Paper feeding device and image processing device

Abstract

A paper feeding device and an image processing device, the paper feeding device of an embodiment has a paper feeding roller and a separation roller that line up in a line-up direction and clamp a sheet. The paper feeding device has the paper feeding roller, the separation roller, a shaft, a holding member, and a rotation-stopping portion. The paper feeding roller conveys the sheet in a conveying direction. The separation roller pushes against the paper feeding roller. The shaft rotatably supports the separation roller through a torque limiter. The holding member has a support portion. On the support portion, a first guide surface and a second guide surface that oppose each other and extend along the line-up direction are provided. The rotation-stopping portion is attached to the shaft. The rotation-stopping portion is inserted between the first guide surface and the second guide surface. The rotation-stopping portion has a first sliding surface and a second sliding surface. The first sliding surface opposes the first guide surface on the paper feeding roller side in the line-up direction and on the downstream side in the conveying direction with respect to the rotation axis of the separation roller. The second sliding surface opposes the second guide surface on the opposite side of the paper feeding roller in the line-up direction and on the upstream side in the conveying direction with respect to the rotation axis of the separation roller.

Description

Technical Field

[0001] This embodiment generally relates to a paper feeding device and an image processing device. Background Technology

[0002] A paper feeding device is known in the past, comprising: a feeding roller for conveying sheets; and a separating roller for applying a load to the conveyed sheets. The separating roller separates overlapping sheets.

[0003] The separating roller is slidably supported by the feed roller in a state of pushing against it. When the sliding resistance of the sliding part increases, the pushing force of the separating roller against the feed roller becomes insufficient. In the paper feeding device, it is necessary to suppress the sliding resistance of the sliding part supporting the separating roller. Summary of the Invention

[0004] The paper feeding device according to the embodiment includes a feed roller and a separation roller arranged in an arrangement direction and clamping a sheet. The paper feeding device comprises: the feed roller, which feeds the sheet in a conveying direction orthogonal to the arrangement direction; the separation roller, which pushes against the feed roller; a shaft, which supports the separation roller to be rotatable by a torque limiter; a retainer having a support portion, the support portion being provided with a first guide surface and a second guide surface that are opposite to each other and extend along the arrangement direction; and an anti-rotation portion mounted on the shaft and inserted between the first guide surface and the second guide surface, wherein the anti-rotation portion has: a first sliding surface facing the first guide surface on the feed roller side of the arrangement direction and downstream of the conveying direction relative to the rotation axis of the separation roller; and a second sliding surface facing the second guide surface on the opposite side of the feed roller of the arrangement direction and upstream of the conveying direction relative to the rotation axis of the separation roller. Attached Figure Description

[0005] Figure 1 This is a perspective view of the image processing apparatus according to the embodiment.

[0006] Figure 2 This is a perspective view of the paper feeding device according to the embodiment.

[0007] Figure 3 This is a cross-sectional view of the paper feeding device according to the embodiment.

[0008] Figure 4 This is a schematic diagram of the support and anti-rotation parts.

[0009] Figure 5 yes Figure 2 A magnified view of region V.

[0010] Explanation of reference numerals in the attached figures:

[0011] 1: Paper feeding device; 10: Paper feeding roller; 20: Separating roller; 30: Shaft; 32: End; 39: Torque limiter; 40: Anti-rotation part; 46: Leg; 51: First sliding surface; 52: Second sliding surface; 53: Third sliding surface; 54: Fourth sliding surface; 59: Recess; 60: Holding member; 64: Through hole; 65: First rib; 66: First guide surface; 67: Second guide surface; 68: Second rib; 69: Support part; 70: Sheet guiding component; 72: Sheet guiding surface; 90: Image processing device; Lt: Radius; S: Sheet; PD: Arrangement direction; TD: Conveying direction. Detailed Implementation

[0012] The paper feeding device of this embodiment is a paper feeding device having a paper feeding roller and a separation roller. The paper feeding roller and the separation roller are arranged in an arrangement direction. The paper feeding roller and the separation roller clamp the sheet. The paper feeding device includes a paper feeding roller, a separation roller, a shaft, a retainer, and an anti-rotation part. The paper feeding roller feeds the sheet in a conveying direction orthogonal to the arrangement direction. The separation roller pushes against the paper feeding roller. The shaft supports the separation roller in a rotatable manner by a torque limiter. The retainer has a support portion. On the support portion, a first guide surface and a second guide surface are provided that are opposite to each other and extend along the arrangement direction. The anti-rotation part is mounted on the shaft. The anti-rotation part is inserted between the first guide surface and the second guide surface. The anti-rotation part has a first sliding surface and a second sliding surface. The first sliding surface faces the first guide surface relative to the rotation axis of the separation roller, on the paper feeding roller side in the arrangement direction and downstream side in the conveying direction. The second sliding surface faces the second guide surface relative to the rotation axis of the separation roller, on the opposite side of the paper feeding roller in the arrangement direction and upstream side in the conveying direction.

[0013] Hereinafter, embodiments for carrying out the invention will be described with reference to the accompanying drawings. Furthermore, the same symbols are used to label the same parts in each drawing.

[0014] Figure 1 This is a perspective view of an image processing apparatus 90 having a paper feeding device 1 according to an embodiment. Figure 2 This is a perspective view of the paper feeding device 1 according to the embodiment. Figure 3 This is a cross-sectional view of the paper feeding device 1 according to the embodiment.

[0015] In the following explanations, a Cartesian coordinate system of X, Y, and Z will be used as needed. The defined direction in the horizontal plane is designated as the X direction; the direction orthogonal to the X direction in the horizontal plane is designated as the Y direction; and the directions orthogonal to both the X and Y directions (i.e., vertical directions) are designated as the Z direction. The arrows in the X, Y, and Z directions are designated as positive (+) directions, and the opposite direction is designated as negative (-) directions. The +X direction is designated as forward, the -X direction as backward, the +Y direction as right, the -Y direction as left, the +Z direction as upward, and the -Z direction as downward.

[0016] The image processing apparatus 90 will be described.

[0017] The image processing apparatus 90 in this embodiment is a multifunction printer (MFP). For example, the image processing apparatus 90 uses a developer such as a toner to form an image on paper. For example, the paper can be paper or label paper. As for the paper, any type of paper can be used, as long as an image can be formed on its surface. Figure 1 In this example, the image processing apparatus 90 includes a display 91, a printing unit 92, a control panel 93, a paper receiving unit 94, and an image reading unit 95. The paper receiving unit 94 includes multiple layers of paper trays arranged in the vertical direction (Z direction). The paper feeding device 1 of this embodiment is disposed inside the image processing apparatus 90 and is disposed on the upper side of at least one paper tray. The paper feeding device 1 of this embodiment may also be disposed at the paper feed port of a manually fed paper tray.

[0018] Furthermore, according to this embodiment, a multifunction printer is shown as an image processing apparatus equipped with a paper feeding device 1. However, the paper feeding device 1 can also be mounted on other image processing apparatuses. Examples of image processing apparatuses equipped with a paper feeding device 1 include an automatic document feeder, a scanner, and a decolorizing device.

[0019] The paper feeding device 1 will be described.

[0020] like Figure 2 and Figure 3 As shown, the paper feeding device 1 includes: a paper feeding roller 10, a separating roller 20, a torque limiter 39, a shaft 30, two anti-rotation parts 40, a retaining member 60, and a sheet guide member 70 (see reference). Figure 3 ) and pressurization section 80 (refer to) Figure 2 Furthermore, the paper feeding device 1 may also include a paper feed roller (not shown). In this case, the paper feed roller supplies the top sheet of the stacked paper to the paper feeding roller 10.

[0021] like Figure 2 As shown, the paper feed roller 10 is cylindrical with a first rotation axis J1 as its center. In this embodiment, the first rotation axis J1 is parallel to the horizontal direction (X-axis). The paper feed roller 10 is connected to a drive unit (not shown). The paper feed roller 10 is driven to rotate with the first rotation axis J1 as its center.

[0022] The separating roller 20 is cylindrical with the second rotating shaft J2 as its center. In this embodiment, the second rotating shaft J2 is parallel to the horizontal direction (X-axis). The first rotating shaft J1 and the second rotating shaft J2 are parallel to each other.

[0023] like Figure 3As shown, the separating roller 20 is arranged with the paper feed roller 10 in the arrangement direction PD. Here, the arrangement direction PD refers to the direction in which the paper feed roller 10 and the separating roller 20 are arranged. More specifically, the arrangement direction PD refers to the direction in which the line segment connecting the first rotation axis J1 and the second rotation axis J2 extends when viewed from the axial direction of the first rotation axis J1 and the second rotation axis J2. The arrangement direction PD is orthogonal to the first rotation axis J1 and the second rotation axis J2.

[0024] like Figure 2 As shown, the separating roller 20 is supported by the shaft 30 via the torque limiter 39. The separating roller 20 is pushed against the feed roller 10 by the pressure section 80. The separating roller 20 is capable of rotating about the second rotation axis J2. The separating roller 20 rotates together with the feed roller 10 due to the frictional force acting on its outer peripheral surface.

[0025] A sheet S is held between the feed roller 10 and the separation roller 20. The upper surface of the sheet S is in contact with the feed roller 10. The lower surface of the sheet S is in contact with the separation roller 20. The feed roller 10 is driven to rotate to transport the sheet S. When two or more sheets S are fed in overlapping manner, the separation roller 20 applies a load to the lower sheet S under the action of the torque limiter 39, causing it to separate from the upper sheet S.

[0026] like Figure 3 As shown, the sheet S, held between the feed roller 10 and the separation roller 20, is conveyed in the conveying direction TD. Here, the conveying direction TD refers to the direction orthogonal to the arrangement direction PD when viewed axially from the first rotation axis J1 and the second rotation axis J2. The conveying direction TD is orthogonal to the first rotation axis J1 and the second rotation axis J2. In this specification, the side where the sheet S is discharged is referred to as the "downstream side of the conveying direction TD". The side where the sheet S is attracted is referred to as the "upstream side of the conveying direction TD". In this embodiment, the downstream side of the conveying direction TD is the +Y side. In this embodiment, the upstream side of the conveying direction TD is the -Y side.

[0027] like Figure 2 As shown, the torque limiter 39 is disposed inside the separating roller 20. The torque limiter 39 includes an outer cylinder portion 38, fixed to the separating roller 20, and an inner cylinder portion 37, fixed to the shaft 30. Friction is generated between the outer cylinder portion 38 and the inner cylinder portion 37. The outer cylinder portion 38 and the inner cylinder portion 37 rotate relative to each other when a torque exceeding a predetermined value is applied.

[0028] Shaft 30 extends horizontally with the second rotating shaft J2 as its center. Shaft 30 is cylindrical. A torque limiter 39 is fixed on the outer circumferential surface of shaft 30. Shaft 30 rotatably supports the separating roller 20 via the torque limiter 39.

[0029] At both ends 32 of the shaft 30, an upward force from the pressurizing part 80 is applied. Figure 2 As shown, the pressure unit 80 has two pressure rods 81 and a pressure spring 89. Each pressure rod 81 has a cylindrical portion 84, a wrist portion 82, and a hook portion 83. The cylindrical portion 84 is cylindrical with a third rotation axis J3 as its center. The third rotation axis J3 extends along the Y-axis. A support shaft (not shown) is inserted into the cylindrical portion 84. The shaft 30 is rotatable about the third rotation axis J3. The wrist portion 82 and the hook portion 83 are connected to the outer circumferential surface of the cylindrical portion 84. The wrist portion 82 is positioned below the end 32 of the shaft 30. A pressure spring 89 is attached to the hook portion 83. The pressure spring 89 causes the pressure rods 81 to rotate about the third rotation axis J3. The pressure spring 89 also causes the wrist portion 82 to push against the end 32 of the shaft 30. The shaft 30 is pushed towards the paper feed roller 10 by the pressure unit 80.

[0030] D-shaped cut surfaces 31 are provided on both ends 32 of the shaft 30. The cross-sectional shape of the ends 32 of the shaft 30 is D-shaped. Anti-rotation parts 40 are installed on both ends 32 of the shaft 30. Torque limiter 39 and separation roller 20 are arranged axially on the shaft 30 between the two anti-rotation parts 40.

[0031] The anti-rotation portion 40 is a flat plate along a plane (YZ plane) orthogonal to the second rotation axis J2. Outer ribs 49 extending along the outer shape are provided on the anti-rotation portion 40. The outer ribs 49 protrude to both sides in the thickness direction of the anti-rotation portion 40. The outer ribs 49 reinforce the anti-rotation portion 40.

[0032] like Figure 3 As shown, the anti-rotation part 40 has a generally rectangular main body 45 and a leg 46 extending downward from the main body 45. The leg 46 extends from the main body 45 along the arrangement direction PD. The leg 46 extends in a direction away from the paper feed roller 10.

[0033] A support hole 47 extending through the thickness direction of the plate is provided in the main body 45. The support hole 47 is D-shaped. The end 32 of the shaft 30 is inserted into the support hole 47. The relative rotation between the shaft 30 and the anti-rotation part 40 is restricted. An inner rib 48 is provided on the inner edge of the support hole 47. The inner rib 48 protrudes along the thickness direction of the anti-rotation part 40. The inner rib 48 can improve the rigidity of the anti-rotation part 40 near the support hole 47. The inner rib 48 enables the anti-rotation part 40 to stably support the shaft 30.

[0034] A first end edge 55 and a second end edge 56 are provided on the outer periphery of the anti-rotation part 40. The first end edge 55 and the second end edge 56 extend in a generally straight line along the arrangement direction PD.

[0035] The first end edge 55 is located downstream of the second rotation axis J2 in the conveying direction TD. The first end edge 55 is the end edge of the main body 45. The second end edge 56 is located upstream of the second rotation axis J2 in the conveying direction TD. On the other hand, the second end edge 56 is an end edge that spans the main body 45 and the leg 46.

[0036] The first end edge 55 has a first sliding surface 51 and a third sliding surface 53. On the other hand, the second end edge 56 has a second sliding surface 52 and a fourth sliding surface 54. That is, the anti-rotation part 40 has a first sliding surface 51, a second sliding surface 52, a third sliding surface 53 and a fourth sliding surface 54.

[0037] The first sliding surface 51 and the third sliding surface 53 face downstream of the conveying direction TD. The first sliding surface 51 and the third sliding surface 53 are planes orthogonal to the conveying direction TD. The first sliding surface 51 is disposed on the upper end side of the first end edge 55. Conversely, the third sliding surface 53 is disposed on the lower end side of the first end edge 55. The third sliding surface 53 is located opposite to the first sliding surface 51 to the paper feed roller 10 in the arrangement direction PD. The third sliding surface 53 is configured with the same planar shape as the first sliding surface 51. Recesses 59 for accommodating lubricating grease are provided on both the first sliding surface 51 and the third sliding surface 53.

[0038] A first notch 57 is provided between the first sliding surface 51 and the third sliding surface 53. The first notch 57 opens on the downstream side of the conveying direction TD. The first notch 57 is recessed relative to the first sliding surface 51 and the third sliding surface 53 towards the upstream side of the conveying direction TD.

[0039] The second sliding surface 52 and the fourth sliding surface 54 face downstream of the conveying direction TD. The second sliding surface 52 and the fourth sliding surface 54 are planes orthogonal to the conveying direction TD. The second sliding surface 52 is disposed on the lower end side of the second end edge 56. The second sliding surface 52 is disposed at the front end of the leg portion 46. On the other hand, the fourth sliding surface 54 is disposed on the upper end side of the second end edge 56. The fourth sliding surface 54 is disposed on the main body portion 45. The fourth sliding surface 54 is located on the feed roller 10 side in the arrangement direction PD relative to the second sliding surface 52. The fourth sliding surface 54 is configured as a plane with the same shape as the second sliding surface 52. A recess 59 for accommodating lubricating grease is provided on the second sliding surface 52.

[0040] A second notch 58 is provided between the second sliding surface 52 and the fourth sliding surface 54. The second notch 58 opens on the upstream side of the conveying direction TD. The second notch 58 is recessed relative to the second sliding surface 52 and the fourth sliding surface 54 toward the downstream side of the conveying direction TD.

[0041] The retainer 60 supports the end 32 of the shaft 30 via the anti-rotation part 40. The retainer 60 is made of resin material. The retainer 60 is disposed on the underside of the separating roller 20.

[0042] The retainer 60 has two support portions 69 that respectively support the anti-rotation portion 40. For example... Figure 3 As shown, the support portion 69 in this embodiment is a notch-shaped opening on the upper side. The support portion 69 has a first opposing wall 61, a second opposing wall 62, and a bottom wall portion 63.

[0043] The first opposing wall 61 and the second opposing wall 62 are opposite each other in the conveying direction TD. The first opposing wall 61 and the second opposing wall 62 extend along the arrangement direction PD, respectively. The bottom wall is connected to the lower end of the first opposing wall 61 and the lower end of the second opposing wall 62.

[0044] The first opposing wall 61 has a first guide surface 66 facing the upstream side of the conveying direction TD. The second opposing wall 62 has a second guide surface 67 facing the downstream side of the conveying direction. The first guide surface 66 and the second guide surface 67 are provided on the support portion 69. The first guide surface 66 and the second guide surface 67 are flat surfaces extending along the arrangement direction PD. The first guide surface 66 and the second guide surface 67 are opposite to each other in the conveying direction TD.

[0045] Figure 4 This is a diagram schematically showing the relationship between the support part 69 and the anti-rotation part 40.

[0046] An anti-rotation part 40 is inserted between the first guide surface 66 and the second guide surface 67.

[0047] The first guide surface 66 is opposite to the first sliding surface 51 and the third sliding surface 53 of the anti-rotation part 40. The first sliding surface 51 and the third sliding surface 53 are opposite to the first guide surface 66 on the downstream side of the second rotation axis J2 in the conveying direction TD. The first sliding surface 51 is opposite to the first guide surface 66 on the side of the paper feed roller 10 in the arrangement direction PD, relative to the second rotation axis J2. The third sliding surface 53 is opposite to the first guide surface 66 on the opposite side of the paper feed roller 10 in the arrangement direction PD, relative to the second rotation axis J2.

[0048] The second guide surface 67 is opposite to the second sliding surface 52 and the fourth sliding surface 54 of the anti-rotation part 40. The second sliding surface 52 and the fourth sliding surface 54 are opposite to the second guide surface 67 on the upstream side of the second rotation axis J2 in the conveying direction TD. The second sliding surface 52 and the fourth sliding surface 54 are opposite to the second guide surface 67 on the opposite side of the paper feed roller 10 in the arrangement direction PD relative to the second rotation axis J2.

[0049] Shaft 30 is pushed towards the paper feed roller 10 by the pressure section 80. When the sheet S is sandwiched between the paper feed roller 10 and the separating roller 20, the axial distance between the first rotating shaft J1 and the second rotating shaft J2 changes. In this case, the first sliding surface 51 and the third sliding surface 53 slide relative to the first guide surface 66 in the alignment direction PD. The second sliding surface 52 and the fourth sliding surface 54 slide relative to the second guide surface 67 in the alignment direction PD.

[0050] The width of the anti-rotation part 40 in the conveying direction TD is slightly smaller than the distance between the first guide surface 66 and the second guide surface 67. The anti-rotation part 40 can slide smoothly between the first guide surface 66 and the second guide surface 67.

[0051] Downstream of the second rotating shaft J2 in the conveying direction TD, the two sliding surfaces (first sliding surface 51 and third sliding surface 53) of the anti-rotation portion 40 face the first guide surface 66. Upstream of the second rotating shaft J2 in the conveying direction TD, the two sliding surfaces (second sliding surface 52 and fourth sliding surface 54) of the anti-rotation portion 40 face the second guide surface 67. According to this embodiment, the sliding area of ​​the anti-rotation portion 40 can be ensured to be large in the arrangement direction PD, thereby improving the sliding efficiency. Moreover, regardless of which direction the torque is applied to the anti-rotation portion 40, the sliding surfaces of multiple locations achieve anti-rotation.

[0052] On the first end edge 55 of the anti-rotation portion 40, a first notch 57 is provided between the first sliding surface 51 and the third sliding surface 53. The first sliding surface 51 and the third sliding surface 53 are divided by the first notch 57. On the second end edge 56, a second notch 58 is provided between the second sliding surface 52 and the fourth sliding surface 54. The second sliding surface 52 and the fourth sliding surface 54 are divided by the second notch 58. The anti-rotation portion 40 contacts the first guide surface 66 and the second guide surface 67 with a defined area. This facilitates the dimensional management of the anti-rotation portion 40.

[0053] In this embodiment, grease that suppresses sliding resistance is filled between the first sliding surface 51 and the third sliding surface 53 and the first guide surface 66. Grease that suppresses sliding resistance is also filled between the second sliding surface 52 and the fourth sliding surface 54 and the second guide surface 67.

[0054] On the first sliding surface 51, the second sliding surface 52, and the third sliding surface 53, there are recesses 59 for receiving grease. The recesses 59 are grooves extending axially along the second rotation axis J2. The grease in the recesses 59 is supplied to the first sliding surface 51, the second sliding surface 52, and the third sliding surface 53, thereby continuously suppressing sliding resistance.

[0055] In this embodiment, no recess 59 is provided on the fourth sliding surface 54. However, recesses 59 may be provided on all sliding surfaces (first sliding surface 51, second sliding surface 52, third sliding surface 53, and fourth sliding surface 54). Moreover, as long as a recess 59 is provided on at least one of the sliding surfaces, a certain effect can be obtained from the viewpoint of smooth sliding.

[0056] When sheet S is conveyed downstream in the conveying direction TD, the anti-rotation part 40 is subjected to a torque acting as a reaction force to the torque limiter 39. The direction of the torque acting on the anti-rotation part 40 is... Figure 4 In the clockwise direction. When the sheet S is conveyed downstream, the first sliding surface 51 is pressed against the first guide surface 66. When the sheet S is conveyed downstream, the second sliding surface 52 and the fourth sliding surface 54 are pressed against the second guide surface 67. The first guide surface 66 and the second guide surface 67 restrict the clockwise rotation of the anti-rotation part 40. Conversely, when the sheet S is moved upstream in reverse, the third sliding surface 53 is pressed against the first guide surface 66. The first guide surface 66 restricts the counterclockwise rotation of the anti-rotation part 40. The first guide surface 66 and the second guide surface 67 also restrict the rotation of the anti-rotation part 40 in either direction.

[0057] According to this embodiment, the anti-rotation portion 40 has a first sliding surface 51 and a second sliding surface 52. The first sliding surface 51 contacts the first guide surface 66 on the downstream side of the second rotation axis J2 in the conveying direction TD and on the side of the separation roller 20 in the arrangement direction PD. On the other hand, the second sliding surface 52 contacts the second guide surface 67 on the upstream side of the second rotation axis J2 in the conveying direction TD and on the opposite side of the separation roller 20 in the arrangement direction PD. The torque applied to the separation roller 20 when conveying the sheet S is effectively borne by the first guide surface 66 and the second guide surface 67. The first sliding surface 51 and the second sliding surface 52 are respectively away from the second rotation axis J2 in the arrangement direction PD. The reaction force of the first guide surface 66 and the second guide surface 67 is reduced. As a result, the sliding resistance acting between the first sliding surface 51 and the first guide surface 66 and between the second sliding surface 52 and the second guide surface 67 can be suppressed.

[0058] like Figure 4 As shown, the distance between the second rotation axis J2 on the arrangement direction PD and the first sliding surface 51 is set as the first distance L1. The distance between the second rotation axis J2 on the arrangement direction PD and the second sliding surface 52 is set as the second distance L2.

[0059] Slight gaps are provided between the first sliding surface 51 and the first guide surface 66, and between the second sliding surface 52 and the second guide surface 67. When the anti-rotation part 40 is applied in a clockwise direction ( Figure 4When the torque is applied, the point on the first sliding surface 51 furthest from the second rotation axis J2 contacts the first guide surface 66. A slight gap is provided between the first sliding surface 51 and the first guide surface 66. When the anti-rotation part 40 is applied in a clockwise direction (… Figure 4 When the torque is applied, the point on the second sliding surface 52 furthest from the second rotation axis J2 contacts the second guide surface 67. Therefore, the first distance L1 is the distance between the point on the first sliding surface 51 furthest from the second rotation axis J2 and the second rotation axis J2. Similarly, the second distance L2 is the distance between the point on the second sliding surface 52 furthest from the second rotation axis J2 and the second rotation axis J2.

[0060] according to Figure 4 The balance of torque of the anti-rotation part 40 during the conveying of sheet S is discussed.

[0061] The force exerted by the separating roller 20 on the sheet S during conveying is defined as the separating force T. As a reaction force, the separating roller 20 bears the force T from the sheet S. The anti-rotation part 40 is subjected to a torque equal to the product of the separating force T and the radius Lt of the separating roller 20 (T × Lt).

[0062] On the other hand, the first sliding surface 51 of the anti-rotation part 40 contacts the first guide surface 66 and bears the first reaction force N1. The second sliding surface 52 of the anti-rotation part 40 contacts the second guide surface 67 and bears the second reaction force N2. The anti-rotation part 40 is subjected to a torque equal to the sum of the product of the first reaction force N1 and the first distance L1 (N1×L1) and the product of the second reaction force N2 and the second distance L2 (N2×L2).

[0063] Given the balance of torques in the anti-rotation part 40, the following equation (1) holds.

[0064] T×Lt=(N1×L1)+(N2×L2)…(1)

[0065] The force balance of the anti-rotation part 40 during the conveying of sheet S is discussed.

[0066] The anti-rotation part 40 is subjected to a separation force T and a second reaction force N2 acting as a reaction force in the downstream side of the conveying direction TD, and a first reaction force N1 acting in the upstream side of the conveying direction TD.

[0067] Given the force balance of the anti-rotation part 40, the following equation (2) holds.

[0068] T+N2=N1…(2)

[0069] According to equation (2), the first reaction force N1 is always greater than the second reaction force N2. In order for the anti-rotation part 40 to slide smoothly on the support part 69, it is important to make the first reaction force N1 smaller.

[0070] Based on equations (1) and (2), the following equations (3) and (4) are derived.

[0071] N1=T×(Lt+L2) / (L1+L2)…(3)

[0072] N2=T×(Lt-L1) / (L1+L2)…(4)

[0073] According to equations (3) and (4), by making the first distance L1 a value greater than 0, the first reaction force N1 and the second reaction force N2 are reduced. According to this embodiment, since the first distance L1 is a value greater than 0, the first reaction force N1 can be suppressed and the anti-rotation part 40 can slide smoothly on the support part 69.

[0074] In this embodiment, the first distance L1 is greater than half the radius Lt of the separating roller 20. By making the first distance L1 greater than half the radius Lt of the separating roller 20, the first reaction force N1 can be effectively suppressed.

[0075] Preferably, the first distance L1 is smaller than the radius Lt of the separating roller 20. When the first distance L1 is larger than the radius Lt of the separating roller 20, the first sliding surface 51 is disposed on the side of the feed roller 10 of the sheet S. In this case, in order to prevent the anti-rotation part 40 from obstructing the feeding of the sheet S, the first sliding surface 51 is disposed outside the passage area of ​​the sheet S. In this case, it is possible to increase the size of the paper feeding device 1. According to this embodiment, by making the first distance L1 smaller than the radius Lt of the separating roller 20, the paper feeding device 1 can be miniaturized.

[0076] According to equation (4), it can be seen that by making the second distance L2 larger, the second reaction force N2 can be made smaller. According to this embodiment, since the second distance L2 is a sufficiently large value, the second reaction force N2 can be suppressed and the anti-rotation part 40 can slide smoothly on the support part 69.

[0077] In this embodiment, the second distance L2 is larger than the radius Lt of the separating roller 20. By making the second distance L2 larger than the radius Lt of the separating roller 20, the second reaction force N2 can be effectively suppressed.

[0078] According to this embodiment, anti-rotation portions 40 are respectively installed on both ends 32 of the clamping and separating roller 20 of the shaft 30. The retaining member 60 has two support portions 69 supporting the anti-rotation portions 40. The first reaction force N1 and the second reaction force N2 are distributed and borne by the two anti-rotation portions 40. This makes the first reaction force N1 and the second reaction force N2 acting on each anti-rotation portion 40 smaller, thereby allowing the anti-rotation portions 40 to slide smoothly. Furthermore, the rotation of the shaft 30 is restricted by the two ends 32, thereby suppressing the torsion of the shaft 30.

[0079] Figure 5 yes Figure 2 A magnified view of a portion of region V. For example... Figure 5 As shown, the first opposing wall 61 of the support portion 69 has a first rib 65.

[0080] like Figure 3 As shown, the first rib 65 extends along the arrangement direction PD. The first rib 65 protrudes upstream of the conveying direction TD. A first guide surface 66 is provided on the first rib 65. By providing the first guide surface 66 at the front end of the first rib 65, the contact area between the support portion 69 and the first sliding surface 51 can be limited. This facilitates the dimensional management of the first guide surface 66.

[0081] The second opposing wall 62 of the support portion 69 has a second rib 68. The second rib 68 extends along the arrangement direction PD. The second rib 68 protrudes downstream in the conveying direction TD. A second guide surface 67 is provided on the second rib 68. By providing the second guide surface 67 at the front end of the second rib 68, the contact area between the support portion 69 and the second sliding surface 52 can be limited. This facilitates the dimensional management of the second guide surface 67.

[0082] like Figure 3 As shown, a through hole 64 extending through the thickness direction is provided on the bottom wall portion 63 of the support portion 69. The leg portion 46 of the anti-rotation portion 40 is inserted into the through hole 64.

[0083] According to this embodiment, the leg 46 having the second sliding surface 52 is inserted through the through hole 64 of the retainer 60. By providing the second sliding surface 52 on the leg 46, a larger second distance L2 can be ensured. By inserting the leg 46 through the through hole 64, the dimension in the arrangement direction PD of the retainer 60 can be suppressed. Miniaturization of the paper feeding device 1 can be achieved.

[0084] like Figure 3 As shown, the sheet guiding member 70 has a plate-shaped guide plate 71. The guide plate 71 covers the retaining member 60 from above. An opening (not shown) is provided on the guide plate 71 to expose the separating roller 20. The guide plate 71 has an upward-facing sheet guiding surface 72. That is, the sheet guiding member 70 is provided with a sheet guiding surface 72. The sheet guiding surface 72 guides the conveyed sheet S.

[0085] In this embodiment, the sheet guide surface 72 is inclined relative to the conveying direction TD. More specifically, viewed from the axial direction of the separating roller 20, the sheet guide surface 72 is inclined toward the downstream side of the conveying direction TD toward the feed roller 10.

[0086] The sheet S is conveyed in the conveying direction TD between the feed roller 10 and the separation roller 20. The sheet S contacts the sheet guide surface 72 on the downstream side of the feed roller 10 and the separation roller 20, causing it to bend and conveyed.

[0087] The sheet guide surface 72 is inclined towards the feed roller 10 on the downstream side of the conveying direction TD, thereby ensuring a large space on the downstream side of the separating roller 20 in the conveying direction TD. The position of the first sliding surface 51 in the arrangement direction PD is close to the feed roller 10 side. This makes the first distance L1 larger and allows the anti-rotation part 40 and the support part 69 to slide smoothly.

[0088] like Figure 4 As shown, the distance between the second rotating shaft J2 in the conveying direction TD and the first sliding surface 51 is set as a third distance L3. In this embodiment, the third distance L3 is larger than the radius Lt of the separating roller 20. As described above, the sheet guiding surface 72 is close to the paper feed roller 10 side on the downstream side of the conveying direction TD. By making the third distance L3 larger and positioning the first sliding surface 51 on the downstream side of the conveying direction TD, the first sliding surface 51 can be made close to the paper feed roller 10 side in the arrangement direction PD. Making the first distance L1 larger allows the anti-rotation part 40 and the support part 69 to slide smoothly.

[0089] While certain embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. In fact, the novel embodiments described herein can be embodied in various other forms, and various omissions, substitutions, and changes can be made to the forms of the embodiments described herein without departing from the spirit of the invention. The appended technical solutions and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of the invention.

Claims

1. A paper feeding device comprising a feeding roller and a separating roller arranged in an arrangement direction for clamping a sheet of paper, the paper feeding device comprising: The paper feed rollers convey the sheet in a conveying direction orthogonal to the arrangement direction; The separating roller pushes against the paper feeding roller; The shaft, via a torque limiter, supports the separating roller to enable rotation; A retainer having a support portion, the support portion being provided with a first guide surface and a second guide surface that are opposite to each other and extend along the arrangement direction; as well as An anti-rotation portion is mounted on the shaft and inserted between the first guide surface and the second guide surface. The anti-rotation portion has: a first sliding surface facing the first guide surface on the downstream side of the feed roller in the arrangement direction relative to the rotation axis of the separating roller, and facing the second guide surface on the opposite side of the feed roller in the arrangement direction relative to the rotation axis of the separating roller, and facing the upstream side in the conveying direction. The anti-rotation part has legs extending along the arrangement direction. A second sliding surface is provided at the front end of the leg. The support portion is provided with a through hole for the leg to be inserted.

2. The paper feeding device according to claim 1, wherein, The distance between the rotation axis of the separating roller and the point on the first sliding surface furthest from the rotation axis of the separating roller in the arrangement direction is smaller than the radius of the separating roller.

3. The paper feeding device according to claim 2, wherein, The distance between the rotation axis of the separating roller and the point on the first sliding surface furthest from the rotation axis of the separating roller in the arrangement direction is greater than half the radius of the separating roller.

4. The paper feeding device according to claim 1, wherein, The distance between the rotation axis of the separating roller and the point on the second sliding surface furthest from the rotation axis of the separating roller in the arrangement direction is greater than the radius of the separating roller.

5. The paper feeding device according to any one of claims 1 to 4, wherein, The anti-rotation part is installed at both ends of the shaft that clamps the separating roller. The retainer has two support portions that respectively support the anti-rotation portion.

6. The paper feeding device according to any one of claims 1 to 4, wherein, The paper feeding device includes a sheet guiding component, which has a sheet guiding surface for guiding the conveyed sheet. Viewed axially from the separating roller, the sheet guide surface is inclined toward the feed roller side on the downstream side in the conveying direction.

7. The paper feeding device according to any one of claims 1 to 4, wherein, The anti-rotation part has: a third sliding surface, which is configured to be the same planar shape as the first sliding surface and faces the first guide surface; And a fourth sliding surface, configured as a plane like the second sliding surface, and facing the second guide surface.

8. The paper feeding device according to any one of claims 1 to 4, wherein, The support portion has ribs that extend along the arrangement direction and are provided with the first guide surface or the second guide surface.

9. An image processing apparatus, wherein, The image processing apparatus has a paper feeding device as described in any one of claims 1 to 8.

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