Image reading device and image forming apparatus

Abstract

To reduce the positional deviation between a light guide member and a support member.SOLUTION: An image reading device comprises: a light guide unit that has a light guide member (314); a reading section that reads an image of a document; and a support member (313) having a support section that has the light guide unit bonded thereto to support the light guide member; a first facing section (313W1) that is arranged facing a first end (314E1) of the light guide member in a longitudinal direction, and a second facing section that is arranged facing a second end on the opposite side of the first end of the light guide member in the longitudinal direction. One of the first end and the first facing section has a first projection (314P1) that projects in the longitudinal direction, and the other of the first end and the first facing section has a first regulation section (313C1) into which the first projection is inserted. One of the second end and the second facing section has a second projection that projects in the longitudinal direction, and the other of the second end and the second facing section has a second regulation section into which the second projection is inserted.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an image reading device and an image forming apparatus in which a light guide member is supported by a support member. [Background technology]

[0002] Generally, image reading devices installed in image forming apparatuses and the like are equipped with an illumination device in which multiple LEDs are arranged in a line to illuminate a document when reading the document image. When multiple LEDs are used as light sources, a transparent light-guiding member made of resin or the like is provided between the document surface and the LEDs to prevent unevenness in the illuminance distribution on the document surface in the LED array direction. This light-guiding member guides the circularly diffused light emitted from the multiple LEDs toward the document surface along the main scanning direction (LED array direction) when reading the document.

[0003] However, if there is variation in the position or posture of the LED and the light-guiding member, the illumination position on the document surface may deviate from the designed position, which may result in a blurred read image due to an insufficient amount of light or a blurred read image due to variations in the optical path length. For this reason, a device has been proposed that enables highly accurate positioning of the light-guiding member and the support member by abutting and bonding abutting surfaces provided on both longitudinal ends of the light-guiding member to abutting surfaces of the support member (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-149778 Summary of the Invention [Problem to be solved by the invention]

[0005] Light guide members made of resin materials, for example, are generally produced by injection molding, but residual stress may occur in the parts depending on the molding conditions of the molding machine (holding pressure, material injection speed, etc.) In addition, depending on the molding conditions, so-called warping may occur, in which the part bends in a direction perpendicular to the longitudinal direction, and such warped parts may need to be corrected before being assembled to the support member.

[0006] However, these residual stresses and corrected warpage may be released, for example, when the temperature environment in which the image reading device is actually used or the storage temperature during transportation is high. That is, depending on the magnitude of the residual stress in the light-guiding member or the force attempting to restore the corrected warpage, the adhesive portion between the light-guiding member and the support member may peel off, causing the light-guiding member to become misaligned with respect to the support member. As a result, as described above, the light-guiding member may be positioned off-center relative to the support member, resulting in an insufficient amount of illumination light relative to the design value and possibly resulting in image degradation.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image reading device and an image forming device that are capable of reducing misalignment between a light guide member and a support member. [Means for solving the problem]

[0008] One aspect of the present invention is an image reading device comprising: a light guide unit having a substrate with a plurality of light sources arranged in a longitudinal direction and a light guide member that guides light emitted from the light sources to a document; a reading unit that reads an image of the document reflected from the light emitted from the light source through the light guide member; a support unit that supports the light guide member by adhering the light guide unit; and a support member having a first opposing portion arranged opposite a first end of the light guide member in the longitudinal direction and a second opposing portion arranged opposite a second end of the light guide member opposite the first end in the longitudinal direction, wherein one of the first end and the first opposing portion has a first protrusion protruding in the longitudinal direction, the other of the first end and the first opposing portion has a first regulating portion into which the first protrusion is inserted, one of the second end and the second opposing portion has a second protrusion protruding in the longitudinal direction, and the other of the second end and the second opposing portion has a second regulating portion into which the second protrusion is inserted. [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce the positional misalignment between the light guide member and the support member. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view illustrating an image forming apparatus according to a first embodiment. [Figure 2] 1 is an external perspective view showing an image reading device according to a first embodiment. [Figure 3] 1 is a cross-sectional view showing an image reading device according to a first embodiment. [Figure 4] FIG. 2 is an external perspective view showing the reading unit according to the first embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the front surface reading unit according to the first embodiment. [Figure 6] 1 is an external perspective view showing an illumination unit according to a first embodiment. [Figure 7]1A is an exploded perspective view of the light guide unit according to the first embodiment, FIG. 1B is a perspective view showing the back surface of the light guide according to the first embodiment, and FIG. 1C is an enlarged perspective view showing the back surface of the end portion of the light guide according to the first embodiment. [Figure 8] 1A is a top view showing the light guide stay according to the first embodiment, and FIG. 1B is an enlarged perspective view showing an end portion of the light guide stay according to the first embodiment. [Figure 9] 1A is a top view showing an end portion of the lighting unit according to the first embodiment, and FIG. 1B is a side view showing the lighting unit according to the first embodiment. [Figure 10] FIG. 3 is an explanatory diagram showing the warping direction of the light guide according to the first embodiment. [Figure 11] 10(a) is a top view showing an end portion of a lighting unit according to a second embodiment, and (b) is a side view showing the lighting unit according to the second embodiment. [Figure 12] FIG. 10 is a top view showing an end portion of the lighting unit according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment The first embodiment will be described below with reference to the drawings.

[0012] [Schematic configuration of image forming device] First, the general configuration of an image forming apparatus 100 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing the image forming apparatus according to the first embodiment.

[0013] As shown in Fig. 1, image forming apparatus 100 includes an image reading device 101 capable of reading an image of an original document, and an image forming apparatus main body 104 capable of forming an image read by image reading device 101 on a sheet P. Image reading device 101, which will be described in detail later, includes a reading unit 103 that reads an image of an original document, and an automatic document feeder (hereinafter referred to as "ADF") 102 that can automatically feed an original document to reading unit 103, and is disposed above image forming apparatus main body 104. Note that image forming apparatus 100 shown in Fig. 1 is an electrophotographic laser beam printer, but image reading device 101 of this embodiment can also be similarly applied to image forming apparatuses that use an inkjet system or other image forming methods as image forming means.

[0014] The image forming apparatus main body 104 roughly comprises a feeding section 104A that feeds a sheet P, an image forming section 104B that forms an image on the sheet P fed by the feeding section 104A, and a discharge section 104C that discharges the sheet P on which the image has been formed by the image forming section 104B.

[0015] The feeding unit 104A is configured to include cassettes 105, 105 that support and store a plurality of sheets P, and feeding rollers 106, 106 that pick up the sheets P from the cassettes 105, 105 and start feeding them. The sheets P fed by the feeding rollers 106 are fed toward a secondary transfer roller 116 of the image forming unit 104B.

[0016] Image forming section 104B is configured to include laser scanners 107, 108, 109, and 110, image forming units 111, 112, 113, and 114, an intermediate transfer belt 115, a secondary transfer roller 116, a pre-fixing conveying section 117, and a fixing section 118. Image forming unit 111 develops the electrostatic latent image exposed by laser scanner 107 as a yellow (Y) toner image and primarily transfers it to intermediate transfer belt 115. Similarly, image forming unit 112 develops the electrostatic latent image exposed by laser scanner 108 as a magenta (M) toner image and primarily transfers it to intermediate transfer belt 115. Similarly, image forming unit 113 develops the electrostatic latent image exposed by laser scanner 109 as a cyan (C) toner image and primarily transfers it to intermediate transfer belt 115. Similarly, the image forming unit 114 develops the electrostatic latent image exposed by the laser scanner 110 into a black (K) toner image and primarily transfers it onto the intermediate transfer belt 115. As a result, a full-color toner image is formed on the surface of the intermediate transfer belt 115.

[0017] The full-color toner image transferred onto the surface of intermediate transfer belt 115 is transported to secondary transfer roller 116, where it is secondarily transferred onto the surface of sheet P fed by feeding unit 104A. Sheet P onto which the toner image has been transferred is transported to fixing unit 118 by pre-fixing transport unit 117, which transports the sheet by a transport belt (not shown) or the like. Then, fixing unit 118 heats (and pressurizes) sheet P, thereby fixing the toner image to sheet P. Thereafter, sheet P onto which the toner image has been fixed is transported by discharge unit 104C and discharged to be stacked on discharge tray 119.

[0018] The configuration of the image forming apparatus main body 104 described above is one example, and various modifications are possible. For example, it may be equipped with a reversing unit that turns over the sheet to enable double-sided printing, a re-conveying path that re-conveys the sheet to the secondary transfer roller 116, etc. Also, it may be equipped with a device that transfers a toner image directly from the image forming unit to the sheet, or a device that forms a monochrome image. Furthermore, it may be equipped with a manual feed tray for manually feeding sheets.

[0019] [Image reader configuration] Next, the configuration of the image reading device 101 according to the first embodiment will be described with reference to Figs. 2, 3, and 4. Fig. 2 is an external perspective view showing the image reading device according to the first embodiment. Fig. 3 is a cross-sectional schematic view showing the image reading device according to the first embodiment. Fig. 4 is an external perspective view showing the image reading unit according to the first embodiment.

[0020] 2 and 3, image reading device 101, as described above, has reading unit 103 and ADF 102. As shown in Fig. 3, ADF 101 has document tray 200 on which documents D are placed, discharge tray 201 on which documents D, whose images have been read, are discharged and placed, and document transport section 210 that transports documents D from document tray 200 to discharge tray 201. Document transport section 210 has pickup roller 202 that abuts against the uppermost document D in document tray 200 and starts feeding the document D, and separation roller pair 203 that separates and transports documents D fed by pickup roller 202 one by one. Furthermore, the document transport unit 210 has a plurality of transport roller pairs 204a, 204b, 204c, 204d, 204e, and 204f that transport the document D transported from the separation roller pair 203, and a discharge roller pair 206 that discharges the document D onto the discharge tray 201. Of these transport roller pairs, a flow reading glass 303 for reading the front side of the document D, which will be described in detail later, is disposed between the transport roller pair 204d and the transport roller pair 204e in the transport direction of the document D. Furthermore, a back side reading unit 205 for reading the back side of the document D is disposed between the transport roller pair 204e and the transport roller pair 204f.

[0021] 3 and 4, the reading unit 103 has a flow reading glass 303 and a document table glass 302 on the top surface, and below that is provided a front surface reading section 301 as a reading section for reading the front surface of a document D. The front surface reading section 301 is supported by a guide shaft 304 so as to be movable in the sub-scanning direction of the front surface reading section 301, and is configured so that its movement in the sub-scanning direction can be controlled by a belt 305 driven by a drive motor (not shown). Note that below the document table glass 302 is provided a document detection sensor 306 that detects a document D when the document D is placed on it.

[0022] The image reading device 101 configured as described above can selectively operate in a fixed reading mode in which the image of the document placed on the document glass 302 is scanned and read, or in a flow reading mode in which the image of the document D is scanned and read while the document D is being fed by the ADF 102.

[0023] The flow reading mode is selected, for example, when a sensor (not shown) detects that an original D has been placed on the original tray 200 of the ADF 102, or when a user explicitly instructs this via an operation panel (not shown) or the like provided on the image forming apparatus 100. In this mode, the front side reading unit 301 is moved along the guide shaft 304 to a predetermined image reading position below the flow reading glass 303. The ADF 102 then transports the originals D placed on the original tray 200 one by one so that they pass through the flow reading glass 303 and read the image on the front side, and then transports them so that they pass through the back side reading unit 205 and read the image on the back side.

[0024] 3, the user places one or more originals D on the original tray 200 and then executes the flow-read mode. Then, the pickup roller 202 starts feeding the topmost original D from the originals D placed on the original tray 200. If multiple originals D are fed, they are separated one by one by the separation roller pair 203. The originals D are then transported by the transport roller pairs 204a, 204b, 204c, and 204d to the reading position of the front-side reading unit 301, where the image of the front side of the original D is read. Furthermore, the original D is transported by the transport roller pair 204e to the reading position of the back-side reading unit 205, where the image of the back side of the original D is read. The original D, whose image has been read, is then transported by the transport roller pair 204f to the discharge roller pair 206, where it is discharged onto the discharge tray 201.

[0025] The fixed reading mode is selected, for example, when the document detection sensor 306 detects that a document D has been placed on the document glass 302, or when the user explicitly instructs it via an operation panel (not shown) of the image forming apparatus 100.

[0026] In the fixed reading mode, first, the user opens the ADF 102 provided in the reading unit 103 so as to be able to open and close, places the original D at a predetermined position on the platen glass 302, and closes the ADF 102 to position the original D on the platen glass 302. At this time, the original detection sensor 306 detects the presence or absence and size of the original D. Then, while the front surface reading unit 301 moves in the sub-scanning direction along the platen glass 302 by a drive motor (not shown), the front surface reading unit 301 scans the original D placed on the platen glass 302 in the main scanning direction while irradiating it with light, and reads the image of the original D.

[0027] In this embodiment, the reading unit 103 is described as being provided with the back side reading unit 205, but is not necessarily limited to being provided with the back side reading unit 205. As another embodiment, the reading unit 103 may be provided with a reading unit for executing the skimming mode and a reading unit for executing the fixed reading mode separately.

[0028] [Configuration of the surface reading unit] Next, the configuration of the front surface reading unit 301 will be described with reference to Figures 5, 6, 7, 8, and 9. Figure 5 is a schematic cross-sectional view of the front surface reading unit according to the first embodiment. Figure 6 is an external perspective view showing the illumination unit according to the first embodiment. Figure 7(a) is an exploded perspective view of the light guide unit according to the first embodiment. Figure 7(b) is a perspective view showing the back surface of the light guide according to the first embodiment. Figure 7(c) is an enlarged perspective view showing the back surface of the end portion of the light guide according to the first embodiment. Figure 8(a) is a top view showing the light guide stay according to the first embodiment. Figure 8(b) is an enlarged perspective view showing the end portion of the light guide stay according to the first embodiment. Figure 9(a) is a top view showing the end portion of the illumination unit according to the first embodiment. Figure 9(b) is a side view showing the illumination unit according to the first embodiment.

[0029] 5, the front surface reading unit 301 has a box frame 307 and an illumination unit 308 attached to the upper part inside the box frame 307. The front surface reading unit 301 also has, inside the box frame 307 and below the illumination unit 308, folding mirrors 309a, 309b, 309c, 309d, and 309e, a lens unit 310, and a sensor board 311 as a reading unit.

[0030] The illumination unit 308 has light guide units 312L and 312R as two light guide units. Light L1 and L2 emitted from these light guide units 312L and 312R toward the original D are condensed at an illumination position F set on the surface (bottom surface) of the original D and reflected by the original D. Reflected light L3 reflected by the original D forms an image on a sensor element (not shown) of a sensor substrate 311 via mirrors 309a, 309b, 309c, 309d, and 309e and a lens unit 310. The sensor substrate 311 photoelectrically converts the image formed on the sensor element by the reflected light L3 and outputs an electrical signal corresponding to the image on the surface of the original D to a control unit (not shown).

[0031] 6, the illumination unit 308 includes a light guide stay 313 as a support member to which light guide units 312L and 312R are attached. The light guide units 312L and 312R have the same configuration and are arranged symmetrically in the sub-scanning direction. Since the configurations of the light guide units 312L and 312R and the method of attaching them to the light guide stay 313 are the same, the light guide unit 312R will be described below as an example, and a description of the light guide unit 312L will be omitted.

[0032] As shown in FIGS. 5, 6, and 7(a), the light guide unit 312R includes a light guide 314 as a light-guiding member and an LED substrate 316 as a substrate having a plurality of LEDs 315 as light sources. As shown in FIG. 7(a), the light guide 314 is provided with a plurality of (five) slots 314S1, 314S2, 314S3, 314S4, and 314S5 for holding the LED substrates 316. The LED substrate 316 includes a substrate portion 316B, a plurality of LEDs 315 as light sources mounted on the substrate portion 316B, and a connector portion 316C electrically connected to the plurality of LEDs 315. The plurality of LEDs 315 are mounted linearly in the longitudinal direction (x direction) on the substrate portion 316B, and receive power via electrical wiring (not shown) through the connector portion 316C. The area enclosed by the dashed line in Figure 7(a) is the insertion section 316Ba included in the substrate section 316B, and the insertion section 316Ba is inserted into the slots 314S1, 314S2, 314S3, 314S4, and 314S5 of the light guide 314. In this way, the LED substrate 316 is assembled to the light guide 314. In the following description, the main scanning direction of the front surface reading section 301 or the longitudinal direction of the light guide 314 is also referred to as the x-direction. The sub-scanning direction, which is the movement direction of the front surface reading section, or the lateral direction of the light guide 314 is also referred to as the y-direction. The up-down direction perpendicular to the x-direction and y-directions is also referred to as the z-direction.

[0033] 7(a) and 7(b), the light guide 314 has a flat plate portion 314A. The lower surface of the flat plate portion 314A serves as an incident surface 314Aa onto which light emitted from the plurality of LEDs 315 is incident, and the upper surface of the flat plate portion 314A serves as an exit surface 314Ab from which the incident light is emitted toward an illumination position F (see FIG. 3) on the document D. The light from the plurality of LEDs 315 that is incident on the incident surface 314Aa is reflected multiple times within the flat plate portion 314A, and then guided to the exit surface 314Ab and emitted.

[0034] The light guide 314 also has a first end 314E1 and a second end 314E2, which are opposite ends in the x-direction, which is the longitudinal direction. That is, the light guide 314 has the first end 314E1 at one end in the x-direction and the second end 314E2 on the opposite side to the first end 314E1. As shown in FIG. 7(b), the light guide 314 has contact surfaces 314b, 314b serving as a first contact surface and a second contact surface below the first end 314E1 and the second end 314E2 in the z-direction. These contact surfaces 314b, 314b are formed in an arc shape when viewed from the x-direction and come into contact with support surfaces 313a, 313a serving as a first support surface and a second support surface of the light guide stay 313, which will be described in detail later (see FIG. 8(b)). The light guide 314 also has an opposing surface 314c located below the slot portion 314S3 in the z direction, which is approximately the center in the x direction (i.e., the longitudinal direction), that faces a restricting surface 313f (see FIG. 8(a)) of the light guide stay 313, which will be described in detail later, via a gap. This opposing surface 314c is formed in a flat shape. The light guide 314 also has a positioning pin 314a that is formed in a rod shape extending downward below the slot portion 314S1, and that is inserted into an elongated hole portion 313b (see FIG. 8(b)) of the light guide stay 313, which will be described in detail later.

[0035] 6, 9(a), and 9(b), the light guide 314 has a first protrusion 314P1 and a second protrusion 314P2 each having an axis shape extending in the x direction from a first end 314E1 and a second end 314E2, respectively. The functions of the first protrusion 314P1 and the second protrusion 314P2 will be described in detail later.

[0036] On the other hand, as shown in Figures 8(a) and 8(b), the light guide stay 313 has support portions 313SL and 313SR formed in a flat shape to support the two light guide units 312L and 312R. The light guide stay 313 also has a wall portion 313W formed upright to surround the support portions 313SL and 313SR, with the support portions 313SL and 313SR forming the bottom surfaces. As described above, the light guide unit 312R is described as an example in this specification, and therefore the support portion 313SR will be described and a description of the support portion 313SL, which has the same configuration as the support portion 313SR, will be omitted. That is, the support portions 313SL and 313SR are formed symmetrically in the sub-scanning direction on the light guide stay 313 to mount the light guide units 312L and 312R. The light guide stay 313 has an opening 313AP formed between the support portions 313SL and 313SR to allow reflected light from the document D to pass into the box frame. The light guide stay 313 also has a positioning hole 313c formed therein, which is a through hole for positioning the light guide stay 313 relative to the upper part of the box frame 307 (see FIG. 5).

[0037] The support portion 313SR of the light guide stay 313 has support surfaces 313a, 313a consisting of two inclined surfaces formed in a V-shape when viewed from the x direction. The support surfaces 313a, 313a constitute a first support surface located at one end of the light guide stay 313 in the longitudinal direction, that is, the x direction, and a second support surface located at the other end on the opposite side. These support surfaces 313a, 313a abut against abutment surfaces 314b, 314b of the light guide 314, respectively, and support the light guide 314 while positioning it in the y direction. The support portion 313SR also has an elongated hole portion 313b into which the positioning pin 314a of the light guide 314 is inserted. 8(a), the support portion 313SR is provided with a positioning surface 313d as a third support surface, an adjustment hole 313e, and a restriction surface 313f, which are located approximately in the center in the x-direction (i.e., the longitudinal direction) between the support surfaces 313a. That is, when the light guide 314 is attached, an end face 314d as a third abutment surface of the light guide 314 abuts against the positioning surface 313d of the light guide stay 313, thereby restricting and positioning the position of the light guide 314 in the y-direction. A tool (not shown) is inserted into the adjustment hole 313e, and the position of the light guide 314 in the z-direction is adjusted when the light guide 314 is attached. The restriction surface 313f is arranged opposite the opposing surface 314c of the light guide 314 with a gap therebetween, and is configured to be able to abut against the opposing surface 314c when the adhesion between the light guide stay 313 and the light guide 314 peels off, as will be described in detail later.

[0038] The wall portion 313W of the light guide stay 313 has portions that are arranged opposite the first end portion 314E1 and the second end portion 314E2 of the light guide 314 in the x-direction, which is the longitudinal direction, and that form a first opposing portion W1 and a second opposing portion W2, respectively. As shown in FIGS. 6, 9(a), and 9(b), the first opposing portion W1 and the second opposing portion W2 are formed with a first restricting portion 313C1 and a second restricting portion 313C2 that are recessed in the z-direction, which intersects with the x-direction. That is, the first restricting portion 313C1 and the second restricting portion 313C2 are formed in a groove shape that is wider than the first protruding portion 314P1 and the second protruding portion 314P2. That is, when the light guide 314 is attached to the light guide stay 313, the first protruding portion 314P1 and the second protruding portion 314P2 are configured to fit into the first restricting portion 313C1 and the second restricting portion 313C2. 9(b), there are gaps dy, dy in the y direction between the first restricting portion 313C1 and the second restricting portion 313C2 and the first protruding portion 314P1 and the second protruding portion 314P2, respectively, and there is a gap dz in the z direction. That is, the first protruding portion 314P1 and the second protruding portion 314P2 are inserted into the first restricting portion 313C1 and the second restricting portion 313C2, respectively, with gaps therebetween.

[0039] [Assembly process of light guide to light guide stay] Next, the process of assembling the light guide 314 to the light guide stay 313 will be described. First, the insertion portion 316Ba of the LED substrate 316 is inserted a predetermined amount into the slots 314S1 to 314S5 of the light guide 314 to assemble the light guide units 312R and 312L (see FIG. 7(a)). Next, the light guide units 312R and 312L are attached to the light guide stay 313 (see FIG. 6). At this time, for positioning in the y direction, the arc-shaped abutment surfaces 314b, 314b at both ends of the light guide 314 are abutted against the V-shaped support surfaces 313a, 313a at both ends of the light guide stay 313 (see FIGS. 7(c) and 8(b)). Furthermore, for positioning in the x direction, the positioning pin 314a of the light guide 314 is fitted into the elongated hole 313b of the light guide stay 313 (see FIGS. 7(c) and 8(b)). At this time, the opposing surface 314c located approximately in the center of the longitudinal direction of the light guide 314 is arranged so as to have a gap with the restricting surface 313f arranged at the corresponding position of the light guide stay 313. Then, as shown in FIG. 9(b), the first protrusion 314P1 and the second protrusion 314P2 of the light guide 314 are arranged so as to face the first restricting portion 313C1 and the second restricting portion 313C2 of the light guide stay 313, and are arranged so as to have gaps dy, dy, dz.

[0040] Thereafter, UV adhesive is applied to the contact surfaces 314b, 314b of the light guides 314 of the light guide units 312R, 312L and the support surfaces 313a, 313a of the light guide stay 313, where they abut, to perform UV bonding. Furthermore, UV adhesive is applied to multiple locations (e.g., five locations) at predetermined intervals (e.g., 50 to 100 mm intervals) in the x direction in the gap between the LED substrates 316 of the light guide units 312R, 312L and the light guide stay 313, to perform UV bonding. This fixes and attaches the light guide units 312R, 312L (i.e., the respective light guides 314) to the light guide stay 313. Note that UV bonding is a bonding method in which a UV-curable resin used as an adhesive is cured by ultraviolet light. However, it is not limited to UV bonding; other fixing methods, such as bonding with an adhesive that does not use a UV-curable resin, crimping, heat bonding, or screw fastening, may also be used.

[0041] [Problems caused by warping of light guides] Here, we will explain the problems caused by warping of the light guide 314. Figure 10 is an explanatory diagram showing the warping direction of the light guide according to the first embodiment.

[0042] The light guide 314 is typically formed from a highly transparent resin material, such as acrylic or polycarbonate. As described above, the light guide 314 has a complex shape, including a shape for forming an optical path that reflects light from the incident surface 314Aa and a shape for positioning. Therefore, it is typically manufactured by injection molding using an injection molding machine. Injection molding is a method in which a resin material molten at high temperature is poured into a mold under pressure, cooled, and then removed from the mold to form a component. The manufactured light guide 314 component contains considerable variation in its shape due to tolerances, and may not be manufactured to the theoretical dimensions. The light guide 314 may not be able to accurately reproduce the shape that reflects light incident from the incident surface 314Aa toward the exit surface 314Ab or the fine details of the exit surface 314Ab. That is, if the light guide 314 is manufactured according to the theoretical dimensions and the shape dimensions are accurately reproduced down to the smallest detail, it is said to have good transferability, and if there is a lot of variation, it is said to have poor transferability. Generally, to obtain good transferability in injection molding, for example, setting the temperature of the mold or resin high, or increasing the pressure and speed when pouring the material into the mold tends to result in good transferability.

[0043] Furthermore, the light guide 314, which is a component extending in the longitudinal direction, may warp partially or entirely in the y or z direction. In other words, in a component that is elongated in one direction, such as the light guide 314, even a small amount of warping can vary greatly from location to location, significantly impacting product quality. Causes of warping include uneven cooling timing of heat accumulated during molding of the component and residual stress due to uneven material density within the component. To reduce warping, or residual stress, generally, it is beneficial to design the component so that it cools evenly throughout and to increase the pressure when pouring the material into the mold.

[0044] However, although this also depends on the shape of the light guide 314 as a component, generally there is a trade-off between good transferability and small warpage. Components that form an optical path, such as the light guide 314, are required to have good transferability of the fine shape, small warpage as a component, and the posture and position of the exit surface 314Ab when the light guide 314 is attached to the light guide stay 313 according to design values. For this reason, it is desirable for the light guide 314 attached to the light guide stay 313 to satisfy these contradictory requirements.

[0045] In the light guide 314 according to this embodiment, warping may occur in the direction of arrow W shown in Fig. 10. The light guide 314 is molded under molding conditions that prioritize transferability, and a certain amount of warping is tolerated. Therefore, when attaching the light guide units 312L and 312R to the light guide stay 313, the light guide 314 is attached by bonding while correcting the warping.

[0046] At this time, the light guide 314 and the light guide stay 313 are positioned in the y direction by abutment between abutment surfaces 314b, 314b of the light guide 314 and support surfaces 313a, 313a of the light guide stay 313. Furthermore, an opposing surface 314c disposed approximately at the center in the longitudinal direction of the light guide 314 and a restricting surface 313f disposed approximately at the center in the longitudinal direction of the light guide stay 313 are designed to have a gap between them. When warping occurs in the light guide 314, the opposing surface 314c and the restricting surface 313f come into contact with each other, thereby suppressing warping of the central portion of the light guide 314 to a predetermined amount, that is, it is possible to achieve an attached state in which the warped shape of the light guide 314 is corrected. In the initial state after the light guide 314 and the light guide stay 313 are attached, there are gaps dy, dy, dz between the first protrusion 314P1 and the second protrusion 314P2 and the first restricting portion 313C1 and the second restricting portion 313C2 (see Figure 9(b)).

[0047] The image forming apparatus 100 incorporating the image reading device 101 according to this embodiment may be used in a hot and humid environment. Furthermore, when the image reading device 101 is transported from the country where it was manufactured to the country where it will be used, it may be transported by sea, for example, by ship. Depending on the route taken by the ship, the image reading device 101 may be exposed to an even more severe hot and humid environment than the user's environment. When the image reading device 101 is exposed to such a high-temperature environment, residual stress generated during molding and installation of the light guide 314, a resin component, may gradually be released, causing deformation. This may result in the UV adhesive bonding the light guide 314 and LED substrate 316 to the light guide stay 313 peeling off due to deformation of the light guide 314. This peeling of the adhesive may change the position and orientation of the light guide 314 relative to the light guide stay 313, potentially preventing the image reading device 101 from achieving its designed performance and resulting in a deterioration in the quality of the scanned image. Therefore, in this embodiment, as described below, the objective is to keep the deformation of the light guide 314 below a certain amount even if the adhesion between the light guide stay 313 and the light guide 314 peels off due to deformation caused by the release of residual stress.

[0048] [Functions of the first protruding portion, the second protruding portion, and the first restricting portion and the second restricting portion] Next, the functions of the first protrusion 314P1 and second protrusion 314P2 of the light guide 314 and the first restricting portion 313C1 and second restricting portion 313C2 of the light guide stay 313 will be described. As described above, the light guides 314 of the light guide units 312L, 312R may be deformed, such as warped, if a portion of the adhesive peels off. Note that even if the adhesive between the light guide stay 313 and the light guide units 312R, 312L peels off in a portion where stress is concentrated due to deformation, it is unlikely that the entire adhesive will peel off, meaning that there is almost no possibility of the light guides falling off.

[0049] When a portion of the adhesive peels off in this manner, the gaps dy, dy, dz are formed between the first protrusion 314P1 and the second protrusion 314P2 and the first restricting portion 313C1 and the second restricting portion 313C2 as described above, but they move in the direction of deformation and come into contact. The contact position is then restricted. At this time, the opposing surface 314c of the light guide 314 may come into contact with the restricting surface 313f of the light guide stay 313 near the center in the x direction. In this case, warping of the central portion of the light guide 314 is also restricted at that position. This limits the amount of deformation of the light guide 314 to a certain amount or less, thereby reducing misalignment between the light guide 314 and the light guide stay 313. This makes it possible to reduce deterioration in the quality of images read by the image reading device 101.

[0050] Second Embodiment Next, a second embodiment, which is a partial modification of the first embodiment, will be described with reference to Fig. 11. Fig. 11(a) is a top view showing an end portion of a lighting unit according to the second embodiment. Fig. 11(b) is a side view showing a lighting unit according to the second embodiment. In the description of this second embodiment, the same reference numerals are used for parts similar to those in the first embodiment, and their description will be omitted.

[0051] In the front surface reading unit 301 of the image reading device 101 according to the second embodiment, the first protrusion 314P1 and the second protrusion 314P2 of the light guide 314 are bonded to the first restricting portion 313C1 and the second restricting portion 313C2 of the light guide stay 313. Specifically, similar to the first embodiment, the light guide units 31LR and 312R are bonded and fixed to the light guide stay 313. In this state, as shown in FIGS. 11(a) and 11(b), a first adhesive portion 320 is formed by applying a UV adhesive or the like between the first protrusion 314P1 and the second protrusion 314P2 and the first restricting portion 313C1 and the second restricting portion 313C2. In other words, the first adhesive portion 320 is formed by filling the gaps dy, dy, and dz shown in FIG. 9(b) with adhesive. Although not shown, a second adhesive portion is also formed between the second protruding portion 314P2 of the light guide 314 and the second restricting portion 313C2 of the light guide stay 313 in a similar manner.

[0052] That is, as described above, the light guide 314 of the light guide units 312L and 312R may be deformed, such as warped, if a portion of the adhesive peels off. However, the first protrusion 314P1 and the second protrusion 314P2 and the first restricting portion 313C1 and the second restricting portion 313C2 are positioned by the first adhesive portion 320 and the second adhesive portion, and are restricted at that position. This limits the amount of deformation of the light guide 314 to a certain amount or less, thereby reducing misalignment between the light guide 314 and the light guide stay 313. This makes it possible to reduce deterioration in the quality of images read by the image reading device 101.

[0053] It is unlikely that the first adhesive portion 320 or the second adhesive portion will peel off and fall off from the first protruding portion 314P1 and the second protruding portion 314P2, but it is possible that they may peel off from the first restricting portion 313C1 and the second restricting portion 313C2. However, because the adhesive portion 320 has hardened, the positioning of the first protruding portion 314P1 and the second protruding portion 314P2 and the first restricting portion 313C1 and the second restricting portion 313C2 is maintained.

[0054] Furthermore, if the first protrusion 314P1 and the first restricting portion 313C1 are shaped to fit together without a gap, and the second protrusion 314P2 and the second restricting portion 313C2 are shaped to fit together without a gap, there is a risk that assembly will not be satisfactory due to component tolerances. Therefore, even when bonding is performed at the first adhesive portion 320 and the second adhesive portion as in the second embodiment, it is preferable to provide a gap.

[0055] Third Embodiment Next, a third embodiment, which is a partial modification of the first embodiment, will be described with reference to Fig. 12. Fig. 12 is a top view showing an end portion of an illumination unit according to the third embodiment. In the description of the third embodiment, the same reference numerals are used for parts similar to those in the first embodiment, and their description will be omitted.

[0056] In the first embodiment, the light guide 314 is formed with a shaft-shaped first protrusion 314P1 and a second protrusion 314P2, and the light guide stay 313 is formed with a groove-shaped first restriction portion 313C1 and a second restriction portion 313C2. In the third embodiment, on the contrary, as shown in Fig. 12, the light guide stay 313 is formed with a shaft-shaped first protrusion 313P1, and the light guide 314 is formed with a groove-shaped first restriction portion 314C1.

[0057] In detail, a shaft-shaped first protrusion 313P1 is formed on the first opposing portion W1 of the wall portion 313W of the light guide stay 313 so as to protrude toward the light guide 314 in the x direction. Meanwhile, a groove-shaped first restriction portion 314C1 wider than the first protrusion 313P1 is formed on the first end portion 314E1 of the light guide 314 so as to be recessed in the z direction intersecting the x direction. Therefore, the first protrusion 313P1 and the first restriction portion 314C1 are disposed opposite each other with a gap formed between them. Although not shown, a second protrusion is also formed on the second opposing portion W2 of the light guide stay 313, and a second restriction portion is also formed on the second end portion 314E2 of the light guide 314.

[0058] Even in the third embodiment configured as described above, if the adhesive between the light guide stay 313 and the light guide units 312L and 312R is partially separated, the light guide 314 may be deformed. In this case, the first protrusion 313P1 and the first restricting portion 314C1 move in the direction of deformation and come into contact with each other, and are restricted at the contact position. Note that the second protrusion and the second restricting portion (not shown) also come into contact with each other and restrict the position of the light guide 314 when the light guide 314 is deformed. This limits the amount of deformation of the light guide 314 to a certain amount or less, thereby reducing misalignment between the light guide 314 and the light guide stay 313. This makes it possible to reduce deterioration in the quality of images read by the image reading device 101.

[0059] <Possibilities for other embodiments> In the first to third embodiments described above, the first protrusions 314P1, 313P1 and the second protrusions 314P2, 313P2 are described as having an axial shape. However, the present invention is not limited to this, and the first protrusions 314P1, 313P1, 314P2, 313P2 may have any shape, such as a cylindrical shape, a prismatic shape, a conical shape, or a plate shape, as long as they can contact or be bonded to the first restricting portion and the second restricting portion.

[0060] In the first to third embodiments, the first restricting portions 313C1, 314C1 and the second restricting portions 313C2, 314C2 have been described as having a groove shape. However, the present invention is not limited to this and the restricting portions may have any shape, such as an elongated hole, a slit, or a through hole, as long as they can come into contact with or be bonded to the first protruding portion or the second protruding portion.

[0061] In the first and second embodiments, the light guide 314 is formed with a first protrusion 314P1 and a second protrusion 314P2, and the light guide stay 313 is formed with a first restricting portion 313C1 and a second restricting portion 313C2. In the third embodiment, the light guide stay 313 is formed with a first protrusion 313P1 and a second protrusion, and the light guide 314 is formed with a first restricting portion 314C1 and a second restricting portion. That is, the light guide 314 is formed with two protrusions or two restricting portions, and the light guide stay 313 is formed with two restricting portions or two protrusions. However, the present invention is not limited to this, and the light guide 314 may be formed with one protrusion and one restricting portion, and the light guide stay 313 may be formed with one restricting portion and one protrusion. In other words, it is sufficient that one of the first end portion 314E1 and the first opposing portion 313W1 has a first protruding portion protruding in the longitudinal direction, and the other of the first end portion 314E1 and the first opposing portion 313W1 has a first restricting portion arranged opposite the first protruding portion on the support portion side. Also, it is sufficient that one of the second end portion 314E2 and the second opposing portion 313W2 has a second protruding portion protruding in the longitudinal direction, and the other of the second end portion 314E2 and the second opposing portion 313W2 has a second restricting portion arranged opposite the second protruding portion on the support portion side.

[0062] In the first to third embodiments, gaps are provided between the first protrusions 314P1, 313P1 and the second protrusions 314P2, 313P2 and the first restricting portions 313C1, 314C1 and the second restricting portions 313C2, 314C2. However, a press-fit type may be adopted without providing gaps therebetween. In short, it is sufficient that the position of the light guide 314, from which the adhesive has come off, is restricted and positioned relative to the light guide stay 313.

[0063] Furthermore, in the first to third embodiments, the front side reading unit 301 in which the light guide units 312L and 312R are bonded to the light guide stay 313 has been described as an example, but the back side reading unit 205 can also be configured in the same way.

[0064] Furthermore, in the first to third embodiments, the image reading device 101 is described as being provided in the image forming device 100, but this is not limited to this, and any image reading device that has a reading unit that reads images, such as a scanner device or an inspection device, may be used. [Explanation of symbols]

[0065] 100...image forming apparatus / 101...image reading device / 104A...image forming unit / 311...reading unit (sensor board) / 312L...light guide unit (light guide unit) / 312R...light guide unit (light guide unit) / 313...light guide stay (support member) / 313C1...first restricting portion / 313C2...second restricting portion / 313P1...first protruding portion / 313P2...second protruding portion / 313SR...supporting portion / 313SL...supporting portion / 313W1...first opposing portion / 313W2...second opposing portion / 13a...support surface (first support surface, second support surface) / 313d...positioning surface (third support surface) / 314...light guide (light guiding member) / 314C1...first restricting portion / 314C2...second restricting portion / 314E1...first end portion / 314E2...second end portion / 314P1...first protruding portion / 314P2...second protruding portion / 314b...contact surface (first contact surface, second contact surface) / 314d...end surface (third contact surface) / 315...LED (light source) / 316...LED substrate (substrate) / 320...first adhesive portion / dy...gap / dz...gap

Claims

1. a light guide unit including a substrate having a plurality of light sources arranged in a line in the longitudinal direction and a light guide member that guides light emitted from the light sources to a document; a reading unit that reads an image of an original document reflected by light irradiated from the light source through the light guide member; a support member including: a support portion that supports the light guide member by bonding the light guide unit; a first opposing portion that is disposed opposite a first end portion of the light guide member in the longitudinal direction; and a second opposing portion that is disposed opposite a second end portion of the light guide member opposite the first end portion in the longitudinal direction, one of the first end portion and the first opposing portion has a first protruding portion protruding in the longitudinal direction, the other of the first end portion and the first opposing portion has a first restricting portion into which the first protruding portion is inserted, one of the second end portion and the second opposing portion has a second protruding portion protruding in the longitudinal direction, the other of the second end portion and the second opposing portion has a second restricting portion into which the second protruding portion is inserted; An image reading device characterized by:

2. the first protruding portion is disposed with a gap from the first restricting portion, the second protruding portion is disposed with a gap from the second restricting portion, when the adhesion between the light guide member and the support portion of the support member is separated, at least one of the first protrusion and the first restricting portion and the second protrusion and the second restricting portion can come into contact with each other.

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

3. the first protrusion and the second protrusion have an axial shape extending in the longitudinal direction, the first restricting portion and the second restricting portion have a groove shape that is recessed in a direction intersecting the longitudinal direction and is wider than the shaft shape, the shaft shape of the first protrusion is arranged to be inserted into the groove shape of the first restriction portion, The shaft shape of the second protrusion is arranged to be inserted into the groove shape of the second restriction portion.

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

4. the first protrusion is formed on the first end, the first restricting portion is formed on the first opposing portion, the second protrusion is formed on the second end, The second restricting portion is formed on the second opposing portion.

4. The image reading device according to claim 3, wherein:

5. the first protruding portion is formed on the first opposing portion, The first restricting portion is formed on the first end portion, the second protruding portion is formed on the second opposing portion, The second restricting portion is formed on the second end portion.

4. The image reading device according to claim 3, wherein:

6. a first adhesive portion that adheres the first protruding portion and the first restricting portion; a second adhesive portion that adheres the second protruding portion and the second restricting portion to each other, 2. The image reading device according to claim 1, wherein:

7. the first protrusion and the second protrusion have an axial shape extending in the longitudinal direction, the first restricting portion and the second restricting portion have a groove shape that is recessed in a direction intersecting the longitudinal direction and is wider than the shaft shape, the shaft shape of the first protrusion is arranged to be inserted into the groove shape of the first restriction portion, The shaft shape of the second protrusion is arranged to be inserted into the groove shape of the second restriction portion.

7. The image reading device according to claim 6, wherein:

8. the support portion has a first support surface disposed at one end in the longitudinal direction, a second support surface disposed at the other end opposite to the one end in the longitudinal direction, and a third support surface disposed between the first support surface and the second support surface in the longitudinal direction, The light guide unit has a first abutment surface that is supported by being in contact with the first support surface when adhered to the support portion, a second abutment surface that is supported by being in contact with the second support surface, and a third abutment surface that is supported by being in contact with the third support surface.

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

9. An image reading device according to any one of claims 1 to 8; an image forming unit that forms an image on a sheet, An image forming apparatus characterized by:

Images