ensure an appropriate gap by adjusting the protrusion amount of the remaining abutment portion.

[0040] 5 shows how the reading unit 24 is attached to the internal frame 18 of the device body 1A. The reading unit 24 is attached to the internal frame 18 by engaging the protrusion 241 on one side wall with the protrusion 241 on the other side wall in the recesses 183, 183 provided in the internal frame 18, for example, in the order of arrows Ar4 and Ar5. Here, the protrusion 241 is slidable relative to the side wall surface 185 of the recess 183. Therefore, the reading unit 24 is supported so as to be movable in the direction approaching and moving away from the white reference plate 32 (arrow Ar3 in FIG. 4) as described above.

[0041] As shown in Fig. 5, the internal frame 18 has two spring mounting holes 180. The coil portions of the torsion coil springs 30 are fitted into the spring mounting holes 180, whereby the torsion coil springs 30 are held in the internal frame 18. The two arms of each torsion coil spring 30 press the reading unit 24 in the direction of the white reference plate 32 along the arrow Ar3 in Fig. 4. When the image forming apparatus 100 is in a normal operating state, the abutment portions 243, 321 of the reading unit 24 and the white reference plate 32 abut against each other due to the biasing force of the torsion coil springs 30, whereby the reading unit 24 is positioned in the direction of the arrow Ar3.

[0042] In addition, the internal frame 18 may be provided with a stopper for preventing the reading unit 24 from being pushed out by the biasing force of the torsion coil spring 30 when the maintenance door 23 is opened to separate the white reference plate 32 from the reading unit 24. The stopper may be any that abuts against any part of the reading unit 24 to restrict movement in the direction of the arrow Ar3. For example, as shown in FIG. 5, a part 184 of the wall surface of the recess 183 may come into contact with a protrusion 241 to function as a stopper. In addition, for example, the stopper may be a separate member attached to the internal frame 18, or the internal frame 18 may be provided with a snap-fit ​​shape, or the stopper may come into contact with the protrusion 241 at a location other than the recess 183.

[0043] In this way, by biasing the reading unit 24 with an elastic body such as a spring, even if the position of the opposing member, the white reference plate 32, varies slightly, the reading unit 24 can follow the white reference plate 32. This allows the gap between the reading unit 24 and the white reference plate 32 to be properly maintained.

[0044] Furthermore, by using the above-mentioned torsion coil spring 30 as an elastic body, the reading unit 24 is supported by two arms, and thus the reading unit 24 is biased in a well-balanced manner. In the first embodiment, as shown in FIG. 5, two torsion coil springs 30 are arranged at a predetermined interval in the y direction (sheet width direction) of the sheet S, but a compression spring or a leaf spring may be used instead of the torsion coil spring. The number of springs does not have to be two. The width direction of the sheet S is parallel to the longitudinal direction of the reading unit 24. Furthermore, instead of a spring, for example, a rubber member may be used as the elastic body that biases the reading unit 24.

[0045] While the reading unit 24 is reading an image on the sheet S being transported, for example, the reading unit 24 may receive a force in a direction away from the white reference plate 32 due to the rigidity of the sheet. In addition, tension may act on the sheet due to a difference in transport speed between the pairs of transport rollers 3, 5 upstream and downstream of the reading section, and the reading unit 24 may be pressed against the sheet. According to the configuration of this embodiment, the reading unit 24 can change its position by following the sheet, so that it is possible to stably maintain focus. In addition, since the reading unit 24 follows the sheet, strong rubbing against the sheet is suppressed, which is also advantageous in suppressing wear on the contact glass 29 and the like due to sliding.

[0046] 3. White reference unit The white reference unit 200 according to this embodiment will be described in detail with reference to Figures 3, 4, 6, and 7. The white reference unit 200 described here is configured as a unit that includes a white reference plate 32, a transport roller 3a on the upstream side of the reading unit, and gears for driving the transport roller 3a, and is detachably attached to the image forming apparatus.

[0047] 3, the white reference plate 32 is provided on both outer sides (both ends of the main body 320) of the sheet passing area in the sheet width direction perpendicular to the sheet conveying direction (arrow Ar1), and has side portions 322 extending to intersect with the sheet width direction (particularly, extending along the sheet conveying direction). Each side portion 322 has a wall surface portion 322a intersecting (preferably intersecting substantially perpendicularly) the rotation axis of the conveying roller 3a extending in the sheet width direction. Each wall surface portion 322a is provided with a bearing support portion 323 for rotatably supporting the roller shaft of the conveying roller 3a. The bearing support portion 323 is a hole penetrating the wall surface portion 322a in the sheet width direction.

[0048] 6, the conveying roller 3a has a roller shaft 3a1 extending in the sheet width direction (the direction of the rotation axis of the conveying roller 3a), two roller bodies 3a3 provided on the outer periphery of the roller shaft 3a1 and in contact with the sheet, and bearings 3a2 provided on both sides in the sheet width direction. The conveying roller 3a is rotatably supported by the white reference plate 32 constituting the reading unit by fitting the bearings 3a2 attached to the roller shaft 3a1 into the bearing support parts 323.

[0049] 6 and 8, the roller shaft 3a1 is located upstream in the sheet conveying direction with respect to the guide surface of the main body 320, which is a guide portion of the white reference plate 32. Meanwhile, a part of each roller body 3a3 is accommodated inside a recess 32e (cutout shape) provided in the white reference plate 32. That is, each roller body 3a3 is located inside the recess 32e with respect to the sheet width direction (the rotation axis direction of the conveying roller 3a). Also, when viewed in the sheet width direction, a part of the roller body 3a3 overlaps with a part of the guide surface (particularly, the upstream end in the sheet conveying direction).

[0050] In this way, the white reference plate 32 is provided with a recess 32e, and a part of the roller body 3a3 is disposed so as to intrude into the upstream end 32d of the guide surface of the main body 320 in the sheet conveying direction. This allows the conveying roller 3a to be disposed at a position closer to the reading position of the reading unit 24, as compared to, for example, a configuration without the recess 32e (configuration in which the upstream end 32d is a straight line). By shortening the distance in the sheet conveying direction from the position where the conveying roller 3a contacts the sheet (the nip position of the conveying roller pair 3) to the reading position, the position of the sheet at the reading position becomes more stable, and the accuracy of the read image can be improved.

[0051] The width of the recess 32e in the sheet width direction (the direction of the rotation axis of the conveying roller 3a) is set to be wider than the width of the roller body 3a3 in the sheet width direction. This makes it possible to mount the conveying roller 3a on the bearing support portion 323 while reciprocating in the sheet width direction. That is, in a state in which the conveying roller 3a is not mounted on the white reference plate 32, the conveying roller 3a is moved toward one side in the sheet width direction to insert one bearing 3a2 into the bearing support portion 323. Thereafter, the conveying roller 3a is moved toward the other side in the sheet width direction to insert the other bearing 3a2 into the bearing support portion 323, so that both ends of the conveying roller 3a are supported by the bearing support portions 323 of the white reference plate 32.

[0052] By supporting the transport roller 3a for feeding the sheet towards the reading unit on the white reference plate 32 in this way, the positional accuracy of the transport roller 3a and the white reference plate 32 is improved compared to when the transport roller 3a is supported on the maintenance door 23 separately from the white reference plate 32. In other words, the positional relationship between the nip where the transport roller pair 3 clamps and feeds the sheet S and the gap between the contact glass 29 and the white reference plate 32 in the reading unit is determined with high accuracy, so that the sheet fed from the nip passes smoothly through the gap.

[0053] In this embodiment, the white reference plate 32 is fixed to the maintenance door 23, and the reading unit 24 is biased toward the white reference plate 32 by the torsion coil spring 30, thereby ensuring the gap in the reading section. In this case, by integrating the conveying roller 3a and the white reference plate 32, it can be specified that the positional relationship between the nip of the conveying roller pair 3 and the gap in the reading section can be determined with higher accuracy.

[0054] As shown in FIG. 6, the white reference plate 32 further supports a plurality of gears 34 that transmit a driving force to the conveying roller 3a. When the maintenance door 23 is closed, one of the plurality of gears 34, 34A is configured to mesh with a distribution gear G2 that rotates by a driving force from a drive motor M1 provided in the apparatus main body 1A, enabling the transmission of the driving force to the conveying roller 3a. The distribution gear G2 is provided between a drive input gear G1 provided in the maintenance door 23 to which the driving force from the drive motor M1 is input, and the conveying roller 1a of the conveying roller pair 1 (see FIG. 1) on the upstream side of the conveying roller 3a supported by the white reference plate 32. The distribution gear G2 is a gear that rotates together with the conveying roller 1a. In other words, the conveying roller 3a supported by the white reference plate 32 receives a part of the driving force of the drive motor M1 via the distribution gear G2 as a distributor, and is driven by one driving source common to the other conveying roller 1a upstream. That is, in the configuration in which the transport roller 3a is supported by the white reference plate 32 to form a unit, the gears 34, 34A, which are the transmission mechanism for driving the transport roller 3a, are also incorporated in the same unit, and the drive force can be supplied from an external drive source. Therefore, for example, by utilizing the configuration of an image forming apparatus that does not have a reading function in the second transport path 22b, it is possible to provide an image forming apparatus 100 that has a reading function in the second transport path 22b with a simple configuration in which the reading unit 24 and the white reference plate 32 are disposed.

[0055] The gears 34, 34A include a gear 34A equipped with a one-way clutch mechanism. In the illustrated example, the gear 34A attached to the roller shaft 3a1 of the conveying roller 3a is provided with a one-way clutch mechanism. The one-way clutch mechanism absorbs the conveying speed difference (difference in peripheral speed) between the upstream conveying roller 1a and the conveying roller 3a. If the conveying speed of the conveying roller 3a is slower than that of the upstream conveying roller 1a due to some circumstances, the one-way clutch mechanism causes the conveying roller 3a to rotate freely, thereby preventing the sheet from being jammed between the upstream conveying roller 1a and the conveying roller 3a. In addition, for example, if the driving motor M1 stops after the rear end of the sheet leaves the upstream conveying roller 1a but before it passes through the conveying roller 3a, the conveying roller 3a rotates freely, allowing the downstream conveying roller pair 5 (FIG. 1) to pull out the sheet and continue conveyance.

[0056] It is also possible to add a support structure (gear shaft, etc.) for supporting the gear 34 to the maintenance door 23, instead of the structure in which the gear 34 is supported by the white reference plate 32. In contrast to this, in this embodiment, the gear 34 is supported by a support structure provided on the white reference plate 32, so that the drive train up to the conveying roller 3a can be supported by the same part, and the meshing accuracy between the gears 34 can be improved.

[0057] In this embodiment, the shape of the white reference plate 32 is determined so that the multiple gears 34 can be attached to the white reference plate 32 from the opposite side to the surface (guide surface) of the white reference plate 32 on the sheet transport path side (arrow Ar6). Specifically, as shown in Fig. 7, a gear mounting portion 322c that opens in a U-shape (angular C-shape) toward the opposite side of the sheet transport path (positive x direction) is provided on a wall surface portion 322a of the side portion 322 of the white reference plate 32. The operator can mount each gear 34 at a predetermined position of the gear mounting portion 322c by inserting the gear 34 in the negative x direction while slightly pushing and widening the gear mounting portion 322c in the y direction, which is the rotation axis direction of the gear 34.

[0058] The white reference unit 200 including the white reference plate 32 is attached to the maintenance door 23 as shown in Fig. 8. The maintenance door 23 can be opened and closed with respect to the apparatus main body 1A, with a hinge 230 as a fulcrum. A user or a maintenance person can open the maintenance door 23 to access the white reference plate 32 and the contact glass 29 and clean them. In addition, by opening the maintenance door 23, the user or the maintenance person can open the second transport path 22b and perform a jam clearance operation to remove a jammed sheet remaining in the second transport path 22b.

[0059] In addition, when the white reference unit 200 is attached to the maintenance door 23, the wall surface 326 of the white reference plate 32 shown in Figs. 6 and 8 functions as a cover portion that covers the gears 34, 34A. When the maintenance door 23 is open, the wall surface 326 is exposed in the space between the maintenance door 23 and the apparatus main body 1A, and covers at least a part of the gears 34, 34A when viewed from the apparatus main body 1A side (the reading unit 24 side in the x direction). This prevents the user from touching the gears 34, 34A when the maintenance door 23 is open, reducing the possibility of accidentally removing the gears 34, 34A, and further improving safety. Furthermore, even if grease is applied to the gears 34, 34A, it is possible to prevent the user from touching them or the grease from scattering onto the guide surface of the white reference plate 32 without adding any additional parts.

[0060] A method of attaching the white reference unit 200 to the maintenance door 23 will be described with reference to FIGS. 6 and 9. FIG. 9 is an enlarged view of a part of the maintenance door (area A in FIG. 8) to which the white reference unit 200 is not attached. As shown in FIG. 6, on the outer side of the paper passing area in the sheet width direction (y direction) of the white reference plate 32, an insertion part 324 having a U-shaped groove shape is provided on one side, and a positioning hole 325 is provided on the other side. In addition, a screw hole for attaching the screw 31 is formed near the positioning hole 325. As shown in FIG. 9, the maintenance door 23 is provided with a positioning boss 231 and a pressing part 234 that engage with the insertion part 324, a positioning boss 232 that engages with the positioning hole 325, and a female screw (not shown) into which the screw 31 fits.

[0061] When attaching the white reference unit 200, the position of the white reference unit 200 in the sheet conveying direction is determined by aligning the insertion portion 324 of the white reference plate 32 with the positioning boss 231 (FIG. 9). At this time, the position of the white reference unit 200 in the x direction (the sheet thickness direction in the reading section, the depth of field direction of the reading unit 24) is regulated by the eaves-shaped pressing portion 234, so fixing with a screw or the like is not necessary. Next, the positioning hole 325 of the white reference plate 32 is fitted into the positioning boss 232, and the screw 31 is tightened, so that the white reference unit 200 is fixed to the maintenance door 23. Since the white reference unit 200 is positioned at both ends of the white reference plate 32 in the sheet width direction in this way, the position accuracy of the white reference plate 32 can be improved, such as the perpendicularity of the white reference plate 32 with respect to the sheet conveying direction and the angle of the guide surface as viewed from the sheet width direction.

[0062] Here, when the maintenance door 23 is closed, the conveying roller 3a is configured to come into contact with the conveying roller 3b (FIG. 1) on the apparatus main body side with an appropriate pressure force to sandwich and convey the sheet. Therefore, as shown in FIG. 9, the maintenance door 23 has two protrusions 233 for receiving the pressure force received by the conveying roller 3a. The protrusions 233 are arranged so as to come into contact with the wall surface portions 322a (FIG. 3) on both sides of the white reference plate 32, for example, at the position of the rotation axis of the conveying roller 3a in the sheet conveying direction. By arranging the protrusions 233 as pressure receiving portions that receive the pressure force of the conveying roller pair 3 at both ends in the sheet width direction, the white reference plate 32 does not receive all the pressure force, so that it is less likely to bend, and the positional accuracy of the white reference plate 32 and the conveying roller 3a can be improved.

[0063] (Modification) A white reference unit 200 according to a modification of the first embodiment will be described with reference to Figs. 14 to 16. Fig. 14 is a perspective view of the white reference unit 200 according to this modification, seen from the side of the reading unit 24 in the x direction. Fig. 15 is a perspective view of the white reference unit 200 according to this modification, seen from the opposite side to the reading unit 24 in the x direction. Fig. 16 shows a cross section perpendicular to the x direction of the white reference unit 200 at the position of line X1-X1 in Fig. 14. In the following description, elements with the same reference symbols as those in the first embodiment have substantially the same configurations and functions as those in the first embodiment, and the description will be focused on the parts different from the first embodiment.

[0064] The white reference unit 200 of this modification shown in FIG. 14 includes a white reference plate 32 on which a white sheet 19 is attached, a conveying roller 3a rotatably supported on a side portion 322 of the white reference plate 32, and gears 34, 34A for transmitting a driving force to the conveying roller 3a, as in the first embodiment. One side portion 322 has a wall surface 326 as a cover portion that covers at least a part of the gears 34, 34A when viewed from the reading unit 24 side in the x direction, although the shape of the wall surface 326 is different from that of the first embodiment. In addition, the roller body 3a3 of the conveying roller 3a is located inside the recess 32e provided in the white reference plate 32 with respect to the sheet width direction (the direction of the rotation axis of the conveying roller 3a). As shown in FIG. 16, a part (upstream end 32d) of the white reference plate 32 overlaps with the roller body 3a3 of the conveying roller 3a when viewed in the sheet width direction.

[0065] As shown in Fig. 15, a metal plate 35 is attached as a reinforcing member to the back side of the main body 320 of the white reference plate 32 (the side opposite the reading unit 24 in the x direction). The metal plate 35 extends in the sheet width direction at least across the entire paper passing area. An engagement hole 35a is provided in the metal plate 35, and by engaging the claw portion 32g of the white reference plate 32, the metal plate 35 is fixed in a state in which it abuts against the white reference plate 32 in the x direction as shown in Fig. 16. By using the white reference plate 32 made of resin, which has a high degree of freedom in shape, and supporting the back side of the white sheet 19 with the metal plate 35, which has high strength (rigidity), it is possible to suppress bending deformation of the white sheet 19 and improve the reading accuracy of the reading unit 24.

[0066] As shown in FIG. 15, the coil spring 36 is disposed so that one end surface of the coil spring 36 is in contact with the metal plate 35. The arm 36a of the coil spring 36 is hooked on a hole 322b provided in the side portion 322 of the white reference plate 32 while being in contact with the bearing 3a2 of the conveying roller 3a. The coil spring 36 is electrically grounded by contacting a conductive member (not shown) (for example, a metal wire connected to the metal frame of the apparatus main body 1A). Therefore, both the conveying roller 3a and the metal plate 35 are electrically grounded via the coil spring 36 as a grounding member. This simple configuration using a common grounding member suppresses sheet conveyance failure and discharge due to charging of the conveying roller 3a or the metal plate 35. By using an elastic member such as the coil spring 36 or a metal leaf spring as the grounding member, contact with the conveying roller 3a and the metal plate 35 can be more reliably maintained.

[0067] As described above, by unitizing the white reference plate 32, the transport roller 3a, the gear 34, etc., when the transport roller 3a on the upstream side of the reading unit wears out and needs to be replaced, the replacement work can be easily performed. Furthermore, by unitizing in this way, it becomes possible to easily change the specifications of the image forming apparatus 100 between a model with an image reading function and a model without the image reading function. That is, a model without the image reading function can be prepared by removing the reading unit 24 and the white reference unit 200 from the image forming apparatus 100 of this embodiment and adding an appropriate guide shape to the apparatus main body 1A and the maintenance door 23 as necessary. Furthermore, it is also easy to set a model without the image reading function as a basic model and treat the image reading function as an option to be added later. EXAMPLES

[0068] Next, a description will be given of Example 2. Example 2 differs from Example 1 in that the reading unit is fixed and the white reference unit is biased toward the reading unit. In the following, elements with the same reference numerals as Example 1 have substantially the same configurations and functions as Example 1, and the following description will focus on the parts that are different from Example 1.

[0069] 10 is a cross-sectional view of the vicinity of the reading unit of the image forming apparatus according to this embodiment as viewed from the sheet width direction (y direction). The reading unit 41 is supported by the internal frame 43 of the apparatus main body 1A as in the first embodiment, but in this embodiment, it is not pressed by an elastic body, and is fixed by abutting the bottom surface 410 against the internal frame 43. The abutting portion of the reading unit 41 may be a portion other than the bottom surface 410, and may have, for example, a protrusion for abutment.

[0070] On the other hand, the white reference unit 300 is supported by the maintenance door 23 so as to be movable in a direction approaching and moving away from the reading unit 41, and is pressed toward the reading unit 41 by a spring member 44. The white reference unit 300 is configured as an integrated unit of at least the white reference plate 42 and the conveying roller 3a on the upstream side of the reading section, similar to the first embodiment. Also, similar to the first embodiment, the portions where the reading unit 41 and the white reference plate 42 come into contact with each other have a convex shape (see abutment portions 243, 321 in FIG. 4).

[0071] In the configuration shown in this embodiment, as in the first embodiment, the relative positional accuracy of the white reference plate 42 and the conveying roller 3a on the upstream side of the reading unit can be improved, so that the sheet can be stably conveyed to the reading unit, and reading accuracy can be improved. In addition, other effects obtained by unitizing the white reference plate are the same as in the first embodiment.

[0072] In addition, in this embodiment, the position of the reading unit 41 is fixed relative to the internal frame 43 of the device body 1A, so the positioning accuracy of the reading section relative to the device body 1A is improved. Also, the reading unit 41, which is a precision component, is rigidly connected to the internal frame 43. This reduces the risk of the reading unit 41 being damaged or falling off due to strong impacts or vibrations during transportation or operation, and also suppresses the impact of vibrations of the reading unit 41 during reading on the accuracy of the read image. EXAMPLES

[0073] Next, a description will be given of Example 3. Example 3 differs from Example 1 in that the conveying roller is supported by a maintenance door, and the white reference unit is supported by the maintenance door while being fitted into the bearing of the conveying roller. In the following, elements with the same reference numerals as Example 1 have substantially the same configurations and functions as Example 1, and the following description will focus on the parts that are different from Example 1.

[0074] 11 is a diagram showing a part of the maintenance door 51 before the transport roller 3a is attached and the white reference plate is attached. The maintenance door 51 is provided with a pair of wall surfaces 510 on both outer sides of the paper passing area in the sheet width direction. A bearing 52 that rotatably supports the roller shaft 3a1 of the transport roller 3a on the upstream side of the reading unit is fitted into the wall surfaces 510. In other words, the maintenance door 51 rotatably supports the roller shaft 3a1, which is the shaft portion of the transport roller 3a, via the wall surfaces 510 and the bearing 52.

[0075] 12 shows the white reference plate 53 in this embodiment. A pair of wall surfaces 530 are provided on both outer parts of the paper passing area in the sheet width direction of the white reference plate 53 (particularly, both ends in the sheet width direction). A U-shaped groove 531 that opens toward the attachment direction (arrow Ar7) of the white reference plate 53 to the maintenance door 51 is provided on the wall surface 530, and the groove 531 is formed with a shape and dimensions that fit with the outer circumferential surface of the bearing 52. In particular, it is preferable that the bottom of the U-shaped groove 531 is a semicircular cylindrical surface with an inner diameter approximately the same as the outer diameter of the bearing 52 with respect to the cylindrical outer circumferential surface of the bearing 52. The detailed configuration and functions of the white reference plate 53 other than those described above are similar to those of the white reference plate 32 in the first embodiment.

[0076] When attaching the white reference plate 53 to the maintenance door 51, the white reference plate 53 is moved in the direction indicated by the arrow Ar7 to position the groove 531 by fitting it into the bearing 52, and then fixed to the maintenance door 51 using screws (not shown).

[0077] The configuration is not limited to the one fixed by screws, and the white reference plate 53 may be pressed by an elastic body as shown in the embodiment 2. In that case, the white reference plate 53 may be configured to be swingable around the fitting portion between the bearing 52 and the groove 531 as a fulcrum, or the white reference plate 53 may be configured to slide at the fitting portion.

[0078] Also, the opening direction of groove 531 does not necessarily have to be the direction shown in Fig. 12. In that case, the mounting direction indicated by arrow Ar7 also changes according to the direction of the opening. Furthermore, the shape of groove 531 does not have to be a perfect U-shape, and for example, it may be configured such that the width of the opening side is slightly narrower, and groove 531 is pushed in while being pushed out during assembly, and groove 531 grips bearing 52 in the mounting position.

[0079] According to this embodiment, in a configuration in which the transport roller 3a and the white reference plate 53 are each supported by the maintenance door 51, the white reference plate 53 is positioned with respect to the shaft portion of the transport roller 3a assembled to the maintenance door 51. Therefore, even in a configuration in which the transport roller 3a is supported by the maintenance door 51, the relative positions of the white reference plate 53 and the transport roller 3a can be assembled with high precision. Therefore, in the configuration shown in this embodiment, as in the first embodiment, the sheet can be stably transported to the reading unit, enabling improved reading precision.

[0080] In addition, in this embodiment, when considering changing to a model without the image reading function, the support structure of the conveying roller 3a can be shared between the model of this embodiment with the image reading function and the model without the image reading function, so it is possible to reduce the number of parts that need to be replaced when changing models. EXAMPLES

[0081] Next, a fourth embodiment will be described. The fourth embodiment differs from the first embodiment in that the white reference plate supports a plurality of conveying rollers. In the following, elements with the same reference numerals as the first embodiment have substantially the same configurations and functions as the first embodiment, and the following description will focus on the differences from the first embodiment.

[0082] FIG. 13 is a perspective view of the white reference unit 400 according to this embodiment. The white reference unit 400 includes a white reference plate 61, two transport rollers 3a and 62, a plurality of gears 34, and a timing belt 63. The transport roller 3a is a roller that constitutes the transport roller pair 3 (FIG. 1) on the upstream side of the reading unit. In this embodiment, a transport roller pair is added between the transport roller pairs 3 and 5 in FIG. 1 and on the downstream side of the reading unit, and the transport roller 62 constitutes the transport roller pair on the downstream side of the reading unit. In other words, the transport roller 62 and a driven roller (not shown) arranged in the internal frame 18 (FIG. 1) of the apparatus main body 1A form a transport roller pair that sandwiches and transports a sheet on the downstream side of the reading unit.

[0083] The white reference plate 61 rotatably supports both the upstream transport roller 3a and the downstream transport roller 62. The white reference plate 61 also has a white sheet 19 attached thereto, and rotatably supports a plurality of gears 34 that transmit driving force to the upstream transport roller 3a. The upstream transport roller 3a and the downstream transport roller 62 are drivingly connected by a timing belt 63, and the two transport rollers 3a, 62 are rotationally driven by the driving force input via the gear 34. Note that a transmission mechanism other than the timing belt 63 (for example, a gear train) may be used.

[0084] Here, if the sheet conveying speed of the downstream conveying roller 62 is configured to be faster than that of the upstream conveying roller 3a, the sheet slack in the reading section can be suppressed, and the accuracy of the read image can be further improved. However, the sheet conveying speed refers to the peripheral speed of the conveying rollers 3a, 62 in the reading section. For example, it is possible to set the outer diameter of the downstream conveying roller 62 to be larger than that of the upstream conveying roller 3a. Also, it is possible to set the speed ratio of the transmission mechanism so that the rotation amount of the downstream conveying roller 62 is greater than that of the upstream conveying roller 3a (for example, by making the outer diameter of the pulley part of the timing belt 63 non-uniform).

[0085] According to this embodiment, the white reference plate 61 is rotatably supported by the transport rollers 3a and 62 arranged upstream and downstream near the reading unit, so that the relative positional accuracy of the white reference plate 61 and the upstream and downstream transport rollers 3a and 62 can be improved. Therefore, the sheet can be transported to the reading unit more stably, and the reading accuracy can be improved. In addition, other effects of unitizing the white reference plate are the same as those of the first embodiment.

[0086] (Other embodiments) In the above embodiment, the image reading device incorporated inside the image forming apparatus (particularly, the conveying path for double-sided image formation) has been described, but the present technology can also be applied to other image reading devices. For example, in an image forming apparatus (system) in which a sheet processing device that performs processing such as binding on sheets on which images have been formed by the image forming apparatus main body is connected to the image forming apparatus main body, the image reading device may be disposed on the discharge path to the sheet processing device or within the sheet processing device.

[0087] Also, for example, in an image reading device that reads an image of a document sheet, the above embodiments may be applied to a white reference plate facing a reading unit and a conveying roller that conveys the document sheet toward the reading unit. In particular, an image reading device to which the present technology can be applied includes an image reading device having a reading device main body with a reading unit, and an ADF that has a white reference plate and a conveying roller and feeds document sheets one by one, and is configured to be able to open and close the ADF with respect to the reading device main body. [Explanation of symbols]

[0088] 1A...housing, device main body / 3a...conveying roller / 3a1...shaft portion (roller shaft) / 7...image forming means (image forming section) / 22a...first conveying path / 22b...second conveying path / 23,51...housing, opening / closing member (maintenance door) / 24...reading means (reading unit) / 30...elastic body (torsion coil spring) / 32,42,53,61...opposing member (white reference plate) / 44...elastic body (spring member) / 100...image forming device

Claims

1. An apparatus body, an opening / closing member that is openable and closable relative to the device body; an image forming means disposed on a first transport path and forming an image on a sheet transported on the first transport path; a second conveying path branched off from the first conveying path, the second conveying path being disposed on the second conveying path along which the sheet is conveyed when an image is formed on a second surface of the sheet opposite to the first surface on which an image has been formed by the image forming means, the second conveying path being configured to read image information from the sheet; an opposing member fixed to the opening / closing member by a screw member, the opposing member facing the reading means across a space through which the sheet passes; a conveying roller that conveys the sheet through a space between the reading means and the opposing member; having The conveying roller is rotatably supported by the opposing member, The opposing member has a support portion that rotatably supports the conveying roller.

1. An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, the opposing member is detachable from the opening / closing member while supporting the transport roller; 1. An image forming apparatus comprising:

3. 3. The image forming apparatus according to claim 1, the conveying roller is disposed upstream of the reading means and the opposing member with respect to a conveying direction of the sheet by the conveying roller; 1. An image forming apparatus comprising:

4. 4. The image forming apparatus according to claim 3, The conveying roller is an upstream conveying roller, and further includes a downstream conveying roller that is disposed downstream of the reading means and the opposing member in the conveying direction, The downstream conveying roller is rotatably supported by the opposing member.

1. An image forming apparatus comprising:

5. 5. The image forming apparatus according to claim 1, The conveying device further includes a transmission mechanism for transmitting a driving force to the conveying roller. the opposing member is detachable from the opening / closing member while supporting the conveying roller and the transmission mechanism.

1. An image forming apparatus comprising:

6. 6. The image forming apparatus according to claim 5, the opposing member has a cover portion that covers at least a part of the transmission mechanism when the opposing member is viewed from the side of the reading means in a direction perpendicular to a rotation axis direction of the conveying roller and a conveying direction of the sheet by the conveying roller; 1. An image forming apparatus comprising:

7. 6. The image forming apparatus according to claim 5, another conveying roller disposed upstream or downstream of the conveying roller in the second conveying path and rotated by a driving force of a driving source; a distributor that transmits a portion of the driving force of the driving source to the transmission mechanism; Further comprising:

1. An image forming apparatus comprising:

8. 8. The image forming apparatus according to claim 7, the transmission mechanism includes a one-way clutch that allows the conveying roller to rotate idly relative to the distribution unit so as to absorb a difference in conveying speed between the conveying roller and the other conveying roller.

1. An image forming apparatus comprising:

9. 9. The image forming apparatus according to claim 1, the opposing member has a guide portion that faces the reading means and guides the sheet, the guide portion is provided with a recess in which an upstream end of the guide portion in a conveying direction of the sheet by the conveying roller is recessed toward a downstream side in the conveying direction, The conveying roller has a roller shaft extending in a rotational axis direction of the conveying roller, and a roller body provided on an outer periphery of the roller shaft and contacting the sheet, the roller body is located inside the recess in the direction of the rotation axis, and the roller body and the guide portion overlap each other when viewed in the direction of the rotation axis; 1. An image forming apparatus comprising:

10. 9. The image forming apparatus according to claim 1, the opposing member has a guide portion that faces the reading means and guides the sheet, and a metal plate that is provided on the opposite side of the guide portion from the reading means and supports the guide portion, The conveying roller has a roller shaft extending in a rotational axis direction of the conveying roller, and a roller body provided on an outer periphery of the roller shaft and contacting the sheet, the image forming apparatus further includes a grounding member arranged in contact with both the metal plate and the roller shaft to electrically ground the metal plate and the roller shaft; 1. An image forming apparatus comprising:

11. 11. The image forming apparatus according to claim 1, the reading means is movably supported by the device body so as to move toward and away from the opposing member, The opposing member is restricted in movement relative to the opening / closing member, the image forming apparatus further includes an elastic body that biases the reading unit toward the opposing member; 1. An image forming apparatus comprising:

12. 11. The image forming apparatus according to claim 1, the reading means is restricted in movement relative to the device body, the opposing member is supported by the opening / closing member so as to be movable toward and away from the reading means, the image forming apparatus further includes an elastic body that biases the opposing member toward the reading means; 1. An image forming apparatus comprising:

13. 13. The image forming apparatus according to claim 1, At least one of the reading means and the opposing member has a contact portion that protrudes toward the other of the reading means and the opposing member and contacts the other of the reading means and the opposing member when the opening / closing member is in a closed state to secure the space.

1. An image forming apparatus comprising:

14. 14. The image forming apparatus according to claim 13, the abutting portions are provided on both outer sides of a passing area through which the sheet can pass through the space in a rotational axial direction of the conveying roller, The opposing member is positioned with respect to the opening / closing member on both outer sides of the passage area with respect to the rotation axis direction.

1. An image forming apparatus comprising:

15. 15. The image forming apparatus according to claim 1, the transport roller is a first roller, the image forming apparatus further includes a second roller supported by the apparatus body; the first roller and the second roller are a pair of conveying rollers that contact each other when the opening / closing member is closed and convey the sheet by sandwiching the sheet therebetween; 1. An image forming apparatus comprising:

16. 16. The image forming apparatus according to claim 15, the opening / closing member has a pressure receiving portion that receives the opposing member from the opposite side to the reading means in a direction perpendicular to both a conveying direction of the sheet by the conveying roller and a rotation axis direction of the conveying roller, the pressure receiving portion is in contact with the opposing member at a position overlapping with a rotation axis of the conveying roller in the conveying direction; 1. An image forming apparatus comprising:

17. 17. The image forming apparatus according to claim 1, the opposing member has a white sheet-like member on a surface facing the reading means; 1. An image forming apparatus comprising:

18. 17. The image forming apparatus according to claim 1, the opposing member has a surface facing the reading means, the surface being made of a white resin material; 1. An image forming apparatus comprising:

19. An apparatus body, an opening / closing member that is openable and closable relative to the device body; an image forming means disposed on a first transport path and forming an image on a sheet transported on the first transport path; a reading unit arranged on one side of a second transport path branched off from the first transport path, and configured to read image information from the sheet fed from the first transport path to the second transport path; an opposing member fixed to the opening / closing member by a screw member, the opposing member facing the reading means; a conveying roller that conveys a sheet through a space between the reading means and the opposing member and rotates around a roller shaft supported by the opening / closing member; having The opposing member is positioned relative to the roller shaft.

1. An image forming apparatus comprising:

Images