Sheet alignment device and image formation system

Abstract

To make one side of a sheet abut against a reference member provided on the side part of a conveyance path, without buckling the sheet.SOLUTION: A sheet alignment device includes a conveyance roller for conveying a sheet S in a predetermined conveyance direction A along a conveyance path 10A, a reference member 48 for defining one boundary of the conveyance path 10A, and an alignment roller 41 for making the sheet S conveyed by the conveyance roller abut against the reference member 48, wherein the side face on the alignment roller 41 side of the reference member 48 has a first side face 48A along a boundary of the conveyance path 10A, and a second side face 48B which is provided continuous to the first side face 48A on at least one of an upstream side and a downstream side in a conveyance direction A of the first side face 48A, and is separated from the conveyance path 10A as getting away from the first side face 48A.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet aligning device and an image forming system. [Background technology]

[0002] In an image forming apparatus, a sheet is transported along a transport path that passes through an imaging unit that forms an image on the sheet, but if the sheet enters the imaging unit in an inclined position relative to the transport direction, the image will be formed at an angle on the sheet, so it is necessary to correct the position of the sheet before it enters the imaging unit. Registration rollers are generally used as a means for correcting the position of the sheet, but a configuration in which the sheet is abutted against a reference member provided on the side of the transport path is also known (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 58-109344 [Patent Document 2] Japanese Patent Application Publication No. 61-51445 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configurations disclosed in Patent Documents 1 and 2, a roller that moves the sheet in a direction intersecting the conveying direction strikes the sheet against a reference member. However, if the sheet is tilted with respect to the conveying direction, one end of the side of the sheet that faces the reference member first comes into contact with the reference member, and the roller continues to translate the sheet thereafter, causing the sheet to buckle before the other end of the side comes into contact with the reference member, making it impossible to correct its posture.

[0005] SUMMARY OF THE INVENTION In consideration of the above circumstances, an object of the present invention is to abut one side of a sheet against a reference member provided on the side of a conveying path without buckling the sheet. [Means for solving the problem]

[0006] In order to solve the above problem, the sheet alignment device of the present invention comprises a conveying roller that conveys a sheet in a predetermined conveying direction along a conveying path, a reference member that defines one boundary of the conveying path, and an alignment roller that abuts the sheet conveyed by the conveying roller against the reference member, and the side of the reference member facing the alignment roller has a first side that follows the boundary of the conveying path, and a second side that is continuous with the first side on at least one of the upstream and downstream sides of the first side in the conveying direction, and that moves away from the conveying path the more it moves away from the first side.

[0007] The alignment roller may be closer to a boundary between the first side surface and the second side surface than to an end of the reference member in the transport direction.

[0008] The alignment rollers may be provided at two locations in the transport direction.

[0009] An image forming system according to the present invention includes the sheet aligning device and an image forming device that forms an image on the sheet aligned by the sheet aligning device. [Effects of the Invention]

[0010] According to the present invention, one side of the sheet can be abutted against a reference member provided on the side of the conveying path without buckling the sheet. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a front view schematically illustrating an internal configuration of an image forming system according to an embodiment of the present invention. [Figure 2] 1 is a perspective view showing a sheet aligning device according to an embodiment of the present invention; [Figure 3] 1 is a plan view showing a main part of a sheet aligning device according to an embodiment of the present invention; [Figure 4]1 is a schematic diagram illustrating a main part of a sheet aligning device according to an embodiment of the present invention. [Figure 5] FIG. 2 is a plan view showing a reference member according to an embodiment of the present invention. [Figure 6] FIG. 10 is a plan view showing the operation of a conventional sheet conveying device. [Figure 7] 5A and 5B are plan views illustrating the operation of the sheet conveying device according to the embodiment of the present invention. [Figure 8] FIG. 10 is a plan view showing the operation of a conventional sheet conveying device. [Figure 9] 5A and 5B are plan views illustrating the operation of the sheet conveying device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] An image forming system 100 according to an embodiment of the present invention will be described below with reference to the drawings.

[0013] Fig. 1 is a front view showing a schematic internal configuration of image forming system 100. In the following description, the front side of the paper in Fig. 1 is the front side (front side) of image forming system 100, and left and right directions are described based on the direction when image forming system 100 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and rear, respectively.

[0014] The image forming system 100 includes a paper feeder 110, an inkjet recording apparatus 1, and a drying apparatus 120. The paper feeder 110 stores sheets S and supplies the sheets S to the inkjet recording apparatus 1. The inkjet recording apparatus 1 forms an image on the sheets S using an inkjet method. The drying apparatus 120 heats the sheets S transported from the inkjet recording apparatus 1 to dry the ink. A post-processing apparatus (not shown) for stacking the discharged sheets S may be provided to the left of the drying apparatus 120. The post-processing apparatus may have functions such as stapling, folding, and punching.

[0015] The sheet feeding device 110 includes a sheet feeding cassette 4, a sheet feeding roller 5, a conveying path 10A, a sheet aligning device 6, and an evacuation tray 9. The sheet feeding cassette 4 stores stacked sheets S. The sheet feeding roller 5 sends the sheets S one by one from the sheet feeding cassette 4 to the conveying path 10A. Two sheet aligning devices 6, each having the same basic configuration, are arranged one above the other. The sheet aligning devices 6 have the function of correcting the inclination of the sheet S with respect to the conveying direction A and the function of correcting the positional deviation of the sheet S in the width direction X that intersects with the conveying direction A. The conveying path 10A leads to the sheet aligning device 6 on the lower side. The conveying path 10B branches off from the conveying path 10A and leads to the sheet aligning device 6 on the upper side. The conveying path 10C branches off from the conveying path 10B and leads to the evacuation tray 9. Conveying rollers 17 for conveying the sheet S are provided in the conveying paths 10A, 10B, and 10C.

[0016] At the branch point between conveying paths 10A and 10B, there is provided an opening / closing member 8A that swings about an axis to open either conveying path 10A or conveying path 10B and close the other. When opening / closing member 8A opens conveying path 10A, sheet S is guided into conveying path 10A, and when opening / closing member 8B opens conveying path 10B, sheet S is guided into conveying path 10B.

[0017] At the branch point between conveying path 10B and conveying path 10C, there is provided an opening / closing member 8B that swings about an axis to open one of conveying path 10B and conveying path 10C and close the other. When opening / closing member 8B opens conveying path 10B, sheet S is guided to conveying path 10B, and when opening / closing member 8B opens conveying path 10C, sheet S is guided to conveying path 10C.

[0018] The inkjet recording apparatus 1 includes a transport unit 7 that adsorbs a sheet S and transports it in a predetermined transport direction Y. Four head units 11 that eject ink to form an image are provided above the transport unit 7. The inkjet recording apparatus 1 includes a transport path 10D that passes through the gap between the transport unit 7 and the head units 11. Transport paths 10A and 10B merge into transport path 10D.

[0019] The transport unit 7 includes an endless transport belt 21 and a suction unit 24. The transport belt 21 has a number of air holes (not shown) and is wound around a drive roller 25 and a driven roller 22. The upper surface of the suction unit 24 has a number of air holes (not shown) and is in contact with the inner surface of the transport belt 21. The suction unit 24 sucks air through the air holes of the transport belt 21 and the suction unit 24, thereby adsorbing the sheet S to the transport belt 21. The drive roller 25 is driven counterclockwise by a drive unit (not shown) including a motor and a reduction gear, causing the transport belt 21 to rotate counterclockwise, and the sheet S adsorbed to the transport belt 21 is transported in the Y direction.

[0020] Each head unit 11 includes one or more inkjet heads 12. An ink container 20 filled with black, cyan, magenta, or yellow ink is connected to each head unit 11. The four head units 11 are arranged spaced apart from one another, and a maintenance unit 13 that performs maintenance on the inkjet heads 12 is arranged to the right of each head unit 11.

[0021] The control unit 2 (see FIG. 2) includes a calculation unit and a storage unit (not shown). The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit performs various processes by reading and executing control programs stored in the storage unit. Note that the control unit 2 may be realized by an integrated circuit that does not use software.

[0022] The display operation unit 19 includes a display panel, a touch panel laminated on the display panel, and a keypad (not shown). The control unit 2 displays a screen showing the operation menu and status of the inkjet recording apparatus 1 on the display panel, and controls each part of the inkjet recording apparatus 1 in response to operations detected by the touch panel and the keypad.

[0023] The drying device 120 includes a transport unit 90 and a heating unit 95. The transport unit 90 adsorbs the sheet S onto a transport belt 91 using the same principle as the transport unit 7, and transports the sheet S in the Y direction. The heating unit 95 includes a heat source such as an infrared heater, and dries the ink on the sheet S.

[0024] The drying device 120 includes a conveying path 10E that passes through the gap between the conveying unit 90 and the heating unit 95. The conveying path 10D is connected to the conveying path 10E. The conveying path 10F branches downward from the conveying path 10E. The conveying path 10F branches into the conveying paths 10G and 10J. The conveying paths 10G and 10J are curved in an arc shape. The conveying path 10H branches off to the right from the conveying path 10G, and the conveying path 10K branches off to the right from the conveying path 10J. The conveying paths 10H and 10K merge into the conveying path 10M. The conveying path 10L branches off downward from the conveying path 10M, passes below the conveying paths 10J, 10G, and 10F, and merges with the conveying path 10E. Conveyance rollers 17 for conveying the sheet S are provided on the conveyance paths 10E, 10F, 10G, 10H, 10J, 10K, 10L, and 10M.

[0025] At the branch point between conveying path 10E and conveying path 10F, there is provided an opening / closing member 8C that swings about an axis to open one of conveying path 10E and conveying path 10F and close the other. When opening / closing member 8C opens conveying path 10E, sheet S is guided into conveying path 10E, and when opening / closing member 8C opens conveying path 10F, sheet S is guided into conveying path 10F.

[0026] At the branch point between conveying path 10G and conveying path 10K, there is provided an opening / closing member 8D that swings about an axis to open one of conveying path 10G and conveying path 10K and close the other. When opening / closing member 8D opens conveying path 10G, sheet S is guided into conveying path 10G, and when opening / closing member 8D opens conveying path 10K, sheet S is guided into conveying path 10K.

[0027] At the branch point between conveying paths 10G and 10H, there is provided an opening / closing member 8E that swings about an axis to open one of conveying paths 10G and 10H and close the other. When turning over sheet S, opening / closing member 8E opens conveying path 10G, and conveying rollers 17 convey sheet S counterclockwise until the rear end of sheet S that has entered conveying path 10G passes the branch point, after which opening / closing member 8E opens conveying path 10H, and conveying rollers 17 convey sheet S clockwise.

[0028] At the branch point between conveying path 10J and conveying path 10K, there is provided an opening / closing member 8F that swings about an axis to open one of conveying path 10J and conveying path 10K and close the other. When turning over sheet S, opening / closing member 8F opens conveying path 10J, and conveying rollers 17 convey sheet S counterclockwise until the rear end of sheet S that has entered conveying path 10J passes the branch point, after which opening / closing member 8F opens conveying path 10K, and conveying rollers 17 convey sheet S clockwise.

[0029] At the branch point between conveying path 10L and conveying path 10M, there is provided an opening / closing member 8G that swings about an axis to open one of conveying path 10L and conveying path 10M and close the other. When opening / closing member 8G opens conveying path 10L, sheet S is guided into conveying path 10L, and when opening / closing member 8G opens conveying path 10M, sheet S is guided into conveying path 10M.

[0030] The inkjet recording apparatus 1 includes a conveying path 10N connected to the conveying path 10M, and the paper feeder 110 includes a conveying path 10P extending from the conveying path 10N to the sheet alignment device 6 below. The conveying path 10N includes, for example, an electrostatic adsorption type conveying belt 26 that adsorbs and conveys the sheet S using static electricity.

[0031] The basic operation of the image forming system 100 is as follows. When an image formation job is input to the inkjet recording apparatus 1 from the display / operation unit 19, an external computer, or the like, the paper feed roller 5 feeds sheets S one by one from the paper feed cassette 4 to the conveying path 10A. Each time a sheet S is fed, the open / close member 8A alternately opens the conveying paths 10A and 10B, and the lower and upper sheet alignment devices 6 alternately perform sheet alignment processing. When the sheet alignment device 6 feeds the sheet S to the conveying unit 7 at a predetermined timing, the conveying unit 7 attracts the sheet S to the conveying belt 21 and conveys it in the Y direction. When the control unit 2 supplies raster-format image data to the head unit 11 in synchronization with the conveyance of the sheet S, ink is ejected from the head unit 11, and an image is formed on the sheet S. The sheet S with the image formed thereon is conveyed to the drying device 120.

[0032] In the drying device 120, the ink on the sheet S transported along the transport path 10E is dried. In the case of an image forming job for single-sided printing of only one sheet, the sheet S is guided to the transport path 10E and transported to a post-processing device (not shown) connected to the left of the drying device 120. On the other hand, in the case of an image forming job for single-sided printing of multiple sheets, the sheet S is guided to the transport path 10F, and after being inverted using the transport paths 10G and 10J alternately, it is transported to the post-processing device via the transport path 10L.

[0033] On the other hand, in the case of a double-sided printing image formation job, the sheet S is inverted by alternately using the conveying paths 10G and 10J, and then conveyed to the sheet aligning device 6 below via the conveying paths 10M, 10N, and 10P, where an image is formed on the back side by the inkjet recording device 1. Thereafter, the ink is dried by the drying device 120, and the sheet S is inverted by alternately using the conveying paths 10G and 10J, and then conveyed to the post-processing device via the conveying path 10L.

[0034] [Sheet alignment device] Fig. 2 is a perspective view showing the sheet alignment device 6. Fig. 3 is a plan view showing the main parts of the sheet alignment device 6. Fig. 4 is a schematic view showing the main parts of the sheet alignment device 6. The sheet alignment device 6 is arranged with the conveying direction A of the sheet S (see Figs. 2 and 3) inclined relative to the horizontal (see Fig. 1), but for the sake of convenience, the following description will be given assuming that the conveying direction A is horizontal.

[0035] The sheet alignment device 6 includes a frame 31, a conveying roller 32, an alignment roller 41, and a reference member 48. The frame 31 is formed in a generally rectangular shape that is longer in the front-to-rear direction than in the left-to-right direction. The frame 31 supports various components described below. The conveying roller 32 includes a shaft 32A and a plurality of roller bodies 32B. The conveying roller 32 is provided at two locations, one on the right end side and one on the left end side of the frame 31, with the front-to-rear direction as the axial direction. The conveying roller 32 is driven by a motor 33 via a timing belt 34.

[0036] The reference member 48 is disposed behind the sheet S conveyed by the right conveyance roller 32. The reference member 48 is a roughly rectangular parallelepiped member with its longitudinal direction in the left-right direction. The alignment rollers 41 are provided between the left and right conveyance rollers 32 and in two locations in front of the reference member 48.

[0037] Next, the right-side alignment roller 41 and its surrounding structure will be described. The alignment roller 41 has a shaft 41A and a roller body 41B. The alignment roller 41 is supported by a box-shaped holder 42 with its axial direction extending in the left-right direction. The driving force of the motor 43 is transmitted to the alignment roller 41 via a gear train 44, a drive gear 45, and a gear train 47, in that order. The gear train 47 is provided on the right side of the holder 42 and has, from rear to rear, gears 51, 52, 53, and 54. Of these, gear 54 is attached to the right end of the shaft 41A of the alignment roller 41.

[0038] Similar to the right-hand alignment roller 41, the left-hand alignment roller 41 is also provided with a holder 42, a drive gear 45, and a gear train 47. However, the gear train 47 of the left-hand alignment roller 41 is provided on the left side surface of the holder 42. Because the left and right drive gears 45 are attached to a common shaft 46, the left and right alignment rollers 41 are driven synchronously.

[0039] The gear 51 and the drive gear 45 are attached to a connecting member 66. A pinion 64 is attached to the connecting member 66. The left and right pinions 64 are attached to a common shaft 63, which is driven by a motor 61 via a worm gear 62. The pinion 64 is meshed with a rack 65 fixed to the frame 31. Rotation of the pinion 64 moves the alignment roller 41 back and forth via the connecting member 66 and the holder 42. With this configuration, the position of the alignment roller 41 in the front-to-rear direction can be adjusted.

[0040] FIG. 5 is a plan view showing the reference member 48. The side of the reference member 48 facing the alignment roller 41 includes a first side surface 48A and a second side surface 48B. The first side surface 48A defines one boundary between the conveying paths 10A and 10B (in this example, the boundary between the rear sides of the conveying paths 10A and 10B). The second side surface 48B is provided contiguous with the first side surface 48A on at least one of the upstream and downstream sides of the first side surface 48A in the conveying direction A. The further away from the first side surface 48A it is, the further away it is from the conveying paths 10A and 10B it becomes. A boundary 48P between the first side surface 48A and the second side surface 48B forms an obtuse angle. Note that in this example, the second side surface 48B is provided both upstream and downstream of the first side surface 48A in the conveying direction A. However, the second side surface 48B may be provided on either the upstream or downstream side of the first side surface 48A in the conveying direction A.

[0041] 6 is a plan view showing the operation of a conventional sheet alignment device 6. The reference member 48 is formed in a rectangular parallelepiped shape. When the sheet S is conveyed in direction A while tilted counterclockwise, the sheet S is conveyed backward with one side of the sheet S contacting the upstream corner of the reference member 48 in the conveying direction A, and the sheet S rotates clockwise around the contact point between the sheet S and the reference member 48. In this case, the distance L1 between the contact point and the alignment roller 41 is long, so the degree of freedom of deformation of the sheet S increases, making the sheet S more likely to buckle.

[0042] 7 is a plan view showing the operation of the sheet aligning device 6 according to this embodiment. The reference member 48 has a first side surface 48A and a second side surface 48B. When the sheet S is conveyed in direction A while tilted counterclockwise, the sheet S is conveyed rearward with one side of the sheet S in contact with a boundary portion 48P on the upstream side of the reference member 48 in the conveying direction A, and the sheet S rotates clockwise around the contact point between the sheet S and the reference member 48. In this case, the distance L2 between the contact point and the alignment roller 41 is shorter than the distance L1, so the degree of freedom of deformation of the sheet S is reduced, and the sheet S is less likely to buckle.

[0043] 8 is a plan view showing the operation of a conventional sheet alignment device 6. The reference member 48 is formed in a rectangular parallelepiped shape. When the sheet S is transported in direction A while tilted clockwise, the sheet S is transported backward with one side of the sheet S contacting a corner of the reference member 48 on the downstream side in the transport direction A, and the sheet S rotates counterclockwise around the contact point between the sheet S and the reference member 48. In this case, the distance L1 between the contact point and the alignment roller 41 is long, so the degree of freedom of deformation of the sheet S increases, making the sheet S more likely to buckle.

[0044] 9 is a plan view showing the operation of the sheet aligning device 6 according to this embodiment. The reference member 48 has a first side surface 48A and a second side surface 48B. When the sheet S is conveyed in direction A while tilted clockwise, the sheet S is conveyed rearward with one side of the sheet S in contact with a boundary portion 48P on the downstream side of the reference member 48 in the conveying direction A, and the sheet S rotates counterclockwise around the contact point between the sheet S and the reference member 48. In this case, the distance L2 between the contact point and the alignment roller 41 is shorter than the distance L1, so the degree of freedom of deformation of the sheet S is reduced, and the sheet S is less likely to buckle.

[0045] The sheet aligning device 6 according to the present embodiment described above includes a conveyance roller 32 that conveys the sheet S in a predetermined conveyance direction A along the conveyance path 10A, a reference member 48 that defines one boundary of the conveyance path 10A, and an alignment roller 41 that abuts the sheet S conveyed by the conveyance roller 32 against the reference member 48. The reference member 48 has a side facing the alignment roller 41 that includes a first side 48A that follows the boundary of the conveyance path 10A, and a second side 48B that is continuous with the first side 48A and is provided at least either upstream or downstream of the first side 48A in the conveyance direction A, and that is further away from the conveyance path 10A as it moves away from the first side 48A. According to the present embodiment, one side of the sheet S can abut against the reference member 48 provided on the side of the conveyance path 10A without buckling the sheet S.

[0046] Furthermore, in the sheet alignment device 6 according to this embodiment, the alignment roller 41 is closer to the boundary 48P between the first side surface 48A and the second side surface 48B than to the end of the reference member 48 in the conveying direction A. According to this embodiment, the distance L2 between the alignment roller 41 and the contact point between the sheet S and the reference member 48 is closer, so the degree of freedom of the sheet S is lowered and the sheet S is less likely to buckle.

[0047] Furthermore, according to the sheet alignment device 6 of this embodiment, the alignment rollers 41 are provided at two locations in the conveying direction A. According to this embodiment, the sheet S is more easily aligned with the reference member 48 than when there is only one alignment roller 41.

[0048] Furthermore, the image forming system 100 according to this embodiment includes a sheet alignment device 6 and an image forming apparatus (inkjet recording apparatus 1) that forms an image on the sheet S aligned by the sheet alignment device 6. According to this embodiment, it is possible to suppress tilting and misalignment of the image.

[0049] The above embodiment may be modified as follows.

[0050] In the above embodiment, the boundary 48P between the first side surface 48A and the second side surface 48B forms an obtuse angle, but the boundary 48P may be curved in an arc shape. This configuration can suppress deformation of the portion of the sheet S that abuts against the boundary 48P.

[0051] In the above embodiment, an example was shown in which the image forming apparatus was the inkjet recording apparatus 1, but the image forming apparatus may also be an apparatus that forms images by a method other than the inkjet method (for example, an electrophotographic method). [Explanation of symbols]

[0052] 1. Inkjet recording device (image forming device) 10A, 10B transport path 32 Transport roller 41 Alignment roller 48 Reference member 48A 1st side 48B 2nd side 48P border A Conveying direction S seat

Claims

1. a conveying roller that conveys the sheet in a predetermined conveying direction along a conveying path; a reference member defining one boundary of the transport path; an alignment roller that abuts the sheet conveyed by the conveyance roller against the reference member, The side surface of the reference member on the alignment roller side is a first side surface along a boundary of the transport path; A sheet alignment device characterized by having a second side that is continuous with the first side at least on either the upstream side or downstream side of the first side in the conveying direction, and that becomes more distant from the conveying path as it moves away from the first side.

2. 2. The sheet aligning device according to claim 1, wherein the alignment roller is closer to a boundary between the first side surface and the second side surface than to an end of the reference member in the conveying direction.

3. 3. The sheet aligning device according to claim 1, wherein the aligning rollers are provided at two positions in the conveying direction.

4. The sheet aligning device according to claim 1; an image forming apparatus that forms an image on the sheet aligned by the sheet alignment apparatus.

Images