JPWO2016067750A1 - Image reading apparatus and image forming apparatus provided with the image reading apparatus - Google Patents

Abstract

The guide member (271) forming the document conveyance path accommodates the contact image sensor (211) inside and has a recess (273) covered with a transparent glass plate (274), and an open side of the recess (273). The surface of the transparent glass plate (274) on the side of the document conveyance path is formed at a predetermined height with respect to the document conveyance surface (271d) of the guide member. And a positioning surface (271b) for positioning the transparent glass plate (274), and a detachable fixing member for pressing the transparent glass plate (274) against the positioning surface (271) to fix the transparent glass plate (274). Further prepare.

Description

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

  2. Description of the Related Art Conventionally, an image reading apparatus that reads an image of a document conveyed from a paper feed tray by an image sensor and discharges the document after the reading to a paper discharge tray is known. The document conveyance path is formed by a guide plate arranged along the conveyance path. For example, a contact image sensor (also referred to as CIS (contact image sensor)) is used as the image sensor (see, for example, Patent Document 1). This contact image sensor is housed in a housing whose one side surface is covered with contact glass. The housing is arranged so that the contact glass faces the document conveyance path. The housing is disposed between the guide plates adjacent to each other in the document conveyance direction.

JP 2009-143696 A

  By the way, since the contact image sensor has a narrow depth of field, it is preferable to keep the distance between the contact image sensor and the original passing through the original conveyance path as constant as possible in order to read the image satisfactorily.

  However, in the image reading apparatus shown in Patent Document 1, the assembly position of the housing that accommodates the contact image sensor with respect to the document conveyance path varies in the assembly process, and as a result, the distance between the contact image sensor and the document varies. There is a problem that reading cannot be performed well.

  The present invention has been made in view of the above points, and an object of the present invention is to improve the accuracy of reading a document image by the contact image sensor by improving the positioning accuracy of the contact image sensor with respect to the document conveyance path. There is to make it.

  An image reading apparatus according to the present invention includes a document feeding mechanism, a guide member, a contact image sensor, and a transparent glass plate. The document feeding mechanism transports the document placed on the paper feed tray along a predetermined document transport path and discharges it to the paper discharge tray. The guide member is disposed along the predetermined document transport path to form the document transport path. The contact image sensor is arranged on the side of the predetermined document transport path and reads an image of the document passing through the predetermined document transport path. The transparent glass plate covers the document conveyance path side in the contact image sensor.

  The guide member has a recess and a positioning surface. The recess accommodates the contact image sensor therein and is covered with the transparent glass plate. The positioning surface is formed at the peripheral edge of the recess on the open side, and comes into contact with the peripheral edge of the transparent glass plate so that the surface of the transparent glass plate on the side of the document transport path is opposite to the document transport surface of the guide member. Thus, the transparent glass is positioned so as to have a predetermined height.

  According to this configuration, since the concave portion that accommodates the contact image sensor is formed integrally with the guide member that forms the document conveyance path, the sensor unit is compared with the case where the sensor unit is configured separately from the guide member. The positioning accuracy of the contact image sensor with respect to the conveyance path can be improved. And the positioning surface which contact | abuts the transparent glass plate which covers this recessed part is formed in the peripheral part of the open side of this recessed part. When the transparent glass plate is in contact with the positioning surface, the surface of the transparent glass plate on the side of the document conveyance path and the document conveyance surface of the guide member are flush with each other. Accordingly, it is possible to prevent the transparent glass plate from being arranged in a state where it is displaced inward or outward of the transport path with respect to the document transport surface of the guide member. As a result, the distance between the contact image sensor and the document passing through the document transport path (on the contact glass) can be kept constant. Therefore, the reading accuracy of the original image by the contact image sensor can be further improved.

  An image forming apparatus according to the present invention includes the image reading apparatus.

  According to this configuration, since the reading accuracy of the original image by the contact image sensor is improved, the original image can be accurately reproduced and printed on the paper by the image forming unit.

  According to the present invention, it is possible to improve the accuracy of reading a document image by the contact image sensor by improving the positioning accuracy of the contact image sensor with respect to the document conveyance path.

FIG. 1 is a schematic diagram showing the inside of an image forming apparatus provided with a document feeding device (corresponding to an image reading device) in the embodiment. FIG. 2 is an external perspective view showing the document feeder. FIG. 3 is a schematic longitudinal sectional view showing the document feeder. FIG. 4 is an external perspective view showing the upstream guide member of the inner guide portion disposed along the document conveyance path. FIG. 5 is an external perspective view showing a state in which the upper cover of the document feeder is removed. FIG. 6 is an external perspective view showing a state where the upper cover of the document feeder is removed. 7 is a cross-sectional view taken along line VII-VII in FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is a perspective view of a side wall portion located closer to the rear side of the image forming apparatus among a pair of side wall portions of the document feeder, as viewed from the inside of the pair of side wall portions. FIG. 10 is a view taken in the direction of the arrow X in FIG. 9 and is an enlarged view showing the positioning portion formed at the lower end of the groove.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

<Embodiment>
FIG. 1 shows an image forming apparatus 1 including a document feeding device (corresponding to an image reading device) 221 according to this embodiment. The image forming apparatus 1 is a laser printer using an electrophotographic method. The image forming apparatus 1 includes an image forming apparatus main body 100, an image reading unit 200 attached to an upper part of the image forming apparatus main body 100, and an operation panel 290 that can be operated by a user. In the following description, the front side and the rear side mean the front side and the rear side (left and right sides in the left-right direction in FIG. 1), respectively, and the left side and the right side refer to the image forming apparatus 1 from the front side. It means the left side and the right side (front side and rear side in the direction perpendicular to the paper surface in FIG. 1) when viewed.

  The image forming apparatus main body 100 has a box-shaped housing 60. An image reading unit 200 is provided on the top of the housing 60. In the housing 60, the paper feeding unit 10, the image forming unit 20, and the fixing unit 40 are accommodated. A plurality of transport roller pairs 11 to 13 that sandwich and transport the paper P are disposed in the paper transport path L from the paper supply unit 10 to the paper discharge tray unit 50. In addition, a reverse conveyance path L ′ that branches from the downstream side of the sheet conveyance path L and joins the upstream side is provided in the housing 60. Conveying roller pairs 14 to 16 are arranged in the reverse conveying path L ′.

  The paper feeding unit 10 is disposed in the lower part of the housing 60. The paper feed unit 10 includes a paper feed cassette 10a in which sheet-like paper P is accommodated, and a pickup roller 10b for taking out the paper P in the paper feed cassette 10a and sending it out of the cassette. The paper P sent out of the cassette from the paper feed cassette 10 a is supplied to the image forming unit 20 through the transport roller pair 11.

  In the image forming unit 20, image forming units 20Bk, 20M, 20C, and 20Y that form toner images corresponding to the respective colors of black, magenta, cyan, and yellow are arranged in a line. Each of the image forming units 20Bk, 20M, 20C, and 20Y includes a photosensitive drum 21, a charging device 22, a developing device 23, and a cleaning device 24. Below the image forming units 20Bk, 20M, 20C, and 20Y, an exposure device 25 that irradiates the surface of each photosensitive drum 21 with laser light is disposed. An intermediate transfer unit 26 is disposed above the image forming units 20Bk, 20M, 20C, and 20Y. The intermediate transfer unit 26 is provided with an intermediate transfer belt 27 that travels in contact with each photosensitive drum 21. A primary transfer roller 28 is provided inside the intermediate transfer belt 27 so as to sandwich the intermediate transfer belt 27 with the photosensitive drum 21. A secondary transfer roller 29 is provided on the downstream side of the image forming unit 20Bk so as to be in contact with the surface of the intermediate transfer belt 27. On the upper side of the intermediate transfer unit 26, toner containers 30Bk, 30M, 30C, and 30Y are arranged. The toner containers 30Bk, 30M, 30C, and 30Y store toners of respective colors that are supplied to the developing devices 23 of the image forming units 20Bk, 20M, 20C, and 20Y.

  In the image forming unit 20, the exposure device 25 electrostatically irradiates the surface of each photosensitive drum 21 with laser light based on predetermined image data (original image data read by the image reading unit 200 in this embodiment). A latent image is formed. The image forming unit 20 develops the formed electrostatic latent image with the developing device 23 to form a toner image of each color. Each color toner image formed on the surface of each photosensitive drum 21 is transferred onto the surface of the intermediate transfer belt 27 by the primary transfer roller 28 and superimposed. The toner image transferred onto the intermediate transfer belt 27 is transferred onto the paper P supplied from the paper supply unit 10 by the secondary transfer roller 29. The sheet P after the transfer is supplied to the fixing unit 40. The fixing unit 40 fixes the toner image on the paper P by pressing the paper P supplied from the image forming unit 20 between the fixing roller 40a and the pressure roller 40b. Then, the paper P on which the toner image is fixed by the fixing unit 40 is sent out to the downstream side by both rollers 40a and 40b. The paper P sent out from the fixing unit 40 is discharged to the paper discharge tray unit 50 through the conveyance roller pair 13. When toner images are formed on both sides of the paper P, the paper P is switched back by the transport roller pair 13 and transported to the reverse transport path L ′.

  The image reading unit 200 includes a substantially rectangular parallelepiped case body 250, a document pressing cover 240, and a document feeding device 221. An upper surface of the case body 250 forms a document placement surface 250a on which a document is placed. The image reading unit 200 reads the image of the document placed on the document placement surface 250a, and the scanning reading mode for reading the image while continuously feeding the document one by one by the document feeding device 221. And. A scanner unit 210 (see FIG. 3) is accommodated in the case body 250. The scanner unit 210 optically reads an original image placed on the original placement surface 250a in the fixed reading mode, and optically reads an image on the surface of the original in the flow reading mode to generate the image data. . The scanner unit 210 includes, for example, a reflection mirror, a CCD sensor, and the like. The document pressing cover 240 covers the document placement surface 250a so that it can be opened and closed. The document pressing cover 240 is rotatably attached to the case body 250 via a hinge mechanism (not shown).

  The document feeder 221 is provided on the upper surface side of the document pressing cover 240. As shown in FIG. 2, the document feeder 221 has a main body case 222. The main body case 222 is provided at the left end portion on the upper surface side of the document pressing cover 240. The main body case 222 has a pair of side wall portions 222e and an upper cover 222k that can be opened and closed. The lower surface of the main body case 222 is constituted by the upper surface of the document pressing cover 240. The pair of side wall portions 222e are disposed to face each other in the front-rear direction across a document conveyance path 225 (see FIG. 3) provided in the document feeder 221. The pair of side wall portions 222 e are fixed to the upper surface of the document pressing cover 240.

  FIG. 3 is a longitudinal sectional view of the document feeder 221. As shown in the figure, on the right side surface of the main body case 222, a paper feed port 222f and a paper discharge port 222g arranged in the vertical direction are formed. A paper feed tray 223 and a paper discharge tray 228 are provided on the right side of the paper feed port 222f and the paper discharge port 222g, respectively. A substantially U-shaped document transport path 225 is formed in the main body case 222 from the paper feed port 222f to the paper discharge port 222g. A feed roller 261, a paper feed roller 262, a transport roller pair 263, 264, 265 and a paper discharge roller pair 266 are provided in the main body case 222 in this order from the upstream side to the downstream side along the transport path 225. It has been. These rollers 261 and 262 and the conveying roller pairs 263 to 265 are arranged so as to extend in the front-rear direction. An inner guide portion 270 and an outer guide portion 280 are provided on the sides of the document conveyance path 225. The inner guide portion 270 and the outer guide portion 280 are disposed to face each other with the document conveyance path 225 interposed therebetween. The inner guide portion 270 and the outer guide portion 280 are arranged along the document conveyance path 225. The inner guide portion 270 forms an inner wall surface of the U-shaped document conveyance path 225, and the outer guide portion 280 forms an outer wall surface of the document conveyance path 225.

  The feed roller 261 and the paper feed roller 262 are connected via a bracket 231. During the paper feeding operation, the bracket portion 231 rotates around the support shaft 232 in the clockwise direction in the drawing, so that the feed roller 261 contacts the upper surface of the document. Note that reference numeral 205 in FIG. 3 denotes a stopper that regulates the leading end position of the document placed on the document feed tray 223.

  When the document feeding operation of the document feeder 221 starts, the document placed on the sheet feed tray 223 is supplied to the document transport path 225 by the feed roller 261 and the feed roller 262, and then the transport roller pair 263. ˜265, the paper is discharged to the paper discharge tray 228 by the paper discharge roller pair 266 (see the thick arrow in FIG. 3). A first image reading position 226 and a second image reading position 227 for reading a document image in the flow-reading mode are set in the middle of the document conveyance path 225. At the first image reading position 226, an image on the back side of the document is read by a contact image sensor 211. At the second image reading position 227, the scanner unit 210 reads an image on the surface of the document.

  The contact image sensor 211 is provided in the vicinity of the inside of the document conveyance path 225. The contact image sensor 211 is arranged so that the image reading surface faces the document conveyance path 225 side. The contact image sensor 211 is aligned with a light source (not shown) that emits light toward a document passing through the document conveyance path 225 and a document width direction (a direction perpendicular to the document conveyance direction and perpendicular to the paper surface in FIG. 3). A plurality of light receiving elements (not shown). Each light receiving element receives reflected light from the document and outputs an image signal having a magnitude corresponding to the amount of received light. The image signal output from each light receiving element is transmitted to the controller. The controller generates image data on the back side of the document based on the image signal received from each light receiving element.

  The inner guide portion 270 includes an upstream guide member 271 provided on the upstream side of the transport roller pair 265 and a downstream guide member 272 provided on the downstream side of the transport roller pair 265.

  As shown in FIG. 4, a concave portion 273 that extends in the document width direction and accommodates the contact image sensor 211 is formed at the center of the upstream guide member 271 in the document conveyance direction. The concave portion 273 is formed in a rectangular cross section that opens to the document conveyance path 225 side. The recess 273 is formed over the entire document width direction of the upstream guide member 271. Specifically, the recess 273 is formed by a pair of vertical wall portions 271e facing each other with a gap in the document transport direction and a bottom wall portion 271f connecting the lower ends of the vertical wall portions 271e. Projections 271m projecting outward in the document width direction are formed at both ends of the upstream guide member 271 in the document width direction. Each protrusion 271m is inserted into a groove 224 (see FIG. 9) formed on the opposing surfaces of the pair of side walls 222e of the document feeder 221. Details of the groove 224 will be described later.

  Three upstream openings 271g and three downstream openings 271h are formed in the upstream guide member 271 on the upstream side and the downstream side in the document transport direction from the recess 273, respectively. As shown in FIGS. 5 and 6, the drive roller 263a of the transport roller pair 263 is exposed from the upstream opening 271g, and the drive roller 264a of the transport roller pair 264 is exposed from the downstream opening 271h. The open side of the recess 273 is closed by a contact glass 274 as a transparent glass plate. That is, the recess 273 is covered with the contact glass 274. The contact glass 274 is composed of a rectangular plate extending in the document width direction.

  As shown in FIG. 7, a biasing spring 276 is disposed between the contact image sensor 211 accommodated in the recess 273 and the bottom wall portion 271 f of the recess 273. The biasing spring 276 is a compression coil spring, and biases the contact image sensor 211 upward. The biasing spring 276 presses the contact image sensor 211 against the lower surface of the contact glass 274 so as to be in close contact therewith.

  The contact glass 274 is supported by an L-shaped step 271a. The stepped portion 271a is formed at each of two edge portions that are located at the open side end of the concave portion 273 and that face each other in the document conveying direction. Each stepped portion 271a has a contact surface 271b that contacts the contact glass 274 and a vertical surface 271c formed perpendicular to the corresponding contact surface 271b. The contact surface 271b is formed in parallel with the document conveying surface 271d of the upstream guide member 271. The contact surface 271b is positioned below the document conveying surface 271d by the thickness of the contact glass 274. The vertical surface 271c connects the corresponding contact surface 271b and the document conveying surface 271d of the upstream guide member 271. The document conveyance surface 271d is a surface that forms the document conveyance path 225, and is formed of a portion of the upper surface of the upstream guide member 271 that is located upstream and downstream of the recess 273. The contact surface 271b functions as a positioning surface for positioning the contact glass 274 so that the document conveying surface 271d and the upper surface of the contact glass 274 are flush with each other (that is, the same height).

  As shown in FIG. 8, the contact glass 274 is fixed by being pressed against the contact surface 271b by a pair of detachable fixing members 275. The pair of fixing members 275 respectively fix both end portions of the contact glass 274 in the longitudinal direction. The fixing member 275 has a fixing plate portion 275a and a pair of leg portions 275b. The fixed plate portion 275a is a plate portion that comes into contact with the upper surface of the contact glass 274 and is formed in a U shape in plan view (see, for example, FIGS. 5 and 6). The pair of leg portions 275b extend downward from both ends of the fixed plate portion 275a in the document conveyance direction. The pair of leg portions 275b is configured to be flexible in the document conveyance direction (left-right direction in FIG. 8) with the base end portion (connection portion with the fixing member 275) as a fulcrum. The fixing member 275 is preferably made of a resin material in order to provide such flexibility. An engaging claw portion 275c is formed at the lower end portion of each leg portion 275b. Each engagement claw portion 275c protrudes inward from the inner surface of the pair of leg portions 275. The engagement claw portion 275c is engaged with an engagement recess portion 271k formed on the outer surfaces of the pair of vertical wall portions 271e.

  The upstream guide member 271 is inserted and set from above between a pair of side wall portions 222e (see FIGS. 5 and 6) of the document feeder 221. As shown in FIG. 9, a groove portion 224 is formed on the opposing surfaces of a pair of side wall portions 222e (only the rear side wall portion 222e is shown in FIG. 9). The groove portion 224 extends substantially in the vertical direction. The groove part 224 includes an insertion side guide part 224a, a guide part 224b, and a positioning part 224c. The insertion side guide part 224a is open to the upper side, and receives the protrusion 271m of the upstream side guide member 271 from the upper side. The guide part 224b is connected to the lower end part of the insertion side guide part 224a. The guide part 224b is disposed adjacent to the upper side of the positioning part 224c. As shown in an enlarged view in FIG. 10, the guide portion 224b is formed so that the groove width becomes narrower toward the lower side. The guide portion 224b guides the protrusion 271m of the upstream guide member 271 received from the insertion side guide portion 224a to the positioning portion 224c. The positioning part 224c is connected to the lower end of the guide part 224b. The lower end side of the positioning part 224c is closed. The positioning portion 224c engages with the protrusion (engagement portion) 271m of the upstream guide member 271 to position the upstream guide member 271.

  In the setting operation of the upstream guide member 271, first, the upstream guide member 271 is inserted between the pair of side wall portions 222e from above. At this time, the protrusion 271m formed on the upstream guide member 271 is inserted into the groove 224 formed on the inner surface of the side wall 222e. When the upstream guide member 271 is gradually moved downward while being supported by the hand, the protrusion 271m is fitted into the lower end portion (that is, the positioning portion 224c) of the groove portion 224. Thus, the positioning of the upstream guide member 271 is completed when the protrusion 271m of the upstream guide member 271 is fitted (engaged) with the positioning portion 224c. In the present embodiment, as shown in FIG. 10, when the positioning of the upstream guide member 271 is completed, the outer periphery of the protrusion 271 m is in point contact with the side wall of the groove 224.

  As described above, in the above embodiment, the concave portion 273 for accommodating the contact image sensor 211 is formed integrally with the upstream guide member 271 that forms the document conveyance path 225. Compared with the case where the sensor unit is provided separately, the positioning accuracy of the contact image sensor 211 with respect to the document conveyance path 225 can be improved.

  In addition, contact surfaces 271b that contact the contact glass 274 and position the contact glass 274 are formed on the pair of edge portions on the open side of the recess 273, respectively. When the contact glass 274 comes into contact with the contact surface 271, the surface of the contact glass 274 on the document transport path 225 side becomes flush with the document transport surface 271 d of the upstream guide member 271. Accordingly, it is possible to prevent the contact glass 274 from being arranged in a state of being shifted to the inner side or the outer side of the conveyance path 225 from the document conveyance surface 271d of the upstream guide member 271. As a result, the distance between the contact glass 274 and the document passing through the document transport path 225 can be kept constant. Therefore, the reading accuracy of the original image by the contact image sensor 211 can be improved with certainty.

  Further, the contact glass 274 is pressed and fixed to the contact surface 271b by a detachable fixing member 275. Therefore, the cleaning operation in the recess 273 and the replacement operation of the contact image sensor 211 can be easily performed only by removing the fixing member 275.

  Further, in the above embodiment, the contact image sensor 211 is urged upward by the urging spring 276 and is in close contact with the contact glass 274.

  Therefore, the position of the contact image sensor 211 with respect to the contact glass 274 can always be kept constant. As a result, the position of the contact image sensor 211 with respect to the upstream guide member 271 that supports the contact glass 274 can always be kept constant, and the variation in the position of the contact image sensor 211 with respect to the document conveyance path 225 can be further ensured. Can be suppressed.

  Further, in the above embodiment, the groove portions 224 extending in the vertical direction are formed on the opposing surfaces of the pair of side wall portions 222e of the document feeder 221. A positioning portion 224c that positions the upstream guide member 271 by engaging with a protrusion 271m formed on the upstream guide member 271 is formed at the lower end of the groove 224.

  Accordingly, the upstream guide member 271 can be set with high positional accuracy between the pair of side wall portions 222e, and the position of the document conveying surface 271d of the upstream guide member 271 can be prevented from varying. it can. Accordingly, it is possible to prevent the document being conveyed from being displaced in the thickness direction in the conveyance path 225 because the gap between the document conveyance paths 225 is too wide. Therefore, variation in the distance between the document being conveyed and the contact image sensor 211 can be more reliably suppressed.

  Further, a guide portion 224b whose groove width becomes narrower toward the lower side is formed in a portion of the groove portion 224 adjacent to the upper side of the positioning portion 224c.

  Accordingly, when the upstream guide member 271 is set, the protrusion 271m can be smoothly guided to the positioning portion 224c by the guide portion 224b. Therefore, the setting work of the upstream guide member 271 can be easily performed.

  Further, the protrusion 271m of the upstream guide member 271 is formed so as to make point contact with the side wall of the positioning portion 224c in a state where the protrusion 271m is engaged with the positioning portion 224c at the lower end of the groove portion 224.

  According to this configuration, even when the upstream guide member 271 is tilted during the setting operation of the upstream guide member 271, it is difficult to cause a twist due to contact between the protrusion 271m and the side wall of the groove 224. Therefore, the setting work of the upstream guide member 271 can be further facilitated.

  The image forming apparatus 1 in the embodiment includes the document feeding device 221. Accordingly, since the accuracy of reading the original image by the contact image sensor 211 is improved, the original image can be reproduced and printed on the paper P with high accuracy by the image forming unit 20.

<< Other embodiments >>
In the above embodiment, the contact image sensor 211 is provided inside the document conveyance path 225. However, the present invention is not limited to this. For example, the contact image sensor 211 may be provided both inside and outside the document conveyance path 225. .

  In the above embodiment, the contact glass 274 is fixed to the contact surface 271b by the detachable fixing member 275. However, the present invention is not limited to this, and the contact glass 274 is fixed to the contact surface 271b by an adhesive or the like. You may make it fix to.

  In the above embodiment, the contact surface 271b is configured to position the contact glass 274 so that the document conveying surface 271d and the upper surface of the contact glass 274 are flush with each other. Not a thing. That is, the contact surface 271b may be configured to position the contact glass 274 such that the document transport surface 271d is higher or lower than the upper surface of the contact glass 274d by a predetermined height.

  In the above embodiment, an example in which the image forming apparatus 1 is a printer has been described. However, the present invention is not limited to this, and the image forming apparatus 1 may be, for example, a facsimile machine, a copier, and a multifunction machine.

  As described above, the present invention is useful for an image reading apparatus and an image forming apparatus including the image reading apparatus.

Claims (9)

A document feed mechanism that transports a document placed on a paper feed tray along a predetermined document transport path and discharges it to a paper discharge tray, and is disposed along the predetermined document transport path to form the document transport path A guide member, a contact image sensor that is arranged on a side of the predetermined document conveyance path and reads an image of a document that passes through the predetermined document conveyance path, and a transparent glass plate that covers the document conveyance path side in the contact image sensor An image reading apparatus comprising:
The guide member accommodates the contact image sensor therein and is formed in a concave portion covered with the transparent glass plate and a peripheral portion on an open side of the concave portion, and comes into contact with the peripheral portion of the transparent glass plate. An image reading apparatus comprising: a positioning surface for positioning the transparent glass plate so that a surface of the transparent glass plate on the side of the document conveyance path is at a predetermined height with respect to the document conveyance surface of the guide member. The image reading apparatus according to claim 1.
The image reading apparatus, wherein the predetermined height is a height such that a surface on the document conveying side of the transparent glass plate is flush with a document conveying surface of the guide member. The image reading apparatus according to claim 1.
An image reading apparatus, further comprising a biasing member that biases the contact image sensor so that the contact image sensor is in close contact with the transparent glass plate. The image reading apparatus according to claim 1.
An image reading apparatus further comprising a detachable fixing member that presses and fixes the transparent glass plate against the positioning surface formed on the guide member. The image reading apparatus according to claim 1,
A pair of side wall portions arranged opposite to each other across the document conveyance path in the width direction of the document,
Positioning portions for positioning the guide member by engaging with engaging portions respectively formed at both ends of the guide member in the document width direction are formed on the opposing surfaces of the side wall portion. Image reading device. The image reading apparatus according to claim 5.
The guide member is set from above between the pair of side wall portions,
The engaging portions are a pair of protrusions that protrude from both ends of the guide member in the document width direction,
Grooves that extend in the vertical direction and receive the protrusions from above are formed on the opposing surfaces of the pair of side wall portions,
The image reading apparatus, wherein a lower end portion of the groove portion functions as the positioning portion that positions the guide member by engaging with the protrusion. The image reading apparatus according to claim 6.
An image reading apparatus in which a guide portion whose groove width becomes narrower toward the lower side is formed in a portion adjacent to the upper side of the positioning portion in the groove portion. The image reading apparatus according to claim 7.
The image reading device, wherein the protrusion is formed so as to make point contact with the side wall of the groove in a state where the protrusion is engaged with the positioning portion at the lower end of the groove.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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