Image reading device and image forming apparatus

Abstract

To provide an image reading device and an image forming apparatus that, when a document feeding unit is opened at less than a predetermined angle, can prevent a document from protruding from a document reading surface, and when the document feeding unit is opened at the predetermined angle or more, allow the document to be taken out from the document reading surface.SOLUTION: An image reading device 100 comprises a document reading surface 1, a document feeding unit 2, and a document holding mechanism 3. The document reading surface 1 reads an image of a document D. The document feeding unit 2 is openable and closable relative to the document reading surface 1. The document holding mechanism 3 can hold the document D placed on the document reading surface 1. When the document feeding unit 2 is opened at less than a predetermined angle relative to the document reading surface 1, the document holding mechanism 3 holds the document D, and when the document feeding unit is opened at the predetermined angle or more relative to the document reading surface, releases the holding of the document D.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image reading device and an image forming device. [Background technology]

[0002] The image reading device described in Patent Document 1 includes a restricting member that restricts the movement of the document, thereby preventing the document placed on the document reading surface from shifting out of position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-137437 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the image reading device of Patent Document 1, the restricting member is provided on a cover member that opens and closes with respect to the document reading surface. Therefore, when the cover member is opened to cover the document reading surface, the document placed on the document reading surface does not come into contact with the restricting member, and there is a risk that the document may jump out of the document reading surface.

[0005] Therefore, in the image reading device of Patent Document 1, it is conceivable to hold the document placed on the document reading surface so that it does not pop out. However, it is not easy for a user to remove the document that is being held.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an image reading device and an image forming device that can prevent the document from popping out from the document reading surface if the opening is less than a specified amount, and can put the document into a state where it can be removed from the document reading surface if the opening is greater than a specified amount. [Means for solving the problem]

[0007] According to a first aspect of the present invention, an image reading device includes an original reading surface, an original feeding unit, and an original holding mechanism. The original reading surface reads an image of an original. The original feeding unit is openable and closable relative to the original reading surface. The original holding mechanism can hold an original placed on the original reading surface. The original holding mechanism holds the original when the opening of the original feeding unit relative to the original reading surface is less than a predetermined opening, and releases the holding of the original when the opening is equal to or greater than the predetermined opening.

[0008] According to a second aspect of the present invention, an image forming apparatus includes an image reading device and an image forming section. The image reading device is as described in the first aspect. The image forming section forms an image on a recording medium. Effect of the Invention

[0009] According to the image reading device and image forming device of the present invention, if the opening is less than a predetermined amount, the document can be prevented from popping out from the document reading surface, and if the opening is greater than a predetermined amount, the document can be removed from the document reading surface. [Brief description of the drawings]

[0010] [Figure 1] 2 is a perspective view of the image reading device in a state where a document feed unit is opened less than a predetermined angle relative to a document reading surface. FIG. [Diagram 2] 2 is a perspective view of the image reading device in a state where a document feed unit is opened to a predetermined extent or more with respect to a document reading surface. FIG. [Diagram 3] 5 is an enlarged cross-sectional view illustrating the periphery of a rotary holding claw in the document holding mechanism, showing the holding posture. FIG. [Figure 4] FIG. 4 is a perspective view of FIG. [Diagram 5] 11 is an enlarged cross-sectional view illustrating the periphery of a rotary holding claw in the document holding mechanism, showing the release position. FIG. [Figure 6] FIG. 6 is a perspective view of FIG. [Figure 7] 11 is an enlarged cross-sectional view illustrating the periphery of a rotary holding claw in the document holding mechanism, showing a fully released position. FIG. [Figure 8] FIG. 8 is a perspective view of FIG. [Figure 9]11 is a perspective view illustrating a document holding mechanism in which a plurality of rotating holding claws are arranged, showing a holding posture. FIG. [Figure 10] 11 is a perspective view illustrating a document holding mechanism in which a plurality of rotating holding claws are arranged, showing a fully released position. FIG. [Figure 11] 1 is a plan view of an original holding mechanism in which a plurality of rotating holding claws are arranged vertically and horizontally, showing a holding posture. [Figure 12] 1 is a plan view of a document holding mechanism having a plurality of rotating holding claws arranged vertically and horizontally, showing a release position. FIG. [Figure 13] 2 is a perspective view of an image forming apparatus including the image reading device of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description will not be repeated. In addition, even if the terms "upper" or "lower" meaning a specific position and direction are used in the following description, these terms are used for convenience to facilitate understanding of the contents of the embodiment, and are not related to the directions in which the embodiment is actually implemented. <Embodiment>

[0012] The image reading device 100 and image forming device 200 according to this embodiment will be described below. First, the image reading device 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a perspective view of the image reading device 100 in a state in which the document feed unit 2 is opened less than a predetermined amount relative to the document reading surface 1. Fig. 2 is a perspective view of the image reading device 100 in a state in which the document feed unit 2 is opened more than a predetermined amount relative to the document reading surface 1.

[0013] The image reading device 100 is, for example, a multifunction device having a scanner function. In addition to the scanner function, the multifunction device has a copy function, a printer function, a fax receiving function, a fax sending function, a finisher function, and an optional paper feeding function. The image reading device 100 only needs to have the scanner function, and does not need to have other functions.

[0014] 1 and 2, the image reading device 100 includes a document reading surface 1, a document feeding section 2, and a document holding mechanism 3. The document reading surface 1 reads an image of a document D. The document feeding section 2 can be opened and closed relative to the document reading surface 1.

[0015] The document holding mechanism 3 can hold a document D placed on the document reading surface 1. The document holding mechanism 3 holds the document D when the opening of the document feeding section 2 relative to the document reading surface 1 (hereinafter, sometimes simply referred to as the opening) is less than a predetermined amount (see FIG. 1). The document holding mechanism 3 releases the hold on the document D when the opening is equal to or greater than the predetermined amount (see FIG. 2).

[0016] 1, if the opening is less than a predetermined amount, the document D placed on the document reading surface 1 remains held by the document holding mechanism 3. As a result, if the opening is less than a predetermined amount, the image reading device 100 can prevent the document D from popping out of the document reading surface 1 even if the document feeding unit 2 is opened or closed relative to the document reading surface 1. Also, as shown in FIG. 2, the image reading device 100 can be set in a state in which the document D can be removed from the document reading surface 1 if the opening is equal to or greater than a predetermined amount.

[0017] The image reading device 100 and the document holding mechanism 3 will be described in detail below with reference to FIGS.

[0018] 1 and 2, the document reading surface 1 constitutes the upper surface of the image scanner unit 10. The image scanner unit 10 is a portion that reads an image of a document D. The document reading surface 1 is constituted by, for example, a platen glass.

[0019] The state in which the document feeding unit 2 is closed relative to the document reading surface 1 means that the document reading surface 1 and the lower surface 20 of the document feeding unit 2 face each other in parallel. Hereinafter, the angle formed between the document reading surface 1 and the lower surface 20 of the document feeding unit 2 may be referred to as the opening angle θ. When the document feeding unit 2 is closed relative to the document reading surface 1, the opening angle θ is 0°.

[0020] The predetermined opening is an arbitrary angle where the opening angle θ is more than 0° and not more than 90°. The predetermined opening is preferably an arbitrary angle where the opening angle θ is more than 30° and not more than 60°, and most preferably the opening angle θ is 45°. When the predetermined opening is the preferable opening angle θ, the document D is held when the user opens and closes with the intention of not removing the document D, and the holding of the document D is released when the user opens and closes with the intention of removing the document D.

[0021] The document feeder 2 includes an automatic document transport mechanism (not shown) called an ADF (Automatic Document Feeder). While transporting the document D, the ADF reads an image of the document D on the document reading surface 1, and then discharges the document D from the document feeder 2.

[0022] 1 and 2, the document holding mechanism 3 includes a rotating holding claw 4 and a switching unit 6. The rotating holding claw 4 is rotatable about an axis 5 along the document reading surface 1. The switching unit 6 switches the posture of the rotating holding claw 4.

[0023] The rotating holding claw 4 can be switched, by rotation, between a holding position (see FIG. 1) in which the original D is sandwiched between the original reading surface 1 and the rotating holding claw 4, and a release position (see FIG. 2) in which the original D is not sandwiched between the original reading surface 1 and the rotating holding claw 4. The switching unit 6 switches the rotating holding claw 4 between the holding position and the release position.

[0024] Therefore, the document D is held and released by the rotation of the rotary holding claw 4 by the switching unit 6. As a result, the image reading device 100 can simplify the configuration of the document holding mechanism 3.

[0025] The document holding mechanism 3 further includes a cover 11. The cover 11 covers the switching unit 6. The cover 11 has a slit 12 at a position where the rotation holding claw 4 is disposed. The rotation holding claw 4 has a base end 41 close to the rotation axis 5 and a tip end 42 far from the rotation axis 5. The base end 41 is located inside the slit 12. The tip end 42 protrudes from the slit 12 towards the document reading surface 1. In the holding position, the tip end 42 holds the document D by sandwiching it between the document reading surface 1 and the document. In the release position, the tip end 42 releases the holding of the document D by not sandwiching the document D between the document reading surface 1 and the document.

[0026] The document holding mechanism 3 will be described in further detail below with reference to Figs. 3 to 8. Fig. 3 is an enlarged cross-sectional view illustrating the periphery of the rotary holding claw 4 in the document holding mechanism 3, showing the holding posture. Fig. 4 is a perspective view of Fig. 3. Fig. 5 is an enlarged cross-sectional view illustrating the periphery of the rotary holding claw 4 in the document holding mechanism 3, showing the released posture. Fig. 6 is a perspective view of Fig. 5. Fig. 7 is an enlarged cross-sectional view illustrating the periphery of the rotary holding claw 4 in the document holding mechanism 3, showing the fully released posture. Fig. 8 is a perspective view of Fig. 7.

[0027] 3 to 8, the document holding mechanism 3 further includes a biasing section 7. The biasing section 7 biases the rotating holding claw 4 in a direction in which the rotating holding claw 4 rotates from the holding position to the release position.

[0028] The switching unit 6 restricts the urging when the opening of the document feed unit 2 relative to the document reading surface 1 is less than a predetermined amount (see Figs. 3 and 4). When the opening of the document feed unit 2 relative to the document reading surface 1 is equal to or greater than a predetermined amount, the switching unit 6 allows the urging (see Figs. 5 to 8).

[0029] Therefore, the document D is held and released by restricting and allowing the urging by the urging unit 7. As a result, the image reading device 100 can simplify the configuration of the document holding mechanism 3.

[0030] As shown in FIG. 3, the switching unit 6 further includes a rotating shaft 60 , a rotating arm body 61 , and a variable width belt 62 .

[0031] The rotating shaft 60 can rotate around an axis 5 along the document reading surface 1. The rotating shaft 60 is a shaft body connected to the rotating holding claw 4. The rotating arm body 61 is connected to the rotating shaft 60. The rotating arm body 61 rotates around the axis 5 along the document reading surface 1, thereby rotating the rotating holding claw 4 in conjunction with the rotating shaft 60. The rotating arm body 61 extends in a direction away from the document reading surface 1. A variable width belt 62 can receive the rotating arm body 61.

[0032] The biasing portion 7 is, for example, a torsion spring. The biasing portion 7, which is a torsion spring, has a bent end portion 71 and a coil portion 72. The bent end portion 71 contacts the bottom surface of the case. The coil portion 72 is provided on the rotating shaft 60. The biasing portion 7, which is a torsion spring, biases the rotating shaft 60 to rotate. The direction in which the rotating shaft 60 is biased is the direction in which the rotating holding claw 4 is changed from the holding position to the release position, i.e., the direction in which the rotating arm body 61 is pressed against the variable width belt 62.

[0033] 4, the variable width belt 62 changes its width in a direction perpendicular to the axis 5 in a direction along the axis 5 of rotation. Specifically, the variable width belt 62 has a narrow portion 63 and a switching wide portion 64.

[0034] The switching wide portion 64 has a widened portion 65 and a maximum constant width portion 66. The widened portion 65 is continuous with the narrow portion 63 and gradually becomes wider from the narrow portion 63. The maximum constant width portion 66 is continuous with the widest part of the widened portion 65 and has a constant width. When the opening is less than a predetermined amount, the rotating arm body 61 is supported by the maximum constant width portion 66 of the switching wide portion 64. When the rotating arm body 61 is supported by the maximum constant width portion 66, the biasing force is restricted by the maximum constant width portion 66, and the rotating holding claw 4 does not rotate from the holding position. Therefore, the rotating holding claw 4 is in the holding position.

[0035] 5 and 6, as the opening increases, the variable width belt 62 moves in the direction of the rotation axis 5. When the opening reaches a predetermined position, the rotating arm body 61 is received by the widened portion 65 which is narrower than the maximum fixed width portion 66. When the rotating arm body 61 is received by the widened portion 65, biasing is partially permitted at the widened portion 65, and the rotating support claw 4 has partially rotated from the support position. Therefore, the rotating support claw 4 is in the released position.

[0036] While the rotating arm body 61 is received by the widened portion 65, as the opening becomes larger, the rotating arm body 61 is received by a narrower portion of the widened portion 65. Therefore, while the rotating arm body 61 is received by the widened portion 65, as the opening becomes larger, the distance between the tip 42 of the rotating support claw 4 and the document reading surface 1 becomes wider.

[0037] 7 and 8, as the opening becomes wider, the variable width belt 62 moves further in the direction of the rotation axis 5. When the opening sufficiently exceeds a predetermined value, the rotating arm body 61 is received by the narrow width portion 63. When the rotating arm body 61 is received by the narrow width portion 63, the narrow width portion 63 is sufficiently permitted to apply bias, and the rotating holding claw 4 has sufficiently rotated from the holding position. Therefore, the rotating holding claw 4 is in a fully released position. In the fully released position, the angle between the tip 42 of the rotating holding claw 4 and the document reading surface 1 is greater than 65° and equal to or less than 75° (for example, 70°).

[0038] The document holding mechanism 3 will be described in more detail below with reference to Figures 9 and 10. Figure 9 is a perspective view of the document holding mechanism 3 in which multiple rotating holding claws 4 are arranged, showing the holding posture. Figure 10 is a perspective view of the document holding mechanism 3 in which multiple rotating holding claws 4 are arranged, showing the fully released posture.

[0039] 9 and 10, the document holding mechanism 3 has a plurality of rotating holding claws 4. The switching unit 6 switches the postures of the plurality of rotating holding claws 4 simultaneously.

[0040] Therefore, if the opening is less than the predetermined amount, the document D placed on the document reading surface 1 remains held at multiple positions. As a result, if the opening is less than the predetermined amount, the image reading device 100 can sufficiently prevent the document D from popping out from the document reading surface 1 even if the document feeding unit 2 is opened or closed relative to the document reading surface 1.

[0041] The multiple rotational hold claws 4 are disposed at equal intervals in the direction of the shaft 5. The multiple rotational hold claws 4 are connected to the rotating shaft 60 in the same posture. When the rotating arm body 61 rotates around the shaft 5, the multiple rotational hold claws 4 rotate simultaneously in conjunction with the rotating shaft 60. Therefore, the multiple rotational hold claws 4 are simultaneously switched between the holding posture (see FIG. 9) and the release posture (see FIG. 10) by rotation.

[0042] The document holding mechanism 3 will be described in more detail below with reference to Figures 11 and 12. Figure 11 is a plan view of the document holding mechanism 3 in which multiple rotating holding claws 4 are arranged vertically and horizontally, showing the holding position. Figure 12 is a plan view of the document holding mechanism 3 in which multiple rotating holding claws 4 are arranged vertically and horizontally, showing the released position.

[0043] 11 and 12, the document holding mechanism 3 has a vertical claw group 4A and a horizontal claw group 4B. The vertical claw group 4A is made up of a plurality of rotating holding claws 4 arranged vertically on the document reading surface 1. The horizontal claw group 4B is made up of a plurality of rotating holding claws 4 arranged horizontally on the document reading surface 1.

[0044] Therefore, the document D is held and released vertically and horizontally by the vertical claw group 4A and the horizontal claw group 4B. As a result, the image reading device 100 can hold and release the document D sufficiently.

[0045] The document holding mechanism 3 has a plurality of switching units 6. The plurality of switching units 6 has a vertical switching unit 6A and a horizontal switching unit 6B.

[0046] The vertical switching unit 6A simultaneously switches the postures of the multiple rotation support claws 4 that make up the vertical claw group 4A. The horizontal switching unit 6B simultaneously switches the postures of the multiple rotation support claws 4 that make up the horizontal claw group 4B.

[0047] Therefore, if the opening is less than the predetermined amount, the document D placed on the document reading surface 1 remains held at multiple positions both vertically and horizontally. As a result, if the opening is less than the predetermined amount, the image reading device 100 can sufficiently prevent the document D from jumping out of the document reading surface 1 even if the document feeding unit 2 is opened or closed relative to the document reading surface 1.

[0048] The document holding mechanism 3 further has a gear 8. The gear 8 rotates in association with the opening and closing of the document feeding section 2 relative to the document reading surface 1. The gear 8 moves the vertical switching section 6A in the vertical direction as it rotates in association with the opening and closing. The vertical switching section 6A moves the horizontal switching section 6B in the horizontal direction as it moves in the vertical direction. The vertical switching section 6A and the horizontal switching section 6B simultaneously switch the posture of the rotating holding claw 4 as they move.

[0049] Therefore, the gear 8 and the vertical switching portion 6A and the horizontal switching portion 6B simultaneously switch the postures of the rotating holding claws 4 that constitute the vertical claw group 4A and the horizontal claw group 4B. As a result, the image reading device 100 can simplify the configuration of the document holding mechanism 3.

[0050] The vertical direction is the longitudinal direction of the variable width belt 62 at the vertical switching portion 6A, and the horizontal direction is the longitudinal direction of the variable width belt 62 at the horizontal switching portion 6B.

[0051] The variable width belt 62 of the vertical switching unit 6A further has a rack portion 68 and a wide sliding portion 69. The rack portion 68 meshes with the gear 8. The rack portion 68 moves vertically together with the variable width belt 62 of the vertical switching unit 6A as the gear 8 rotates. The wide sliding portion 69 moves vertically to slide the variable width belt 62 of the horizontal switching unit 6B horizontally.

[0052] The switching wide portion 64 of the variable width belt 62 at the vertical switching portion 6A and the switching wide portion 64 of the variable width belt 62 at the horizontal switching portion 6B have the same shape. The positional relationship between the switching wide portion 64 and the rotating arm body 61 at the vertical switching portion 6A is the same as the positional relationship between the switching wide portion 64 and the rotating arm body 61 at the horizontal switching portion 6B.

[0053] Therefore, when the gear 8 rotates as the opening becomes larger, the rack portion 68 that meshes with the gear 8 moves vertically together with the variable width belt 62 of the vertical switching unit 6A. As the variable width belt 62 of the vertical switching unit 6A moves vertically, the rotating arm body 61 of the vertical switching unit 6A changes from a state in which it was received by the maximum fixed width portion 66 of the vertical switching unit 6A to a state in which it is received by the widened portion 65 or narrowed width portion 63 of the vertical switching unit 6A. As a result, the vertical switching unit 6A changes from a state in which it restricted the urging force from the urging unit 7 to a state in which it allows it. As a result, all the rotating holding claws 4 that constitute the vertical claw group 4A change from the holding position to the released position.

[0054] On the other hand, as the variable width belt 62 of the vertical switching part 6A moves vertically, the variable width belt 62 of the horizontal switching part 6B moves horizontally by the sliding wide part 69. As the variable width belt 62 of the horizontal switching part 6B moves horizontally, the rotating arm body 61 of the horizontal switching part 6B changes from a state in which it was received by the maximum constant width part 66 of the horizontal switching part 6B to a state in which it is received by the widened part 65 or narrowed part 63 of the horizontal switching part 6B. As a result, the horizontal switching part 6B changes from a state in which it restricted the urging from the urging part 7 to a state in which it allows it. As a result, all the rotating holding claws 4 that constitute the horizontal claw group 4B change from the holding position to the release position.

[0055] As a result, the postures of all of the rotation holding claws 4 that constitute the vertical claw group 4A and the horizontal claw group 4B can be switched simultaneously with a simple configuration. As a result, the image reading device 100 can simplify the configuration of the document holding mechanism 3.

[0056] The above describes the switch from the holding posture to the released posture as the opening increases from less than a predetermined value to more than a predetermined value. The reverse of the above-described flow is the switch from the released posture to the holding posture as the opening decreases from more than a predetermined value to less than a predetermined value. In other words, as the opening decreases from more than a predetermined value to less than a predetermined value, the rotating arm body 61 goes from being supported by the narrow width portion 63 and the wide width portion 65 to being supported by the maximum fixed width portion 66. Therefore, the state in which the force from the biasing portion 7 was permitted goes to a state in which the force is restricted. As a result, the rotating holding claw 4 switches from the released posture to the holding posture.

[0057] The switching unit 6 further has a compression spring 67. The compression spring 67 biases the variable width belt 62 of the horizontal switching unit 6B in the horizontal direction toward the vertical switching unit 6A. By biasing the variable width belt 62 of the horizontal switching unit 6B in the horizontal direction toward the vertical switching unit 6A, all of the rotation holding claws 4 constituting the horizontal claw group 4B smoothly switch from the release position to the holding position when the opening is changed from a predetermined opening amount to less than a predetermined opening amount.

[0058] Next, an image forming apparatus 200 according to this embodiment will be described with reference to Fig. 13. Fig. 13 is a perspective view of the image forming apparatus 200 including the image reading device 100 of Fig. 1.

[0059] As shown in Fig. 13, the image forming apparatus 200 includes the image reading device 100 and an image forming unit 220. The image forming unit 220 forms an image on a recording medium M. The image forming unit 220 includes, for example, a photosensitive drum, a charging device, an exposure device, a developing device, a replenishing device, a transfer roller, a cleaning device, and a charge removing device. Note that the image forming unit 220 is not limited to an electrophotographic type. The image forming unit 220 may be an inkjet type.

[0060] Therefore, by including the image reading device 100, the image forming device 200 achieves the effects of the image reading device 100. Specifically, if the opening is less than a predetermined amount, the document D placed on the document reading surface 1 remains held by the document holding mechanism 3. As a result, if the opening is less than a predetermined amount, the image forming device 200 can prevent the document D from popping out of the document reading surface 1 even if the document feeding unit 2 is opened and closed relative to the document reading surface 1. Also, if the opening is equal to or greater than the predetermined amount, the image forming device 200 can set the document D to a state in which it can be removed from the document reading surface 1.

[0061] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the spirit of the present invention. The drawings are mainly schematic illustrations of each component for ease of understanding, and the thickness, length, number, spacing, etc. of each component shown in the drawings are different from the actual ones due to the convenience of drawing. In addition, the speed, material, shape, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited, and various changes are possible within a range that does not substantially deviate from the configuration of the present invention. [Industrial Applicability]

[0062] The present invention provides an image reading device and an image forming device, and has industrial applicability. [Explanation of symbols]

[0063] 1: Document reading side 2: Document feed section 3: Original holding mechanism 4: Rotation support claw 4A: Vertical claws 4B:Horizontal claw group 5: Axis 6: Switching section 6A: Vertical switching section 6B: Lateral switching section 7: Pressurizing section 8: Gear 100: Image reader 200: Image forming device 220: Image forming unit D: Manuscript M: Recording medium

Claims

1. a document reading surface for reading an image of a document; a document feed section that can be opened and closed relative to the document reading surface; a document holding mechanism capable of holding a document placed on the document reading surface; Equipped with The document holding mechanism holds the document when an opening of the document feed section with respect to the document reading surface is less than a predetermined opening, and releases the document from the holding when the opening is equal to or greater than the predetermined opening.

2. The document holding mechanism includes: a rotation holding claw that is rotatable about an axis along the document reading surface; A switching unit that switches the posture of the rotation holding claw; having the rotating holding claw is switchable between a holding position in which the original is sandwiched between the rotating holding claw and the original reading surface and a release position in which the original is not sandwiched between the rotating holding claw and the original reading surface, 2. The image reading device according to claim 1, wherein the switching unit switches the rotation holding claw between the holding position and the release position.

3. the document holding mechanism further includes a biasing portion that biases the rotary holding claw in a direction in which the rotary holding claw rotates from the holding position to the release position, 3. The image reading device according to claim 2, wherein the switching section restricts the urging when the opening of the document feed section with respect to the document reading surface is less than the predetermined value, and allows the urging when the opening is equal to or greater than the predetermined value.

4. the document holding mechanism has a plurality of the rotary holding claws, 4. The image reading device according to claim 2, wherein the switching section simultaneously switches the postures of a plurality of the rotation holding claws.

5. The document holding mechanism includes: a vertical claw group including a plurality of the rotation support claws arranged in a vertical direction on the document reading surface; a horizontal claw group consisting of a plurality of the rotation support claws arranged in a horizontal direction on the document reading surface; The image reading device according to claim 4 .

6. the document holding mechanism has a plurality of the switching units, The plurality of switching sections include vertical switching sections and horizontal switching sections, The vertical switching unit simultaneously switches the postures of the plurality of rotation support claws that constitute the vertical claw group, The image reading device according to claim 5 , wherein the lateral switching section simultaneously switches the postures of the plurality of rotation support claws that constitute the lateral claw group.

7. the document holding mechanism further includes a gear that rotates in association with opening and closing of the document feed unit relative to the document reading surface, The gear moves the vertical switching portion in the vertical direction by rotating in association with the opening and closing, the vertical switching portion moves the horizontal switching portion in the horizontal direction by moving in the vertical direction, 7. The image reading device according to claim 6, wherein the vertical switching portion and the horizontal switching portion simultaneously switch the orientation of the rotation holding claw by moving respectively.

8. An image reading device according to any one of claims 1 to 7, an image forming unit for forming an image on a recording medium; An image forming apparatus comprising:

Images