Sheet conveying apparatus and image forming apparatus

Abstract

The invention provides a sheet conveying apparatus and an image forming apparatus. The sheet conveying apparatus includes a correction section and a side end detection section for detecting a side end of a sheet. The correcting portion includes a first roller rotatable about a first axis in an intersecting direction intersecting the conveying direction and the width direction and configured to correct a position of the sheet in the width direction, and a second roller disposed at a position different from the first roller in the width direction and rotatable about a second axis in the intersecting direction and configured to correct a position of the sheet in the width direction. And corrects the position of the sheet in the width direction. The control section performs first correction control in which the correction section corrects a position of the sheet in the width direction based on a detection result of the side end detection section, and performs second correction control in which the correction section corrects the position of the sheet in the width direction after the first correction control.

Description

Technical Field

[0001] The present invention relates to a sheet conveying apparatus and an image forming apparatus that correct an oblique movement and a position of a conveyed sheet in a width direction. Background Art

[0002] In an image forming apparatus that forms an image on a sheet, in order to form an image without tilt relative to the sheet, tilt movement correction is performed to correct the tilt movement of the sheet conveyed to the image forming portion.

[0003] In addition to the inclination of the conveyed sheet, lateral registration correction is performed to correct the position of the sheet in the width direction.

[0004] Furthermore, in image forming apparatuses that require high-precision printing, in particular, as disclosed in Japanese Patent Application Laid-Open No. 2022-65880, an apparatus is proposed that performs skew movement correction and lateral registration correction of a sheet in two stages: coarse adjustment and fine adjustment.

[0005] However, in Japanese Patent Laid-Open No. 2022-65880, when performing tilt movement correction and lateral alignment correction, the correction roller rotates around the approximate center of the sheet in the width direction. In this configuration, the end portions of the correction roller in the width direction rotate greatly, which may lead to an increase in the size of the device. Summary of the invention

[0006] An object of the present invention is to reduce the size of a sheet conveying device provided with a rotating roller.

[0007] According to one aspect of the present invention, a sheet conveying device is provided, which includes: a correction unit, which is equipped with a first correction roller and a second correction roller, the first correction roller can rotate around a first axis along a cross direction that intersects the conveying direction of the sheet and the width direction perpendicular to the conveying direction, and is configured to correct the position of the sheet in the width direction, the second correction roller is arranged at a position different from the first correction roller in the width direction, can rotate around a second axis along the cross direction, and is configured to correct the position of the sheet in the width direction; a driving unit, which is configured to rotationally drive the first correction roller and the second correction roller; a side end detection unit, which is configured to detect the side end of the sheet in the width direction of the sheet; and a control unit, which is configured to control the driving unit, wherein the control unit performs a first correction control based on a detection result of the side end detection unit, and performs a second correction control after the first correction control, in which the correction unit corrects the position of the sheet in the width direction, and in which the correction unit corrects the position of the sheet in the width direction.

[0008] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram showing the overall configuration of an inkjet recording system according to Embodiment 1.

[0010] Figure 2 is a top view showing an alignment unit of a printing module according to Example 1.

[0011] Figure 3 is a perspective view showing an alignment unit of a printing module according to Embodiment 1.

[0012] Figure 4A is a perspective view showing the alignment unit before the alignment driving roller is rotated.

[0013] Figure 4B is a perspective view showing the alignment unit after the alignment driving roller is rotated.

[0014] Figure 5A is a top view of the alignment unit before the sheet is conveyed.

[0015] Figure 5B 1 is a plan view showing the alignment unit in a state of performing tilt movement correction on a sheet.

[0016] Figure 5C 1 is a plan view showing the alignment unit in a state of performing lateral alignment correction.

[0017] Figure 6 A side sectional view showing an alignment unit of a printing module according to Embodiment 1.

[0018] Fig. 7A is a schematic diagram showing an example of measurement of the tilt movement amount.

[0019] Figure 7B is a diagram showing an example of a tilt movement correction curve.

[0020] Figure 7C is a schematic diagram illustrating the tilt movement correction operation.

[0021] Fig. 8A is a schematic diagram showing an example of measurement of the lateral alignment misalignment amount.

[0022] Figure 8B is a graph showing an example of a lateral registration misalignment correction curve.

[0023] Figure 8C is a schematic diagram illustrating a lateral registration misalignment correction operation.

[0024] Fig. 9 is a flowchart showing the control of the printing module according to Example 1.

[0025] Fig.10 is a block diagram showing the configuration of a control system according to Embodiment 1.

[0026] Fig.11A is a plan view showing the arrangement of an image sensor, a first front end alignment sensor, and a second front end alignment sensor according to Embodiment 1.

[0027] Fig. 11B is a top view showing the arrangement of an image sensor, a first front end alignment sensor, and a second front end alignment sensor in a case where only one image sensor is used.

[0028] Fig. 11C is a top view showing the arrangement of an image sensor, a first front end alignment sensor, and a second front end alignment sensor in a case where the image sensor is configured as a single image sensor.

[0029] Fig.11D : is a top view showing the arrangement of image sensors in the case where the tilt movement and position of the sheet in the width direction are detected by a single image sensor.

[0030] Fig.12 is a diagram showing an example of a correction curve when performing lateral registration misalignment correction.

[0031] Fig.13 is a diagram describing conversion of the velocity component and the angle component of the registration drive roller in the case where the tilt movement correction and the lateral registration misalignment correction are performed simultaneously.

[0032] Fig.14 is a diagram showing an example of a correction curve when the tilt movement correction and the lateral registration misalignment correction are performed simultaneously.

[0033] Fig.15 is a flowchart showing the control of the printing module according to Example 2. DETAILED DESCRIPTION

[0034] <Example 1>

[0035] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In Embodiment 1, a case where an inkjet recording system 1 is employed as an image forming system will be described.

[0036] [Inkjet recording system]

[0037] First, we will use Figure 1 The overall configuration of an inkjet recording system 1 according to Embodiment 1 is described. Figure 11 is a schematic diagram showing the overall configuration of an inkjet recording system 1 according to Embodiment 1. The inkjet recording system 1 as an image forming system is a sheet-feed type inkjet recording system that forms an ink image on a sheet S using two liquids, a reaction liquid and an ink, to produce recording. Figure 1 As shown, 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, a reversing module 600, and a discharge module 700. The cut-paper-like sheet S supplied from the feeding module 100 is conveyed along a conveying path, processed by each module, and discharged by the discharge module 700 as a sheet stacking device. In addition, in the inkjet recording system 1, in the printing module 200 as an image forming device, an image is formed on a sheet, and downstream of the printing module 200 in the conveying direction of the sheet, various processes are performed on the sheet on which the image is formed. Therefore, the drying module 300, the fixing module 400, the cooling module 500, the reversing module 600, the discharge module 700, etc. can also be called a processing device.

[0038] The feeding module 100 is provided with three storages 110a, 110b, and 110c for accommodating sheets S. Each of the storages 110a, 110b, and 110c is configured to be pulled out toward the front side of the apparatus. The sheets S are fed one by one through the separation belt and the conveying roller of each of the storages 110a, 110b, and 110c, and are conveyed to the printing module 200. Incidentally, the number of the storages 110a, 110b, and 110c is not limited to three, and the system may be configured to include one or two storages, or four or more storages.

[0039] The printing module 200 is equipped with an alignment unit 210 (see Figure 2 ), a printing belt unit 220 and a recording unit 230, the recording unit serving as a tilt movement correction unit for performing tilt movement correction and lateral alignment correction before image formation, as described below. The sheet S conveyed from the feeding module 100 is conveyed by a plurality of conveying roller pairs 208, 209 (see FIG. 1 ) serving as a conveying unit. Figure 2 ) and the alignment unit 210 correct the inclination and position of the sheet and then convey it to the print belt unit 220. The recording unit 230 is arranged at a position opposite to the print belt unit 220 with respect to the conveying path. These conveying roller pairs 208, 209 and the alignment unit 210 constitute a sheet conveying unit 200A as a sheet conveying device that conveys the sheet to the recording unit 230. In addition, the recording unit 230 constitutes an image forming unit that forms an image by performing a recording process (printing) on ​​the sheet S being conveyed from above by a plurality of recording heads 230H (see Figure 2 ).

[0040] A plurality of recording heads 230H are arranged along the conveying direction of the sheet (hereinafter referred to as the "conveying direction"). In the present embodiment, a total of five linear recording heads corresponding to four colors of Y (yellow), M (magenta), C (cyan) and Bk (black) and the reaction fluid are provided. Incidentally, the number of colors and recording heads is not limited to five. As an inkjet method, it is possible to adopt: a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS element, etc. Ink of each color is supplied to the recording head from an ink cartridge via an ink tube. The sheet S printed in the recording section 230 is conveyed while ensuring a gap with the recording head by being sucked and conveyed by the printing belt unit 220. For the sheet S printed in the recording section 230, the misalignment and color density of the image formed on the sheet S are detected by an online scanner arranged downstream of the recording section along the conveying direction. The detection result is used to correct the printed image.

[0041] The drying module 300 is provided with a decoupling portion 320, a drying belt unit 330, and a hot air blowing portion 340, which reduces the liquid content contained in the ink applied on the sheet in the recording portion 230 of the printing module 200 and enhances the fixing performance of the ink to the sheet S. The sheet S printed in the recording portion 230 of the printing module 200 is conveyed to the decoupling portion 320, which is arranged on the upstream side of the drying module 300 in the conveying direction. The decoupling portion 320 can convey the sheet S using the wind pressure from above and the friction of the belt, and prevent the misalignment of the sheet S on the printing belt unit 220 where the ink image is formed by slightly holding and conveying the sheet S on the belt. The drying belt unit 330 is arranged below the belt, and the hot air blowing portion 340 is arranged above the belt, and the two are opposite to each other with the belt interposed therebetween. The sheet S conveyed from the decoupling portion 320 is sucked and conveyed by the drying belt unit 330, and at the same time, the surface to which the ink is applied is dried by receiving hot air from the hot air blowing portion 340. Incidentally, as for the drying type, in addition to the type of applying hot air, a type of irradiating electromagnetic waves (such as ultraviolet rays or infrared rays) to the surface of the sheet S may be configured in combination with a conduction heat transfer type by contact of a heating element.

[0042] The fixing module 400 is provided with a fixing belt unit 410. The fixing belt unit 410 is provided with an upper belt unit and a lower belt unit, and the ink is fixed to the sheet S by passing the sheet S conveyed from the drying module 300 between the upper belt unit and the lower belt unit which are heated.

[0043] The cooling module 500 is provided with a plurality of cooling portions 510, and cools the hot sheet S conveyed from the fixing module 400. The cooling portions 510 are configured to cool the sheet S by sucking external air into a cooling box with a fan, increasing the pressure in the cooling box, and blowing air blown from nozzles formed on a conveying guide toward the sheet S. The cooling portions 510 are arranged on both sides, the upper side and the lower side, with respect to the conveying path, and cool the sheet S from both sides.

[0044] In addition, the cooling module 500 is also provided with a conveying path switching section that can switch the conveying path of the sheet S according to the case where the sheet S is conveyed to the reversing module 600 or the case where the sheet S is conveyed to the duplex conveying path used in duplex printing. During duplex printing, the sheet S is conveyed to the conveying path in the lower part of the cooling module 500. In this case, the sheet S is further conveyed along the duplex conveying path from the cooling module 500 through the fixing module 400, the drying module 300, the printing module 200, and the feeding module 100. In the duplex conveying path of the fixing module 400, a first reversing section 420 is provided to reverse the front and back sides of the sheet S. Then, the sheet S is conveyed again from the feeding module 100 through the pre-image formation alignment correction section of the printing module 200, the printing belt unit 220, and the recording section 230, and is printed in the recording section 230.

[0045] The reversing module 600 is provided with a second reversing section 640, and can reverse the front and back sides of the conveyed sheet and change the front and back directions of the discharged sheet. The discharge module 700 is provided with a top tray 720 and a stacking section 750, and adjusts and stacks the sheet S conveyed from the reversing module 600 on the top tray 720 or the stacking section 750, or discharges the sheet S to an external tray, etc.

[0046] [Alignment unit of the printing module and its surrounding structure]

[0047] Next, we will use Figure 2 , Figure 3 and Figure 6 The alignment unit 210 in the printing module 200 and the surrounding structure are described. Figure 2 is a top view showing an alignment unit of a printing module according to Example 1. Figure 3 is a perspective view showing an alignment unit of a printing module according to Embodiment 1. Figure 6 is a side sectional view showing an alignment unit of a printing module according to Embodiment 1.

[0048] In the printing module 200, as Figure 2 and Figure 3 As shown, in the sheet conveying section 200A (see Figure 1), the conveying roller pairs 208, 209 are arranged in sequence along the conveying direction X. Incidentally, these conveying roller pairs 208, 209 are equipped with a lower roller and an upper roller, the lower roller includes a roller made of, for example, EPDM, and the upper roller includes a rubber roller made of, for example, polyurethane, and the lower roller is pressed against the upper roller by a spring. Incidentally, the conveying direction X mentioned here indicates the direction in the case where the sheet S does not show an inclined movement, and does not refer to the conveying direction in the steering operation described below.

[0049] Furthermore, in the sheet conveying section 200A of the printing module 200, an alignment unit 210 as a correction section is arranged downstream of the conveying roller pair 208, 209 in the conveying direction X. That is, the alignment unit 210 corrects the posture of the sheet conveyed by the conveying roller pair 208, 209. Furthermore, in the printing module 200, a printing belt unit 220 is arranged downstream of the alignment unit 210 in the conveying direction X. The printing belt unit 220 is composed of a printing belt 25 and a recording section 230 (a plurality of recording heads 230H) (see Figure 2 ) is configured, the printing belt 25 rotates to attract and convey the sheet, and the recording unit 230 forms an image on the sheet conveyed by the printing belt 25.

[0050] [Register roller pair]

[0051] like Figure 6 As shown, the alignment unit 210 is provided with a left alignment roller pair (hereinafter referred to as "alignment roller pair") 240L (see FIG. 2 ) on the left side of the conveying center when facing the conveying direction X of the sheet. Figure 2 In addition, the alignment unit 210 is also provided with a right alignment roller pair (hereinafter referred to as "alignment roller pair") 240R (see FIG. 24) on the right side of the conveying center when the sheet is conveyed in the conveying direction X, in a manner parallel to the left alignment roller pair 240L. Figure 2). The alignment roller pair 240L is composed of an alignment drive roller 212L (as a first tilt movement correction roller) and an alignment driven roller 252L, which is arranged opposite to the alignment drive roller 212L and is driven when it contacts the alignment drive roller 212L. In addition, the alignment roller pair 240R is similarly composed of an alignment drive roller 212R (as a second tilt movement correction roller) and an alignment driven roller 252R, which is arranged opposite to the alignment drive roller 212R and is driven when it contacts the alignment drive roller 212R. Incidentally, the alignment drive rollers 212L, 212R are composed of rubber rollers made of, for example, polyurethane, and the alignment driven rollers 252L, 252R are composed of rollers made of, for example, EPDM. Incidentally, the alignment follower rollers 252L, 252R in these alignment roller pairs 240L, 240R are constructed to be movable between a contact position and a separation position, in which the alignment follower rollers 252L, 252R are in contact with the alignment drive rollers 212L, 212R, and in the separation position, the alignment follower rollers 252L, 252R are separated from the alignment drive rollers 212L, 212R by a separation mechanism 270.

[0052] [Drive rotation mechanism]

[0053] Next, the driving rotation mechanisms 211L, 211R in the alignment unit 210 will be described. Figure 2 and Figure 3 As shown, the alignment unit 210 is equipped with: driving rotation mechanisms 211L, 211R, which respectively rotationally drive and rotate the alignment drive rollers 212L, 212R. Each of the driving rotation mechanisms 211L, 211R includes: an alignment drive motor M1L as a first rotation drive motor and an alignment drive motor M1R as a second rotation drive motor. In addition, each of the driving rotation mechanisms 211L, 211R includes: a steering motor M2L as a first rotation drive motor and a steering motor M2R as a second rotation drive motor. In addition, each of the driving rotation mechanisms 211L, 211R includes: motor gears 213L, 213R, drive input gears 214L, 214R and steering shafts 215L, 215R for transmitting the rotation of the steering motors M2L, M2R.

[0054] The rotation shaft of each of the alignment drive motors M1L, M1R is drivingly connected to the alignment drive rollers 212L, 212R. In other words, the alignment drive rollers 212L, 212R are rotationally driven so that their rotation speeds can be independently changed by the rotation of the alignment drive motors M1L, M1R.

[0055] Each of the steering shafts 215L, 215R rotatably supports the frames 216L, 216R (see Figure 3), the frames 216L and 216R support the alignment drive rollers 212L and 212R and the alignment drive motors M1L and M1R, respectively. That is, the alignment drive rollers 212L and 212R and the alignment drive motors M1L and M1R are rotatably (rotatably) supported around the steering shafts 215L and 215R, respectively, and the axial directions of the steering shafts 215L and 215R are the intersecting directions (perpendicular) intersecting the conveying direction X and the width direction W perpendicular to the conveying direction X.

[0056] On the other hand, each of the steering motors M2L and M2R is arranged in an axial direction parallel to the axial direction of the steering shafts 215L and 215R, and the motor gears 213L and 213R are fixed to the respective rotating shafts. The drive input gears 214L and 214R fixed to the respective steering shafts 215L and 215R mesh with each of the motor gears 213L and 213R. Thus, by controlling the rotation of the steering motors M2L and M2R, the alignment drive rollers 212L and 212R and the alignment drive motors M1L and M1R can be rotated (rotated) around the steering shafts 215L and 215R.

[0057] In short, the registration drive rollers 212L and 212R are configured to be rotationally driven by the registration drive motors M1L and M1R, and rotated by the steering motors M2L and M2R to a direction inclined relative to the conveying direction X. Thus, the registration roller pairs 240L and 240R can change the conveying speed and conveying direction independently.

[0058] Incidentally, a home position sensor is arranged near each of the registration drive rollers 212L, 212R, and the home position of the registration drive rollers 212L, 212R is detected by the home position sensor. In other words, the home position of the registration drive rollers 212L, 212R is a position where the registration roller pair 240L, 240R faces straight (without tilt) in the conveying direction X. In other words, it is configured so that the registration roller pair 240L, 240R can be positioned back to a position where the registration roller pair 240L, 240R is not tilted relative to the conveying direction.

[0059] [Structure for detecting tilt movement of a sheet]

[0060] Near each roller gap of the registration roller pair 240L, 240R, at the same position in the conveying direction X (i.e., so as to be aligned in the width direction W), leading registration sensors SN2L, SN2R as a detection section or a first tilt movement amount detection section composed of, for example, an optical sensor are arranged. That is, these leading registration sensors SN2L, SN2R are arranged immediately downstream of the registration roller pair 240L, 240R in the conveying direction X. The controller 260 (see FIG. 260 ) as a control section described below Fig.10 ) The oblique movement amount of the sheet S is calculated based on the timing difference of each leading end registration sensor SN2L, SN2R detecting the leading end of the sheet S and the conveying speed at which the sheet S is conveyed.

[0061] Similarly, downstream of the front end alignment sensors SN2L and SN2R, front end alignment sensors SN3L and SN3R, which are composed of optical sensors, are arranged as detection units or second tilt movement amount detection units. Fig.10 ) The amount of tilted movement of the sheet S is calculated based on the timing difference of the leading end alignment sensors SN3L and SN3R detecting the leading end of the sheet S and the conveying speed at which the sheet S is conveyed. That is, the leading end alignment sensors SN3L and SN3R detect the amount of tilted movement of the sheet conveyed from the first position of the sheet to the second position downstream in the conveying direction, and the leading end alignment sensors SN2L and SN2R detect the amount of tilted movement of the sheet at the first position. Incidentally, the interval in which the leading end of the sheet reaches the leading end alignment sensors SN3L and SN3R from the leading end alignment sensors SN2L and SN2R is defined as the first correction interval CS1, and the first correction control to be described in detail below is performed in this interval. In addition, the interval in which the leading end of the sheet reaches the printing belt 25 from the leading end alignment sensors SN3L and SN3R is defined as the second correction interval CS2, and the second correction control to be described in detail below is performed in this interval.

[0062] [Structure for detecting the position of the sheet in the width direction]

[0063] Image sensors SN1L, SN1R are arranged as detection sections or width direction position detection sections upstream of each registration roller 240L, 240R in the conveying direction X. The image sensor SN1L detects the edge position of the left end portion of the sheet S, and the image sensor SN1R detects the edge position of the right end portion of the sheet S. For these image sensors SN1L, SN1R, for example, an optical sensor such as a CIS sensor can be used. And, these image sensors SN1L, SN1R detect the position of the sheet S in the width direction based on the edge positions of the left end portion and the right end portion of the sheet, and the controller 260 (see Fig.10 ) Based on the detection result, the misalignment amount of the position in the width direction (the so-called lateral alignment misalignment position) is calculated.

[0064] Incidentally, when the leading end of a sheet of the minimum size that can be conveyed by the printing module 200 reaches the leading end alignment sensors SN3L, SN3R, these image sensors SN1L, SN1R are arranged at positions capable of detecting the position of the sheet in the width direction. In other words, the configuration is such that the positional misalignment amount in the width direction can be detected when the tilted movement amount is detected when the sheet is in the first position and when the tilted movement amount is detected when the sheet is in the second position. Thus, in the case of conveying sheets of any size, the tilted movement amount and the position in the width direction of the sheet in the first position and the tilted movement amount and the position in the width direction of the sheet in the second position can be detected.

[0065] [Modification of Detecting the Tilt Movement and the Position in the Width Direction of the Sheet]

[0066] Here, we will use Fig.11A , Fig. 11B , Fig. 11C and Fig.11D Modifications of the configuration for detecting the oblique movement of the sheet and the configuration for detecting the position of the sheet in the width direction are described. Fig.11A is a plan view showing the arrangement of an image sensor, a first front end alignment sensor, and a second front end alignment sensor according to Embodiment 1. Fig. 11B is a top view showing the arrangement of an image sensor, a first front end alignment sensor, and a second front end alignment sensor in a case where only one image sensor is used. Fig. 11C is a top view showing the arrangement of an image sensor, a first front end alignment sensor, and a second front end alignment sensor in a case where the image sensor is configured as a single image sensor. Fig.11D : is a top view showing the arrangement of image sensors in the case where the oblique movement of the sheet and the position of the sheet in the width direction are detected by a single image sensor.

[0067] like Fig.11A As shown, in Embodiment 1, the front end alignment sensors SN2L, SN2R are arranged downstream of the alignment roller pair 240L, 240R along the conveying direction X. In addition, the front end alignment sensors SN3L, SN3R are arranged downstream of the front end alignment sensors SN2L, SN2R along the conveying direction X. Furthermore, the image sensors SN1L, SN1R are arranged upstream of the alignment roller pair 240L, 240R along the conveying direction X.

[0068] In contrast, as a modified example, Fig. 11B The configuration shown in FIG. 1 is as follows: only the image sensor SN1L is arranged and the image sensor SN1R is eliminated. That is, when the controller 260 (see Fig.10) When identifying the size of a sheet, if the edge position of the left end of the sheet can be detected by only one image sensor SN1L, the position of the sheet in the width direction can be calculated. Incidentally, it can be configured so that the image sensor SN1R detects the edge position of the right end of the sheet and calculates the position of the sheet in the width direction.

[0069] In addition, as a modification example, Fig. 11C The structure shown in FIG. 1 is as follows: in the width direction, the image sensor SN1 is arranged over the entire conveying area where the sheet can be conveyed, in other words, the image sensor SN1 is provided with an image sensor SN1 that is longer in the width direction than the image sensors SN1L and SN1R. The image sensor SN1 can scan both ends in the width direction of the sheet and can detect the edge positions of the left and right ends of the sheet.

[0070] And, as a modification example, Fig.11D The structure shown in FIG. 1 is as follows: only the image sensor SN1 is provided, and the front end alignment sensors SN2L, SN2R and the front end alignment sensors SN3L, SN3R are eliminated. Even in this structure, if the image sensor SN1 continuously detects the positions of the two ends in the width direction of the sheet, the position and movement (tilt movement) of the ends of the sheet can be calculated. That is, by monitoring the position of the ends of the sheet detected by the image sensor SN1 for a certain period of time when the sheet is at the first position or the second position, the tilt movement amount of the sheet can be calculated, and the position of the sheet in the width direction can also be calculated.

[0071] By the way, using Fig. 11B , Fig. 11C and Fig.11D A modified example is described, however, it is not limited thereto, and any configuration or arrangement of sensors may be employed as long as the tilting movement amount and the position in the width direction when the sheet is in the first position and the tilting movement amount and the position in the width direction when the sheet is in the second position can be detected.

[0072] [Structure of the control system of the printing module]

[0073] Next, we will use Fig.10 The configuration of the control system in the printing module 200 is described. Fig.10 is a block diagram showing the configuration of a control system according to Embodiment 1.

[0074] like Fig.10As shown, the controller 260 serving as a control section is connected to the CPU 261, the ROM 262, and the RAM 263, and the CPU 261 executes a program stored in the ROM 262 and the like while using a storage area of ​​the RAM 263. In addition, an operation section 290 such as an operation panel and an external computer are connected to the controller 260 via an interface to receive various inputs or display results.

[0075] Furthermore, various types of sensors such as the above-mentioned image sensors SN1L, SN1R, the first leading end alignment sensors SN2L, SN2R, and the second leading end alignment sensors SN3L, SN3R are connected to the controller 260. In addition, various types of motors such as the above-mentioned alignment drive motors M1L, M1R, the steering motors M2L, M2R, and the conveying motor M3 that drives the conveying roller pairs 208, 209 are connected to the controller 260. Based on the detection results of these various types of sensors, while the controller 260 performs drive control of the various types of motors to convey the sheet, the controller 260 performs correction control including both tilt movement correction and lateral alignment misalignment correction as width position correction, which will be described in detail later.

[0076] [Tilt movement correction operation]

[0077] Next, we will use Figure 4A , Figure 4B , Figure 5A , Figure 5B , Figure 5C , Fig. 7A , Figure 7B and Figure 7C The principle of the tilt movement correction operation (active alignment operation) is described.

[0078] Figure 4A is a perspective view showing the alignment unit before the alignment driving roller is rotated. Figure 4B is a perspective view showing the alignment unit after the alignment driving roller is rotated. Figure 5A is a top view showing the alignment unit before the sheet is conveyed. Figure 5B It is a plan view showing the alignment unit in a state where the tilt movement correction of the sheet is being performed. Figure 5C It is a plan view showing the alignment unit in a state where the lateral alignment correction of the sheet is being performed. Fig. 7A is a schematic diagram showing an example of measurement of the tilt movement amount. Figure 7B is a diagram showing an example of a tilt movement correction curve. Figure 7C 2 is a schematic diagram showing an oblique movement correction operation. Incidentally, the oblique movement correction is to correct the angle of the moving direction of the sheet so as to be parallel to the conveyance center which is the center in the width direction of the conveyance path in which the sheet is conveyed.

[0079] In the alignment unit 210, as described above, the alignment drive rollers 212L, 212R are independently driven by the alignment drive motors M1L, M1R, and are constructed so that the rotation speed can be changed independently. The controller 260 determines a tilt movement correction curve for correcting the tilt movement of the sheet based on the tilt angle of the sheet detected by the front end alignment sensors SN2L, SN2R or the front end alignment sensors SN3L, SN3R. The tilt movement correction curve is a control amount for controlling the speed difference between the alignment drive rollers 212L, 212R. And the controller 260 drives the alignment drive motors M1L, M1R based on the tilt movement correction curve to rotate the alignment drive rollers 212L, 212R.

[0080] Here, the tilt movement correction curve will be described. Figure 4A and Figure 5B As shown, when the tilt movement correction is not performed, the registration drive rollers 212L, 212R face the conveying direction X and rotate to convey the sheet at the same speed VL, VR. Here, the sheet is conveyed, and, as shown in FIG. Figure 4B and Fig. 7A As shown, for example, the amount of tilt movement of the sheet is detected by the front end alignment sensors SN2L and SN2R. Then, the controller 260 generates a signal based on the detected amount of tilt movement. Figure 7B The tilt movement correction curve is generated as a speed table so that the tilt movement amount detected by the front end alignment sensors SN2L and SN2R is equal to the difference between the integral value of the speed LVx of the alignment drive roller 212L and the integral value of the speed RVx of the alignment drive roller 212R. Figure 7B As shown in FIG. 1 , the tilt movement correction curve is set by multiplying a coefficient corresponding to the tilt movement amount. The controller 260 drives the alignment drive motors M1L and M1R according to the tilt movement correction curve thus generated. Figure 7C As shown, a speed difference is generated between the registration drive roller 212L (LVx) rotationally driven by the registration drive motor M1L and the registration drive roller 212R (RVx) rotationally driven by the registration drive motor M1R. As a result, the sheet conveyed by the registration drive rollers 212L, 212R rotates and the tilt movement is corrected. Figure 7B In the example of the tilt movement correction curve shown, an example of using curve driving is used for explanation, but triangle driving, trapezoidal driving, etc. may also be used.

[0081] [Lateral registration misalignment correction operation]

[0082] Next, we will use Fig. 8A , Figure 8B , Figure 8C and Fig.12The principle of the lateral alignment misalignment correction operation (steering operation) is described. Fig. 8A is a schematic diagram showing an example of measurement of the lateral alignment misalignment amount. Figure 8B is a graph showing an example of a lateral registration misalignment correction curve. Figure 8C is a schematic diagram illustrating a lateral registration misalignment correction operation. Fig.12 FIG. 1 is a diagram showing an example of a correction curve when performing lateral registration misalignment correction.

[0083] By the way, Fig. 8A The vertical direction in FIG. 8 corresponds to the conveying direction X of the sheet, and the horizontal direction in FIG. 8 corresponds to the width direction Z perpendicular to the conveying direction X. The lateral registration misalignment correction is to correct the position of the sheet in the width direction so that it is aligned with the position in the width direction of the formed image, and in most cases, the center of the sheet in the width direction is aligned with the center (reference position) of the conveying path in the width direction. In addition, in the case where the position in the width direction of the image formed on the sheet in the image forming section (recording section 230) is not aligned with the center in the width direction of the conveying path, it is not limited to this.

[0084] As described above, the conveying direction of the alignment drive rollers 212L, 212R can be changed by the steering motors M2L, M2R around the steering shafts 215L, 215R via the drive input gears 214L, 214R, respectively. For example, when the tilt movement correction of the sheet is not performed, the operation is such that the speeds VL, VR and the conveying direction of the alignment drive rollers 212L, 212R are the same. The controller 260 determines a curve as a control amount for correcting the lateral alignment misalignment based on the position of the sheet end detected by the image sensors SN1L, SN1R. That is, the controller 260 determines the curve of the steering motors M2L, M2R that changes the conveying direction of the alignment drive rollers 212L, 212R.

[0085] Here, the curve of lateral alignment misalignment correction will be described. Fig. 8A As shown, the image sensors SN1L and SN1R detect the lateral misalignment, which is the position misalignment in the lateral direction. Then, the controller 260 generates a lateral misalignment image based on the detected lateral misalignment. Figure 8B The lateral alignment misalignment correction curve (speed of the Z direction component) is shown. The lateral alignment misalignment correction curve is generated as a speed table so that the detected lateral misalignment amount and the integral value of the roller speed Vz of the component in the lateral direction Z in the preset correction interval are equal. That is, Figure 8B As shown, the lateral alignment misalignment correction curve is set by multiplying a coefficient corresponding to the lateral alignment misalignment amount.

[0086] In the case where the lateral registration misalignment correction and the tilt movement correction are not performed simultaneously, it is preferable that the speed Vx of the roller as the component in the conveying direction X is the same as the conveying speed of the printing tape unit 220 arranged downstream in the conveying direction X. By determining the speed Vx of the roller as the component in the conveying direction X and the speed Vz of the roller as the component in the width direction Z, as Figure 8C As shown, the angle θ of the roller and the speed V of the roller can be calculated using trigonometric functions based on the speed Vx and the speed Vz. By respectively calculating the angle θL, θR and the speed VL, VR of the roller per unit time, as Fig.12 As shown in FIG. 1 , the operation curves of the steering motors M2L, M2R and the alignment drive motors M1L, M1R can be generated. According to the curves, the steering motors M2L, M2R and the alignment drive motors M1L, M1R are driven. Figure 4B , Figure 5C and Figure 8C As shown, the registration drive roller 212L is rotated by the steering motor M2L, and the registration drive roller 212R is rotated by the steering motor M2R. Therefore, the sheet is obliquely conveyed by the registration drive rollers 212L, 212R, and the lateral registration misalignment is corrected. By the way, in the same Figure 8B In the example of the speed correction curve shown, the example of using the curve drive is also explained, but the triangle drive, trapezoidal drive, etc. can also be used.

[0087] [Simultaneous correction of tilt shift correction and lateral alignment misalignment correction]

[0088] Next, we will use Fig.13 and Fig.14 Simultaneous correction for tilt movement correction and lateral alignment misalignment correction is described. Fig.13 is a diagram describing conversion between the velocity component and the angle component of the registration drive roller when the tilt movement correction and the lateral registration misalignment correction are performed simultaneously. Fig.14 : is a diagram showing an example of a correction curve when the tilt movement correction and the lateral registration misalignment correction are performed simultaneously.

[0089] As described above, the tilt movement of the sheet can be corrected by correcting the speed difference of the registration drive motors M1L and M1R. In addition, the lateral registration misalignment of the sheet can be corrected by the registration drive rollers 212L and 212R rotated by the steering motors M2L and M2R.

[0090] In these descriptions, the operation of tilt movement correction and the operation of lateral alignment misalignment correction are described separately, but these operations may be performed simultaneously. Fig.13As shown, by synthesizing the component of the lateral alignment misalignment in the width direction Z (Z correction component) and the component of the tilt movement amount (angle of the tilt movement) (θ correction component), these components can be converted into the speed VL, VR and angle (steering angle) of each alignment drive roller 212L, 212R. In short, as Fig.14 As shown, the speeds LVz and RVz of the alignment drive rollers 212L and 212R in the curve for lateral alignment misalignment correction and the speeds LVx and RVx of the alignment drive rollers 212L and 212R in the curve for tilt movement correction are synthesized. Then, the angles Lθ and Rθ and the speeds VL and VR of the rollers per unit time are determined to generate a simultaneous correction curve for performing tilt movement correction and lateral alignment misalignment correction simultaneously. Then, according to the generated curve for simultaneous correction, the alignment drive motors M1L and M1R and the steering motors M2L and M2R are driven. Thus, tilt movement correction and lateral alignment misalignment correction can be performed simultaneously.

[0091] [Operations in the Print module]

[0092] Next, we will use Fig. 9 To describe the operation of the printing module 200. Fig. 9 is a flowchart showing the control of the printing module according to Embodiment 1. Fig. 9 In the control of image formation shown, an example in which an image is formed on one side of a sheet will be described; however, even in the case of forming images on both sides of a sheet, this control is repeatedly performed.

[0093] For example, if the accuracy of the above-mentioned tilt movement correction and lateral alignment misalignment correction is not good, the image formed on the sheet may be tilted, misaligned or distorted. In addition, especially when forming images on both sides of the sheet, if the accuracy of the above-mentioned tilt movement correction and lateral alignment misalignment correction is not good, the image on the front side of the sheet and the image on the back side of the sheet may be significantly misaligned. In the present control, by performing the first correction control and the second correction control, that is, performing the tilt movement correction and lateral alignment misalignment correction as described in detail below, the accuracy of the tilt movement correction and lateral alignment misalignment correction can be improved.

[0094] (Printing starts)

[0095] First, when the controller 260 receives the timing of the print job, the controller 260 starts to control Fig. 9 The image formation shown in FIG. 2 is performed by either directly receiving the print job from the operation unit 290 or receiving the print job from an external computer connected to the controller via a network. The print job received by the controller 260 includes information such as the number of prints specified by the user and the size of the sheet S to be printed. That is, the controller 260 determines the start of printing according to the received print job (S1).

[0096] Next, the controller 260 selects a sheet S of a size specified in the print job from one of the memories 110a, 110b, or 110c, for example, and feeds the sheet S through the feeding module 100. Then, the controller 260 drives a drive motor or the like to transfer the sheet S to the conveyor roller pair 208, 209 (see FIG. Figure 2 ) The sheet S is conveyed to the registration unit 210, and the sheet S reaches the registration roller pair 240L, 240R (S2).

[0097] (First Correction Control)

[0098] Next, the controller 260 enters a series of processes from step S3 to step S6 as the first correction control (i.e., the first correction control). First, when the sheet S reaches the leading end alignment sensors SN2L, SN2R, the controller 260 calculates the tilt movement amount of the sheet S based on the detection results input from the leading end alignment sensors SN2L, SN2R (S3). That is, when the leading end of the sheet S reaches the two leading end alignment sensors SN2L, SN2R, the detection operation of the first correction control is started. Incidentally, the tilt movement amount of the sheet S here is the tilt angle relative to the conveying direction X, or more precisely, the tilt angle of the leading end of the sheet S relative to the width direction Z. Specifically, as described above, the controller 260 determines the tilt movement amount of the sheet S based on the timing difference between each of the two leading end alignment sensors SN2L, SN2R detecting the leading end of the conveyed sheet S and the speed V (conveying speed) of the sheet S.

[0099] Next, the controller 260 calculates the position of the sheet S in the width direction, in other words, the lateral offset position, based on the detection results input from the image sensors SN1L and SN1R (S4). That is, the controller 260 calculates the lateral offset amount between the conveying center and the center of the sheet at both ends of the sheet S in the width direction Z (perpendicular to the conveying direction X) by detecting the extent to which a portion of the image sensors SN1L and SN1R is covered by the sheet S.

[0100] Next, the controller 260 generates a tilt movement correction curve as a first control amount based on the tilt movement amount of the sheet S determined as described above, so as to correct the tilt movement of the sheet S. In addition, the controller 260 also generates a curve for lateral alignment misalignment correction as a first control amount based on the lateral misalignment amount of the sheet S determined as described above, so as to correct the lateral misalignment of the sheet S. Then, the controller 260 generates a correction curve synthesized by these tilt movement correction curves and the curve for lateral alignment misalignment correction (S5). That is, the curve generation operation in the first correction control is performed.

[0101] Next, the controller 260 controls the alignment drive motors M1L, M1R and the steering motors M2L, M2R according to the generated correction curve. In other words, the controller 260 performs a correction operation for the first correction control including tilt movement correction and lateral alignment misalignment correction as a correction operation of the first correction control based on the detection results of the front alignment sensors SN2L, SN2R and the detection results of the image sensors SN1L, SN1R (S6). This correction operation of the first correction control is performed in the first correction interval CS1 above (see Figure 2 and Figure 3 ). Thus, the oblique movement and lateral misalignment of the sheet are roughly adjusted.

[0102] (Second Correction Control)

[0103] Next, the controller 260 enters a series of processing from step S7 to step S10 as the second correction control (i.e., the second correction control). First, the tilt movement amount of the sheet S is calculated based on the detection results input from the front end alignment sensors SN3L and SN3R (S7). That is, when the front end of the sheet S reaches the two front end alignment sensors SN3L and SN3R, the detection operation for the second correction control is started. In addition, similarly, the controller 260 calculates the position of the sheet S in the width direction, in other words, the lateral misalignment position (S8) based on the detection results input from the image sensors SN1L and SN1R. Incidentally, the tilt movement amount and lateral misalignment position of the sheet S obtained here can be obtained in the same manner as the first correction control.

[0104] Next, the controller 260 generates a tilt movement correction curve as a second control amount based on the tilt movement amount of the sheet S determined as described above, to correct the tilt movement of the sheet S. Furthermore, the controller 260 generates a curve for lateral alignment misalignment correction as a second control amount based on the lateral misalignment amount of the sheet S determined as described above, to correct the lateral misalignment of the sheet S. Then, the controller 260 generates a correction curve synthesized by these tilt movement correction curves and the curve for lateral alignment misalignment correction (S9). That is, the curve generation operation in the second correction control is performed.

[0105] Next, the controller 260 controls the alignment drive motors M1L, M1R and the steering motors M2L, M2R according to the generated correction curve. In other words, the controller 260 performs the correction operation of the second correction control including the tilt movement correction and the lateral alignment misalignment correction based on the detection results of the front end alignment sensors SN3L, SN3R and the image sensors SN1L, SN1R as the correction operation of the second correction control (S10). The correction operation of the second correction control is performed in the above second correction interval CS2 (see Figure 2 and Figure 3). Thus, the oblique movement and lateral misalignment of the sheet material that have been roughly adjusted by the first correction control are further finely adjusted.

[0106] (Image Formation Process)

[0107] Next, the controller 260 transfers the sheet S to the printing belt 25 (see Figure 2 )(S11). Next, the controller 260 performs image formation on the sheet S using the recording unit 230 (S12). Then, the sheet S is discharged to the discharge module 700 (see Figure 1 )(S13), and the controller 260 completes the print job and completes the image forming operation of the single sheet.

[0108] Incidentally, in the case of double-sided printing, image formation is performed on both sides (front and back) of the sheet S, and the controller 260 reverses the sheet S using the reversing module 600 after the operation of step S13, and conveys the sheet S to the registration roller pair 240L, 240R again. Then, the operation after step S2 is performed in the same manner.

[0109] [Overview of Example 1]

[0110] As described above, in the present embodiment, the controller 260 performs the first correction control using the alignment unit 210, and after the first correction control, performs the second correction control using the same alignment unit 210. Thus, it is no longer necessary to arrange two or more mechanisms for performing the tilt movement correction and the lateral alignment misalignment correction side by side in the conveying direction, thereby preventing the size of the device from increasing. In addition, since the alignment unit 210 performs the tilt movement correction (active alignment operation) and the lateral alignment misalignment correction (steering operation) while conveying the sheet, it is not necessary to stop the sheet once, thereby preventing the improvement in productivity from being suppressed. Therefore, using the sheet conveying unit 200A in the present embodiment, while the first correction control (coarse adjustment) and the second correction control (fine adjustment) can be performed, the size of the device can be prevented from increasing or the improvement in productivity can be prevented from being suppressed.

[0111] In addition, in the present embodiment, front end alignment sensors SN2L and SN2R are provided to detect the amount of tilted movement of the sheet, and front end alignment sensors SN3L and SN3R are arranged downstream thereof in the conveying direction X and detect the amount of tilted movement of the sheet. In addition, image sensors SN1L and SN1R are provided to detect the position of the sheet in the width direction. Thus, a first correction control can be performed based on the amount of tilted movement of the sheet detected by the front end alignment sensors SN2L and SN2R and the amount of lateral misalignment detected by the image sensors SN1L and SN1R. In addition, a second correction control can be performed based on the amount of tilted movement of the sheet detected by the front end alignment sensors SN3L and SN3R and the amount of lateral misalignment detected by the image sensors SN1L and SN1R.

[0112] Furthermore, in the present embodiment, by performing the second correction control before the trailing end of the sheet passes through the registration drive rollers 212L, 212R, it is possible to finely adjust the correction of the oblique movement of the sheet and the correction of the lateral registration misalignment.

[0113] <Example 2>

[0114] Next, we will use Fig.15 Embodiment 2 is described in which a part of Embodiment 1 is changed. Fig.15 : is a flowchart showing control of the printing module according to Embodiment 2. Incidentally, in the description of Embodiment 2, the same reference numerals are used for the same parts as those of Embodiment 1, and the description thereof is omitted.

[0115] In Embodiment 2, compared with Embodiment 1, it is determined whether the tilt movement amount or the lateral misalignment amount detected in the first correction control or the second correction control can be corrected by the alignment unit 210. If it cannot be corrected by the alignment unit 210, correction is performed using the upper limit value that can be corrected by the alignment unit 210.

[0116] Specifically, Fig.15 As shown, with Example 1 (see Fig. 9 ), the first correction control is started, the tilt movement amount of the sheet is detected by the front end alignment sensors SN2L and SN2R (S3), and the lateral misalignment amount of the sheet is detected by the image sensors SN1L and SN1R (S4). Here, it is determined whether the detected tilt movement amount and the detected lateral misalignment amount can be corrected by the alignment unit 210 (S14). If correction is possible ("Yes" in S14), as in Example 1, a correction curve is generated based on the detected tilt movement amount and the detected lateral misalignment amount (S5), and the first correction control (coarse adjustment) is performed (S6).

[0117] On the other hand, it is assumed that it is determined that the detected tilt movement amount cannot be corrected even if the tilt movement correction is performed by the alignment unit 210, or the detected lateral misalignment amount cannot be corrected even if the lateral alignment misalignment correction is performed by the alignment unit 210 ("No" in S14). In other words, it is assumed that it is determined that at least one of the tilt movement amount and the lateral misalignment amount cannot be corrected using the first correction control. In this case, an upper limit value that can be corrected using the alignment unit 210 is set for one or both of the uncorrectable tilt movement amount and the lateral misalignment amount. Then, a correction curve is generated by synthesizing a tilt movement correction curve and a curve for lateral alignment misalignment correction (at least one of which is generated using the upper limit value) together (S15). Then, the first correction control (coarse adjustment) is performed by controlling the alignment drive motors M1L, M1R and the steering motors M2L, M2R according to the correction curve generated in this way (S6).

[0118] In short, when the first correction control is performed, it is assumed that at least one of the detected amount of oblique movement of the sheet and the detected position of the sheet in the width direction has a value that cannot be corrected even if the alignment unit 210 is controlled with the correctable upper limit control amount. In this case, the correction curve as the first control amount is set to a correction curve set by the upper limit value as the upper limit control amount.

[0119] Therefore, if a correction curve having an upper limit value is generated in this way, the alignment unit 210 performs maximum tilt movement correction or lateral alignment misalignment correction, however, the tilt movement amount or lateral misalignment amount exceeding the upper limit value is not corrected. However, in a state where only the first correction control is performed, correction can be successfully performed by the second correction control that is performed next.

[0120] Then, the second correction control is started, and the front end alignment sensors SN3L and SN3R detect the tilt movement amount of the sheet (S7), and the image sensors SN1L and SN1R detect the lateral misalignment amount of the sheet (S8). Here, it is determined whether the detected tilt movement amount and the detected lateral misalignment amount can be corrected by the alignment unit 210 (S16). If correction is possible ("Yes" in S16), a correction curve is generated based on the detected tilt movement amount and the detected lateral misalignment amount (S9), and the second correction control (fine adjustment) is performed (S10) as in Example 1.

[0121] On the other hand, it is assumed that it is determined that at least one of the tilt movement amount and the lateral misalignment amount cannot be corrected using the second correction control (No in S16). In this case, an upper limit value that can be corrected using the alignment unit 210 is set for one or both of the uncorrectable tilt movement amount and the lateral misalignment amount. Then, a correction curve is generated by synthesizing a tilt movement correction curve and a curve for lateral alignment misalignment correction (at least one of which is generated using the upper limit value) together (S17).

[0122] In short, when the second correction control is performed, it is assumed that at least one of the detected oblique movement amount of the sheet and the detected position of the sheet in the width direction has a value that cannot be corrected even if the alignment unit 210 is controlled with the correctable upper limit control amount. In this case, the correction curve as the second control amount is set to a correction curve set by the upper limit value as the upper limit control amount.

[0123] In addition, in this case, the image formed on the sheet is tilted or has a lateral misalignment, which cannot be correctly corrected by the second correction control, resulting in an image defect. Therefore, the controller 260 regards the sheet as an error sheet. First, in step S17, the controller 260 outputs a signal for error notification to, for example, the operation unit 290 or an external computer, that is, performs error notification.

[0124] Then, the controller 260 performs a second correction control (S10) by controlling the alignment drive motors M1L, M1R and the steering motors M2L, M2R according to the correction curve generated with the upper limit value in this way while performing the error notification. Thereby, the tilting movement and lateral misalignment (i.e., posture) of the sheet can be corrected as much as possible, thereby reducing the occurrence of jams and the like. If no jam occurs, the inkjet recording system 1 can convey the sheet to, for example, the top tray 720 or the stacking section 750 to complete the discharge without emergency stop. In particular, by defining the top tray 720 as an error tray for discharging sheets in which errors occur, only sheets with image formation defects can be easily excluded. By the control as described above, the workload of jam handling can be reduced, and productivity can be improved without emergency stopping the inkjet recording system 1.

[0125] Incidentally, in the first correction control, in the case where the correction curve is generated with the upper limit value (see S15), an example is described in which it is not regarded as an error, however, it is not limited to this, and the sheet may be regarded as a sheet in which an error occurs, as in step S17. In particular, in the second correction control, since the sheet conveyance is being performed toward the recording section 230, the tilt movement correction and the lateral registration misalignment correction are fine adjustments, and thus the correctable upper limit value may be smaller than the coarse adjustment as in the first correction control. Therefore, if the first correction control cannot correct the tilt movement or lateral misalignment of the sheet, the second correction control may not correct any of them, and thus it may be configured to be regarded as an error at the stage of the first correction control.

[0126] Incidentally, other configurations, actions, and effects of the above-described embodiment 2 are the same as those in embodiment 1, and thus descriptions thereof will be omitted.

[0127] [Possibility of other embodiments]

[0128] Incidentally, in the present embodiment described above, an example is described in which the alignment unit 210 performs tilt movement correction upstream in the conveying direction of the recording section 230 as the image forming section. However, it is not limited thereto, and, for example, it may be configured such that the tilt movement correction is performed upstream in the conveying direction of the image reading section that reads a sheet image, the punching section that punches holes in a sheet, or the folding section that folds a sheet.

[0129] In short, the sheet conveying apparatus that performs the skew movement correction may be any apparatus, or may be incorporated in any apparatus.

[0130] In addition, in Embodiment 1 and Embodiment 2, the following example is described: the tilt movement amount and the position in the width direction of the sheet are detected by the image sensors SN1L and SN1R, the front end alignment sensors SN2L and SN2R, and the front end alignment sensors SN3L and SN3R as the detection unit. In addition, as other configurations of the detection unit, Fig. 11B , Fig. 11C and Fig.11D However, without limitation thereto, any configuration may be used as long as the oblique movement amount and the position in the width direction of the sheet can be detected, for example, a configuration that captures and analyzes an image or the like.

[0131] In addition, in Embodiment 1 and Embodiment 2, the following configuration is described, in which, when the front end of the sheet reaches the front end alignment sensors SN3L, SN3R, the image sensors SN1L, SN1R can detect the position of the sheet in the width direction, regardless of the size of the sheet, as long as the size of the sheet can be conveyed. However, it is not limited to this, but it can be configured, for example, to perform the first correction control only on the sheet with the minimum size that can be conveyed, and perform both the first correction control and the second correction control on other sizes. In other words, it can be configured in any way as long as the configuration makes it possible to perform both the first correction control and the second correction control on at least one size.

[0132] In addition, in Embodiment 1 and Embodiment 2, an example is described in which the alignment drive rollers 212L, 212R and the drive rotation mechanism 211L, 211R that drives the alignment drive rollers 212L, 212R are used as parts that perform both tilt movement correction and lateral alignment misalignment correction. However, this is not limited to this, and any structure is acceptable as long as the structure can perform both tilt movement correction and lateral alignment misalignment correction while conveying the sheet. In particular, it can be constructed to include a mechanism that can perform tilt movement and lateral alignment misalignment correction upstream or downstream in the conveying direction of the alignment drive rollers 212L, 212R, so as to perform a total of three or more tilt movement corrections or a total of three or more lateral alignment misalignment corrections.

[0133] The present invention can also be implemented in the following manner: a program that implements one or more functions of the above-mentioned embodiments is supplied to a system or device via a network or storage medium, and one or more processors in a computer of the system or device read out and execute the program. In addition, the present invention can also be implemented by a circuit (such as an ASIC) that implements one or more functions.

[0134] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A sheet conveying device, comprising: a correction section provided with a first correction roller and a second correction roller, the first correction roller being rotatable about a first axis in a cross direction intersecting a conveying direction of the sheet and a width direction perpendicular to the conveying direction, and being configured to correct a position of the sheet in the width direction, and the second correction roller being arranged at a position different from that of the first correction roller in the width direction, being rotatable about a second axis in the cross direction, and being configured to correct a position of the sheet in the width direction; a driving portion configured to rotationally drive the first correction roller and the second correction roller; a side end detection portion configured to detect a side end of the sheet in a width direction of the sheet; as well as a control unit configured to control the driving unit, Among them, the control unit performs a first correction control based on the detection result of the side end detection unit, and performs a second correction control after the first correction control. In the first correction control, the correction unit corrects the position of the sheet in the width direction, and in the second correction control, the correction unit corrects the position of the sheet in the width direction.

2. The sheet material conveying device according to claim 1, wherein: The driving unit is provided with a first rotation driving unit and a second rotation driving unit, the first rotation driving unit is configured to rotationally drive the first correction roller, the second rotation driving unit is configured to rotationally drive the second correction roller, and The first correction roller and the second correction roller are capable of rotating independently.

3. The sheet material conveying device according to claim 1, wherein: The driving unit is provided with a first rotation driving unit and a second rotation driving unit, the first rotation driving unit is configured to rotationally drive the first correction roller, the second rotation driving unit is configured to rotationally drive the second correction roller, and The first correction roller and the second correction roller are capable of rotating independently.

4. The sheet material conveying device according to claim 3, further comprising: a first oblique movement detecting portion configured to detect an oblique movement of the sheet; as well as a second oblique movement detecting portion which is arranged downstream of the first oblique movement detecting portion in the conveying direction and is configured to detect oblique movement of the sheet, wherein the control unit corrects the oblique movement of the sheet by a rotation speed difference between a first correction roller rotationally driven by a first rotation driving unit and a second correction roller rotationally driven by a second rotation driving unit, and Among them, the control unit performs a third correction control, and performs a fourth correction control after the third correction control. In the third correction control, the correction unit corrects the tilt movement of the sheet and the position of the sheet in the width direction based on the detection results of the side end detection unit and the first tilt movement detection unit, and in the fourth correction control, the correction unit corrects the tilt movement of the sheet and the position of the sheet in the width direction based on the detection results of the side end detection unit and the second tilt movement detection unit.

5. The sheet material conveying apparatus according to claim 4, wherein: When the leading end of a sheet of a minimum size that can be conveyed by the sheet conveying apparatus reaches the second oblique movement detecting portion, the side end detecting portion is arranged at a position capable of detecting the position of the sheet in the width direction.

6. The sheet material conveying apparatus according to claim 1, wherein: The control section performs the second correction control after the first correction control and before the trailing end of the sheet passes through the first correction roller and the second correction roller.

7. The sheet material conveying apparatus according to claim 4, wherein: The control section sets a first control amount of the correction section when executing the third correction control based on the oblique movement amount of the sheet and the position of the sheet in the width direction detected by the first oblique movement detection section, the second oblique movement detection section, and the side end detection section, and Among them, when executing the third correction control, when at least one of the inclination movement amount of the sheet and the position of the sheet in the width direction detected by the first inclination movement detection unit, the second inclination movement detection unit and the side end detection unit is a value that cannot be corrected by the correction unit even if the correction unit is controlled with the upper limit control amount that the correction unit can correct, the control unit sets the first control amount to the upper limit control amount.

8. The sheet material conveying apparatus according to claim 7, wherein: The control portion performs error notification when the first control amount is set as the upper limit control amount.

9. The sheet material conveying apparatus according to claim 7, wherein: The control section sets a second control amount of the correction section when executing the fourth correction control based on the oblique movement amount of the sheet and the position of the sheet in the width direction detected by the first oblique movement detection section, the second oblique movement detection section, and the side end detection section, and Among them, when executing the fourth correction control, when at least one of the inclination movement amount of the sheet and the position of the sheet in the width direction detected by the first inclination movement detection unit, the second inclination movement detection unit and the side end detection unit is a value that cannot be corrected by the correction unit even if the correction unit is controlled with the upper limit control amount that the correction unit can correct, the control unit sets the second control amount to the upper limit control amount.

10. The sheet material conveying apparatus according to claim 9, wherein: When the second control amount is set as the upper limit control amount, the control portion performs error notification.

11. An image forming apparatus, comprising: The sheet conveying device according to claim 1; as well as The image forming section is configured to form an image on a sheet conveyed by the sheet conveying device.

Images