Paper feeding tray and image forming device

Abstract

To provide an image forming device with a paper feeding tray that can smoothly move a pair of side cursors.SOLUTION: An image forming device includes a table on which sheets to be fed in a particular paper feeding direction are placed, a pair of side cursors that are supported on the table so as to be movable in a width direction intersecting the paper feeding direction, a pair of rack gears 69 that are fixed to the pair of side cursors and extend along the width direction, a pinion gear 25 that fits with the pair of rack gears 69, an elastically deformable rotating shaft 35 that is fixed to the table and rotatably supports the pinion gear 25, and an energizing member 27 that energizes the rotating shaft 35 in a direction to be in contact with the pinion gear 25.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a paper feed tray and an image forming apparatus that are provided with a side cursor for aligning a sheet in the width direction. [Background technology]

[0002] A paper feed tray provided in an image forming apparatus is provided with a pair of side cursors that move along a width direction intersecting with the paper feed direction to align sheets. The pair of side cursors are generally supported on the table of the paper feed tray by a rack and pinion mechanism so as to move synchronously in opposite directions to each other, as described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-88629 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned rack and pinion mechanism, the meshing depth between the rack gear and the pinion gear is set deep so that the side cursor does not move after being positioned. This causes problems such as some users finding it difficult to move the side cursor or being unable to move the side cursor smoothly.

[0005] SUMMARY OF THE DISCLOSURE In order to solve the above-mentioned problems, an object of the present invention is to provide a paper feed tray and an image forming apparatus that allow a pair of side cursors to move smoothly. [Means for solving the problem]

[0006] The image forming apparatus of the present invention is characterized in that it comprises a table on which a sheet to be fed along a predetermined paper feed direction is placed, a pair of side cursors supported on the table so as to be movable in a width direction intersecting the paper feed direction, a pair of rack gears fixed to the pair of side cursors and extending along the width direction, a pinion gear that meshes with the pair of rack gears, an elastically deformable rotating shaft fixed to the table and rotatably supporting the pinion gear, and a biasing member that biases the rotating shaft in a direction toward contact with the pinion gear.

[0007] In the present invention, the rotating shaft may have a cylindrical shape with a hollow portion, be inserted into an axial hole of the pinion gear to rotatably support the pinion gear, and the biasing member may be disposed in the hollow portion of the rotating shaft.

[0008] In the present invention, the pinion gear may be made of a material having better sliding properties than the rotating shaft.

[0009] In the present invention, the rotating shaft may be divided into two in the circumferential direction.

[0010] In the present invention, the biasing member may bias the rotating shaft in a direction in which the pinion gear and the pair of rack gears mesh with each other.

[0011] The image forming apparatus of the present invention is characterized in that it comprises a document transport unit that includes the paper feed tray and feeds and transports sheets from the paper feed tray, an image reading unit that reads an image of the sheet transported by the document transport unit, and an image forming unit that forms an image based on the image read by the image reading unit. Effect of the Invention

[0012] According to the present invention, the rotation of the pinion gear is braked by the elastic deformation of the rotating shaft by the biasing member, so that the side cursor can be maintained in a predetermined position with an appropriate force and can be moved smoothly. [Brief description of the drawings]

[0013] [Figure 1] 1 is a front view showing an image forming apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a perspective view showing a document transport unit of an image forming apparatus according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a perspective view showing a table and a pair of side cursors of a paper feed tray according to an embodiment of the present invention. [Figure 4A] FIG. 4 is a perspective view showing a rotation shaft portion of the paper feed tray according to the embodiment of the present invention. [Figure 4B] 4 is a plan view showing a rotation shaft portion of the paper feed tray according to the embodiment of the present invention. [Diagram 5] FIG. 4 is a cross-sectional perspective view showing a pinion gear of the paper feed tray according to the embodiment of the present invention. [Figure 6A] FIG. 4 is a cross-sectional perspective view showing a rotating shaft portion before a pinion gear and a coil spring are attached in the paper feed tray according to the embodiment of the present invention. [Figure 6B] FIG. 4 is a cross-sectional perspective view showing a rotating shaft portion after a pinion gear and a coil spring are attached in the paper feed tray according to the embodiment of the present invention. [Figure 7] FIG. 2 is a cross-sectional view showing the paper feed tray in the embodiment of the present invention. [Figure 8] FIG. 2 is a cross-sectional view showing a paper feed tray according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper feed tray and an image forming apparatus according to an embodiment of the present invention will now be described with reference to the drawings.

[0015] First, an image forming apparatus 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a front view showing the image forming apparatus 1. Fr, Rr, L, and R in each drawing indicate the front, rear, left, and right sides of the image forming apparatus 1, respectively.

[0016] The image forming device 1 includes an image forming unit 3, an image reading unit 5 disposed above the image forming unit 3, and an original transport unit 7 disposed above the image reading unit 5. An internal paper discharge space 9 is formed between the image forming unit 3 and the image reading unit 5.

[0017] The document transport unit 7 includes a paper feed tray 11 on which documents are placed, a discharge tray 13 provided below the paper feed tray 11, and a transport section 15 having a horizontal U-shaped transport path along which the documents are transported from the paper feed tray 11 to the discharge tray 13. The documents placed on the paper feed tray 11 are fed to the transport section 15 and transported along the transport path. At that time, an image on the document is read by the image reading unit 5. The document from which the image has been read is discharged from the transport section 15 to the discharge tray 13 and placed on the discharge tray 13. The image forming unit 3 forms an image on a sheet based on the image read by the image reading unit 5.

[0018] Next, the document transport unit 7 will be described with reference to Fig. 2. Fig. 2 is a perspective view showing the document transport unit 7. As described above, the document transport unit 7 includes the paper feed tray 11, the discharge tray 13, and the transport section 15.

[0019] The paper feed tray 11 will be described with reference to Fig. 2, Fig. 3, Fig. 4A, Fig. 4B, and Fig. 5. Fig. 3 is a perspective view showing the table 21 and the front and rear side cursors 23F and 23R, Fig. 4A and Fig. 4B are views showing the rotation shaft 35, and Fig. 5 is a sectional perspective view showing the pinion gear 25.

[0020] The paper feed tray 11 includes a table 21 on which documents are placed, front and rear side cursors 23F, 23R (collectively referred to as side cursors 23), a pinion gear 25, and a coil spring 27 (not shown in Figures 2 to 5, but will be described later with reference to Figures 6A and 6B, etc.).

[0021] First, the table 21 will be described with reference to FIG. 3. The table 21 has a substantially rectangular upper plate 21a and a side plate 21b formed along the periphery of the upper plate 21a. The front right corner of the upper plate 21a is cut out in a substantially rectangular shape. The upper surface of the upper plate 21a is a flat document placement surface 21x on which a document is placed. The document placed on the document placement surface 21x is fed toward the conveying unit 15 by a pickup roller (not shown) provided in the conveying unit 15. The direction in which the document is fed (direction from right to left in this example) is defined as the paper feed direction. The upper plate 21a is formed with two shallow rectangular recesses 31 spaced apart from each other in the width direction (front-rear direction in this example) that intersects with the paper feed direction. Each recess 31 has a slit 33 formed along the width direction. The table 21 is made of resin such as ABS resin.

[0022] A rotating shaft 35 is formed between the two recesses 31 on the back surface (lower surface) of the table 21. The rotating shaft 35 supports the pinion gear 25 and the coil spring 27, as described below. The rotating shaft 35 will be described with reference to Figs. 4A and 4B. Fig. 4A is a perspective view of the rotating shaft 35 seen from below, and Fig. 4B is a plan view of the rotating shaft 35 seen from below. The rotating shaft 35 is formed integrally with the upper plate 21a of the table 21.

[0023] The rotating shaft 35 has left and right split portions 41L, 41R (collectively referred to as split portion 41) that split a cylinder R (see FIG. 4B) into two in the circumferential direction. The left and right split portions 41L, 41R are formed point-symmetrically with respect to the center C of the cylinder R in a plan view. The split portion 41 has a substantially semicylindrical tube portion 43, and a first leg portion 45 and a second leg portion 47 that are provided on both ends of the tube portion 43 in the circumferential direction and fixed to the rear surface of the upper plate 21a. The length of the first leg portion 45 in the circumferential direction is longer than the length of the second leg portion 47 in the circumferential direction.

[0024] The first leg portion 45 has an inner peripheral surface formed in a flat shape parallel to the axial direction of the cylinder R, and is thicker than the tube portion 43. Therefore, an inclined portion 49 is formed between the inner peripheral surface of the first leg portion 45 and the inner peripheral surface of the tube portion 43. An inclined surface 45a is formed between the tip surface and the inner peripheral surface of the first leg portion 45. Also, a cylindrical boss 51 is formed on the inner peripheral surface of the first leg portion 45, which protrudes inward along the radial direction of the cylinder R. An inclined surface 51a is formed between half of the tip surface of the boss 51 (the half opposite the upper plate 21a) and the side surface. A hook 53 protruding outward in the radial direction is formed on the tip portion (the end opposite the upper plate 21a) of the outer peripheral surface of the first leg portion 45. An inclined surface 53a is formed between the outer peripheral surface of the hook 53 and the tip surface. A part of the outer peripheral surface of the first leg portion 45 on the upper plate 21a side from the hook 53 is formed in a flat shape parallel to the axial direction.

[0025] An axially extending rib 55 is formed on the inner peripheral surface of the second leg portion 47. An inclined surface 55a is formed between the inner peripheral surface of the rib 55 and the tip surface.

[0026] As shown in Fig. 4B, the left and right divided parts 41L, 41R are arranged so that the bosses 51 face each other in the left-right direction, and both legs 45, 47 are fixed to the rear surface of the upper plate 21a of the table 21. As shown in Fig. 4A, a gap is provided between the upper plate 21a and the tube part 43.

[0027] Next, the front and rear side cursors 23F, 23R will be described with reference to FIG. 3. The front and rear side cursors 23F, 23R align the document placed on the document placement surface 21x to the center in the width direction. The side cursor 23 stands approximately perpendicular to the document placement surface 21x and has a standing portion 61 parallel to the transport direction and a base portion 63 bent at approximately a right angle from the lower end of the standing portion 61. A pressing piece 65 is provided on the inner surface of the standing portion 61 (the surface facing the standing portions 61 of the front and rear side cursors 23F, 23R) to press the upper surface of the document placed on the document placement surface 21x. A protruding portion 67 is formed on the lower surface of the base portion 63 along the width direction.

[0028] The base portion 63 of the side cursor 23 is accommodated in a recess 31 (see FIG. 2) formed in the upper plate 21a of the table 21, and the protrusion portion 67 is inserted into the slit 33. As a result, as shown in FIG. 2, the side cursor 23 is supported by the table 21 so as to be movable in the width direction.

[0029] 3 again, a rack gear 69 extending in the width direction is fixed to a protrusion 67 of the side cursor 23 protruding downward from the slit 33 of the upper plate 21a of the table 21. The rack gear 69 of the front cursor 23F has rack teeth formed on its end face (left end face) on the downstream side in the paper feed direction. The rack gear 69 of the rear cursor 23R has rack teeth formed on its end face (right end face) on the upstream side in the paper feed direction.

[0030] Next, the pinion gear 25 will be described with reference to Fig. 5. The pinion gear 25 has a gear portion 71 that can mesh with the rack gear 69 of the side cursor 23. The diameter of the shaft hole 73 of the gear portion 71 is slightly larger than the outer diameter of the rotating shaft 35 (the outer diameter of the cylindrical portions 43 of both divided portions 41). The shaft hole 73 is formed so that the inner diameter becomes wider from the center toward one end in the axial direction.

[0031] A flange portion 75 is formed on one end side of the gear portion 71, projecting in the radial direction of the shaft hole 73. The inner diameter of the flange portion 75 is larger than the inner diameter of the shaft hole 73. Therefore, a step portion 77 is formed between the inner peripheral surface of the shaft hole 73 and the inner peripheral surface of the flange portion 75. The back surface of the flange portion 75 (the surface on the gear portion 71 side) is formed in a flat shape perpendicular to the axial direction. In addition, a rib 79 is formed along the circumferential direction on the back surface. The front surface of the flange portion 75 (the surface opposite to the gear portion 71) is inclined in a stepped manner so that the thickness becomes thinner toward the outside in the radial direction. An annular portion 81 is formed along the periphery of the shaft hole 73 on the end surface on the other end side in the axial direction of the gear portion 71 (the surface opposite to the flange portion 75). The tip portion of the annular portion 81 is formed in an arc shape in cross section. The pinion gear 25 is made of a material with good sliding properties (for example, POM).

[0032] Next, a description will be given of the coil spring 27. The coil spring 27 has a length longer than the inner diameter of the rotating shaft 35 (the inner diameter of the cylindrical portions 43 of both divided portions 41) when no load is applied.

[0033] Next, a procedure for fixing the pinion gear 25 to the rotating shaft 35 will be described with reference to Figures 6A and 6B. Figure 6A is a perspective view of the rotating shaft 35 from below before the pinion gear 25 and the coil spring 27 are attached, and Figure 6B is a perspective view of the rotating shaft 35 from below after the pinion gear 25 and the coil spring 27 are attached. The front and rear side cursors 23F, 23R (only the rack gear 69 is shown in Figures 6A and 6B) have moved to be farthest apart.

[0034] First, as shown in Fig. 6A, the pinion gear 25 is held in a position in which the gear portion 71 faces upward and the flange portion 75 faces downward, and the rotating shaft 35 is inserted into the shaft hole 73 of the gear portion 71. At this time, when the annular portion 81 of the gear portion 71 hits the inclined surface 53a of the hook 53 of the rotating shaft 35 (see Figs. 4A and 4B), the first leg portion 45 is pushed by the annular portion 81 and elastically deforms inward in the radial direction of the rotating shaft 35.

[0035] After that, the rotating shaft 35 is further inserted into the shaft hole 73 of the pinion gear 25 while the teeth of the gear portion 71 of the pinion gear 25 and the rack teeth of the rack gear 69 are meshed. The hook 53 moves along the inner peripheral surface of the shaft hole 73 while being elastically deformed. Then, when the hook 53 eventually leaves the inner peripheral surface of the shaft hole 73, the first leg 45 elastically returns. As a result, the hook 53 is engaged with the step portion 77 of the pinion gear 25. Also, the annular portion 81 of the gear portion 71 of the pinion gear 25 comes into contact with the back surface of the upper plate 21a. Furthermore, the annular rib 79 on the back surface of the flange portion 75 comes into contact with the lower surface of the rack gear 69. As a result, the rack gear 69 is supported from below by the flange portion 75.

[0036] In this way, the pinion gear 25 is rotatably supported on the rotating shaft 35 and is prevented from coming off the rotating shaft 35. The pinion gear 25 also meshes with the rack gear 69. At this time, the outer circumferential surface of the rotating shaft 35 contacts the inner circumferential surface of the shaft hole 73 of the pinion gear 25, but no force is applied to the pinion gear 25 in the radial direction.

[0037] Next, the coil spring 27 is disposed between the bosses 51 of the left and right divided parts 41L, 41R. First, one end of the coil spring 27 is inserted into one of the bosses 51, and then the other end of the coil spring 27 is pressed along the inclined surface 51a (see also Figs. 4A and 4B) of the other boss 51. Then, the coil spring 27 is gradually compressed. Then, when the other end of the coil spring 27 is aligned with the other boss 51, the coil spring 27 elastically returns to its original state, and the other end is inserted into the other boss 51. The coil spring 27 has not returned to its natural length, and is compressed between the two bosses 51. That is, the coil spring 27 biases the two bosses 51, i.e., the two first legs 45, in a direction separating them from each other.

[0038] As a result, as shown in FIG. 6B and FIG. 7, an outward force (see the arrows in FIG. 6B and FIG. 7) along the radial direction is applied to the first leg parts 45 of the left and right divided parts 41L, 41R. The divided parts 41 are integral with the resin table 21 and are elastically deformable. Therefore, when such a force is applied to the divided parts 41, the left and right divided parts 41L, 41R elastically deform outward along the radial direction, and the outer peripheral surface of the first leg part 45 contacts the inner peripheral surface of the shaft hole 73 of the pinion gear 25. As a result, a frictional force is generated between the two surfaces, and the rotation of the pinion gear 25 relative to the rotating shaft 35 is braked. In this way, the coil spring 27 is an example of a biasing member that biases the rotating shaft 35 in a direction in which it contacts the pinion gear 25.

[0039] However, as mentioned above, a portion of the outer peripheral surface of the first leg portion 45 is formed into a flat surface parallel to the axial direction of the rotation shaft 35 (see FIG. 7), so that the frictional force between the two surfaces is strong enough not to hinder the rotation of the pinion gear 25.

[0040] The alignment operation of the document in the feed tray 11 having the above configuration will be described. In the initial state, the front and rear side cursors 23F, 23R are moved to the positions most separated in the width direction. The user positions the leading edge of the document at a predetermined position and places the document on the document placement surface 21x of the feed tray 11. Then, one side cursor 23 is moved toward the document. This causes the rack gear 69 to move together with the one side cursor 23, causing the pinion gear 25 to rotate. The rotation of the pinion gear 25 causes the rack gear 69 of the other side cursor 23 to move, and the other side cursor 23 moves toward the document. In this way, the front and rear side cursors 23F, 23R move synchronously by the same distance and come into contact with the side edges of the document. This causes the document to be aligned in the center in the width direction.

[0041] When the pinion gear 25 rotates, the rotation of the pinion gear 25 is braked by the frictional force between the rotating shaft 35 biased by the coil spring 27 and the pinion gear 25. Therefore, after the side cursor 23 is positioned, the pinion gear 25 is less likely to rotate. In other words, the side cursor 23 is less likely to move. Therefore, the side cursor 23 does not move inadvertently while the document is being fed. However, the biasing force of the coil spring 27 does not affect the meshing force between the gear portion 71 of the pinion gear 25 and the rack gear 69 of the side cursor 23, so the pinion gear 25 rotates smoothly as the side cursor 23 moves.

[0042] As is clear from the above description, according to the present invention, the pinion gear 25 and the rack gear 69 are not configured to be deeply meshed in advance, and the rotation of the pinion gear 25 is braked by the elastic deformation of the rotating shaft 35 by the coil spring 27. Therefore, the side cursor 23 can be maintained at a predetermined position with an appropriate force and can be moved smoothly.

[0043] Moreover, the rotating shaft 35 is directly fixed to the upper plate 21a of the table 21 of the paper feed tray 11, and further, the coil spring 27 is housed in the hollow portion of the rotating shaft 35. Therefore, the height H (see FIG. 8) of the rack and pinion mechanism including the coil spring 27 can be reduced, and the thickness of the paper feed tray 11 can be reduced.

[0044] Furthermore, since the rotating shaft 35 is composed of two divided parts 41, it is easily deformed in the radial direction when biased by the coil spring 27. Therefore, the outer peripheral surface of the first leg part 45 of the rotating shaft 35 can be reliably brought into contact with the inner peripheral surface of the shaft hole 73 of the pinion gear 25. Also, the coil spring 27 biases the first leg part 45 of the rotating shaft 35 along the direction in which the pinion gear 25 and the rack gear 69 mesh with each other. Therefore, when the first leg part 45 is biased, the pinion gear 25 is biased, and the effect of reliably meshing the pinion gear 25 and the rack gear 69 is obtained.

[0045] Furthermore, since the pinion gear 25 is made of a material with good sliding properties, it can rotate smoothly relative to the rotating shaft 35.

[0046] In the above embodiment, the side cursor 23 provided in the paper feed tray 11 of the document transport unit 7 has been described, but the present invention can also be applied to a side cursor provided in a paper feed cassette (not shown) of the image forming unit 3.

[0047] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above embodiments, and those skilled in the art may modify the above embodiments without departing from the scope and spirit of the present invention. [Explanation of symbols]

[0048] 1. Image forming device 3 Image forming unit 5 Image reading unit 7 Document transport unit 21 Table 23 Side Cursor 25 Pinion gear 27 Coil spring (biasing member) 35 Rotational Axis 69 Rack Gear

Claims

1. a table on which a sheet is placed to be fed along a predetermined sheet feeding direction; a pair of side cursors supported on the table so as to be movable in a width direction intersecting the sheet feeding direction; A pair of rack gears fixed to the pair of side cursors and extending along the width direction; a pinion gear that meshes with the pair of rack gears; a rotating shaft that is fixed to the table and that rotatably supports the pinion gear; a biasing member that biases the rotation shaft in a direction in which the rotation shaft contacts the pinion gear.

2. the rotating shaft has a cylindrical shape with a hollow portion, and is inserted into a shaft hole of the pinion gear to rotatably support the pinion gear, 2. The paper feed tray according to claim 1, wherein the biasing member is disposed in the hollow portion of the rotating shaft.

3. 2. The paper feed tray according to claim 1, wherein the pinion gear is made of a material having better sliding properties than the rotating shaft.

4. 2. The paper feed tray according to claim 1, wherein the rotation shaft is divided into two parts in the circumferential direction.

5. The sheet feed tray according to claim 1, wherein the biasing member biases the rotation shaft in a direction in which the pinion gear and the pair of rack gears mesh with each other.

6. a document transport unit including the paper feed tray according to claim 1 and configured to feed and transport a sheet from the paper feed tray; an image reading unit that reads an image on a sheet conveyed by the document conveying device; an image forming unit that forms an image based on the image read by the image reading unit.

Images