Image reading apparatus and image forming apparatus

Abstract

To ground a guide shaft without increasing the outside dimension of an image reader having a resin casing.SOLUTION: A document table on which a document is placed, a reading unit configured to read the document placed on the document table while moving in a scanning direction, a holding member configured to hold the reading unit, and a guide shaft configured to movably support the holding member and guide the holding member in the scanning direction, and a grounding member that contacts the guide shaft and grounds the guide shaft, wherein the holding member has a groove shape that is open downward in a vertical direction, the holding member includes a sliding portion that is fitted to the guide shaft and is slidable in the scanning direction with respect to the guide shaft, and the grounding member contacts a surface of the guide shaft along the scanning direction at an open portion of the sliding portion when viewed in the scanning direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image reading device that scans and reads an image on a document placed on a document table, and an image forming apparatus equipped with the same. [Background technology]

[0002] Image reading devices that read images from documents and image forming devices equipped with such devices have traditionally used metal housings for their rigidity, conductivity, and shielding effect. However, in recent years, plastic housings have begun to be used while maintaining rigidity in order to reduce product costs. Resin housings are difficult to ground and lack shielding effect, making them susceptible to interference from other devices.

[0003] Therefore, a configuration has been proposed in which the end of a metal guide shaft that supports and guides the reading unit in the sub-scanning direction is fitted into a shaft support part with a grounding means, thereby grounding it to a metal reinforcing plate at the end of the housing (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-17873 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when adding a grounding member to the end of a guide shaft in a resin housing, space is required to place the grounding member in the axial direction of the guide shaft, which results in a problem of increasing the external dimensions of the image reading device.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to ground a guide shaft without increasing the external dimensions of an image reading device having a resin housing. [Means for solving the problem]

[0007] A typical configuration of the present invention includes a document table on which a document is placed, a reading unit that reads the document placed on the document table while moving in a scanning direction, a holding member that holds the reading unit, a guide shaft that movably supports the holding member and guides it in the scanning direction, a resin housing on whose top surface the document table is placed and that houses the reading unit and the guide shaft, and a grounding member that abuts against the guide shaft and grounds the guide shaft, wherein the holding member is groove-shaped with an open downward side in the vertical direction and includes a sliding part that fits into the guide shaft and is slidable relative to the guide shaft in the scanning direction, and the grounding member abuts against a surface of the guide shaft that is along the scanning direction at the open part of the sliding part when viewed from the scanning direction. [Effects of the Invention]

[0008] According to the present invention, the guide shaft can be grounded without increasing the external dimensions of the image reading device having a resin housing. [Brief explanation of the drawings]

[0009] [Figure 1] Schematic configuration of an image forming apparatus including an image reading device [Figure 2] 1 is a schematic diagram illustrating an example of a schematic configuration of an image reading device; [Figure 3] Top view of the reader body [Figure 4] Schematic diagram showing the internal structure of the reading device main body [Figure 5] A diagram showing the grounding configuration of the reader body. [Figure 6] Cross-sectional view showing the contact area between the guide shaft and the ground spring DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in the following embodiments are not intended to limit the scope of the present invention.

[0011] (Explanation of Image Forming Apparatus) First, a schematic configuration of an image forming apparatus 100 including an image reading device 1 will be described with reference to Figures 1 to 3. Figure 1 is a cross-sectional view of the image forming apparatus 100 including the image reading device 1. The image forming apparatus 100 is, for example, a copying machine, and includes an apparatus main body 100A and an image reading device 1 provided on top of the apparatus main body 100A.

[0012] The image forming apparatus 100 shown in Figure 1 is an intermediate transfer tandem type color image forming apparatus in which four color (yellow, cyan, magenta, and black) image forming units PY, PM, PC, and PK are arranged facing an intermediate transfer belt 112 within the apparatus main body 100A.

[0013] The image forming apparatus 100 includes image forming units PY to PK that form toner images on photosensitive drums 121, an intermediate transfer unit 111 having an intermediate transfer belt 112 that carries the toner images formed on the photosensitive drums 121, and a sheet feeding section 101 that feeds sheets P. In this embodiment, the image forming section that forms toner images on sheets P is made up of the image forming units PY to PK, primary transfer rollers 125Y to 125K, the intermediate transfer belt 112, the inner secondary transfer roller 113, and the outer secondary transfer roller 106. The intermediate transfer unit 111 is made up of the intermediate transfer belt 112, which is an endless belt, a tension roller 114 that tensions the intermediate transfer belt 112, the inner secondary transfer roller 113, etc. The sheet feeding section 101 is made up of a paper feed cassette 102, a paper feed roller 103, a pair of conveying rollers 104, a pair of registration rollers 105, etc.

[0014] The sheets P stored in each paper feed cassette 102 are fed one by one by the corresponding paper feed rollers 103, and are then conveyed by a conveyance roller pair 104 to a registration roller pair 105. The registration roller pair 105 stops the leading edge of the sheet P to correct skew, and resumes conveyance of the sheet P in accordance with the progress of the image formation operation, which is the toner image formation process by the image forming unit.

[0015] The image forming unit PY has a photosensitive drum 121Y, which is a photosensitive member, a charger 122Y, a developing unit 124, etc. Around the photosensitive drum 121Y, there are arranged a charger 122Y, an exposure device 123Y, a developing unit 124Y, a primary transfer roller 125Y, and a cleaner 127Y. Note that the other image forming units PM, PC, and PK all have the same structure as the image forming unit PY except for the toner colors, and therefore detailed description thereof will be omitted.

[0016] The charger 122Y uniformly charges the surface of the photosensitive drum 121Y, and the exposure device 123Y exposes the photosensitive drum 121Y to light based on image information input from the image reading device 1 or the like, thereby forming an electrostatic latent image on the drum. The developing device 124Y develops the electrostatic latent image into a toner image by supplying toner to the photosensitive drum 121Y.

[0017] The toner images carried on each photosensitive drum 121 are transferred onto the intermediate transfer belt 112 by the corresponding primary transfer roller 125 in an overlapping manner. The toner images transferred onto the intermediate transfer belt 112 are then transferred onto the sheet P conveyed from the pair of registration rollers 105 by the outer secondary transfer roller 106. The sheet P onto which the toner images have been transferred is conveyed by the conveying unit 107 towards the fixing unit 108. Note that any deposits such as residual toner that remain on the photosensitive drum 121 without being transferred onto the sheet P are removed by the cleaner 127, and the photosensitive drum 121 prepares for the next image forming operation.

[0018] The sheet P conveyed to the fixing unit 108 is sandwiched between a pair of rollers and heated while being pressed, and the image is fixed by melting and fixing the toner. The sheet P with the fixed image is discharged by a pair of discharge rollers 109 onto a discharge tray 110 protruding outward from the apparatus main body 100A.

[0019] The image forming apparatus 100 described above is controlled by a control unit 130. Here, the control unit 130 is a control board having a CPU.

[0020] (Explanation of image reading device) Next, a schematic configuration of the image reading device 1 will be described. Fig. 2 is a schematic diagram of the image reading device 1 to which this embodiment is applied. The image reading device 1 includes a reading device main body 3 and an automatic document feeder (hereinafter referred to as an ADF unit) 2. The image reading device 1 also includes a scanning unit 41 as an image reading section disposed in the reading device main body 3.

[0021] The image reading device 1 is configured to automatically transport an original (not shown) placed on an original placement tray 21 by a user. The original is a sheet to be read, and may be paper such as paper sheets and envelopes, plastic film such as overhead projector sheets (OHP), cloth, etc. The image reading device 1 reads an image of the original. Specifically, the image reading device 1 receives reflected light irradiated onto the original being transported at the image reading position, optically reads the original, converts the light into an electrical signal, and creates image data (image reading information) based on the electrical signal.

[0022] Each element constituting the image reading device 1 will be described below.

[0023] The reading device main body 3 is fixed to the top surface of the device main body 100A (see FIG. 1). As shown in FIG. 3, a flatbed type document table glass 31 is arranged on the top surface of the reading device main body 3. The scanning unit 41 (reading unit) is an image reading section that reads image information from a document. The image data read by the scanning unit 41 is output to the control unit 130 of the device main body 100A.

[0024] Although not shown, the scanning unit 41 has a light source that irradiates light onto the document placed on the document glass 31, a photoelectric conversion unit that photoelectrically converts light reflected from the document, and the like. The scanning unit 41 is supported by a unit holder 42 that is movable in the direction of arrow S (scanning direction, left and right direction) shown in FIG. 4. The unit holder 42 is an example of a holding member that holds the scanning unit 41. The unit holder 42 is connected to a motor unit 44, which is a drive unit, by a timing belt 45 that is stretched in the direction of arrow S, and is moved in the direction of arrow S along the document glass 31 by rotation of the motor unit 44.

[0025] The ADF unit 2 is supported by a hinge mechanism (not shown) located at the rear of the drawing so as to be able to open and close in the vertical direction relative to the reading device main body 3, and is formed with a pressing section (not shown) that presses a document placed on a document table glass 31 against the document table glass 31. The ADF unit 2 includes a document placement tray 21 and a document transport section (not shown). The document placement tray 21 supports a document placed by a user. The document transport section (not shown) is provided with a transport guide that guides the document and a feed roller that feeds the document, and the document placed on the document placement tray 21 is fed by the feed roller to the scanning unit 41 that is stopped at the reading position.

[0026] The image reading device 1 configured in this manner reads image information from a document in a flow reading mode in which the document image is scanned while the document is fed by the ADF unit 2, and in a fixed reading mode in which the document placed on the document table glass 31 is scanned.

[0027] The fixed reading mode is selected when a detection unit (not shown) detects an original placed on the platen glass 31 and positioned by a pressing unit (not shown) of the ADF unit 2, or when a user explicitly instructs this via an operation unit (not shown) of the device main body 100A. In this case, the scanning unit 41 reads an image of the original placed on the platen glass 31 while moving along the platen glass 31 in the scanning direction.

[0028] Specifically, the scanning unit 41 is moved along the platen glass 31 by the unit holder 42, while irradiating the document with light from a light source and forming an image of the light reflected from the document on a photoelectric conversion unit using a lens. The photoelectric conversion unit photoelectrically converts the formed reflected light and outputs an electrical signal. In this way, the scanning unit 41 reads the image information of the document.

[0029] In this embodiment, the scanning unit 41 employs a CIS (Contact Image Sensor) unit with a 1x magnification optical system. Image information photoelectrically converted according to the density of the original image is converted from an analog signal to a digital signal by an AFE (Analog Front End). In this embodiment, the AFE is implemented within the scanning unit 41.

[0030] On the other hand, the flow reading mode is selected when a detection unit (not shown) detects a document placed on the document tray 21, or when a user explicitly instructs this via an operation unit (not shown) of the device main body 100A. In this case, the scanning unit 41 is moved to the reading position (the position of the flow reading glass 32 shown in FIG. 3) by the unit holder 42 and stopped there. Then, the ADF unit 2 feeds documents one by one toward the reading position where the scanning unit 41 is stopped. The scanning unit 41 stopped at the reading position reads the image of the document fed to the reading position. The read image data is transferred to the control unit 130 of the device main body 100A.

[0031] The upward direction U, downward direction D, rightward direction R, leftward direction L, backward direction B, and forward direction F shown in FIG. 1 and elsewhere are defined as follows: The side of image forming apparatus 100 where an operation unit (not shown) is located is defined as the forward side (near side or front side), and the opposite side where a hinge mechanism (not shown) of image reading device 1 is located is defined as the backward side (rear side or rear side). In FIG. 1, the direction from the back to the front of the page is defined as the forward direction F, and the direction from the front to the back of the page is defined as the backward direction B. Furthermore, when the image forming unit PK that forms a black image is used as a reference, the side where the image forming unit PY that forms a yellow image is located is defined as the left side. When the image forming unit PY that forms a yellow image is used as a reference, the side where the image forming unit PK that forms a black image is located is defined as the right side. Furthermore, the vertically upward direction perpendicular to the front-rear and left-right directions defined herein is defined as the upward direction U, and the vertically downward direction perpendicular to the front-rear and left-right directions defined herein is defined as the downward direction D.

[0032] The scanning direction (first direction) of the scanning unit 41 is the left-right direction, the second direction perpendicular to the first direction is the front-rear direction, and the third direction perpendicular to the first and second directions is the up-down direction.

[0033] (Explanation of the reading device main body 3) Next, the configuration of the reading device main body 3 will be described in detail with reference to Figures 4 to 6. Figure 4 is a schematic diagram showing the internal configuration of the reading device main body 3.

[0034] The reading device main body 3 includes the above-mentioned scanning unit 41 and unit holder 42, as well as a guide shaft 40, a bearing portion 43, a resin housing 49, and ground springs (ground members) 46a and 46b.

[0035] As described above, in the fixed reading mode, the scanning unit 41 reads and scans in the scanning direction an original placed on the platen glass 31. In the flow reading mode, the scanning unit 41 is stopped at the reading position (the position of the flow reading glass 32 shown in FIG. 3) and reads the image of an original fed to the reading position.

[0036] The guide shaft 40 extends in the scanning direction (left and right direction), movably supports the scanning unit 41, and guides the scanning unit 41 in the scanning direction. The guide shaft 40 is made of metal.

[0037] The housing 49 is made of resin and has a mechanical structure that ensures rigidity. By using resin for the housing 49, the production cost is reduced. The document table glass 31 is disposed on the top surface of the housing 49, and the housing 49 houses the scanning unit 41 and the guide shaft 40.

[0038] A bearing portion 43 having a groove shape with a portion (vertically downward) open is attached to the unit holder 42 that holds the scanning unit 41. The bearing portion 43 is fitted with the guide shaft 40 by the groove shape. The bearing portion 43 is configured to grip the guide shaft 40 and be guided by the guide shaft 40 so as to be slidable in the scanning direction (the direction of arrow S in FIG. 4). That is, the unit holder 42 has the bearing portion 43 as a sliding portion that is fitted with the guide shaft 40 and is slidable in the scanning direction relative to the guide shaft 40. Note that, although the bearing portion (sliding portion) 43 of the unit holder 42 has been exemplified as having a groove shape with a portion open vertically downward, the present invention is not limited to this. As long as the bearing portion (sliding portion) 43 has a groove shape with a portion open vertically, it is also acceptable for the portion other than the lower portion to be open in the vertical direction.

[0039] As mentioned above, the scanning unit 41 incorporates an AFE. To speed up image reading, the scanning unit 41 operates the AFE at a high speed, at an internal operating frequency of approximately 200 MHz. This high-speed operation generates interference waves from the scanning unit 41. These interference waves are electromagnetically coupled to the metal guide shaft 40 and are radiated outside the reader main body 3. The radiation of these interference waves must be suppressed so as not to exceed the EMC standard values.

[0040] In order to suppress radiation of interference waves, the guide shaft 40 connects ground springs 46a and 46b to ground points 48a and 48b via contact connectors 47a and 47b, thereby grounding the guide shaft 40. The control unit (control board) 130 described above has a ground point 131 that serves as the reference potential (ground potential) of the control unit 130. The ground point 131 of the control unit 130 on the device main body 100A side is electrically connected to the ground points 48a and 48b on the reading device main body 3 side. In other words, the ground springs 46a and 46b, which serve as grounding members, abut against the guide shaft 40 to ground the guide shaft 40.

[0041] 5 is a diagram showing the grounding configuration of the reading device main body 3, and is a diagram illustrating the configuration related to the grounding of the scanning unit 41 and the guide shaft 40. In this embodiment, the guide shaft 40 is grounded at two points, the ground spring 46a and the ground spring 46b.

[0042] Although the configuration in which two grounding springs 46a, 46b are in contact with the guide shaft 40 and the guide shaft 40 is grounded at two points has been exemplified here, the present invention is not limited to this. A configuration in which one grounding member is in contact with the guide shaft 40, or three or more grounding members are in contact with the guide shaft 40, to ground the guide shaft 40 may also be used.

[0043] The ground spring 46a is a metal compression coil spring. The ground spring 46a presses against and abuts against the side surface of the guide shaft 40, and the ground spring 46a and the guide shaft 40 are electrically connected. When viewed from the scanning direction, the ground spring 46a is a first grounding member that abuts against the surface of the guide shaft 40 along the scanning direction in the open portion of the bearing portion 43, thereby grounding the guide shaft 40.

[0044] On the other hand, the ground spring 46b is a metal leaf spring. The ground spring 46b presses against and abuts against the end of the guide shaft 40, electrically connecting the ground spring 46b and the guide shaft 40. The ground spring 46b is a second grounding member that abuts against one end face of the guide shaft 40 in the scanning direction to ground the guide shaft 40.

[0045] 5 indicates the scanning area of ​​the scanning unit 41. The ground spring 46b is disposed outside the scanning area of ​​the scanning unit 41. In other words, the ground spring 46b abuts against one end face of the guide shaft 40 in the scanning direction outside the scanning area where the scanning unit 41 reads and scans the document.

[0046] In this embodiment, the motor unit 44, which is a drive unit, is provided at one end of the guide shaft in the longitudinal direction and is housed in a housing 49. Therefore, an installation space can be secured for the ground spring 46b to abut against the end face of the guide shaft 40 on the motor unit 44 side (drive unit side).

[0047] On the other hand, the ground spring 46a is disposed within the scanning area of ​​the scanning unit 41. That is, the ground spring 46a abuts against a surface of the guide shaft 40 along the scanning direction within the scanning area where the scanning unit 41 reads and scans the document.

[0048] 6 is a cross-sectional view showing the contact portion between the guide shaft 40 and the ground spring 46a. The bearing portion 43 is configured to grip the guide shaft 40 and to be slidably guided by the guide shaft 40, as described above.

[0049] The bearing portion 43 has opposing portions 43a and 43b that face each other across the guide shaft 40 and are spaced apart so that the surfaces along the scanning direction of the guide shaft 40 are open.

[0050] Specifically, the bearing portion 43 has a first opposing portion 43a and a second opposing portion 43b that faces the first opposing portion 43a across the guide shaft 40 and is spaced apart from the first opposing portion 43a so as to open the surface along the scanning direction of the guide shaft 40.

[0051] As shown in Fig. 6, in the cross section of the guide shaft 40, the lower side of the bearing portion 43 is open. When viewed in the axial direction (scanning direction) of the guide shaft 40, the ground spring 46a abuts against the guide shaft 40 at the open portion of the bearing portion 43. In other words, the surface of the guide shaft 40 along the scanning direction is open between the first opposing portion 43a and the second opposing portion 43b. The ground member 46 abuts against the surface of the guide shaft 40 along the scanning direction that is open between the first opposing portion 43a and the second opposing portion 43b. Note that, although a configuration in which the lower side of the bearing portion 43 is open (a configuration in which the bearing portion 43 is spaced apart) is illustrated here, the present invention is not limited to this.

[0052] With this configuration, when the bearing portion 43 slides in the scanning direction while being guided by the guide shaft 40, it does not interfere with the ground spring 46a that abuts against the guide shaft 40. Therefore, the ground spring 46a and the guide shaft 40 can be grounded even within the scanning area of ​​the scanning unit 41.

[0053] As described above, in this embodiment, no grounding member is provided on the end face of the guide shaft 40 opposite the grounding spring 46a, and the grounding spring 46a is disposed within the scanning area of ​​the scanning unit 41. Therefore, according to this embodiment, compared to a configuration in which grounding members are disposed on both ends of the guide shaft 40, it is possible to ground the guide shaft 40 and suppress interference waves without increasing the external dimensions of the image reading device 1 having the resin housing 49.

[0054] As described above, the ground spring 46a is a metal compression coil spring. The ground spring 46a is pressed against the housing 49 and the guide shaft 40 to come into contact with each other, thereby electrically connecting the ground spring 46a and the guide shaft 40. It is desirable that the ground spring 46a be pressed against the guide shaft 40 with a predetermined force of approximately 1 [N] so that the electrical connection does not become unstable even if vibrations occur due to scanning by the scanning unit 41.

[0055] The ground spring support portion 51 serves as a support member that supports the ground spring 46a. The ground spring support portion 51 is formed integrally inside the resin housing 49. The ground spring support portion 51 surrounds the ground spring 46a in an annular shape and is open at the top. In other words, the ground spring support portion 51 prevents the ground spring 46a, which is pressed against the guide shaft 40, from tilting, so that the ground spring 46a and the guide shaft 40 do not come out of contact with each other. As a result, even if the ground spring 46a is elastically deformed due to vibration, for example, the contact between the ground spring 46a and the guide shaft 40 is maintained, and electrical connection is maintained.

[0056] The ground spring support part 51 is provided between the guide shaft 40 and the bottom surface of the housing 49 in the vertical direction. The ground spring support part 51 is also provided within the range of the scanning area of ​​the scanning unit 41 in the left-right direction. Furthermore, there is a predetermined gap between the ground spring support part 51 and the bearing part 43 in the vertical direction. This predetermined gap is a gap that prevents the bearing part 43, which slides as the scanning unit 41 scans, from colliding with the ground spring support part 51.

[0057] The contact point connecting portion 47a is formed integrally with the ground spring 46a using a metal wire.

[0058] In the above-described embodiment, ground spring 46a is a metal compression coil spring, but it may be a metal leaf spring. Ground spring 46b is a metal leaf spring, but it may be a metal compression coil spring. Furthermore, ground springs 46a and 46b may be made of any conductive elastic material, such as a gasket (a sponge member with a conductive surface) or conductive resin.

[0059] In the above-described embodiment, the contact connecting portion 47a is formed integrally with the ground spring 46a using a metal wire, but this is not limiting. Furthermore, the contact connecting portion 47a may be made of any conductive material, such as a metal plate or metal foil.

[0060] In the above-described embodiment, the ground spring 46a and the ground spring 46b have different configurations, but the same configuration as the ground spring 46a may be provided for each spring. This makes it possible to further reduce the external dimensions of the image reading device 1 having the resin housing 49.

[0061] In the above-described embodiment, the ground spring 46a is configured to be provided within the scanning area of ​​the scanning unit 41, but the ground spring 46a may be provided outside the scanning area of ​​the scanning unit 41. Furthermore, multiple ground springs 46a may be provided. The number and locations of the ground springs 46a and 46b are effectively selected in order to suppress the interference waves, taking into account the relationship between the wavelength of the interference waves and the length of the guide shaft 40.

[0062] In the above-described embodiment, one of the two ground springs 46a, 46b that contact the guide shaft 40, the ground spring 46b, is arranged outside the scanning area of ​​the scanning unit 41, and the other ground spring 46a is arranged inside the scanning area of ​​the scanning unit 41. However, the present invention is not limited to this. For example, both ground springs may be arranged inside the scanning area of ​​the scanning unit 41. This configuration also makes it possible to ground the guide shaft and suppress interference waves without increasing the external dimensions of the device.

[0063] Furthermore, of the two ground springs 46a, 46b that contact the guide shaft 40, the configuration in which one ground spring 46b contacts one end face in the longitudinal direction of the guide shaft 40 and the other ground spring 46a contacts a surface of the guide shaft 40 along the scanning direction has been exemplified, but the present invention is not limited to this. For example, one ground spring may contact a first position on the surface of the guide shaft along the scanning direction and the other ground spring may contact a second position different from the first position on the surface of the guide shaft along the scanning direction, so that both ground springs are disposed on the surface of the guide shaft 40 along the scanning direction. This configuration also makes it possible to ground the guide shaft and suppress interference waves without increasing the external dimensions of the device.

[0064] In the above-described embodiment, the image forming apparatus 100 has a configuration in which the apparatus main body 100A includes the control unit 130 having the ground point 131 that serves as the reference potential, but the present invention is not limited to this. The image reading apparatus 1 may have a configuration in which the reading apparatus main body 3 includes a control unit that has a ground point that serves as the reference potential, and the guide shaft 40 is grounded by electrically connecting the ground point of this control unit to the ground springs 46a and 46b.

[0065] In the above-described embodiment, an image forming apparatus equipped with an image reading device is exemplified, and a copier is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the present invention may be applied to other image forming apparatuses such as a facsimile machine, or other image forming apparatuses such as a multifunction peripheral that combines the functions of these. Alternatively, the present invention may be applied to an image reading device such as a scanner. Similar effects can be obtained by applying the present invention to these image forming apparatuses or image reading devices.

[0066] In the above-described embodiment, an image forming apparatus is exemplified in which an intermediate transfer member is used, toner images of each color are transferred to the intermediate transfer member in a sequentially overlapping manner, and the toner images carried on the intermediate transfer member are then transferred all at once to a sheet (recording material) to be recorded on, but the present invention is not limited to this.An image forming apparatus may also be used in which a recording material carrier is used, toner images of each color are transferred to a recording material carried on the recording material carrier in a sequentially overlapping manner, and similar effects can be obtained by applying the present invention to an image reading device included in the image forming apparatus.

[0067] In the above-described embodiment, the electrophotographic method is used as an example of the recording method, but the present invention is not limited to this, and other recording methods such as an inkjet method may also be used. [Explanation of symbols]

[0068] 1...Image reading device 2...ADF unit 3...Reading device body 31...Document glass 32...Sink reading glass 40...Guide shaft 41...Scanning unit 42...Unit holder 43...Bearing section 44...Motor unit 45...Timing belt 46a, 46b ... Ground spring 47a, 47b ... Contact connection part 48a,48b…Grounding point 49...Case 51 ... Ground spring support part 100...Image forming device 100A...Device body 130...Control unit 131...Grounding point

Claims

1. a document table on which a document is placed; a reading unit that reads the document placed on the document table while moving in a scanning direction; a holding member for holding the reading unit; a guide shaft that movably supports the holding member and guides it in the scanning direction; a resin housing on whose top surface the document table is disposed and which houses the reading unit and the guide shaft; a grounding member that contacts the guide shaft to ground the guide shaft, the holding member has a groove shape that is open downward in the vertical direction, and includes a sliding portion that is fitted onto the guide shaft and is slidable relative to the guide shaft in the scanning direction; the grounding member abuts against a surface of the guide shaft along the scanning direction at an open portion of the sliding portion when viewed from the scanning direction; An image reading device characterized by:

2. The grounding member is a compression coil spring using a metal wire.

2. The image reading device according to claim 1, wherein:

3. The grounding member is pressed against the guide shaft with a predetermined force.

2. The image reading device according to claim 1, wherein:

4. a support member for supporting the grounding member; the grounding member is an elastic body having electrical conductivity, The support member restricts tilting of the ground contact member so that the ground contact member and the guide shaft do not come out of contact with each other.

2. The image reading device according to claim 1, wherein:

5. a control unit having a ground point serving as a reference potential; The grounding point and the grounding member are electrically connected.

2. The image reading device according to claim 1, wherein:

6. the grounding member is a first grounding member that abuts against a surface of the guide shaft along the scanning direction to ground the guide shaft, further comprising a second grounding member that contacts one end surface of the guide shaft in the scanning direction to ground the guide shaft; 2. The image reading device according to claim 1, wherein:

7. the first grounding member abuts against the guide shaft within an area where the reading unit reads and scans the document; the second grounding member abuts against the guide shaft outside an area where the reading unit reads and scans the document; 7. The image reading device according to claim 6, wherein:

8. a drive unit for driving the reading unit; the drive unit is provided on one end side of the guide shaft in the scanning direction and is housed in the housing, the second grounding member abuts on an end surface of the guide shaft on the drive unit side; 7. The image reading device according to claim 6, wherein:

9. the grounding member abuts against the guide shaft within an area where the reading unit reads and scans the document; 2. The image reading device according to claim 1, wherein:

10. The grounding member includes a grounding member that contacts a first position on a surface of the guide shaft along the scanning direction within an area where the reading unit reads and scans the document, thereby grounding the guide shaft, and a grounding member that contacts a second position on a surface of the guide shaft along the scanning direction, which is different from the first position, thereby grounding the guide shaft.

10. The image reading device according to claim 9, wherein:

11. The guide shaft is made of metal.

2. The image reading device according to claim 1, wherein:

12. the sliding portion includes a first opposing portion and a second opposing portion that faces the first opposing portion across the guide shaft and is spaced apart from the first opposing portion so as to expose a surface of the guide shaft along the scanning direction, the grounding member is in contact with a surface of the guide shaft that is open between the first opposing portion and the second opposing portion and that extends along the scanning direction; 2. The image reading device according to claim 1, wherein:

13. An image reading apparatus comprising: the image reading apparatus according to any one of claims 1 to 12; and an image forming unit that forms an image on a sheet. An image forming apparatus characterized by:

Images