Image reading device and image forming apparatus

Abstract

To prevent a situation where the pressing force of a pressing unit reduces the thickness of a conveyance area.SOLUTION: An image reading device comprises: a reading unit (110) that has a holder member (115) and a cover member (116) attached to the holder member; a guide part (123) that is arranged opposite to a transparent member (111) and forms a document conveyance area (AS); a first abutting part and a second abutting part (125A, 125B) that are arranged outside the conveyance area in a main scanning direction (Y); and pressing parts (118A, 118B) that press the reading unit against the guide part through the first abutting part and the second abutting part. The holder member has first contact parts (115a, 115b) and second contact parts (115c, 115d) that are in contact with the cover member, and the first contact parts and the second contact parts are arranged at positions outside the first abutting parts and the second abutting parts in the main scanning direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an image reading device that reads an image on a document, and an image forming apparatus. [Background technology]

[0002] For example, some image forming apparatuses, such as multifunction peripherals, are equipped with an image reading device (image reading unit) that reads images on documents (see Patent Document 1). The image reading unit in Patent Document 1 includes a CIS (30) that reads images on the front side of documents through an ADF glass (23), and a back CIS unit (710) that includes a CIS (31) that reads images on the back side of documents. The back CIS unit (710) secures a document transport area between the glass (705) and the guide unit (702) by abutting a positioning protrusion (711d) against the guide unit (702). A spring (715) provided between the back CIS unit (710) and the frame (8) presses the positioning protrusion (711d) against the guide unit (702). That is, the spring (715) determines the thickness of the document transport area, i.e., the distance between the back CIS unit (710) and the guide unit (702), at a fixed position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-102390 Summary of the Invention [Problem to be solved by the invention]

[0004] The rear CIS unit 710 includes a case member 711 that is made up of a lower case 711b and an upper case 711a and that houses the CIS 31. The spring 715 presses the upper case 711a, thereby pressing the rear CIS unit 710. However, there is a risk that the entire case member 711 will bend when pressed by the spring 715. If the case member 711 bends, the glass 705 will also bend, narrowing the thickness of the transport area and potentially causing document jams.

[0005] 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 can prevent the thickness of the transport area from becoming narrower due to the pressure of the pressure section. [Means for solving the problem]

[0006] One aspect of the present invention is a reading unit including a transparent member, a reading unit that reads an image through the transparent member, a holder member that houses the reading unit and supports the transparent member on one side, and a cover member that is attached to the holder member on the opposite side of the one side; a guide portion that is disposed opposite the transparent member to form a transport area for a document; a first abutment portion and a second abutment portion that are disposed between the guide portion and the transparent member and outside the transport area in a main scanning direction of the reading unit, with the transport area sandwiched therebetween; and a pressing portion that presses the cover member to press the reading unit against the guide portion via the first abutment portion and the second abutment portion, wherein the holder member has a first abutment portion and a second abutment portion that abut against the cover member, and each of the first abutment portion and the second abutment portion is positioned in a position in the main scanning direction where it at least partially overlaps with the first abutment portion and the second abutment portion, or at a position outside the first abutment portion and the second abutment portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent the thickness of the transport area from being narrowed due to the pressure of the pressing portion. [Brief explanation of the drawings]

[0008] [Figure 1] 1A is a schematic diagram illustrating the overall printer according to the present embodiment, and FIG. 1B is a schematic diagram illustrating an image forming engine. [Figure 2] FIG. 2 is a cross-sectional view showing a back side reading unit and a conveyance guide according to the first embodiment. [Figure 3] 4 is a cross-sectional view showing a back side reading unit and a conveyance guide in a state where a CIS according to the first embodiment is removed. FIG. [Figure 4] FIG. 2 is an exploded perspective view showing a CIS holder and a holder cover according to the first embodiment. [Figure 5] 10 is a schematic diagram showing a state in which the CIS unit according to the first embodiment is pressed against a first abutment portion and a second abutment portion by a pressing portion. FIG. [Figure 6] 10 is a schematic diagram showing a state in which a CIS unit according to a second embodiment is pressed against a first abutment portion and a second abutment portion by a pressing portion. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment [Schematic configuration of image forming device] The first embodiment will be described below with reference to the drawings. First, the schematic configuration of a printer 100 as an image forming apparatus according to the first embodiment will be described with reference to Figs. 1(a) and 1(b). Fig. 1(a) is a schematic overall view showing the printer according to this embodiment. Fig. 1(b) is a schematic view showing an image forming engine.

[0010] The printer 100 according to the first embodiment is an electrophotographic laser beam printer. As shown in Fig. 1(a), the printer 100 includes a printer main body 70 and an image reading device 10 attached to the top of the printer main body 70. In the following, the term "sheet" refers to plain paper as well as special paper such as cardboard and coated paper, recording materials in special shapes such as envelopes and index paper, and plastic film or cloth for overhead projectors, and a manuscript is also an example of a sheet.

[0011] The printer main body 70 has an image forming engine 60 therein as an image forming section. As shown in FIG. 1(b), the image forming engine 60 includes an image forming unit PU as an electrophotographic image forming means and a fixing device 67. When a command to start an image forming operation is received, a photosensitive drum 61, which is a photosensitive member, rotates, and the drum surface is uniformly charged by a charging device 62. Then, an exposure device 63 modulates and outputs laser light based on image data transmitted from an image reading device 10 as an image reading means or an external computer, and scans the surface of the photosensitive drum 61 to form an electrostatic latent image. This electrostatic latent image is visualized (developed) into a toner image by toner supplied from a developing device 64.

[0012] In parallel with this image forming operation, a feeding operation is performed to feed sheets loaded on a cassette or manual feed tray (not shown) toward the image forming engine 60. The fed sheets are transported in accordance with the progress of the image forming operation by the image forming unit PU. The toner image carried on the photosensitive drum 61 is then transferred onto the sheet by a transfer roller 65. Any toner remaining on the photosensitive drum 61 after the toner image has been transferred is collected by a cleaning device 66. The sheet onto which the unfixed toner image has been transferred is passed to a fixing device 67, where it is sandwiched between a pair of rollers and heated and pressurized. The sheet onto which the toner has melted and adhered to the sheet and the image has been fixed is discharged by a discharge means such as a pair of discharge rollers.

[0013] [Image reader] Next, the image reading device 10 will be described in detail. As shown in FIG. 1(a), the image reading device 10 includes an ADF (automatic document feeder) 20 that feeds documents loaded on a document tray 121 and discharges them onto a discharge tray 122, and an image reading unit 40 that reads the documents transported by the ADF 20. That is, the ADF 20 transports sheets as documents to the image reading unit 40. The image reading unit 40 has a front surface reading unit 210 that reads an image on the front surface of the document. The ADF 20 is rotatably supported relative to the image reading unit 40 by a hinge mechanism (not shown) so that a platen glass 202 and a document table glass (not shown), which are light-transmitting members, can be opened. Note that the document, which is an example of a sheet, may be blank paper or may have an image formed on one or both sides. 1(a), direction X is the left-right direction of the image reading device 10 and is the sub-scanning direction of a CIS 213 (described later), and direction Z1 is the up-down direction of the image reading device 10. Direction Z2 is more specifically the up-down direction of a back surface reading unit 110 (described later), that is, a direction perpendicular to a reading glass 111 (described later).

[0014] The image reading unit 40 has a platen glass 202 and a front surface reading unit 210 that reads the first surface (front surface) of the sheet through the platen glass 202. The front surface reading unit 210 also has an illumination 211 that irradiates the sheet with light, and a CIS 213 that reads the reflected light of the light irradiated onto the sheet by the illumination 211 via a plurality of mirrors 212.

[0015] Meanwhile, the ADF 20 has a conveying section 109 that conveys the document to a conveying path AS (conveying area) described below, and includes a pickup roller 101, a separation roller pair 102, a registration roller pair 103, conveying roller pairs 104 and 105, and a discharge roller pair 106. The ADF 20 also has a back side reading unit 110 that reads an image on the back side of the document by a CIS 112 through a reading glass 111. The detailed configuration of this back side reading unit 110 will be described later.

[0016] The image reading device 10 can read images from documents in a flow reading mode in which the document images are scanned while the documents loaded on the document tray 121 are fed by the ADF 20, and in a fixed reading mode in which the document placed on a document glass platen (not shown) is scanned. The flow reading mode is selected when a document presence / absence detection sensor (not shown) detects the documents loaded on the document tray 121, or when the user explicitly instructs it via an operation panel or the like of the printer main body 70.

[0017] When the flow reading mode is executed, the pickup roller 101 is driven to rotate and starts feeding the topmost document set on the document tray 121. The documents fed by the pickup roller 101 are separated one by one by the separation roller pair 102 and transported. The leading edge of the transported document hits the registration roller pair 103, which is in a stopped state, and the skew of the document is corrected. The document whose skew has been corrected is transported by the registration roller pair 103, and is transported by the transport roller pair 104 so as to pass over the surface of the platen glass 202, and then is transported so as to pass through the reading position of the back surface reading unit 110.

[0018] An image on the front side of the document is read by the front side reading unit 210 via the platen glass 202, and an image on the back side of the document is read by the back side reading unit 110. Image information photoelectrically converted by the CISs 213 and 112 of the front side reading unit 210 and back side reading unit 110 is transferred to the control unit 80 (see FIG. 1(a)). Then, the document passes through the platen glass 202, is transported by the transport roller pair 105, and passes through the back side reading unit 110, and is discharged onto the discharge tray 122 by the discharge roller pair 106.

[0019] On the other hand, the fixed reading mode is selected when the device detects a document placed on a not-shown document glass or when the user explicitly instructs this via an operation panel or the like of the printer main body 70. In this case, the document on the not-shown document glass does not move, and the front surface reading unit 210 moves along the document glass in direction X to scan the document. Similarly, image information photoelectrically converted by the CIS 213 of the front surface reading unit 210 is transferred to the control unit 80 (see FIG. 1(a)).

[0020] [Back side reading unit configuration] Next, the detailed configuration of the back surface reading unit 110 will be described with reference to Figures 2, 3, and 4. Figure 2 is a cross-sectional view showing the back surface reading unit and transport guide according to the first embodiment. Figure 3 is a cross-sectional view showing the back surface reading unit and transport guide with the CIS removed according to the first embodiment. Figure 4 is an exploded perspective view showing the CIS holder and holder cover according to the first embodiment.

[0021] As shown in FIG. 2, the back surface reading unit 110 is roughly configured to include a reading glass 111 as a transparent member, a CIS 112 as a reading unit, a CIS holder 115 as a holder member, and a holder cover 116 as a cover member. As shown in FIGS. 2 and 4, an opening 115f is formed in a bottom surface 115S, which is one surface of the CIS holder 115, and the reading glass 111 is fitted into the opening 115f. The CIS holder 115 has a side wall 111e extending from the bottom surface 115S to the opposite side from the bottom surface 115S, and is formed in a box shape with an open top. The CIS 112 is disposed facing the reading glass 111 and is housed in the CIS holder 115, surrounded by the side wall 111e. A holder cover 116 is attached and fixed above the side wall 111e of the CIS holder 115. The holder cover 116 has a top plate 116e formed to cover the CIS 112 when attached to the CIS holder 115. The CIS 112 is biased against the reading glass 111 with a slight load by a biasing member (not shown) arranged between the CIS 112 and the top plate 116e.

[0022] Between the back surface reading unit 110 and a frame (not shown) of the image reading device 10, a pressing portion 118A as a first pressing portion and a pressing portion 118B as a second pressing portion are arranged so as to press the top surface 116S of the top plate portion 116e. Each of the pressing portions 118A, 118B is configured to have a spring 118s and a case 118a that covers the spring 118s and abuts against one end of the spring 118s. In addition, the top plate portion 116e of the holder cover 116 is formed with pressure receiving portions 116g, 116g against which the other ends of the springs 118s of the pressing portions 118A, 118B abut. The positions of these pressing portions 118A and 118B, i.e., the positions of the pressure receiving portions 116g and 116g, are arranged inside the contact surfaces 115a, 115b, 115c, and 115d (described later) in the main scanning direction Y of the CIS 112. As a result, the pressing portions 118A and 118B are configured to press the holder cover 116 against a frame (not shown) of the image reading device 10, and to press the reading glass 111 against abutment portions 125A and 125B (described later) via the CIS holder 115.

[0023] The main scanning direction Y is the front-to-back direction perpendicular to the left-to-right direction (direction X) and the up-to-down direction (direction Z2) of the image reading device 10, and is the width direction of the original (sheet). In the following description, the inside or outside of the main scanning direction Y refers to the inside or outside of a reference member when viewed from direction Z2 perpendicular to the main scanning direction Y.

[0024] Below the back surface reading unit 110, a transport guide 123 is disposed opposite the reading glass 111. A guide member 124, which serves as a white plate facing the reading glass 111, is disposed on the upper surface of the transport guide 123. Abutment portion 125A as a first abutment portion and abutment portion 125B as a second abutment portion are disposed and fixed at both ends of the guide member 124 in the main scanning direction Y of the CIS 112, protruding from the surface of the guide member 124 toward the reading glass 111. That is, the reading glass 111 of the back surface reading unit 110 pressed by the pressing portions 118A and 118B abuts against the abutment portions 125A and 125B. As a result, a gap is formed between the reading glass 111 and the guide member 124 of the transport guide 123 due to the thickness of the abutment portions 125A and 125B. In other words, this gap forms a transport path AS, which is a transport area through which the document is transported. In the first embodiment, the abutment portions 125A and 125B are fixed to the guide member 124, but the present invention is not limited to this and they may be fixed to the back-side reading unit 110.

[0025] [CIS holder and holder cover contact area] Next, the contact portion between the CIS holder 115 and the holder cover 116 will be described with reference to Figure 4. As shown in Figure 4, the CIS holder 115 has a side wall portion 115e formed on four sides so as to surround the CIS 112 (see Figure 2). Four contact surfaces 115a, 115b, 115c, and 115d are formed on the upper part of the side wall portion 115e so as to protrude upward more than the other portions. These contact surfaces 115a, 115b, 115c, and 115d are configured to contact the four corresponding contact surfaces 116a, 116b, 116c, and 116d on the holder cover 116 when the holder cover 116 is attached to the CIS holder 115. In this embodiment, the contact surfaces 115a and 115b form a first contact portion, and the contact surfaces 115c and 115d form a second contact portion.

[0026] Of these, the contact surfaces 115a and 115b and the contact surfaces 116a and 116b that contact them are disposed on one side (the left side in FIG. 4) of the center of the holder cover 116 (or the center of the CIS holder 115) in the main scanning direction Y of the CIS 112. Furthermore, the contact surfaces 115c and 115d and the contact surfaces 116c and 116d that contact them are disposed on the other side (the right side in FIG. 4) of the center of the holder cover 116 (or the center of the CIS holder 115) in the main scanning direction Y of the CIS 112. This results in a structure in which gaps (clearances) are formed in areas other than the contact portions between the contact surfaces 115a, 115b, 115c, and 115d and the contact surfaces 116a, 116b, 116c, and 116d of the CIS holder 115 and the holder cover 116. Therefore, when pressed by the pressing portions 118A and 118B, the top plate portion 116e of the holder cover 116 is bent at a position closer to the center in the main scanning direction Y than the four contact surfaces 116a, 116b, 116c, and 116d. However, even if the top plate portion 116e is bent, it is configured not to come into contact with the CIS holder 115 at any position other than the contact surfaces 116a, 116b, 116c, and 116d. In the first embodiment, the contact portions between the contact surfaces 115a, 115b, 115c, and 115d and the contact surfaces 116a, 116b, 116c, and 116d are located outside the abutment portions 125A and 125B in the main scanning direction Y (see FIG. 5). That is, when viewed from a direction Z2 intersecting the main scanning direction Y, the contact portions between the contact surfaces 115a, 115b, 115c, and 115d and the contact surfaces 116a, 116b, 116c, and 116d are shifted so as not to overlap with the abutment portions 125A and 125B.

[0027] [Transmission of pressure by the pressing part] Next, the transmission of pressing force when pressed by pressing portions 118A and 118B in the back side reading unit 110 configured as above will be described with reference to Fig. 5. Fig. 5 is a schematic diagram showing a state in which the CIS unit according to the first embodiment is pressed against the first abutment portion and the second abutment portion by the pressing portions.

[0028] As shown in FIG. 5, the holder cover 116 receives a load P1 at two points downward relative to a frame (not shown) by pressing portions 118A and 118B. Then, a load P2 is applied from the holder cover 116 to the CIS holder 115 at the contact portions between the contact surfaces 115a-115d of the CIS holder 115 and the contact surfaces 116a-116d of the holder cover 116. Here, the contact surfaces 115a-115d and the contact surfaces 116a-116d have a width d in the main scanning direction, but the point of application of the load P1 acting on the holder cover 116 is closer to the center in the main scanning direction than these contact portions. Therefore, the top plate portion 116e of the holder cover 116 bends downward as shown by the dashed line in FIG. 5, and the point of application of the load P2 becomes a position at the end portion closer to the center within the width d.

[0029] Meanwhile, the reading glass 111, located on the underside of the CIS holder 115, is supported from below by abutment portions 125A and 125B fixed to the transport guide 123, generating an upward load P3. Here, the combined body of the CIS holder 115 and the reading glass 111 is subjected to internal forces of loads P2 and P3, as shown in FIG. 5. However, the points of application of these loads P2 and P3 are not the same in the main scanning direction; the point of application of load P2 is located at an outer position in the main scanning direction. Therefore, a bending moment is generated in the reading glass 111, bending the center of the reading glass 111 upward in the main scanning direction, as shown by the dashed line in FIG. 5. This prevents the thickness of the transport path AS (transport area), which is the gap between the reading glass 111 and the transport guide 123, from narrowing due to the deflection of the reading glass 111. Therefore, excessive resistance to transport is not generated in the document during transport, resulting in good transportability and reduced paper jams. Furthermore, since the document transport speed does not fluctuate due to excessive transport resistance, the image quality of the image read by the CIS 112 can be improved in terms of geometric characteristics, color shift, and the like.

[0030] Second Embodiment Next, a second embodiment, which is a partial modification of the first embodiment, will be described with reference to Fig. 6. Fig. 6 is a schematic diagram showing a state in which a CIS unit according to the second embodiment is pressed against a first abutment portion and a second abutment portion by a pressing portion. 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.

[0031] In the first embodiment, the contact surfaces 115a-115d and the contact surfaces 116a-116d were disposed outside the abutment portions 125A and 125B in the main scanning direction of the CIS 112. In contrast, in the second embodiment, as shown in FIG. 6, the contact surfaces 115a-115d and the contact surfaces 116a-116d are disposed so as to overlap with the abutment portions 125A and 125B in the main scanning direction. That is, the contact surfaces 115a-115b and the abutment surfaces 116a-116b are disposed so as to at least partially overlap with the abutment portion 125A in the main scanning direction. Similarly, the contact surfaces 115c-115d and the abutment surfaces 116c-116d are disposed so as to at least partially overlap with the abutment portion 125B in the main scanning direction.

[0032] In the back-side scanning unit 110 according to the second embodiment configured as described above, the directions of the loads P2 and P3 are aligned substantially in a straight line, and no bending moment is generated in the composite body of the CIS holder 115 and the reading glass 111. Therefore, the reading glass 111 is hardly deflected by the loads applied by the pressing portions 118A and 118B. As a result, the thickness of the conveying path AS, which is the gap between the reading glass 111 and the conveying guide 123, is substantially uniform throughout the main scanning direction, ensuring good conveyance performance and reducing the occurrence of paper jams. Furthermore, since unevenness in the document conveying speed due to excessive conveying resistance does not occur, the image quality of the image read by the CIS 112, including geometric characteristics and color shifts, can be improved.

[0033] <Possibilities for other embodiments> While the image reading device 10 according to the first and second embodiments described above has been described as including two pressing portions 118A and 118B, the present invention is not limited to this, and the number of pressing portions may be one, or three or more. In other words, the number of pressing portions may be any number as long as at least one of the pressing portions is disposed inside the contact surfaces 115a and 115b and the contact surfaces 116a and 116b in the main scanning direction Y.

[0034] In the first and second embodiments, the CIS holder 115 has been described as having two contact surfaces 115a and 115b as the first contact portion where the CIS holder 115 contacts the holder cover 116, and two contact surfaces 115c and 115d as the second contact portion. However, the present invention is not limited to this, and the number of contact points in the first contact portion and the second contact portion may be any number as long as it is at least one.

[0035] Furthermore, in the first and second embodiments, the back side reading unit 110 has been described as an example of a reading unit pressed by a pressing portion, but the present invention is not limited to this, and a reading unit that reads the front side of a document may also be used.

[0036] Furthermore, in the first and second embodiments, the image reading device 10 is described as being provided in the printer 100, but this is not limited to this, and any device that reads an image of a document, such as a scanner device or an inspection device, may be used. [Explanation of symbols]

[0037] 10...image reading device / 60...image forming engine (image forming section) / 100...printer (image forming device) / 109...conveying section / 110...rear surface reading unit (reading unit) / 111...reading glass (transparent member) / 112...CIS (reading section) / 115...CIS holder (holder member) / 115a...contact surface (first contact section) / 115b...contact surface (first contact section) / 115c...contact Contact surface (second contact portion) / 115d...contact surface (second contact portion) / 115e...side wall portion / 116...holder cover (cover member) / 118A...pressing portion (first pressing portion) / 118B...pressing portion (second pressing portion) / 123...conveying guide (guide portion) / 125A...butting portion (first butting portion) / 125B...butting portion (second butting portion) / AS...conveying path (conveying area) / Y...main scanning direction

Claims

1. a reading unit including a transparent member, a reading section that reads an image through the transparent member, a holder member that houses the reading section and supports the transparent member on one side, and a cover member that is attached to the holder member on the side opposite to the one side; a guide portion disposed opposite the transparent member and forming a document transport area; a first abutment portion and a second abutment portion disposed between the guide portion and the transparent member and outside the transport region in the main scanning direction of the reading unit, the first abutment portion and a second abutment portion disposed across the transport region; a pressing portion that presses the cover member to press the reading unit against the guide portion via the first abutment portion and the second abutment portion, the holder member has a first contact portion and a second contact portion that contact the cover member, the first contact portion and the second contact portion are disposed at positions at which they at least partially overlap with the first abutting portion and the second abutting portion, respectively, in the main scanning direction, or at positions outside the first abutting portion and the second abutting portion, An image reading device characterized by:

2. the pressing portion is disposed at a position more inward than the first contact portion and the second contact portion in the main scanning direction.

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

3. the pressing portion is a first pressing portion, a second pressing portion that presses the cover member to press the reading unit against the guide portion via the first abutting portion and the second abutting portion; the first pressing portion and the second pressing portion are disposed at positions more inward than the first contact portion and the second contact portion in the main scanning direction, 3. The image reading device according to claim 2, wherein:

4. the first contact portion and the second contact portion are disposed at positions at which they at least partially overlap with the first abutting portion and the second abutting portion in the main scanning direction, respectively; 2. The image reading device according to claim 1, wherein:

5. the first contact portion and the second contact portion are disposed at positions outside the first abutting portion and the second abutting portion in the main scanning direction, respectively; 2. The image reading device according to claim 1, wherein:

6. The holder member is a side wall portion extending from the one surface to the opposite side to the one surface and formed so as to surround the reading unit; the first contact portion and the second contact portion are formed so as to protrude from the side wall portion toward an opposite side to the one surface, 2. The image reading device according to claim 1, wherein:

7. a transport unit that transports the document toward the transport area; 2. The image reading device according to claim 1, wherein:

8. An image reading device according to any one of claims 1 to 7; an image forming unit that forms an image on a sheet, An image forming apparatus characterized by:

Images