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 alignment roller 41 includes a shaft 41A, a first layer 41B1, and a second layer 41B2 which is provided between the shaft 41A and the first layer 41B1, and has hardness lower than that of the first layer 41B1.SELECTED DRAWING: Figure 8

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 inclination of the sheet before it enters the imaging unit.Regarding a means for correcting the inclination of a sheet, a registration roller is generally used, 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 relative to the conveying direction, one end of the four sides 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 the tilt.

[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 alignment roller comprises a shaft, a first layer, and a second layer that is provided between the shaft and the first layer and has a hardness lower than that of the first layer.

[0007] When a sheet is conveyed in an inclined position with respect to the conveying direction, a force for rotating the sheet in a direction to eliminate the inclination of the sheet may be greater than a force for conveying the sheet by the alignment roller.

[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 cross-sectional view showing an alignment roller according to an embodiment of the present invention. [Figure 6] 5A and 5B are plan views illustrating the operation of the sheet aligning device according to the embodiment of the present invention. [Figure 7] 5A and 5B are plan views illustrating the operation of the sheet aligning device according to the embodiment of the present invention. [Figure 8] 5A and 5B are plan views illustrating the operation of the sheet aligning device according to the embodiment of the present invention. [Figure 9] 5A and 5B are plan views illustrating the operation of the sheet aligning device according to the embodiment of the present invention. [Figure 10] 5A and 5B are plan views illustrating the operation of the sheet aligning 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 electrostatically adsorbed 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] 5 is a cross-sectional view showing the alignment roller 41. The alignment roller 41 includes a shaft 41A and a roller body 41B attached to the shaft 41A. The roller body 41B includes at least a first layer 41B1 and a second layer 41B2 attached between the first layer 41B1 and the shaft 41A. The hardness of the second layer 41B2 is lower than the hardness of the first layer 41B1.

[0041] 6 to 10 are plan views illustrating the operation of the sheet alignment device 6. First, the sheet S is conveyed in the direction A by the upstream conveyance roller 32 (see FIG. 6), and the leading edge of the sheet S enters between the alignment roller 41, which is located upstream in the conveyance direction A, and the conveyance paths 10A and 10B (see FIG. 7). At this time, the alignment roller 41 applies a conveying force F1 to the sheet S in a backward direction, but the sheet S resists the conveyance with a resistance force F2. However, because the conveying force F1 is greater than the resistance force F2, the sheet S is gradually conveyed backward. The conveyance roller 32 also conveys the sheet S in the direction A with a conveying force F3. Therefore, a resultant force F4 of the conveying force F3 and the resistance force F2 acts on the alignment roller 41. Then, because the hardness of the second layer 41B2 is lower than that of the first layer 41B1, the second layer 41B2 is twisted, and the alignment roller 41 is driven in a state in which the first layer 41B1 rotates clockwise (see FIG. 8). Therefore, the alignment roller 41 applies a conveying force F5=F1-F2 to the sheet S in a direction slightly inclined to the right. As a result, a resultant force F6 of the conveying forces F5 and F3 acts on the sheet S, and the sheet S is conveyed in the direction A while rotating counterclockwise. Because the resultant force F6 is greater than the conveying force F5, the sheet S is more likely to be aligned with the reference member 48.

[0042] Thereafter, the same behavior as above occurs in the alignment roller 41 on the downstream side in the conveying direction A, and the sheet S is conveyed in the A direction with one entire side of the sheet S in contact with the reference member 48. In this way, the inclination of the sheet S with respect to the conveying direction A and the positional deviation of the sheet S in the width direction X are corrected.

[0043] The conventional alignment roller 41 does not have the second layer 41B2, which has a lower hardness than the first layer 41B1, and therefore the first layer 41B1 cannot rotate in the clockwise direction. As a result, one end of one of the four sides of the sheet S that faces the reference member 48 first comes into contact with the reference member 48, and the alignment roller 41 continues to translate the sheet S backward thereafter, causing the sheet S to buckle before the other end of the side comes into contact with the reference member 48, resulting in a problem that the skew cannot be corrected.

[0044] In contrast, in this embodiment, the alignment roller 41 is driven in a state in which the second layer 41B2 is twisted and the first layer 41B1 is rotating clockwise, so that the sheet S is transported in the direction A while rotating, and one side of the sheet S can be abutted against the reference member 48 without buckling the sheet S.

[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 alignment roller 41 includes a shaft 41A, a first layer 41B1, and a second layer 41B2 that is provided between the shaft 41A and the first layer 41B1 and has a lower hardness than the first layer 41B1. According to the present embodiment, one side of the sheet S can be abutted against the reference member 48 provided on the side of the conveyance path 10A without buckling the sheet S.

[0046] Furthermore, according to the sheet alignment device 6 of this embodiment, when the sheet S is conveyed in an inclined position with respect to the conveying direction A, the force that rotates the sheet S in a direction that eliminates the inclination of the sheet S is greater than the force with which the alignment roller 41 conveys the sheet S. According to this embodiment, the sheet S is more easily aligned with the reference member 48 compared to when the force that rotates the sheet S in a direction that eliminates the inclination of the sheet S is not greater than the force with which the alignment roller 41 conveys the sheet S.

[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, an example has been shown in which the roller body 41B of the alignment roller 41 has the first layer 41B1 and the second layer 41B2, but when comparing the alignment rollers 41 on the upstream and downstream sides in the conveying direction A, the upstream alignment roller 41 rotates the sheet S for a longer period of time, so even if the hardness of the downstream alignment roller 41 is uniform, it is possible to obtain a certain degree of effect in suppressing buckling. Therefore, the hardness of the downstream alignment roller 41 may be uniform.

[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 41A axis 41B1 1st layer 41B2 2nd layer 48 Reference member 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 alignment roller is Axle and The first layer, a second layer disposed between the shaft and the first layer and having a hardness lower than that of the first layer.

2. 2. The sheet alignment device according to claim 1, wherein when a sheet is conveyed in an inclined position relative to the conveying direction, the force that rotates the sheet in a direction that eliminates the inclination of the sheet is greater than the force with which the alignment roller conveys the sheet.

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