Sheet conveyance device, image formation device, and image formation system

Abstract

To reduce deterioration of accuracy of lateral registration correction.SOLUTION: A skew correction part of a sheet conveyance device includes a driving roller unit (210B) which has: a first support member (219) for supporting a first skew correction roller (212L), a second skew correction roller (212R), a first turning mechanism (217L) for turning the first skew correction roller, and a second turning mechanism (217R) for turning the second skew correction roller; and a first positioning part (219H). The skew correction part includes a driven roller unit (270) which has: a second support member (290) for supporting a first driven roller (252L), a second driven roller (252R), a third turning mechanism for turning the first driven roller, and a fourth turning mechanism for turning the second driven roller; and a second positioning part (271H). The first positioning part and the second positioning part are configured to enable positioning when the driving roller unit and the driven roller unit are assembled.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device that corrects skew of a sheet being conveyed, an image forming apparatus, and an image forming system. [Background technology]

[0002] For example, in an image forming apparatus that forms an image on a sheet, a sheet conveying device is provided that corrects skew of the sheet conveyed to the image forming section in order to form an image without tilting the sheet. As a sheet conveying device that performs such skew correction, one that includes multiple skew correction rollers that are arranged in parallel in the width direction of the sheet and can rotate independently has been proposed (see Patent Document 1). The device disclosed in Patent Document 1 corrects skew of the sheet by varying the rotation speeds of the skew correction rollers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-155677 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described method of correcting skew of a sheet by varying the rotation speeds of multiple skew correction rollers, it is difficult to perform so-called lateral registration correction, in which the skew correction rollers move the position of the sheet in the width direction perpendicular to the conveyance direction. This requires providing a separate mechanism, such as a pair of rollers for performing lateral registration correction, in addition to the skew correction rollers, which may result in a longer conveyance path in the sheet conveyance direction. Therefore, it is conceivable to configure the multiple skew correction rollers to be able to skew the sheet by rotating them about an axis in a direction intersecting (perpendicular to) the surface of the sheet while maintaining a parallel state, thereby enabling lateral registration correction of the sheet.

[0005] When the skew correction roller is configured to be rotatable as described above, it is conceivable to configure the driven roller that is driven by the skew correction roller to also rotate in accordance with the skew correction roller. However, if the alignment between the skew correction roller and the driven roller that is driven by it becomes misaligned, for example, during manufacturing of the sheet conveying device or replacement of the skew correction roller, the driven roller will no longer rotate in accordance with the rotation of the skew correction roller. If the rotation of the driven roller does not follow the rotation of the skew correction roller, a force from the driven roller is applied to the sheet in a different direction, causing the sheet to not skew as expected and resulting in a problem of deterioration in the accuracy of lateral registration correction.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sheet conveying device, an image forming apparatus, and an image forming system that are capable of reducing deterioration in the accuracy of lateral registration correction. [Means for solving the problem]

[0007] One aspect of the present invention is a skew correction unit that corrects skew of a sheet, the skew correction unit including a first skew correction roller that can be rotated by a first rotary drive motor to convey a sheet, a second skew correction roller that can be rotated by a second rotary drive motor to convey a sheet, a first turning mechanism that is driven by a first turning drive motor to turn the first skew correction roller around a first axis extending in a transverse direction that intersects a conveyance direction of the sheet and a width direction orthogonal to the conveyance direction, a second turning mechanism that is driven by a second turning drive motor to turn the second skew correction roller around a second axis extending in the transverse direction, a first support member that supports the first skew correction roller, the first turning mechanism, the second skew correction roller, and the second turning mechanism, and a first support member that supports the first skew correction roller, the first turning mechanism, the second skew correction roller, and the second turning mechanism. a drive roller unit having a positioning portion, a first driven roller that is rotated in response to the rotation of the first skew correction roller, a second driven roller that is rotated in response to the rotation of the second skew correction roller, a third pivoting mechanism that rotates the first driven roller around a third axis extending in the intersecting direction, a fourth pivoting mechanism that rotates the second driven roller around a fourth axis extending in the intersecting direction, a second support member that supports the first driven roller, the second driven roller, the third pivoting mechanism, and the fourth pivoting mechanism, and a second positioning portion, wherein the first positioning portion and the second positioning portion are configured to be able to be aligned when the drive roller unit and the driven roller unit are assembled. [Effects of the Invention]

[0008] According to the present invention, it is possible to reduce deterioration in the accuracy of lateral registration correction. [Brief explanation of the drawings]

[0009] [Figure 1] 1A is a schematic diagram showing the general configuration of an inkjet recording system according to an embodiment of the present invention, and FIG. 1B is a block diagram showing a control unit of a print module. [Figure 2] FIG. 4 is a top view showing a registration section of the print module according to the embodiment. [Figure 3] FIG. 2 is a perspective view showing a registration section of the print module according to the embodiment. [Figure 4] 10A is a perspective view showing the registration unit before and after the registration drive roller is rotated, and FIG. [Figure 5] 1A is a top view showing the registration unit before the sheet is conveyed, FIG. 1B is a top view showing the registration unit in a state where skew correction of the sheet is being performed, and FIG. 1C is a top view showing the registration unit in a state where lateral registration correction of the sheet is being performed. [Figure 6] FIG. 3 is a side cross-sectional view showing a registration section of the print module according to the embodiment. [Figure 7] 6 is a flowchart showing control of a print module according to the embodiment. [Figure 8] FIG. 2 is a perspective view showing a registration block according to the embodiment. [Figure 9] FIG. 10 is a top view showing the configuration supported by the registration block according to the embodiment. [Figure 10] FIG. 2 is a perspective view showing a separation mechanism according to the embodiment. [Figure 11] 1A is a top view showing the spacing mechanism according to the present embodiment, FIG. 1B is a front view showing the spacing mechanism according to the present embodiment, and FIG. 1C is a side view showing the spacing mechanism according to the present embodiment. [Figure 12] FIG. 2 is a cross-sectional view showing a pair of registration rollers according to the embodiment. [Figure 13] 1A is a diagram showing the state immediately after the registration drive roller has rotated, FIG. 1B is a diagram showing the restoring force generated in the registration driven roller due to the rotation of the registration drive roller, and FIG. 1C is a diagram showing the rotation of the registration driven roller due to the rotation of the registration drive roller. [Figure 14](a) is a diagram showing the state immediately after the registration drive roller has turned when the registration drive roller and the registration driven roller are misaligned, (b) is a diagram showing the restoring force generated in the registration driven roller when the registration drive roller and the registration driven roller are misaligned and the registration drive roller has turned, and (c) is a diagram showing the registration driven roller turning when the registration drive roller and the registration driven roller are misaligned and the registration drive roller has turned. [Figure 15] FIG. 2 is a perspective view showing a registration drive block and a registration follower block before assembly. [Figure 16] FIG. [Figure 17] 10 is a perspective view showing a case where a registration drive block and a registration follower block are assembled while being positioned; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. In this embodiment, an inkjet recording system 1 is used as an image forming system.

[0011] [Inkjet recording system] First, the general configuration of an inkjet recording system 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1(a) is a schematic diagram showing the general configuration of the inkjet recording system 1 according to this embodiment. Fig. 1(b) is a block diagram showing the control unit of a print module.

[0012] The inkjet recording system 1, which serves as an image forming system, is a sheet-fed inkjet recording system that produces a recorded material by forming an ink image on a sheet S using two liquids: a reaction liquid and ink. As shown in FIG. 1(a), the inkjet recording system 1 is composed of a feeding module 100, a printing module 200, a drying module 300, a fixing module 400, a cooling module 500, an inverting module 600, and a discharging module 700. A cut sheet S supplied from the feeding module 100 is transported along a transport path, processed in each module, and discharged by the discharging module 700. In the inkjet recording system 1, an image is formed on the sheet in the printing module 200, which serves as an image forming device, and various processes are performed on the sheet on which the image has been formed downstream of the printing module 200 in the sheet transport direction. Therefore, the drying module 300, the fixing module 400, the cooling module 500, the inverting module 600, the discharging module 700, etc. can also be considered processing devices.

[0013] The feeding module 100 has three storage cabinets 110a, 110b, and 110c that store sheets S. Each of the storage cabinets 110a, 110b, and 110c is configured to be able to be pulled out toward the front of the device. The sheets S are fed one by one in each of the storage cabinets 110a, 110b, and 110c by a separation belt and a transport roller (not shown), and are transported to the print module 200. The number of storage cabinets 110a, 110b, and 110c is not limited to three, and the configuration may include one, two, four, or more.

[0014] The print module 200 includes a registration unit 210 (see FIG. 2) as a skew correction unit that performs skew correction and lateral registration correction before image formation, which will be described in detail later, a print belt unit 220, and a recording unit 230. The sheet S conveyed from the feeding module 100 has its skew and position corrected by a plurality of conveying roller pairs 208, 209 (see FIG. 2) and the registration unit 210, and is then conveyed to the print belt unit 220. The recording unit 230 is disposed at a position facing the print belt unit 220 with respect to the conveyance path. The plurality of conveying roller pairs 208, 209 and the registration unit 210 constitute a sheet conveying unit 200A as a sheet conveying device that conveys the sheet to the recording unit 230. The recording unit 230 also constitutes an image forming unit that performs recording (printing) on ​​the conveyed sheet S from above using a plurality of recording heads 230H (see FIG. 2).

[0015] The multiple recording heads 230H are arranged in the sheet transport direction. In this embodiment, in addition to the four colors of Y (yellow), M (magenta), C (cyan), and Bk (black), a total of five line-type recording heads corresponding to the reaction liquids are provided. Note that the number of colors and recording heads is not limited to five. The inkjet method can be a method using a heating element, a piezoelectric element, an electrostatic element, or a MEMS element. Ink of each color is supplied to the recording head from an ink tank (not shown) via an ink tube. The sheet S printed by the recording unit 230 is adsorbed and transported by the print belt unit 220, thereby ensuring clearance with the recording head. The sheet S printed by the recording unit 230 is subjected to detection of misalignment and color density of the image formed on the sheet S by an inline scanner (not shown) located downstream of the recording unit in the sheet transport direction. The detection results are used to correct the printed image.

[0016] The drying module 300 includes a decoupling unit 320, a drying belt unit 330, and a hot air blowing unit 340. This unit reduces the liquid content of the ink applied to the sheet S by the recording unit 230 of the print module 200, thereby improving the fixation of the ink to the sheet S. The sheet S printed by the recording unit 230 of the print module 200 is transported to the decoupling unit 320, which is located upstream of the drying module 300 in the sheet transport direction. The decoupling unit 320 transports the sheet S from above using air pressure and belt friction. By loosely holding and transporting the sheet S on the belt, the sheet S on the print belt unit 220, where the ink image is formed, is prevented from shifting. The drying belt unit 330 is located below the belt, and the hot air blowing unit 340 is located above the belt, facing each other across the belt. The sheet S transported from the decoupling unit 320 is adsorbed and transported by the drying belt unit 330, and simultaneously receives hot air from the hot air blowing unit 340 to dry the ink-applied surface. The drying method may be a combination of a method of applying hot air, a method of irradiating the surface of the sheet S with electromagnetic waves (ultraviolet rays, infrared rays, etc.), or a conductive heat transfer method using contact with a heating element.

[0017] The fixing module 400 has a fixing belt section 410. The fixing belt section 410 has an upper belt unit and a lower belt unit, and the sheet S conveyed from the drying module 300 passes between the heated upper belt unit and the lower belt unit, thereby fixing the ink to the sheet S.

[0018] The cooling module 500 has a plurality of cooling sections 510, which cool the high-temperature sheet S transported from the fixing module 400. The cooling sections 510 are configured to cool the sheet S by drawing in outside air into a cooling box with a fan, increasing the pressure inside the cooling box, and blowing air from nozzles formed in the transport guide onto the sheet S. The cooling sections 510 are arranged both above and below the transport path, and cool the sheet S from both sides.

[0019] The cooling module 500 also has a transport path switching unit that can switch the transport path of the sheet S depending on whether the sheet S is transported to the inversion module 600 or to a duplex transport path used for duplex printing. During duplex printing, the sheet S is transported to a transport path below the cooling module 500. In this case, the sheet S is further transported from the cooling module 500 along a duplex transport path through the fixing module 400, drying module 300, print module 200, and feeding module 100. The duplex transport path of the fixing module 400 is provided with a first inversion unit 420 that inverts the sheet S. The sheet S is then transported again from the feeding module 100 to the pre-imaging registration correction unit of the print module 200, the print belt unit 220, and the recording unit 230, where it is printed.

[0020] The reversing module 600 has a second reversing section 640, and can reverse the front and back of the conveyed sheet S, and can change the front and back orientation of the discharged sheet S. The discharge module 700 has a top tray 720 and a stacking section 750, and aligns and stacks the sheets S conveyed from the reversing module 600 on the top tray 720 or the stacking section 750, or discharges them onto an external tray (not shown) or the like.

[0021] As shown in FIG. 1B, the print module 200 includes a control unit 201 as a controller that performs various controls in the inkjet recording system 1 and the print module 200. The control unit 201 includes a CPU 201a, which is an example of a processor, and a RAM 201b, a ROM 201c, and a HDD 201d as storage units. The CPU 201a, RAM 201b, ROM 201c, and HDD 201d are connected by a bus to enable communication of information with each other, and are also connected to the controllers of each module and an operation unit (not shown) via an interface (not shown) to enable communication of information. The control unit 201 is also connected to various motors and sensors of a registration unit 210 (described in detail below) via an interface (not shown). Specifically, the control unit 201 is connected to registration drive motors M1L and M1R, steering motors M2L and M2R, image sensors SN1L and SN1R, tip registration sensors SN2L and SN2R, and home position sensors SN3L and SN3R (described in detail below). The detailed control of the registration unit 210 by the control unit 201 will be described later.

[0022] [Print module registration section and surrounding structure] Next, the registration unit 210 in the print module 200 and its surrounding configuration will be described with reference to Figures 2, 3, and 6. Figure 2 is a top view showing the registration unit of the print module according to this embodiment. Figure 3 is a perspective view showing the registration unit of the print module according to this embodiment. Figure 6 is a side cross-sectional view showing the registration unit of the print module according to this embodiment.

[0023] 2 and 3, in the print module 200, in the sheet conveying section 200A (see FIG. 1), pairs of conveying rollers 208, 209 for conveying a sheet are arranged in this order in the sheet conveying direction V. Note that these pairs of conveying rollers 208, 209 have a lower roller having a roller made of, for example, EPDM and an upper roller being, for example, a rubber roller made of urethane, and the lower roller is biased toward the upper roller by a spring (not shown). Note that the sheet conveying direction V here refers to the direction when the sheet S is not skewed, and does not refer to the conveying direction in the steering operation described below.

[0024] Furthermore, in the sheet conveying section 200A of the print module 200, a registration section 210 that corrects skew of the sheet conveyed by the conveying roller pair 208, 209 is disposed downstream in the sheet conveying direction V of the conveying roller pair 208, 209. Furthermore, in the print module 200, a print belt section 220 is disposed downstream in the sheet conveying direction V of the registration section 210. The print belt section 220 is configured to include a print belt 25 that rotates so as to adsorb and convey the sheet, and a recording section 230 (plurality of recording heads 230H) (see FIG. 2) that forms an image on the sheet conveyed by the print belt 25.

[0025] (Registration roller pair) As shown in FIG. 6, the registration unit 210 includes a left registration roller pair (hereinafter simply referred to as a "registration roller pair") 240L on the left side of the conveyance center in the sheet conveyance direction V (see FIG. 2). The registration unit 210 also includes a right registration roller pair (hereinafter simply referred to as a "registration roller pair") 240R arranged in parallel on the right side of the conveyance center in the sheet conveyance direction V (see FIG. 2). The registration roller pair 240L includes a registration drive roller 212L as a first skew correction roller, and a registration driven roller 252L as a first driven roller that is disposed opposite the registration drive roller 212L and is driven when it comes into contact with the registration drive roller 212L. Similarly, the registration roller pair 240R includes a registration drive roller 212R as a second skew correction roller, and a registration driven roller 252R as a second driven roller that is disposed opposite the registration drive roller 212R and is driven when it comes into contact with the registration drive roller 212R. The registration drive rollers 212L and 212R are made of rubber rollers made of polyurethane, for example, and the registration driven rollers 252L and 252R are made of rollers made of EPDM, for example.

[0026] The registration driven rollers 252L, 252R of the registration roller pair 240L, 240R are included in a separation mechanism 270 (see FIG. 10) as a driven roller unit. The registration driven rollers 252L, 252R are configured to be movable by the separation mechanism 270 between a contact position where they are in contact with the registration drive rollers 212L, 212R and a separation position where they are separated.

[0027] (Drive turning mechanism) Next, the drive turning mechanisms 211L, 211R in the registration unit 210 will be described. As shown in Figures 2 and 3, the registration unit 210 has a drive turning mechanism 211L that rotationally drives and turns a registration drive roller 212L serving as a first skew correction roller capable of conveying a sheet. Similarly, the registration unit 210 has a drive turning mechanism 211R that rotationally drives and turns a registration drive roller 212R serving as a second skew correction roller capable of conveying a sheet.

[0028] The drive turning mechanism 211L has a registration drive motor M1L as a first rotation drive motor. The drive turning mechanism 211L also has a steering motor M2L as a first turning drive motor, and a turning transmission mechanism 217L as a first turning mechanism that turns the registration drive roller 212L by the driving rotation of the steering motor M2L. The turning transmission mechanism 217L is configured with a motor gear 213L, a drive input gear 214L, and a steering shaft 215L. That is, the turning transmission mechanism 217L turns the registration drive roller 212L around the steering shaft 215L as a first shaft that extends in an intersecting direction (perpendicular to the sheet conveyance direction and the width direction perpendicular to the sheet conveyance direction, in this embodiment).

[0029] Similarly, the drive turning mechanism 211R has a registration drive motor M1R as a second rotation drive motor. The drive turning mechanism 211R also has a steering motor M2R as a second turning drive motor, and a turning transmission mechanism 217R as a second turning mechanism that turns the registration drive roller 212R by the driving rotation of the steering motor M2R. The turning transmission mechanism 217R is configured with a motor gear 213R, a drive input gear 214R, and a steering shaft 215R. That is, the turning transmission mechanism 217R turns the registration drive roller 212R around the steering shaft 215R as a second shaft that extends in a direction intersecting (perpendicular to) the sheet conveyance direction and the width direction perpendicular to the conveyance direction (in this embodiment, perpendicular to the sheet conveyance direction).

[0030] The rotation shafts of the registration drive motors M1L and M1R are drivingly connected to the registration drive rollers 212L and 212R, respectively. In other words, the rotation of the registration drive motors M1L and M1R rotates the registration drive rollers 212L and 212R so that the rotation speeds of the registration drive rollers 212L and 212R can be changed independently.

[0031] The steering shafts 215L, 215R rotatably support frames 216L, 216R (see FIG. 3) that support the registration drive rollers 212L, 212R and registration drive motors M1L, M1R, respectively. That is, the registration drive rollers 212L, 212R and registration drive motors M1L, M1R are supported rotatably about the steering shafts 215L, 215R whose axial directions are in a direction intersecting (orthogonal to) the sheet conveying direction V and the width direction W orthogonal to the sheet conveying direction V.

[0032] Meanwhile, the steering motors M2L, M2R are arranged along an axial direction parallel to the axial direction of the steering shafts 215L, 215R, and motor gears 213L, 213R are fixed to the respective rotation shafts of the steering motors M2L, M2R. Drive input gears 214L, 214R fixed to the respective steering shafts 215L, 215R are meshed with the respective motor gears 213L, 213R. This allows the control unit 201 to drive the steering motors M2L, M2R to turn (rotate) the registration drive rollers 212L, 212R and the registration drive motors M1L, M1R around the steering shafts 215L, 215R.

[0033] In short, the registration drive rollers 212L, 212R are rotationally driven by the control unit 201 driving the registration drive motors M1L, M1R. Also, the control unit 21 drives the steering motors M2L, M2R to rotate the registration drive rollers 212L, 212R in a direction inclined with respect to the sheet conveying direction V. This allows the conveying speed and conveying direction of the registration roller pairs 240L, 240R to be changed independently of each other.

[0034] A home position sensor SN3L serving as a first reference position detector and a home position sensor SN3R serving as a second reference position detector are disposed near the registration drive rollers 212L and 212R, respectively. The home position sensors SN3L and SN3R detect the home positions (first and second reference positions) of the registration drive rollers 212L and 212R. The home positions of the registration drive rollers 212L and 212R are positions (steering initial positions) where the registration roller pairs 240L and 240R face straight (without tilt) in the conveyance direction. In other words, detection by the home position sensors SN3L and SN3R enables a steering initial setting operation to be performed to return the registration roller pairs 240L and 240R to positions that are not tilted with respect to the conveyance direction.

[0035] (Configuration of sheet skew detection) Leading edge registration sensors SN2L and SN2R serving as skew detection units, each configured with an optical sensor, are disposed near the nip of each of the registration roller pairs 240L and 240R at the same position in the sheet conveying direction V (i.e., aligned in the width direction W). The control unit 201 (see FIG. 1(b)) calculates the amount of skew of the sheet S conveyed to the registration unit 210 from the difference in timing at which the leading edge of the sheet S is detected by each of the leading edge registration sensors SN2L and SN2R and the conveying speed at which the sheet S is conveyed. Note that, in the present embodiment, the amount of skew of the sheet S is detected by a plurality of leading edge registration sensors SN2L and SN2R. However, the present invention is not limited to this, and other methods may be used, such as detecting the skew of the sheet S by analyzing an image using an image sensor or the like that captures an image.

[0036] (Configuration for detecting the sheet's width direction position) An image sensor SN1L serving as a width position detection unit is disposed upstream of the pair of registration rollers 240L in the sheet conveying direction V. Furthermore, an image sensor SN1R serving as a width position detection unit is disposed downstream of the pair of registration rollers 240R in the sheet conveying direction V. The image sensor SN1L detects the edge position of the left end of the sheet S, and the image sensor SN1R detects the edge position of the right end of the sheet S. These image sensors SN1L and SN1R may be optical sensors such as CIS sensors. Then, the control unit 201 calculates the width direction position (so-called horizontal registration position) of the sheet S conveyed to the registration unit 210 based on the edge positions of the left and right ends.

[0037] In this embodiment, two image sensors SN1L and SN1R are used to detect both end positions of the sheet S in the width direction W, but this is not limiting and a single image sensor that is longer in the width direction W than the range through which the sheet S passes may be used. Alternatively, the position of one end of the sheet S may be detected by a single image sensor, and the position of the sheet S in the width direction may be calculated from the sheet size input to the control unit 201 (or detected by another part), for example. Furthermore, a configuration may be adopted in which the position of one end of the sheet S is detected by a single image sensor, and the movement of the sheet S in the width direction W (lateral registration) is controlled using this as a reference position.

[0038] [Print module operation] Next, the operation of the print module 200 will be described with reference to FIGS. 4(a), 4(b), 5(a), 5(b), 5(c), and 7. FIG. 4(a) is a perspective view showing the registration unit before the registration drive roller is rotated. FIG. 4(b) is a perspective view showing the registration unit after the registration drive roller is rotated. FIG. 5(a) is a top view showing the registration unit before the sheet is conveyed. FIG. 5(b) is a top view showing the registration unit in a state where skew correction of the sheet is being performed. FIG. 5(c) is a top view showing the registration unit in a state where lateral registration correction of the sheet is being performed. FIG. 7 is a flowchart showing control of the print module according to this embodiment. Note that, in the image formation control shown in FIG. 7, an example in which an image is formed on one side of a sheet is described, but this control is repeated even when images are formed on both sides of a sheet.

[0039] In the print module 200, the control unit 201 (see FIG. 1B) receives detection results from the left and right image sensors SN1L and SN1R and the left and right front registration sensors SN2L and SN2R. Based on these detection results, the control unit 201 controls the left and right registration drive motors M1L and M1R and the left and right steering motors M2L and M2R to convey the sheet and perform skew correction and lateral registration correction. Note that skew correction here refers to correcting the inclination with respect to the sheet conveyance direction V, and lateral registration correction refers to correcting the deviation of the sheet from a reference position in the width direction W. However, in this embodiment, the registration unit 210 basically aims to correct skew of the sheet, and as a result of correcting skew of the sheet, it is often necessary to also correct the position in the width direction W. Therefore, both of these corrections are also referred to as skew correction in a broad sense.

[0040] 7 when it receives a print job directly from an operation unit (not shown) or from an external computer connected via a network. The print job received by the control unit 201 includes information such as the number of copies to be printed and the size of the sheets S to be printed, as specified by the user. That is, the control unit 201 determines whether to start printing in accordance with the received print job (S1).

[0041] Next, the control unit 201 selects a sheet S of a size specified by the print job from, for example, one of the storage cabinets 110a, 110b, or 110c, and feeds the sheet S using the feeding module 100. Then, the control unit 201 drives the drive motor and the like to convey the sheet S toward the registration unit 210 using the conveying roller pairs 208 and 209 (see FIG. 2), and causes the sheet S to reach the registration roller pairs 240L and 240R (S2).

[0042] Next, the control unit 201 calculates and determines the attitude (amount of skew) of the sheet S based on the detection results input from the leading edge registration sensors SN2L and SN2R (S3). Note that the attitude (amount of light blocking) of the sheet S here refers to the angle of inclination with respect to the sheet conveyance direction V, more precisely, the angle of inclination with respect to the width direction W at the leading edge of the sheet S. Specifically, as described above, the control unit 201 determines the angle of inclination of the sheet S based on the difference in timing at which the two leading edge registration sensors SN2L and SN2R detect the leading edge of the conveyed sheet S and the conveyance speed of the sheet S.

[0043] Next, the control unit 201 creates a skew correction profile for the pair of registration rollers 240L, 240R to correct the skew of the sheet S based on the skew angle of the sheet S calculated as described above (S4). Then, the control unit 201 executes the skew correction (active operation) in accordance with the skew correction profile (S5).

[0044] Specifically, the registration drive motors M1L and M1R are driven according to the skew correction profile based on instructions from the control unit 201, whereby the rotational speeds of the registration roller pairs 240L and 240R are independently controlled and driven. Then, a speed difference is generated between the rotational speeds of the registration roller pairs 240L and 240R to perform skew correction of the sheet. For example, in the states shown in FIGS. 4A and 5A, the registration drive motors M1L and M1R are controlled so that the registration roller pair 240L has a conveying speed VL and the registration roller pair 240R has a conveying speed VR. Here, as shown in FIG. 5B, the skew angle of the sheet S conveyed skewed is detected, a skew correction profile is created, and the registration drive motors M1L and M1R are independently controlled and driven according to the skew correction profile. Then, the conveying speed VR of the registration roller pair 240R is controlled to be greater than the conveying speed VL of the registration roller pair 240L. As a result, the sheet S is rotated as indicated by the arrow ω, and the skew of the sheet S is corrected as indicated by the broken line in the figure.

[0045] 7, the control unit 201 calculates the lateral registration position (lateral deviation amount) of the sheet S, that is, the positions of both ends of the sheet S in the width direction W, based on the detection of the left and right image sensors SN1L and SN1R (S6). Specifically, the control unit 201 detects the positions of both ends of the sheet S in the width direction W by detecting how much of the image sensors SN1L and SN1R are covered by the sheet S, and calculates the lateral deviation amount of the sheet S from the positions of both ends.

[0046] Next, the control unit 201 creates a lateral registration correction profile for the pair of registration rollers 240L, 240R to correct the lateral registration (lateral deviation) of the sheet S based on the calculated lateral registration position of the sheet S (S7). Then, the control unit 201 executes the lateral registration correction (steering operation) in accordance with the lateral registration correction profile (S8).

[0047] Specifically, the steering motors M2L and M2R are driven according to a lateral registration correction profile based on instructions from the control unit 201, thereby independently controlling the rotation angles of the registration roller pairs 240L and 240R. The registration roller pairs 240L and 240R are then rotated to correct the sheet's widthwise position. For example, in the states shown in FIGS. 4A and 5A, the steering motors M2L and M2R control the angles of the registration drive rollers 212L and 212R so that the registration roller pairs 240L and 240R are positioned as detected by the home position sensors SN3L and SN3R. Therefore, the registration roller pairs 240L and 240R are positioned so as to face straight in the conveyance direction. Here, as shown in FIG. 5C, the lateral registration position of the sheet S conveyed with a lateral deviation is detected, a lateral registration correction profile is created, and the steering motors M2L and M2R are independently controlled and driven according to the lateral registration correction profile. Then, the registration roller pairs 240L and 240R are each rotated, and the sheet S is conveyed in the direction of the rotation by the registration roller pair 240L at a conveying speed VL, and is also conveyed in the direction of the rotation by the registration roller pair 240R at a conveying speed VR. As a result, the sheet S is conveyed while moving in the width direction W as shown by the arrow VB, and the lateral registration position of the sheet S is corrected to a reference position (a position that coincides with the conveying center) as shown by the dashed line in the figure. Note that in this lateral registration correction, in normal times when skew correction is not performed, the conveying speeds VL and VR of the registration roller pairs 240L and 240R are controlled to be the same and the rotation angles to be the same.

[0048] 7, after the above-described lateral registration correction is completed, the control unit 201 transfers the sheet S to the print belt 25 (see FIG. 2) (S9). Then, after transferring the sheet S to the print belt 25, the separation mechanism 270, which will be described in detail later, separates the registration driven rollers 252R, 252L from the registration drive rollers 212R, 212L (S10).

[0049] Next, the control unit 201 causes the recording unit 230 to form an image on the sheet S (S11). After the trailing edge of the sheet S passes through the nip (registration nip) between the pair of registration rollers 240L, 240R, the separation mechanism 270, described in detail below, causes the registration driven rollers 252R, 252L to contact the registration driving rollers 212R, 212L (S12). Then, the sheet S is discharged toward the discharge module 700 (see FIG. 1) (S13), which ends the print job and the image forming operation for one sheet.

[0050] In the case of double-sided printing in which images are formed on both sides (front and back) of the sheet S, the control unit 201 reverses the sheet S in the reversing module 600 after the operation of step S13, and conveys it again toward the pair of registration rollers 240L, 240R. Then, the operations from step S2 onwards are similarly performed.

[0051] In addition, in the flowchart shown in FIG. 7, the skew correction (active operation) and the lateral registration correction (steering operation) are performed separately, but the skew correction and the lateral registration correction may be combined and both corrections may be performed simultaneously.

[0052] [Register Drive Block] Next, the registration drive block 210B, which integrates the registration drive rollers 212L, 212R, registration drive motors M1L, M1R, steering motors M2L, M2R, and rotation transmission mechanisms 217L, 217R, etc., into a single unit, will be described with reference to Figures 8 and 9. Figure 8 is a perspective view showing the registration drive block according to this embodiment. Figure 9 is a top view showing the configuration supported by the registration drive block according to this embodiment.

[0053] (Configuration of the register drive block) As shown in Figures 11 and 12, the registration drive block 210B serving as a drive roller unit includes a support stay 219 serving as a first support member. The support stay 219 generally includes a stay body 219a and a side plate 219b. The stay body 219a is configured as a plate-shaped frame for the registration drive block 210B, and the side plate 219b is attached to the side of the stay body 219a. The registration drive rollers 212L, 212R, registration drive motors M1L, M1R, steering motors M2L, M2R, and rotation transmission mechanisms 217L, 217R are attached to the stay body 219a so as to be supported by the registration drive rollers 212L, 212R. The rotation transmission mechanisms 217L, 217R include motor gears 213L, 213R, drive input gears 214L, 214R, and steering shafts 215L, 215R. In addition, home position sensors SN3L and SN3R are supported on the side plates 219b. Plate-like protrusions 219c, 219c are formed on both sides of the stay body 219a in the width direction perpendicular to the sheet conveying direction. Screw holes 219d, 219d are formed in each of the protrusions 219c to be fastened to a frame (not shown) of the registration unit 210 with screws 800 (see FIG. 15).

[0054] Therefore, the registration drive rollers 212L, 212R, registration drive motors M1L, M1R, steering motors M2L, M2R, turning transmission mechanisms 217L, 217R, and home position sensors SN3L, SN3R are integrated by being supported by the support stay 219. In short, these components are supported by the support stay 219 to form an integrated unit called the registration drive block 210B.

[0055] [About the separation mechanism] Next, the separation mechanism 270 including the registration driven rollers 252L and 252R will be described with reference to Figures 10, 11(a), 11(b), and 11(c). Figure 10 is a perspective view showing the separation mechanism according to this embodiment. Figure 11(a) is a top view showing the separation mechanism according to this embodiment. Figure 11(b) is a front view showing the separation mechanism according to this embodiment. Figure 11(c) is a side view showing the separation mechanism according to this embodiment.

[0056] 10, 11(a), 11(b), and 11(c), the separation mechanism 270 moves the registration driven rollers 252L, 252R between a contact position where the rollers are in contact with the registration drive rollers 212L, 212R and a separation position where the rollers are separated from the registration drive rollers 212L, 212R. That is, the separation mechanism 270 is roughly configured to include the registration driven rollers 252L, 252R, pivoting shafts 255L, 255R as third and fourth shafts, a swing shaft 272, a swing member 271, a drive unit 280, and a frame unit 290 as a second support member. The registration driven rollers 252L, 252R, pivoting shafts 255L, 255R, swing shaft 272, swing member 271, and drive unit 280 are supported by the frame unit 290 and integrated into a unit.

[0057] Specifically, the swing shaft 272 is supported by the frame portion 290, and the swing member 271 is swingably supported by the swing shaft 272. The drive portion 280 drives the swing member 271 to swing. The swing of the swing member 271 moves the registration driven rollers 252L, 252R in the vertical direction, and thereby the registration driven rollers 252L, 252R move between the contact position and the separated position.

[0058] Specifically, the frame unit 290 has a bottom plate 295 fixed to a frame (not shown) provided in the registration unit 210 of the print module 200. Side plates 291 and 294 are fixed to both ends of the bottom plate 295 in the width direction W, extending upright in the vertical direction. A support frame 292 is disposed between the side plates 291 and 294 of the bottom plate 295 in the width direction W, and side plates 292a and 292b of the support frame 292 are fixed to the top ends of the side plates 291 and 294. The swing shaft 272 is fixedly supported at the upper ends of the side plates 291 and 294. The swing member 271 is supported on the swing shaft 272 so as to be swingable about the swing shaft 272 in the directions indicated by arrows Z1 and Z2. In addition, since one side of the swinging member 271 sandwiching the swinging shaft 272 and the other side thereof move in opposite directions in the up and down direction when swinging, one side will be referred to as one end 271A and the other side will be referred to as the other end 271B.

[0059] The other end 271B of the swinging member 271 abuts from below against frames 253L, 253R of swinging mechanisms 251L, 251R (see FIG. 12) serving as third and fourth swinging mechanisms, which will be described in detail later. Therefore, the swinging member 271 moves the registration driven rollers 252L, 252R in the vertical direction, i.e., in the direction of movement between the contact position and the separation position. The other end 271B is biased upward by a spring 273 (see FIG. 11(c)) serving as a biasing member that is compressed between the swinging member 271 and the frame portion 290. Therefore, the registration driven rollers 252L, 252R are biased by the spring 273 toward the registration drive rollers 212L, 212R and abut at the contact position. The pivoting shafts 255L, 255R of the turning mechanisms 251L, 251R, which will be described in detail later, are configured to be extendable and retractable, and support the registration drive rollers 212L, 212R so that they can move up and down. The other end 271B of the swinging member 271 presses the registration driven rollers 252L, 252R via the frames 253L, 253R, but is configured not to interfere with the pivoting movement of the registration driven rollers 252L, 252R around the pivoting shafts 255L, 255R.

[0060] Meanwhile, bent portions 271a, 271a are bent downward at one end 271A of the swinging member 271. A support shaft 286 is fixedly supported by these bent portions 271a, 271a, and a roller 285 is rotatably supported by the support shaft 286. The roller 285, which is rotatably supported by the swinging member 271 in this manner, comes into contact with and is pressed by a cam 284 of the drive unit 280, which will be described later.

[0061] The drive unit 280 includes a registration separation motor M4, an output gear 281, an input gear 282, a rotation shaft 283, and a cam 284. The registration separation motor M4 is attached to the bottom plate 295 and the support frame 292, and the output gear 281 is fixed to the output shaft. An input gear 282 fixed to a rotation shaft 283 is meshed with the output gear 281, and a cam 284 that abuts against the roller 285 is fixed to the rotation shaft 283. The cam 284 is configured so that the distance from the center of rotation varies in the rotation direction. The rotation shaft 283 is rotatably supported by side plates 292a and 292b of the support frame 292.

[0062] When the roller 285 is in contact with the cam 284 at a position where the distance from the rotation center to the outer periphery is near the shortest, the cam 284 does not push up the roller 285. Therefore, one end 271A of the swinging member 271 is not pushed up, and the other end 271B is pressed in the direction of arrow Z1 by the spring 273 (see FIG. 11(c)). As a result, the registration driven rollers 252L, 252R are displaced to contact positions where they come into contact with the registration drive rollers 212L, 212R.

[0063] The control unit 201 controls the rotation of the registration separation motor M4 to rotate the cam 284, and when the cam 284 is controlled to be in a state where the roller 285 is in contact with the position where the distance from the rotation center to the outer periphery of the cam 284 is approximately the longest, the cam 284 pushes up the roller 285. Then, one end 271A of the swinging member 271 is pushed up against the negative force of the spring 273, and the other end 271B is lowered in the direction of arrow Z2 (see FIG. 11(c)). As a result, the registration driven rollers 252L, 252R are moved to a separated position where they are separated from the registration drive rollers 212L, 212R.

[0064] [Configuration of registration driven roller] Next, the configuration of the registration driven rollers 252L, 252R will be described with reference to Figures 12 and 13. Figure 12 is a cross-sectional view showing a pair of registration rollers according to this embodiment. Figure 13(a) is a diagram showing the state immediately after the registration drive roller has turned. Figure 13(b) is a diagram showing the restoring force generated in the registration driven roller due to the turning of the registration drive roller. Figure 13(c) is a diagram showing the turning of the registration driven roller due to the turning of the registration drive roller.

[0065] As shown in FIG. 12, the pair of registration rollers 240R (240L) includes a registration drive roller 212R (212L) and a registration driven roller 252R (252L). The registration driven roller 252R (252L) is rotatably supported by a turning mechanism 251R (a turning mechanism 251L) serving as a fourth turning mechanism. The turning mechanism 251R (251L) includes a turning rotation shaft 255R (a turning rotation shaft 255L) serving as a fourth shaft and a frame 253R (253L). Since the registration driven roller 252L and the registration driven roller 252R have the same configuration, the following description of the registration driven rollers will focus on the registration driven roller 252R, and will omit a description of the registration driven roller 252L.

[0066] More specifically, the driven roller rotation shaft 254R is rotatably supported by the frame 253R, and the registration driven roller 252R is fixedly supported by the driven roller rotation shaft 254R. The frame 253R is supported by a pivoting rotation shaft 255R so that it can pivot (rotate) about that shaft; that is, the registration driven roller 252R is configured to be pivotable about the pivoting rotation shaft 255R. The pivoting rotation shaft 255R is disposed offset by a distance X in the conveyance direction from the position of the nip portion between the registration drive roller 212R and the registration driven roller 252R. This distance X is called the caster trail.

[0067] Next, the pivoting operation of the registration driven roller 252R will be described in detail. When the registration drive roller 212R is driven with a predetermined alignment, the registration driven roller 252R is biased toward the registration drive roller 212R by the spring 273 of the separation mechanism 270, and is rotated by the frictional force of the nip portion with the registration drive roller 212R. Note that the predetermined alignment refers to a state where the roller is aligned with the designed position (correct position).

[0068] At this time, as shown in Figure 13(a), due to the rotation of the registration drive roller 212R, the registration driven roller 252R receives a force in the vector direction indicated by arrow F. As described above, the pivoting rotation shaft 255R of the turning mechanism 251R is located at a distance X, which is the caster trail, in the conveying direction from the position of the nip portion where the force in the vector direction is received. Therefore, when the registration drive roller 212R begins its steering operation, the force in the vector direction (arrow F) acts in the direction shown in Figure 13(a), and is in a state where it acts in a direction inclined with respect to the angle of the registration driven roller 252R.

[0069] As a result, as shown in FIG. 13(b), a moment indicated by arrow Y is generated around the pivoting rotation shaft 255R in the registration driven roller 252R, generating a restoring force that rotates the registration driven roller 252R in a direction facing the registration drive roller 212R and restores its original position. This moment indicated by arrow Y increases or decreases depending on the deviation between the pivoting rotation shaft 255R and the force in the vector direction indicated by arrow F, and decreases as the moment approaches the vector direction. Therefore, the pivoting force becomes zero when the vector direction and the rotation direction of the registration driven roller 252R match. Due to this mechanism, as shown in FIG. 13(c), the registration driven roller 252R rotates, and its conveyance direction alignment with the registration drive roller 212R is matched.

[0070] As described above, in a configuration in which the registration drive roller 212R rotates, there is a predetermined distance (caster trail) in the conveyance direction between the nip portion between the registration drive roller 212R and the registration driven roller 252R and the center of the pivoting rotation shaft 255R. This allows the registration driven roller 252R to follow when the registration drive roller 212R performs a steering operation.

[0071] [Problems when the registration drive block and separation mechanism are misaligned] Here, the problem that occurs when the registration drive block 210B and the separation mechanism 270 are misaligned will be described with reference to FIG. 14. FIG. 14(a) is a diagram showing the state immediately after the registration drive roller has rotated when the registration drive roller and the registration driven roller are misaligned. FIG. 14(b) is a diagram showing the restoring force that occurs in the registration driven roller when the registration drive roller and the registration driven roller are misaligned and the registration drive roller has rotated. FIG. 14(c) is a diagram showing the registration driven roller having rotated when the registration drive roller and the registration driven roller are misaligned. Note that the registration driven roller 252L and the registration driven roller 252R have the same configuration, so in the following description of the registration driven roller, only the registration driven roller 252R will be described and a description of the registration driven roller 252L will be omitted.

[0072] As shown in FIG. 14(a), when viewed from a direction perpendicular to the surface direction of the conveyed sheet, the position of the steering shaft 215R, which is the rotation center of the registration drive roller 212R, and the position of the pivot rotation shaft 255R, which is the rotation center of the registration driven roller 252R, are misaligned. Note that the misaligned positions here refer to deviations from the design position (correct position) shown in FIG. 13(a). When the design position is deviated in this way, the registration driven roller 252R receives a force in the vector direction indicated by arrow F due to the rotation of the registration drive roller 212R at a misaligned position. As a result, the position of the nip between the registration drive roller 212R and the registration driven roller 252R is misaligned, and the force generated at the nip is weakened.

[0073] 14(b), a moment is generated around the pivoting rotation shaft 255R of the registration driven roller 252R, and a restoring force is generated that causes the registration driven roller 252R to pivot in a direction facing the registration drive roller 212R and restore its original position. However, the magnitude of this restoring force depends on the magnitude of the force generated at the nip, and therefore, as this force decreases, the restoring force also decreases. As a result, the pivoting force of the registration driven roller 252R relative to the pivoting movement of the registration drive roller 212R becomes smaller. As a result, the pivoting (following) of the registration driven roller 252R is delayed relative to the pivoting movement of the registration drive roller 212R, which increases resistance to skewed sheet feeding and causes a problem of deteriorating accuracy of lateral registration correction.

[0074] Furthermore, as shown in FIG. 14(c), even if the restoring force is small, the registration driven roller 252R will eventually rotate in response to the pivoting motion of the registration drive roller 212R and will face in the same direction as the conveyance direction of the registration drive roller 212R. However, because the steering shaft 215R of the registration drive roller 212R and the pivoting rotation shaft 255R of the registration driven roller 252R are misaligned, the registration driven roller 252R comes into partial contact with the registration drive roller 212R. Therefore, the resistance force of the registration driven roller 252R, which is driven to rotate, is generated at a position that is misaligned with the registration drive roller 212R, and the registration driven roller 252R applies a force to the sheet in a direction different from that of the registration drive roller 212R. This affects the direction in which the sheet conveyance force is generated.

[0075] As explained above, if the center position between the steering shaft 215R of the registration drive roller 212R and the pivoting rotation shaft 255R of the registration driven roller 252R is misaligned, it will affect the pivoting operation of the registration driven roller 252R, which will affect the accuracy of skew correction (especially lateral registration correction). Therefore, it is desirable that the center position between the steering shaft 215R of the registration drive roller 212R and the pivoting rotation shaft 255R of the registration driven roller 252R be in the correct position (aligned) as far as possible as designed. Therefore, in this embodiment, as will be explained below, the registration drive block 210B and the separation mechanism 270 can be positioned in an aligned state during manufacturing or maintenance.

[0076] [Positioning of the registration drive block and separation mechanism] Next, the alignment of the registration drive block 210B with the separation mechanism 270 and the configuration that enables positioning in that state will be described with reference to Figures 15, 16, and 17. Figure 15 is a perspective view showing the registration drive block and registration follower block before assembly. Figure 16 is a perspective view showing a positioning tool. Figure 17 is a perspective view showing the case where the registration drive block and registration follower block are assembled while being positioned.

[0077] (Through-hole configuration) 15, the registration drive block 210B is unitized and includes a support stay 219 that supports the registration drive rollers 212L, 212R, the registration drive motors M1L, M1R, the steering motors M2L, M2R, the rotation transmission mechanisms 217L, 217R, etc. Two through holes 219H are formed in a stay body 219a of the support stay 219 as first positioning portions or first hole portions.

[0078] One of the separation mechanisms 270 is also unitized and includes a frame portion 290 that supports the registration driven rollers 252L, 252R, the swing shaft 272, the swing member 271, the drive portion 280, etc. Two through-holes 271H are formed in the swing member 271 as second positioning portions or second hole portions. Note that, since the swing member 271 is biased upward by a spring 273 (see FIG. 11(c)), it does not swing when alignment is performed during manufacturing or maintenance, meaning that the positions of the two through-holes 271H do not move.

[0079] As shown in FIG. 16 , a positioning tool 900 serving as a positioning member includes a handle 901 that can be held by an operator and two rod-shaped pins 902 extending parallel to the handle 901. The pins 902 each have a tip 902a and a base 902b closer to the handle 901, with the tip 902a having a smaller diameter than the base 902b. The diameter of the tip 902a is sized to match the inner diameter of the through-hole 271H of the separation mechanism 270, and the diameter of the base 902b is sized to match the inner diameter of the through-hole 219H of the registration drive block 210B. The number of pins 902 is two, which is the same as the number of through-holes 271H and 219H formed in the two locations.

[0080] Then, the through-hole 219H of the registration drive block 210B and the through-hole 271H of the separation mechanism 270 are aligned to coincide when viewed from a direction perpendicular to the surface direction of the conveyed sheet. This positions the registration drive rollers 212L, 212R and the registration driven rollers 252L, 252R (more specifically, the steering shafts 215L, 215R and the swivel rotation shafts 255L, 255R) at their designed positions (correct positions). That is, the positions of the steering shafts 215L, 215R relative to the through-hole 219H and the positions of the swivel rotation shafts 255L, 255R relative to the through-hole 271H are configured to have the correct positional relationship relative to the design.

[0081] The through-hole 219H of the registration drive block 210B and the through-hole 271H of the separation mechanism 270 are located between the two registration drive rollers 212L, 212R or the two registration driven rollers 252L, 252R when viewed from a direction perpendicular to the sheet surface direction. In other words, the positioning tool 900 when inserted into the through-hole 219H and the through-hole 271H is located in an area through which the conveyed sheet passes. However, the present invention is not limited to this, and the positioning tool 900 may be located outside the area through which the sheet passes in the width direction of the sheet, for example.

[0082] (assembly work) Next, the alignment of the registration drive block 210B and the separation mechanism 270 and the fixing of the separation mechanism 270 in the aligned state will be described. The following description will be given assuming that this is performed during the manufacture of the print module 200. However, the assembly process is similar when, for example, replacing the registration drive rollers 212L, 212R or the registration driven rollers 252L, 252R during maintenance due to deterioration or contamination. For example, when replacing the registration drive rollers 212L, 212R, first, the old registration drive block 210B is removed from the frame (not shown) of the print module 200 (including the components supported by the frame). Then, the new registration drive block 210B is attached to the frame (not shown) of the print module 200. When replacing the registration driven rollers 252L, 252R, first, the old registration drive block 210B is removed from the frame (not shown) of the print module 200, and then the old separation mechanism 270 is removed from the frame (not shown). Then, a new spacing mechanism 270 is attached to the frame (not shown) of the print module 200, and finally, a new registration drive block 210B is attached to the frame (not shown) to complete the replacement. In the following explanation, only the attachment process will be described as a work performed during manufacturing.

[0083] In this embodiment, first, the frame portion 290 of the spacing mechanism 270 is fixed and attached to a frame (not shown) of the print module 200. Next, the registration drive block 210B is positioned above and facing the spacing mechanism 270, and the pin 902 of the positioning tool 900 is inserted so as to penetrate and engage with the through-hole 219H of the registration drive block 210B and the through-hole 271H of the spacing mechanism 270. This aligns the registration drive block 210B and the spacing mechanism 270 to their designed correct positions in the surface direction of the conveyed sheet. In other words, the steering shafts 215L, 215R and the swivel rotation shafts 255L, 255R are aligned to the correct positions with a positional relationship having a caster trail.

[0084] Then, with the pins 902 of the positioning tool 900 still inserted through the through holes 219H and 271H, the support stay 219 is fixed to a frame (not shown) of the print module 200 with the screws 800. As a result, the registration drive block 210B and the separation mechanism 270 are fixed in a state where they are aligned at the correct designed positions in the surface direction of the conveyed sheet. Thereafter, the positioning tool 900 is removed from the through holes 219H and 271H and separated, completing the process of assembling the registration drive block 210B to the separation mechanism 270. In this embodiment, the screws 800 and the screw holes 219d form a fixing portion.

[0085] [Summary of this embodiment] As described above, the registration unit 210 according to this embodiment includes the through-holes 219H and 271H into which the positioning tool 900 can be inserted when assembling the registration drive block 210B to the separation mechanism 270. This allows the positioning tool 900 to be inserted into the through-holes 219H and 271H to adjust the alignment between the registration drive block 210B and the separation mechanism 270. Generally, when a unit is separated into upper and lower parts, multiple parts are used, which can result in misalignment between the upper and lower parts due to component tolerances. However, in this embodiment, the registration drive block 210B and the separation mechanism 270 can be directly positioned by the positioning tool 900. This reduces misalignment between the registration drive rollers 212L and 212R and the registration driven rollers 252L and 252R. As a result, when correcting skew of a sheet, the registration driven rollers 252L and 252R follow the registration driving rollers 212L and 212R as expected, and deterioration in the accuracy of skew correction can be reduced.

[0086] Furthermore, the positioning tool 900 inserted into the through-holes 219H and 271H is in an area where the sheet passes. However, by fixing the registration drive block 210B to a frame (not shown) with screws 800 via the screw holes 219d, the positioning tool 900 can be removed. This allows the registration drive block 210B and the separation mechanism 270 to maintain their aligned state without interfering with the conveyance of the sheet.

[0087] [Possibilities for other embodiments] In the embodiment described above, the registration drive block 210B is fixed with the positioning tool 900 inserted into the through holes 219H and 271H using the screws 800, and then the positioning tool 900 is removed. However, this is not limiting. The through holes 219H and 271H may be disposed outside the area through which the sheet passes in the width direction, and the inserted positioning tool may be left in place without being removed. The shape of the positioning tool 900 is not limited to that of this embodiment, and may be any shape that can align the through holes 219H and 271H by inserting them into them. Furthermore, the shape and number of the through holes 219H and 271H may be any. For example, the cross-sectional shape of the hole may be polygonal. In this case, the number of holes may be one, or, of course, three or more.

[0088] Furthermore, in this embodiment, the positioning tool 900 is used to position the registration drive block 210B and the separation mechanism 270, but this is not limiting and a positioning tool may not be used. For example, a recess or a protrusion may be formed as the first positioning portion of the registration drive block 210B, and a protrusion or a recess that fits into the first positioning portion may be formed as the second positioning portion of the separation mechanism 270. In this case, these protrusions or recesses will be positioned outside the area where the sheet passes.

[0089] In addition, in this embodiment, the registration drive block 210B is fixed to a frame (not shown) of the registration unit 210, thereby being relatively fixed to the separation mechanism 270. However, the present invention is not limited to this, and the registration drive block 210B may be fixed directly to the separation mechanism 270.

[0090] Furthermore, in this embodiment, the registration drive motors M1L, M1R are supported by the support stay 219 of the registration drive block 210B. However, this is not limiting, and the registration drive motors M1L, M1R may be located in a location separate from the registration drive block 210B. In other words, when the registration drive block 210B is attached (assembled) to the detachable section 210S, the registration drive motors M1L, M1R may be drivingly connected to the registration drive rollers 212L, 212R.

[0091] Furthermore, in this embodiment, the steering motors M2L, M2R are supported on the support stay 219 of the registration drive block 210B. However, this is not limiting, and the steering motors M2L, M2R may be located in a location separate from the registration drive block 210B. In other words, when the registration drive block 210B is attached (assembled) to the detachable section 210S, the steering motors M2L, M2R may be drivingly connected to the turning transmission mechanisms 217L, 217R.

[0092] In the present embodiment, the registration unit 210 performs skew correction upstream in the sheet conveyance direction of the recording unit 230 as an image forming unit. However, the present invention is not limited to this, and skew correction may be performed upstream in the sheet conveyance direction of, for example, an image reading unit that reads an image on a sheet, a punching unit that punches holes in a sheet, a folding unit that folds a sheet, or the like. In short, the sheet conveying device that performs skew correction may be any device or may be incorporated into any device. [Explanation of symbols]

[0093] 1...inkjet recording system (image forming system) / 200...print module (image forming apparatus) / 200A...sheet conveying section (sheet conveying device) / 201...control section / 210...registration section (skew correction section) / 210B...registration drive block (drive roller unit) / 212L...registration drive roller (first skew correction roller) / 212R...registration drive roller (second skew correction roller) / 215L...steering shaft (first shaft) / 215R...steering 217L...swivel transmission mechanism (first swivel mechanism) / 217R...swivel transmission mechanism (second swivel mechanism) / 219...support stay (first support member) / 219H...through hole (first positioning portion, first hole portion) / 219d...screw hole (fixing portion) / 230H...recording head (image forming portion) / 251L...swivel mechanism (third swivel mechanism) / 251R...swivel mechanism (fourth swivel mechanism) / 252L...registration driven roller (first driven roller) / 252R...registration driven roller (second driven roller) / 255L... Swivel rotation shaft (third shaft) / 255R... Swivel rotation shaft (fourth shaft) / 270... Separation mechanism (driven roller unit) / 271H... Through hole (second positioning portion, second hole portion) / 290... Frame portion (second support member) / 300... Drying module (processing device) / 400... Fixing module (processing device) / 500... Cooling module (processing device) / 600... Reversing module (processing device) / 700... Discharge module (processing device) / 800... Screw (fixing portion) / 900... Position Positioning tool (positioning member) / 902... pin (rod-shaped portion) / M1L... registration drive motor (first rotation drive motor) / M1R... registration drive motor (second rotation drive motor) / M2L... steering motor (first swivel drive motor) / M2R... steering motor (second swivel drive motor) / SN1L... image sensor (width position detection portion) / SN1R... image sensor (width position detection portion) / SN2L... tip registration sensor (skew detection portion) / SN2R... tip registration sensor (skew detection portion)

Claims

1. a skew correction unit for correcting skew of the sheet; The skew correction unit a first skew correction roller capable of conveying a sheet by being rotationally driven by a first rotary drive motor; a second skew correction roller capable of conveying a sheet by being rotationally driven by a second rotary drive motor; a first turning mechanism that is driven by a first turning drive motor to turn the first skew correction roller around a first axis extending in a transverse direction that intersects a sheet conveying direction and a width direction orthogonal to the sheet conveying direction; a second turning mechanism that is driven by a second turning drive motor to turn the second skew correction roller around a second axis extending in the transverse direction; a first support member that supports the first skew correction roller, the first turning mechanism, the second skew correction roller, and the second turning mechanism; and a first positioning portion; a first driven roller that is rotated in response to rotation of the first skew correction roller, a second driven roller that is rotated in response to rotation of the second skew correction roller, a third turning mechanism that turns the first driven roller around a third axis extending in the intersecting direction, a fourth turning mechanism that turns the second driven roller around a fourth axis extending in the intersecting direction, a second support member that supports the first driven roller, the second driven roller, the third turning mechanism, and the fourth turning mechanism, and a second positioning portion, The first positioning portion and the second positioning portion are configured to be able to be aligned when the drive roller unit and the driven roller unit are assembled. A sheet conveying device characterized by:

2. the first positioning portion and the second positioning portion are aligned by being engaged with a positioning member when the drive roller unit and the driven roller unit are assembled together; 2. The sheet transport device according to claim 1.

3. the first positioning portion has a first hole portion formed in the first support member, the second positioning portion has a second hole portion formed in the second support member, the positioning member has a rod-shaped portion that is engaged by being fitted into the first hole portion and the second hole portion; 3. The sheet transport device according to claim 2.

4. the first hole portions and the second hole portions are plural and the same in number, The rod-shaped portions are plural and the number is the same as the number of the first hole portions and the second hole portions.

4. The sheet transport device according to claim 3.

5. the skew correction unit includes a fixing unit that fixes the drive roller unit and the driven roller unit in a state in which the first positioning unit and the second positioning unit are aligned, 3. The sheet transport device according to claim 2.

6. The first positioning portion and the second positioning portion are aligned so that the first axis and the third axis, and the second axis and the fourth axis, respectively, have a positional relationship in which they have a caster trail.

2. The sheet transport device according to claim 1.

7. The drive roller unit includes: the first rotation drive motor that rotates and drives the first skew correction roller; the second rotation drive motor that rotates and drives the second skew correction roller, the support member supports the first rotary drive motor and the second rotary drive motor; 2. The sheet transport device according to claim 1.

8. a skew detection unit that detects the amount of skew of the sheet conveyed to the skew correction unit; a control unit that corrects skew of the sheet by generating a speed difference between the first skew correction roller that is rotationally driven by the first rotary drive motor and the second skew correction roller that is rotationally driven by the second rotary drive motor based on the detection result of the skew detection unit; 8. The sheet transport device according to claim 7, wherein the sheet transport device is a sheet conveying device.

9. The roller unit includes: the first turning drive motor that drives the first turning mechanism to turn the first skew correction roller; the second turning drive motor that drives the second turning mechanism to turn the second skew correction roller, the support member supports the first swing drive motor and the second swing drive motor.

2. The sheet transport device according to claim 1.

10. a width position detection unit that detects a position in the width direction of the sheet conveyed to the skew correction unit; a control unit that corrects the position of the sheet in the width direction by rotating the first skew correction roller with the first turning drive motor and rotating the second skew correction roller with the second turning drive motor based on a detection result of the width position detection unit; 10. The sheet transport device according to claim 9.

11. A sheet conveying device according to any one of claims 1 to 10; an image forming unit that forms an image on the sheet conveyed by the sheet conveying device, An image forming apparatus characterized by:

12. The image forming apparatus according to claim 11; a processing device that processes the sheet on which the image is formed by the image forming device, An image forming system comprising:

Images