Sheet conveyance apparatus, image forming apparatus and image forming system

Abstract

A sheet conveyance apparatus includes a moving unit, a width position detection unit including a plurality of sensor chips, and a control unit. Each sensor chip includes a plurality of light receiving elements. Among the plurality of light receiving elements, a first element is arranged closest to one side in the width direction. A second element is arranged closest to the other side. The control unit is configured to execute a first movement process and a second movement process with respect to all regular size sheets. In the first movement process, the control unit is configured to move a position of a regular size sheet such that an edge portion of the regular size sheet is positioned between the first element and the second element. In the second movement process, the control unit is configured to move the position of the regular size sheet according to a detection result of the width position detection unit after execution of the first movement process.

Description

BACKGROUNDField of the Technology

[0001] The present disclosure relates to a sheet conveyance apparatus, an image forming apparatus that moves a width direction position of a sheet, and an image forming system.Description of the Related Art

[0002] In sheet conveyance apparatuses equipped in an image forming system for forming images on sheets, there may be a state where a sheet being conveyed is displaced from a desirable conveyance position due to skewing of the conveyed sheet, for example. Therefore, a technique is proposed in which an edge portion of a sheet in a width direction is detected by a contact image sensor (CIS), and based on the detection result thereof, the sheet is moved to correct the position of the sheet (refer to Japanese Patent Application Laid-Open Publication No. 2019-136910).SUMMARY

[0003] The CIS as described above is configured by aligning a plurality of sensor chips, each sensor chip including a plurality of light receiving elements arranged in an aligned manner, in a width direction orthogonal to a sheet conveyance direction. However, there are errors in a spacing between the plurality of sensor chips that are aligned in the width direction, and in a case where the edge portions of the sheet are detected by different sensor chips, an accuracy of the position being detected is not good because of the error, such that the positional accuracy of the sheet that has been moved is also not good. If the positional accuracy of the sheet is not good, the positional accuracy of the image being formed on the sheet thereafter is also not good.

[0004] The present disclosure provides a sheet conveyance apparatus and an image forming apparatus capable of realizing a good positional accuracy of a sheet moved by a moving unit.

[0005] According to a first aspect of the present disclosure, a sheet conveyance apparatus includes a moving unit including a roller configured to convey a sheet, the moving unit being configured to move a position of the sheet in a width direction orthogonal to a conveyance direction, a width position detection unit including a plurality of sensor chips aligned in the width direction, the width position detection unit being configured to detect a position of an edge portion of the sheet in the width direction, and a control unit configured to control the moving unit according to a detection result of the width position detection unit. Each sensor chip constituting the plurality of sensor chips includes a plurality of light receiving elements aligned in the width direction. Among the plurality of light receiving elements on the sensor chip, a first element is arranged closest to one side in the width direction among the plurality of light receiving elements on the sensor chip, a second element is arranged closest to the other side in the width direction. The control unit is configured to execute a first movement process and a second movement process with respect to all regular size sheets conveyable in the sheet conveyance apparatus. In the first movement process, the control unit is configured to move a position of a regular size sheet by the moving unit such that an edge portion of the regular size sheet is positioned between the first element and the second element of one of the plurality of sensor chips according to a detection result of the width position detection unit. In the second movement process, the control unit is configured to move the position of the regular size sheet by the moving unit according to a detection result of the width position detection unit after execution of the first movement process.

[0006] According to a second aspect of the present disclosure, a sheet conveyance apparatus includes a first moving unit including an abutment portion arranged on one side in a width direction with respect to a sheet being conveyed, and an obliquely conveying rotary member pair configured to obliquely convey the sheet toward the abutment portion, a second moving unit including a roller configured to convey the sheet, the second moving unit being configured to move a position of the sheet in a width direction orthogonal to a conveyance direction, a width position detection unit including a plurality of sensor chips aligned in the width direction, the width position detection unit being configured to detect a position of an edge portion of the sheet in the width direction, and a control unit configured to control the second moving unit according to a detection result of the width position detection unit. Each sensor chip constituting the plurality of sensor chips includes a plurality of light receiving elements aligned in the width direction. Among the plurality of light receiving elements on the sensor chip, a first element is arranged closest to one side in the width direction. Among the plurality of light receiving elements on the sensor chip, a second element is arranged closest to the other side in the width direction. With respect to all regular size sheets conveyable in the sheet conveyance apparatus, the control unit is configured to execute a process of abutting an edge portion of a regular size sheet against the abutment portion by the first moving unit so that the edge portion of the regular size sheet is positioned between the first element and the second element of one of the plurality of sensor chips, and a process of moving a position of the regular size sheet according to a position of the edge portion of the regular size sheet in the width direction detected by the width position detection unit in a state in which the edge portion of the regular size sheet abuts against the abutment portion.

[0007] Features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings. The following description of embodiments is described by way of example.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic diagram illustrating a schematic configuration of an inkjet recording system according to the first embodiment.

[0009] FIG. 2 is a top view illustrating a registration unit of a print module according to the first embodiment.

[0010] FIG. 3 is a perspective view of the registration unit of the print module according to the first embodiment.

[0011] FIG. 4A is a perspective view of the registration unit prior to turning a registration driving roller.

[0012] FIG. 4B is a perspective view of the registration unit after turning the registration driving roller.

[0013] FIG. 5A is a top view of the registration unit prior to conveying a sheet.

[0014] FIG. 5B is a top view of the registration unit in a state where skew correction of a sheet is performed.

[0015] FIG. 5C is a top view of the registration unit in a state where lateral registration correction of a sheet is performed.

[0016] FIG. 6 is a lateral cross-sectional view of a registration unit of a print module according to the first embodiment.

[0017] FIG. 7A is a schematic diagram of a measurement example of a skewing amount.

[0018] FIG. 7B is a view illustrating an example of a skew correction profile.

[0019] FIG. 7C is a schematic diagram of a skew correction operation.

[0020] FIG. 8A is a schematic diagram of a measurement example of a lateral registration displacement amount.

[0021] FIG. 8B is a view illustrating an example of a lateral registration displacement correction profile.

[0022] FIG. 8C is a schematic diagram illustrating a lateral registration displacement correction operation.

[0023] FIG. 9 is a flowchart illustrating a control of a print module according to the first embodiment.

[0024] FIG. 10 is a block diagram illustrating a configuration of a control system according to the first embodiment.

[0025] FIG. 11 is a view illustrating an example of a correction profile when performing the lateral registration displacement correction.

[0026] FIG. 12 is an explanatory view illustrating a conversion of a velocity component and an angle component of a registration driving roller in a case where skew correction and lateral registration displacement correction are performed at the same time.

[0027] FIG. 13 is a view illustrating an example of a correction profile in a case where skew correction and lateral registration displacement correction are performed at the same time.

[0028] FIG. 14A is a schematic diagram illustrating a configuration of a CIS according to the first embodiment.

[0029] FIG. 14B is an explanatory view illustrating an error in a spacing of the sensor chips of the CIS according to the first embodiment.

[0030] FIG. 15A is a schematic diagram illustrating a state prior to executing a first correction control.

[0031] FIG. 15B is a schematic diagram illustrating a state after executing the first correction control.

[0032] FIG. 15C is a schematic diagram illustrating a state after executing a second correction control.

[0033] FIG. 16A is an explanatory view illustrating a reference example of an arrangement in which a node between sensor chips and a side edge of a regular size sheet are overlapped.

[0034] FIG. 16B is an explanatory view illustrating an arrangement according to the first embodiment in which nodes between sensor chips and side edges of regular size sheets are not overlapped.

[0035] FIG. 17 is a flowchart illustrating a control of a print module according to a second embodiment.

[0036] FIG. 18A is a top view illustrating a state in which skew correction has been performed at a skew correction portion of a registration unit according to a third embodiment.

[0037] FIG. 18B is a top view illustrating a state in which shifting has been performed by a registration roller pair of the registration unit according to the third embodiment.

[0038] FIG. 19A is a top view illustrating a positional relationship between a side edge of a sheet and a CIS sensor chip in a state where skew correction has been performed at the skew correction portion of the registration unit according to the third embodiment.

[0039] FIG. 19B is a top view illustrating a positional relationship between a side edge of a sheet and a CIS sensor chip in a state where shifting has been performed by the registration roller pair of the registration unit according to the third embodiment.DESCRIPTION OF THE EMBODIMENTSFirst Embodiment

[0040] Embodiments of the present disclosure will be described below with reference to the drawings. In the present first embodiment, a case is described where an inkjet recording system 1 is applied as an image forming system.Inkjet Recording System

[0041] First, a schematic configuration of the inkjet recording system 1 according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram illustrating a schematic configuration of the inkjet recording system 1 according to the first embodiment. The inkjet recording system 1 serving as an image forming system is a sheet-type inkjet recording system that creates a recorded matter in which an ink image is formed on a sheet S using two liquids, a reaction liquid and ink. As illustrated in FIG. 1, 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 discharging module 700. The sheet S in a state of cut paper supplied from the feeding module 100 is conveyed along a conveyance path, subjected to processing in each module, and discharged by the discharging module 700 serving as a sheet supporting apparatus. Further according to the inkjet recording system 1, an image is formed on a sheet at the printing module 200 serving as an image forming apparatus, and the sheet on which the image has been formed is subjected to various processing at a position downstream of the printing module 200 in a conveyance direction of the sheet. Therefore, the drying module 300, the fixing module 400, the cooling module 500, the reversing module 600, and the discharging module 700 can also be referred to as processing apparatuses.

[0042] The feeding module 100 includes three storages 110a, 110b, and 110c that store the sheets S. Storages 110a, 110b, and 110c are each configured to be drawn out to a front side of the apparatus. The sheets S are fed one by one by a separation belt and a conveyance roller not shown in each of the storages 110a, 110b, and 110c, and conveyed to the printing module 200. The number of storages 110a, 110b, and 110c is not limited to three, and the number may be one, two, or even four or more.

[0043] The printing module 200 includes a registration unit 210 (refer to FIG. 2) serving as a correction unit that performs skew correction and lateral registration correction prior to creating an image as described in detail later, a print belt unit 220, and a recording unit 230. The sheet S conveyed from the feeding module 100 is subjected to sheet inclination and position correction by a plurality of conveyance roller pairs 208 and 209 (refer to FIG. 2) serving as a conveyance unit and the registration unit 210, and conveyed to the print belt unit 220. The recording unit 230 is arranged at a position facing the print belt unit 220 with respect to the conveyance path. The plurality of the conveyance roller pairs 208 and 209 and the registration unit 210 constitute a sheet conveyance unit 200A serving as a sheet conveyance apparatus that conveys the sheet to the recording unit 230. Further, the recording unit 230 constitutes an image forming unit that forms an image by performing a recording process, i.e., printing, to the sheet S from above the sheet S being conveyed via a plurality of recording heads 230H (refer to FIG. 2).

[0044] The plurality of recording heads 230H are aligned along a conveyance direction of the sheet, which is hereinafter referred to simply as the conveyance direction. In the present embodiment, a total of five line-type recording heads, corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (Bk), and to a reaction liquid. The number of colors and the number of recording heads are not limited to five. An inkjet system may adopt a heat generating element system, a piezoelectric element system, a capacitance element system, and a MEMS element system. The inks of various colors are supplied from an ink tank not shown via respective ink tubes to the recording heads. The sheet S to which printing is performed by the recording unit 230 is attracted to and conveyed on the print belt unit 220, by which the sheet S is conveyed while ensuring a clearance from the recording head. The sheet S to which printing is performed by the recording unit 230 is subjected to detection of displacement or color density of the image formed on the sheet S by an inline scanner not shown disposed downstream of the recording unit in the conveyance direction. The result of detection is used to correct the image to be printed.

[0045] The drying module 300 includes a decoupling unit 320, a drying belt unit 330, and a hot air blow unit 340, and reduces the liquid portion included in the ink applied to the sheet S by the recording unit 230 of the printing module 200 and enhances the fixing performance of the sheet S and the ink. The sheet S printed by the recording unit 230 of the printing module 200 is conveyed to the decoupling unit 320 arranged upstream of the drying module 300 in the conveyance direction. In the decoupling unit 320, the sheet S is conveyed by wind pressure from the upper direction and friction of the belt, and by conveying the sheet S on the belt while holding the sheet with a weak force, the displacement of the sheet S on the print belt unit 220 forming the ink image may be prevented. The drying belt unit 330 is arranged below the belt and the hot air blow unit 340 is arranged above the belt, wherein the units are arranged to face each other with the belt interposed therebetween. The sheet S conveyed from the decoupling unit 320 is attracted to and conveyed on the drying belt unit 330, and at the same time, receives hot air blow from the hot air blow unit 340, by which the ink application surface is dried. The drying system may be composed by combining, other than the hot air applying system, a system in which electromagnetic waves, such as ultraviolet or infrared light, are irradiated on the surface of the sheet S, and a conductive heat transfer system adopting contact of a heating element.

[0046] The fixing module 400 includes a fixing belt unit 410. The fixing belt unit 410 includes an upper belt unit and a lower belt unit, and by passing the sheet S conveyed from the drying module 300 between the heated upper belt unit and lower belt unit, the ink is fixed onto the sheet S.

[0047] The cooling module 500 includes a plurality of cooling portions 510, and cools the heated sheet S conveyed from the fixing module 400. Each cooling portion 510 takes in outer air via fans into a cooling box, increasing the pressure within the cooling box, and blows the air discharged through nozzles formed on the conveyance guide onto the sheet S, thereby cooling the sheet S. The cooling portions 510 are disposed on both upper and lower sides of the conveyance path, cooling the sheet S from both sides.

[0048] The cooling module 500 includes a conveyance path switching portion, and the conveyance path of the sheet S can be switched according to a case where the sheet S is conveyed to the reversing module 600 and a case where the sheet S is conveyed to a duplex conveyance path used for performing duplex printing. During duplex printing, the sheet S is conveyed to a conveyance path on the lower portion of the cooling module 500. In this case, the sheet is further conveyed from the cooling module 500 along the duplex conveyance path via the fixing module 400, the drying module 300, the printing module 200, and the feeding module 100. A first reverse portion 420 for reversing the upper and lower sides of the sheet S is disposed on the duplex conveyance path of the fixing module 400. Then, the sheet S is conveyed again from the feeding module 100 to a pre-image-forming registration correction unit, the print belt unit 220, and the recording unit 230 of the printing module 200, and subjected to printing at the recording unit 230.

[0049] The reversing module 600 includes a second reverse portion 640, by which the upper and lower surfaces of the sheet S being conveyed may be reversed, such that the upper and lower sides of the sheet S being discharged may be changed. The discharging module 700 includes a top tray 720 and a supporting portion 750, and the sheet S conveyed from the reversing module 600 can be aligned and stacked on the top tray 720 or the supporting portion 750, or can be discharged onto an external tray not shown.Configuration of Registration Unit of Print Module and Periphery Thereof

[0050] Next, a configuration of the registration unit 210 of the printing module 200 and a periphery thereof will be described with reference to FIGS. 2, 3, and 6. FIG. 2 is a top view of the registration unit of the print module according to the first embodiment. FIG. 3 is a perspective view of the registration unit of the print module according to the first embodiment. FIG. 6 is a lateral cross-sectional view of the registration unit of the print module according to the first embodiment.

[0051] In the printing module 200, as illustrated in FIGS. 2 and 3, the conveyance roller pairs 208 and 209 that convey the sheets are arranged in order in a conveyance direction X in the sheet conveyance unit 200A (refer to FIG. 1). The conveyance roller pairs 208 and 209 include, for example, a lower roller including a roller made of EPDM, and an upper roller which is a rubber roller made of urethane, wherein the lower roller is urged toward the upper roller by a spring not shown. In this description, the conveyance direction X refers to a direction in a case where the sheet S is not skewed, and does not refer to the conveyance direction according to a steering operation described later.

[0052] Further, in the sheet conveyance unit 200A of the printing module 200, the registration unit 210 serving as a correction unit is arranged downstream of the conveyance roller pairs 208 and 209 in the conveyance direction X. That is, the registration unit 210 corrects the position of the sheet being conveyed by the conveyance roller pairs 208 and 209. Further, in the printing module 200, the print belt unit 220 is arranged downstream of the registration unit 210 in the conveyance direction X. The print belt unit 220 includes a print belt 25 rotated in a manner attracting and conveying the sheet thereon, and the recording unit 230, that is, the plurality of recording heads 230H (refer to FIG. 2), for forming an image on the sheet being conveyed by the print belt 25.Registration Roller Pair

[0053] The registration unit 210 includes, as illustrated in FIG. 6, a left registration roller pair, hereinafter simply referred to as “registration roller pair”, 240L on a left side of a conveyance center line (refer to FIG. 2) with respect to the sheet conveyance direction X. Further, the registration unit 210 includes a right registration roller pair, hereinafter simply referred to as “registration roller pair”240R in a manner arranged in parallel on a right side of the conveyance center line (refer to FIG. 2) with respect to the conveyance direction X. The registration roller pair 240L includes a registration driving roller 212L serving as a sheet moving unit or a first skew correction roller, and a registration follower roller 252L that is arranged to face the registration driving roller 212L and that is driven to rotate when it is in contact therewith. Similarly, the registration roller pair 240R includes a registration driving roller 212R serving as a sheet moving unit or a second screw correction roller, and a registration follower roller 252R that is arranged to face the registration driving roller 212R and that is driven to rotate when it is in contact therewith. Further, the registration driving rollers 212L and 212R are each formed of a rubber roller made of polyurethane, and the registration follower rollers 252L and 252R are each formed of a roller made of EPDM. The registration follower rollers 252L and 252R of the registration roller pairs 240L and 240R are movable between a contact position in contact with the registration driving rollers 212L and 212R and a separation position separated therefrom by a separation mechanism not shown.Turning Mechanism

[0054] Next, turning mechanisms 211L and 211R in the registration unit 210 will be described. As illustrated in FIGS. 2 and 3, the registration unit 210 includes the turning mechanisms 211L and 211R that drive to rotate and turn each of the registration driving rollers 212L and 212R. Each of the turning mechanisms 211L and 211R includes a registration driving motor M1L serving as a first rotational driving motor and a registration driving motor M1R serving as a second rotational driving motor. Further, each of the turning mechanisms 211L and 211R incudes a steering motor M2L serving as a first turning motor and a steering motor M2R serving as a second turning motor. Further, each of the turning mechanisms 211L and 211R includes motor gears 213L and 213R that transmit rotation of the steering motors M2L and M2R, drive input gears 214L and 214R, and steering shafts 215L and 215R.

[0055] The rotation shafts of each of the registration driving motors M1L and M1R are connected to transmit driving force to the registration driving rollers 212L and 212R. That is, the registration driving rollers 212L and 212R are driven to rotate such that rotational speeds of each of the registration driving rollers 212L and 212R can be changed independently by the rotation of the registration driving motors M1L and M1R.

[0056] Each of the steering shafts 215L and 215R rotatably support frames 216L and 216R (refer to FIG. 3) that respectively support each of the registration driving rollers 212L and 212R and the registration driving motors M1L and M1R. In other words, the registration driving rollers 212L and 212R and the registration driving motors M1L and M1R are supported rotatably, i.e., turnably, about the steering shafts 215L and 215R whose axial direction is an intersecting direction intersecting, i.e., orthogonal to, the conveyance direction X and a width direction Z orthogonal to the conveyance direction X.

[0057] Meanwhile, the steering motors M2L and M2R are each arranged along 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 each of the rotation shafts. The drive input gears 214L and 214R fixed to each of the steering shafts 215L and 215R are meshed with each of the motor gears 213L and 213R. By rotating the steering motors M2L and M2R, the registration driving rollers 212L and 212R and the registration driving motors M1L and M1R are turned, i.e., rotated, about the steering shafts 215L and 215R.

[0058] In other words, the registration driving rollers 212L and 212R are configured to be driven to rotate by the registration driving motors M1L and M1R and to turn by the steering motors M2L and M2R in a direction inclined with respect to the conveyance direction X. Thereby, conveyance velocities of the registration roller pairs 240L and 240R can be changed independently, and the conveyance directions thereof can also be changed independently.

[0059] Further, home position sensors not shown are arranged in the vicinity of each of the registration driving rollers 212L and 212R, and the home position sensors detect home positions of the registration driving rollers 212L and 212R. The home positions of the registration driving rollers 212L and 212R are positions where the registration roller pairs 240L and 240R are disposed straight, without being inclined, with respect to the conveyance direction. That is, the registration roller pairs 240L and 240R are configured to be returned to positions where they are not inclined with respect to the conveyance direction based on the detection of the home position sensors.Configuration of Skew Detection of Sheet

[0060] Leading edge registration sensors SN2L and SN2R serving as a skew detection unit or a first skewing amount detection unit composed of optical sensors, for example, are disposed at the same positions in the conveyance direction X, that is, aligned in the width direction Z, at positions near nips of each of the registration roller pairs 240L and 240R. That is, the leading edge registration sensors SN2L and SN2R are arranged immediately downstream of the registration roller pairs 240L and 240R in the conveyance direction X. A controller 260 (refer to FIG. 10) serving as a control unit described later computes the skewing amount of the sheet S from a difference in timing at which each of the leading edge registration sensors SN2L and SN2R detected a leading edge of the sheet S and a conveyance velocity in which the sheet S is conveyed.

[0061] Similarly, leading edge registration sensors SN3L and SN3R serving as a skew detection unit or a second skewing amount detection unit composed of optical sensors, for example, are disposed downstream of the leading edge registration sensors SN2L and SN2R in the conveyance direction X. Similarly, the controller 260 (refer to FIG. 10) computes the skewing amount of the sheet S from a difference in timing at which each of the leading edge registration sensors SN3L and SN3R detected the leading edge of the sheet S and a conveyance velocity in which the sheet S is conveyed. That is, the leading edge registration sensors SN3L and SN3R detect the skewing amount of the sheet at a second position conveyed downstream in the conveyance direction X from a first position of the sheet where skewing amount of the sheet has been detected by the leading edge registration sensors SN2L and SN2R. A section from where the leading edge of the sheet is detected by the leading edge registration sensors SN2L and SN2R to where the leading edge of the sheet reaches the leading edge registration sensors SN3L and SN3R is referred to as a first correction section CS1 where a first correction control serving as a first movement process described later is performed. Further, a section from where the leading edge of the sheet is detected by the leading edge registration sensors SN3L and SN3R to where the leading edge of the sheet reaches the print belt 25 is referred to as a second correction section CS2 where a second correction control serving as a second movement process described later is performed.Configuration of Width Direction Position Detection of Sheet

[0062] Contact image sensors (CIS), hereinafter simply referred to as “image sensors”, SN1L and SN1R serving as width position detection units are arranged upstream of each of the registration roller pairs 240L and 240R in the conveyance direction X. The image sensor SN1L serving as a first width position detecting sensor detects an edge position of a left edge portion of the sheet S, and the image sensor SN1R serving as a second width position detecting sensor detects an edge portion of a right edge position of the sheet S. The image sensors SN1L and SN1R detect the width direction position of the sheet S based on the edge positions of the left edge portion and the right edge portion of the sheet, and the controller 260 (refer to FIG. 14) computes a displacement amount, so-called a lateral registration displacement position, of the width direction position based on the detection result. The detailed configuration of the image sensor SN1L or SN1R will be described below.

[0063] The image sensors SN1L and SN1R are arranged at positions such that width direction positions of the sheet may be detected when leading edges of a minimum size sheet that may be conveyed in the printing module 200 reaches the leading edge registration sensors SN3L and SN3R. In other words, the displacement amount of the sheet in the width direction position can be detected both in a state where the skewing amount is detected when the sheet is at the first position and in a state where the skewing amount is detected when the sheet is at the second position. Thereby, regardless of the size of the sheet being conveyed, the sheet skewing amount and the width direction position at the first position and the sheet skewing amount and the width direction position at the second position can be detected.Configuration of Control System of Print Module

[0064] Next, a configuration of a control system in the printing module 200 will be described with reference to FIG. 10. FIG. 10 is a block diagram illustrating a configuration of a control system according to the first embodiment.

[0065] As illustrated in FIG. 10, the controller 260 that functions as a control unit is connected to a CPU 261, a ROM 262, and a RAM 263, and programs stored in the ROM 262 can be executed by the CPU 261 using storage areas of the RAM 263. Further, the controller 260 is connected to an operation portion 290, such as an operation panel not illustrated in FIG. 1, and to an external computer via an interface not shown, through which various input operations are received or on which results are displayed.

[0066] Further, the controller 260 is connected to various sensors including the above-mentioned image sensors SN1L and SN1R, the first leading edge registration sensors SN2L and SN2R, and the second leading edge registration sensors SN3L and SN3R. The controller 260 is also connected to various motors including the above-mentioned registration driving motors M1L and M1R, the steering motors M2L and M2R, and a conveyance motor M3 that drives the conveyance roller pairs 208 and 209. The controller 260 controls the various motors based on the detection results of the various sensors, conveys the sheets, and executes a correction control including both skew correction described in detail below and a lateral registration displacement correction serving as a width position correction.Skew Correction Operation

[0067] Next, a principle of skew correction operation, i.e., active registration operation, will be described with reference to FIGS. 4A, 4B, 5A, 5B, 5C, 7A, 7B, and 7C. FIG. 4A is a perspective view illustrating a registration unit prior to turning a registration driving roller. FIG. 4B is a perspective view illustrating the registration unit after turning the registration driving roller. FIG. 5A is a top view illustrating the registration unit prior to conveyance of a sheet. FIG. 5B is a top view illustrating the registration unit in a state where skew correction of the sheet is performed. FIG. 5C is a top view illustrating the registration unit in a state where lateral registration correction of the sheet is performed. FIG. 7A is a schematic diagram illustrating a measurement example of a skewing amount. FIG. 7B is a view illustrating an example of skew correction profile. FIG. 7C is a schematic diagram illustrating a skew correction operation. Skew correction refers to correcting an angle of travelling direction of the sheet such that it is in a direction parallel to a conveyance center line which is a center of a conveyance path in a width direction through which the sheet is conveyed.

[0068] In the registration unit 210, as described above, the registration driving rollers 212L and 212R are independently driven by the registration driving motors M1L and M1R, such that the rotational speeds thereof can be changed independently. The controller 260 determines a skew correction profile for correcting skewing of a sheet based on an inclination angle of a sheet detected by the leading edge registration sensors SN2L and SN2R or the leading edge registration sensors SN3L and SN3R. The skew correction profile is a control amount for controlling a velocity difference of the registration driving rollers 212L and 212R. Then, the controller 260 drives the registration driving motors M1L and M1R based on the skew correction profile, and rotates the registration driving rollers 212L and 212R.

[0069] The skew correction profile will be described below. For example, as illustrated in FIGS. 4A and 5A, in a state where skew correction is not performed, the registration driving rollers 212L and 212R face the conveyance direction X, and are rotated by same velocities VL and VR to convey the sheet. The sheet is conveyed, and as illustrated in FIGS. 4B and 7A, for example, the skewing amount of the sheet is detected by the leading edge registration sensors SN2L and SN2R. Then, the controller 260 creates a skew correction profile as illustrated in FIG. 7B according to the detected skewing amount. The skew correction profile is created as a velocity table such that the skewing amount detected by the leading edge registration sensors SN2L and SN2R and a difference between an integrated value of a velocity LVx of the registration driving roller 212L and an integrated value of a velocity RVx of the registration driving roller 212R are equivalent. That is, as illustrated in FIG. 7B, the skew correction profile is set by multiplying a coefficient according to the skewing amount. The controller 260 drives the registration driving motors M1L and M1R according to the skew correction profile created in this manner. Thereby, as illustrated in FIG. 7C, a velocity difference is generated by the registration driving roller 212L rotated by the registration driving motor M1L and the registration driving roller 212R rotated by the registration driving motor M1R. Therefore, the sheet being conveyed by the registration driving rollers 212L and 212R is rotated, and skewing is corrected. An example in which a curve-line drive is used is illustrated as the example of the skew correction profile illustrated in FIG. 7B, but a triangular drive or a trapezoidal drive may also be adopted.Lateral Registration Displacement Correction Operation

[0070] Next, a principle of a lateral registration displacement correction operation, i.e., steering operation, will be described with reference to FIGS. 8A, 8B, 8C, and 11. FIG. 8A is a schematic diagram illustrating a measurement example of a lateral registration displacement amount. FIG. 8B is a view illustrating an example of a lateral registration displacement correction profile. FIG. 8C is a schematic diagram illustrating a lateral registration displacement correction operation. FIG. 11 is a view illustrating an example of a correction profile when performing the lateral registration displacement correction.

[0071] An up-down direction in FIG. 8A is the conveyance direction X of the sheet, and a right-left direction in FIG. 8 is the width direction Z orthogonal to the conveyance direction X. The lateral registration displacement correction refers to performing correction such that the width direction position of the sheet is matched with a width direction position of the image to be formed, and in most cases, a center of the sheet in the width direction is made to correspond to a center of the conveyance path in the width direction, i.e., reference position. This is not the case if the width direction position of the image formed on the sheet in the image forming unit, i.e., the recording unit 230, does not correspond to the width direction center of the conveyance path.

[0072] As described above, the steering motors M2L and M2R can change the conveyance directions of rollers of each of the registration driving rollers 212L and 212R via the drive input gears 214L and 214R by pivoting the rollers about the steering shafts 215L and 215R. For example, if skew correction of the sheets is not performed, the registration driving rollers 212L and 212R are operated such that the velocities VL and VR thereof are the same and the conveyance directions thereof are also the same. Based on the edge portion positions of the sheet detected by the image sensors SN1L and SN1R, the controller 260 determines a profile as a control amount for correcting the lateral registration displacement. That is, the profile of the steering motors M2L and M2R for changing the conveyance direction of the registration driving rollers 212L and 212R is determined.

[0073] The profile of lateral registration displacement correction will be described. As illustrated in FIG. 8A, a lateral displacement amount, which is the positional displacement in the width direction Z, is detected by the image sensors SN1L and SN1R. Then, the controller 260 creates a profile of the lateral registration displacement correction, velocity of the Z direction component, as illustrated in FIG. 8B according to the detected lateral displacement amount. The profile of the lateral registration displacement correction is created as a velocity table such that the detected lateral displacement amount and an integrated value of a velocity Vz of the roller of the component in the width direction in a correction section set in advance are equivalent. That is, as illustrated in FIG. 8B, the profile of the lateral registration displacement correction is set by multiplying a coefficient corresponding to the lateral displacement amount.

[0074] If the lateral registration displacement correction and the skew correction are not performed simultaneously, it is preferable that a velocity Vx of the roller as a conveyance direction X component is set to be equal to a conveyance velocity of the print belt unit 220 arranged downstream in the conveyance direction X. Since the velocity Vx of the roller of the conveyance direction X component and the velocity Vz of the roller of the width direction Z component are determined, as illustrated in FIG. 8C, trigonometric function is used to compute a roller angle θ and a roller velocity V may be computed based on the velocity Vx and the velocity Vz. By computing each of the roller angles θL and θR and the velocities VL and VR per unit time, operation profile of the steering motors M2L and M2R and the registration driving motors M1L and M1R can be created as illustrated in FIG. 11. According to this profile, the steering motors M2L and M2R and the registration driving motors M1L and M1R can be driven. Thereby, as illustrated in FIGS. 4B, 5C, and 8C, the registration driving roller 212L is turned by the steering motor M2L and the registration driving roller 212R is turned by the steering motor M2R. Therefore, the registration driving rollers 212L and 212R convey the sheet diagonally, and the lateral registration displacement is corrected. An example illustrating a curve-line drive is illustrated as an example of velocity correction profile illustrated in FIG. 8B, but a triangular drive or a trapezoidal drive may also be used.Simultaneous Correction of Skew Correction and Lateral Registration Displacement Correction

[0075] Next, a simultaneous correction of skew correction and lateral registration displacement correction will be described with reference to FIGS. 12 and 13. FIG. 12 is a view illustrating a conversion of velocity component and angle component of the registration driving roller in a state where skew correction and lateral registration displacement correction are performed simultaneously. FIG. 13 is a view illustrating an example of a correction profile in a case where the skew correction and the lateral registration displacement correction are performed simultaneously.

[0076] As described, above, skewing of the sheet is corrected by the velocity difference of the registration driving motors M1L and M1R, and skew correction can be performed thereby. Further, lateral registration displacement of the sheet is corrected by the registration driving rollers 212L and 212R being turned by the steering motors M2L and M2R, and thereby, lateral registration displacement correction is performed.

[0077] In the above description, the skew correction operation and the lateral registration displacement correction operation were described independently, but they can also be executed simultaneously. As illustrated in FIG. 12, by combining a component of lateral registration displacement in the width direction Z, i.e., Z correction component, and a component of the skewing amount, i.e., skewing angle, i.e., θ correction component, they can be converted into the velocities VL and VR and angle, i.e., steering angle, of each of the registration driving rollers 212L and 212R. In other words, as illustrated in FIG. 13, velocities LVz and RVz of the registration driving rollers 212L and 212R in the profile of lateral registration displacement correction and velocities LVx and RVx of the registration driving rollers 212L and 212R in the skew correction profile are combined. Roller angles Lθ and Rθ per unit time and the velocities VL and VR are calculated, and a simultaneous correction profile for executing skew correction and lateral registration displacement correction simultaneously is created. Then, according to the created simultaneous correction profile, the registration driving motors M1L and M1R and the steering motors M2L and M2R are driven. Thereby, skew correction and lateral registration displacement correction can be executed simultaneously.Detailed Configuration of Image Sensor (CIS) and Issues Thereof

[0078] Next, a detailed configuration of the image sensors SN1L and SN1R serving as a CIS 50 will be described with reference to FIGS. 14A and 14B. FIG. 14A is a schematic diagram illustrating a configuration of a CIS according to the first embodiment. FIG. 14B is an explanatory view illustrating an error in a spacing of the sensor chips of the CIS according to the first embodiment. The configuration of the CIS 50 is described assuming that the image sensors SN1L and SN1R are configured of line sensors of the same type, which are referred to as the CIS 50. Further according to the present embodiment, a light source unit 60 including LEDs as light sources is disposed as a separate member as the CIS 50, but alternatively, a light source may be disposed integrally in the CIS 50.Detailed Configuration of CIS

[0079] As illustrated in FIG. 14A, the CIS 50 includes a substrate 55, and a plurality of, for example, 18, sensor chips 51 arranged in the width direction Z on the substrate 55. In the width direction Z, a distance between a first sensor chip 51 and an edge portion 55a of the substrate 55, and a distance between an eighteenth sensor chip 51 and an edge portion 55b of the substrate 55, are set to 8 mm, for example, and the size of one sensor chip 51 is 12 mm, for example. Therefore, a distance from the edge portion 55a to the edge portion 55b of the CIS 50 is 232 mm, for example, and on the CIS 50, the sensor chips 51 are aligned on the substrate 55 with a 12-mm spacing therebetween.

[0080] As illustrated in FIG. 14B, the light source unit 60 is arranged to face the CIS 50. Therefore, in a state where the sheet S is conveyed and passes therebetween, the sheet blocks the light of the light source unit 60 from reaching the CIS 50, such that an edge position, hereinafter referred to as a side edge, Sa thereof in the width direction Z can be detected. The respective sensor chips 51, i.e., first sensor chip 51-1 to eighteenth sensor chip 51-18, disposed on the substrate 55 of the CIS 50 has, for example, 96 light receiving elements 52 aligned in the width direction Z. For example, it is assumed that the side edge Sa of the sheet S is positioned to overlap with a seventeenth sensor chip 51-17 in an up-down direction Y that intersects the conveyance direction X and the width direction Z. Then, the position of the side edge Sa of the sheet S can be detected based on a position of the light receiving elements 52 that receive the light from the light source unit 60 and the light receiving elements 52 that do not receive the light therefrom among the light receiving elements 52 on the sensor chip 51-17.Issues

[0081] A spacing, i.e., pixel pitch, between the light receiving elements 52 on one sensor chip 51 is set, for example, to 125 um. However, even if the spacing of the sensor chip 51 is set to 125 um, there may be a case where the light receiving elements 52 are displaced for a distance of approximately 75 um in the width direction Z due to manufacturing error. Accordingly, for example, if the position of the side edge Sa of the first sheet S is detected by the seventeenth sensor chip 51, and the side edge Sa position of the subsequent sheet S is detected by the eighteenth sensor chip 51, a displacement of 75 um may be caused in the positional relationship of the sheets. Therefore, even if lateral registration displacement correction operation is performed, as described above, by the registration roller pairs 240L and 240R, a displacement of 75 um may be caused between the first sheet S and the subsequent sheet S, such that positional accuracy of the sheet may not be good. That is, if images are formed on the sheets S, a displacement of image position on the sheet S occurs, and the positional accuracy of image formation may not be good. Therefore, according to the present first embodiment, this issue is solved by the control described below.Operation, i.e. Control, of Printing Module

[0082] Next, an operation, i.e., control, of the printing module 200 will be described with reference to FIGS. 9, 15, and 16. FIG. 9 is a flowchart illustrating a control of a print module according to the first embodiment. FIG. 15A is a schematic diagram illustrating a state prior to executing a first correction control. FIG. 15B is a schematic diagram illustrating a state after executing the first correction control. FIG. 15C is a schematic diagram illustrating a state after executing a second correction control. FIG. 16A is an explanatory view illustrating a reference example of an arrangement in which a node between sensor chips and a side edge of a regular size sheet are overlapped. FIG. 16B is an explanatory view illustrating an arrangement according to the first embodiment in which nodes between sensor chips and side edges of regular size sheets are not overlapped. According to the image formation control illustrated in FIG. 9, an example where an image is formed on one side of a sheet is illustrated, but even in a case where images are formed on both sides of a sheet, the present control may be repeatedly performed.

[0083] For example, if the accuracy of the skew correction and the lateral registration displacement correction described above is not good, the image formed on the sheet may be tilted, displaced, or distorted. Further, in a case where images are formed on both sides of the sheet, if the accuracy of the skew correction and the lateral registration displacement correction described above is not good, the image on the upper side of the sheet may be displaced greatly from the image on the rear side of the sheet. According to the present control, by executing a first correction control serving as a first movement process and a second correction control serving as a second movement process for performing the skew correction and the lateral registration displacement correction as described in detail below, the accuracy of the skew correction and the lateral registration displacement correction can be improved.Start Printing

[0084] At first, the controller 260 starts image formation control illustrated in FIG. 9 at a timing at which a print job has been received directly from an operation portion not shown or from an external computer connected via a network. The print job received by the controller 260 contains information, such as a number of prints designated by the user, and the size of the sheet S to be printed. That is, the controller 260 determines to start printing based on the received print job (S1).

[0085] Next, the controller 260 selects the sheet S having the size designated by the print job from one of the storages 110a, 110b, and 110c, and causes the sheet to be fed by the feeding module 100. Then, the controller 260 drives a driving motor to convey the sheet S by the conveyance roller pairs 208 and 209 (refer to FIG. 2) to the registration unit 210, and causes the sheet S to reach the registration roller pairs 240L and 240R (S2).First Correction Control

[0086] Next, the controller 260 proceeds to a series of processing of steps S3 to S6 as a first correction control, which is a correction control performed for the first time. At first, when the sheet S arrives at the leading edge registration sensors SN2L and SN2R, the skewing amount of the sheet S is computed and acquired based on the detection results entered from the leading edge registration sensors SN2L and SN2R (S3). That is, when the leading edge of the sheet S reaches both leading edge registration sensors SN2L and SN2R, a detection operation of the first correction control is started. The skewing amount of the sheet S mentioned here refers to an inclination angle of the sheet S with respect to the conveyance direction X, more specifically, the inclination angle of the leading edge of the sheet S with respect to the width direction Z. Specifically, as described above, the controller 260 obtains the skewing amount of the sheet S based on a deviation of timing at which each of the two leading edge registration sensors SN2L and SN2R detects the leading edge of the sheet S being conveyed, and a velocity V, i.e., conveyance velocity, of the sheet S.

[0087] Next, the controller 260 computes the width direction position, that is, a lateral displacement position, of the sheet S based on the detection result entered from the image sensors SN1L and SN1R (S4). That is, the controller 260 computes the lateral displacement amount between a sheet center and a conveyance center line from both end positions of the sheet S in the width direction Z orthogonal to the conveyance direction X by detecting the area of the image sensors SN1L and SN1R conveyed by the sheet S.

[0088] Next, the controller 260 creates a skew correction profile serving as a first control amount for correcting the skewing of the sheet S based on the skewing amount of the sheet S computed as described above. Further, the controller 260 creates a lateral registration displacement correction profile as a first control amount for correcting a lateral displacement of the sheet S based on the lateral displacement amount of the sheet S computed as described above. Then, the controller 260 creates a correction profile having combined the skew correction profile and the lateral registration displacement correction profile (S5). That is, the controller 260 executes a profile creation operation of the first correction control.

[0089] Next, the controller 260 controls the registration driving motors M1L and M1R and the steering motors M2L and M2R according to the created correction profile. That is, the controller 260 executes a correction operation of the first correction control including the skew correction and the lateral registration displacement correction as a correction operation of correction control performed for the first time based on the detection results of the leading edge registration sensors SN2L and SN2R and the detection results of the image sensors SN1L and SN1R (S6). The correction operation of the first correction control is executed so as to be completed in the first correction section CS1 (refer to FIGS. 2 and 3). Thereby, skewing and lateral displacement of the sheet are roughly adjusted.

[0090] The details of the first correction control will be described. Prior to execution of the first correction control, as illustrated in FIG. 15A, for example, it is assumed that a first sheet S1, a second sheet S2, and a third sheet S3 are conveyed to a position displaced in the width direction Z in a state where the leading edges are detected by the leading edge registration sensors SN2L and SN2R. That is, a side edge Sa1 of the first sheet S1, a side edge Sa2 of the second sheet S2, and a side edge Sa3 of the third sheet S3 are arranged at positions dispersed in the width direction Z, as illustrated by an area ZX. In this case, in the image sensor SN1R (or SN1L), the sensor chip 51 detecting the side edge Sa1 of the sheet S1, the sensor chip 51 detecting the side edge Sa2 of the sheet S2, and the sensor chip detecting the side edge Sa3 of the sheet S3 differ. In other words, the side edges of a plurality of sheets are detected across a plurality of sensor chips 51, such that the accuracy of the detected positions of side edges of the respective sheets are not good, since an error in the spacing of the sensor chips 51 is included, as described above.

[0091] However, as illustrated in FIG. 15B, by executing the first correction control, lateral registration displacement correction of respective center positions is performed for each of the first sheet S1, the second sheet S2, and the third sheet S3 with the conveyance center line set as a target position, and the lateral displacement of the sheets are roughly adjusted. Thereby, the side edge Sa1 of the first sheet S1, the side edge Sa2 of the second sheet S2, and the side edge Sa3 of the third sheet S3 can be detected by the same single sensor chip 51. Therefore, in the following second correction control, detection of side edges Sa of a plurality of sheets S that do not include the error of spacing of the sensor chips 51 is enabled.

[0092] Generally, in the inkjet recording system 1, most of the sheets S used for printing are regular size sheets. As illustrated in FIGS. 16A and 16B, the regular sheet sizes are, in the order of the sheet size having a smaller width direction, a postcard, a legal (G-LGL), FPLIO, B5, LETTER, A4 / A3 (landscape orientation), and B3. Now, in a state where the arrangement of the CIS 50 in the width direction Z that is arranged symmetrically about the conveyance center line is a position as illustrated in FIG. 16A, for example, spacing, i.e., CIS nodes, between adjacent sensor chips 51 may approximate the side edge of one of the regular size sheets. Especially, in the arrangement example of FIG. 16A, as illustrated by point A, a side edge of a B5-size sheet may be overlapped with a spacing between sensor chips 51. Even in the case of a LETTER size sheet, the side edge thereof is close to the spacing between sensor chips 51, such that if even a slight lateral displacement or skewing occurs, the side edges of the LETTER size sheets may be overlapped with the spacing between the sensor chips 51.

[0093] Thus, the arrangement of the CIS 50 in the width direction Z is considered to be set as the arrangement example illustrated in FIG. 16B. That is, the CIS 50 is arranged such that the side edges of respective regular size sheets are in a positional relationship distant from the spacing, i.e., CIS nodes, between the plurality of sensor chips 51. That is, the CIS 50, i.e., the image sensors SN1L and SN1R, are arranged such that when a regular size sheet is moved to a target position where the center of the sheet is set to the conveyance center line according to the first correction control, the side edges of the sheet will not be positioned in the spacing between a plurality of sensor chips. This arrangement of the CIS 50 is symmetric about the conveyance center line for both the image sensor SN1L and the image sensor SN1R. That is, both of the CIS 50 of the image sensors SN1L and SN1R are arranged such that side edges of regular size sheets are not positioned in the spacing between a plurality of sensor chips.

[0094] Thereby, for example, even if the regular size sheet is conveyed in a laterally displaced or skewed state, the side edges of the sheet are prevented from being overlapped with the spacing between sensor chips 51 by the lateral registration displacement correction for rough adjustment performed by the first correction control. Therefore, even if a plurality of regular size sheets of the same size are conveyed in a laterally displaced or skewed state, the side edges of the sheets will not be detected across a plurality of sensor chips 51 due to the first correction control, and the side edges can be detected by the same single sensor chip 51. Therefore, by the second correction control described below, detection of the side edges Sa of a plurality of sheets S that does not include spacing error of the sensor chips 51 is enabled.Second Correction Control

[0095] Next, the controller 260 proceeds to a series of processing of steps S7 to S10 as a second correction control, which is a correction control performed for the second time. At first, the controller 260 computes a skewing amount of the sheet S based on detection results entered from the leading edge registration sensors SN3L and SN3R (S7). That is, when the leading edge of the sheet S reaches both leading edge registration sensors SN3L and SN3R, a detection operation of the second correction control is started. Similarly, the controller 260 computes a width direction position of the sheet S, that is, the lateral displacement position, based on the detection result entered from the image sensors SN1L and SN1R (S8). The skewing amount and the lateral displacement position of the sheet S computed above may be obtained by a similar computing method as the first correction control described above. The detection results entered from the image sensors SN1L and SN1R in this state are detection results detected by the same single sensor chip 51 due to the first correction control, such that the detection results have a good accuracy that do not contain errors of spacing of the sensor chips 51.

[0096] Thereafter, the controller 260 creates a skew correction profile serving as a second control amount for correcting skewing of the sheet S based on the skewing amount of the sheet S acquired as described above. Further, the controller 260 creates a lateral registration displacement correction profile serving as a second control amount for correcting the lateral displacement of the sheet S based on the lateral displacement amount of the sheet S acquired as described above. Then, the controller 260 creates a correction profile having combined the skew correction profile and the lateral registration displacement correction profile (S9). That is, the controller 260 executes a profile creation operation of the second correction control.

[0097] Next, the controller 260 controls the registration driving motors M1L and M1R and the steering motors M2L and M2R according to the created correction profiles. That is, the controller 260 executes a correction operation of the second correction control including the skew correction and the lateral registration displacement correction as the correction operation of the correction control performed for the second tine based on the detection results of the leading edge registration sensors SN3L and SN3R and the detection results of the image sensors SN1L and SN1R (S10). The correction operation of the second correction control is executed to be completed in the second correction section CS2 (refer to FIGS. 2 and 3). Thereby, regarding the sheet that has been subjected to rough adjustment by the first correction control, skewing and lateral displacement of the sheet is further subjected to fine adjustment.

[0098] According to the second correction control executed as described above, the lateral registration displacement correction of the sheet serving as a rough adjustment is already executed in the first correction control described above. Therefore, as illustrated in FIG. 15B, the side edges of the plurality of sheets being conveyed in a laterally displaced or skewed manner are detected by a same single sensor chip 51 of each of the image sensors SN1L and SN1R in a state where the leading edges of the sheets have arrived at the leading edge registration sensors SN3L and SN3R. That is, in a state where the leading edges of the first sheet S1, the second sheet S2, and the third sheet S3 are detected by the leading edge registration sensors SN3L and SN3R, the leading edges are detected by the same single sensor chip 51 of each of the image sensors SN1L and SN1R. Therefore, in the second correction control, the positions of the side edges Sa1, Sa2, and Sa3 of the sheets detected by the image sensors SN1L and SN1R are detected as detection results with a preferable accuracy that do not include spacing errors of the sensor chips 51. Then, based on the detection results, lateral registration displacement correction profile of the second correction control is created. According thereto, as illustrated in FIG. 15C, lateral registration displacement corrections of the sheets S1, S2, and S3 are performed with a good accuracy, and the positions of the sheets S1, S2, and S3 in the width direction Z are subjected to fine adjustment preferably.Image Creation Process

[0099] Next, after the second correction control described above is completed, the controller 260 transfers the sheet S to the print belt 25 (refer to FIG. 2) (S11). Thereafter, the controller 260 creates an image on the sheet S by the recording unit 230 (S12). Then, the sheet S is discharged toward the discharging module 700 (refer to FIG. 1) (S13), by which the print job is completed and the image formation operation to one sheet is completed.

[0100] In the case of duplex printing in which image formation is performed to both sides, i.e., the front surface and the rear surface, of the sheet S, after the operation of step S13, the controller 260 reverses the sheet S by the reversing module 600, and reconveys the sheet S toward the registration roller pairs 240L and 240R. Then the operations of step S2 and subsequent steps are performed in a similar manner.Summary of First Embodiment

[0101] As described above, according to the present embodiment, the controller 260 executes the first correction control by the registration unit 210, and after performing the first correction control, executes the second correction control by the registration unit 210. Then, it is assumed that in the first correction control, the positions of side edges Sa of a plurality of sheets S are detected by different sensor chips 51 of the CIS 50. In that case, according to the detection results thereof, the positions of the sheets S are moved by the registration roller pairs 240R and 240L such that the side edges Sa of the plurality of sheets S are positioned within the detection range of the same single sensor chip 51. Then, in the second correction control, the positions of the side edges Sa of the sheets S moved by the first correction control are detected by the same single sensor chip 51, and based on the detection results thereof, the positions of the sheet S are moved by the registration roller pairs 240R and 240L. Thereby, in the second correction control, the positions of side edges Sa of the plurality of sheets S are not detected across different sensor chips 51, such that accurate detection results that do not contain errors of spacing of the sensor chips 51 are obtained. Accordingly, lateral registration displacement correction of a plurality of sheets S may be performed with a preferable accuracy, and the positions of the sheets S in the width direction Z may be corrected preferably, and thereafter, the positional accuracy of the images printed on the sheets S may also be made preferable.

[0102] Further, in the first correction control, the position of the sheet S is moved to a target position where the side edges Sa of the plurality of sheets S being moved is disposed within the detection range of a same single sensor chip 51 by the registration roller pairs 240L and 240R. Specifically, the target position is a position where a center of the sheet S in the width direction Z is set to the conveyance center line of the sheet conveyance path. The image sensors SN1L and SN1R, i.e., the CIS 50, are arranged such that side edges Sa of the regular size sheets S that are moved to a target position are not positioned in the spacing, i.e., node, between a plurality of sensor chips 51 when the regular size sheets S are moved to a target position. Thereby, in a case where the width direction positions of the sheets S having a same regular size are roughly adjusted by the first correction control, the sheets S may be moved such that the side edges Sa of the sheets S are positioned within a detection range of a same single sensor chip 51.

[0103] Further according to the present embodiment, the skew correction and the lateral registration displacement correction are performed by a single registration unit 210, such that there is no need to align two or more mechanisms for performing the skew correction and the lateral registration displacement correction in the conveyance direction, such that increasing of size of the apparatus can be prevented. Further, since the registration unit 210 performs skew correction, i.e., active registration operation, and lateral registration displacement correction, i.e., steering operation, while conveying the sheet, such that there is no need to stop the sheet temporarily, and hinderance of improvement of productivity can be prevented. Therefore, according to the sheet conveyance unit 200A of the present embodiment, both the first correction control, i.e., rough adjustment, and the second correction control, i.e., fine adjustment, are executed, while increase in size of the apparatus may be prevented and hinderance of improvement of productivity may also be prevented.

[0104] According further to the present embodiment, both the leading edge registration sensors SN2L and SN2R that detect the skewing amount of the sheet and the leading edge registration sensors SN2L and SN2R that are arranged downstream in the conveyance direction X and that detect the skewing amount of the sheet are disposed. The present embodiment further includes the image sensors SN1L and SN1R that detect the width direction position of the sheets. Thereby, the first correction control can be executed in response to the skewing amount of the sheet detected by the leading edge registration sensors SN2L and SN2R and the lateral displacement amount of the sheet detected by the image sensors SN1L and SN1R. Further, the second correction control can be executed in response to the skewing amount of the sheet detected by the leading edge registration sensors SN3L and SN3R and the lateral displacement amount of the sheet detected by the image sensors SN1L and SN1R.

[0105] Further according to the present embodiment, by executing the second correction control before the trailing edge of the sheet passes through the registration driving rollers 212L and 212R, fine adjustment of skew correction and lateral registration displacement correction of the sheet can be performed.Second Embodiment

[0106] Next, a second embodiment having changed a portion of the first embodiment will be described with reference to FIG. 17. FIG. 17 is a flowchart illustrating a control of a print module according to a second embodiment. In the description of the present second embodiment, similar components as the first embodiment are denoted with the same reference numbers, and descriptions thereof are omitted.

[0107] The second embodiment differs from the first embodiment in that whether the skewing amount or the lateral displacement amount detected by the first correction control and the second correction control may be corrected by the registration unit 210 is determined. If they cannot be corrected by the registration unit 210, correction is performed based on an upper limit value correctable by the registration unit 210.

[0108] Specifically, as illustrated in FIG. 17, similar to the first embodiment (refer to FIG. 9), a first correction control is started, a skewing amount of a sheet is detected by the leading edge registration sensors SN2L and SN2R (S3), and a lateral displacement amount of the sheet is detected by the image sensors SN1L and SN1R (S4). Whether the detected skewing amount and the lateral displacement amount are correctable by the skew correction and the lateral registration displacement correction performed by the registration unit 210 is determined (S14). If they are correctable (S14: YES), similar to the first embodiment described above, a correction profile is created according to the detected skewing amount and the lateral displacement amount (S5), and a first correction control for rough adjustment is executed (S6).

[0109] Meanwhile, it may be determined that the detected skewing amount cannot be corrected even if the registration unit 210 executes skew correction, or it may be determined that the detected lateral displacement amount cannot be corrected even if the registration unit 210 executes the lateral registration displacement correction (S14: No). That is, it may be determined that at least either one of the skewing amount and the lateral displacement amount cannot be corrected by the first correction control. In that case, the amount that cannot be corrected is, or both the amounts are, set based on an upper limit value correctable by the registration unit 210. Next, a correction profile is created by combining the skew correction profile and the lateral registration displacement correction profile, at least one of which is created by an upper limit value (S15). Then, by controlling the registration driving motors M1L and M1R and the steering motors M2L and M2R according to the correction profile created as described above, a first correction control for rough adjustment is executed (S6).

[0110] In summary, when executing the first correction control, there may be a case where at least one of the detected skewing amount of the sheet and the width direction position of the sheet is a value uncorrectable even by correcting the registration unit 210 based on a correctable upper limit control amount. In that case, the correction profile serving as the first control amount is set to a correction profile set based on an upper limit value serving as the upper limit control amount.

[0111] Therefore, if the correction profile is created based on the upper limit value as described above, a maximum skew correction or lateral registration displacement correction is executed by the registration unit 210, but correction cannot be performed for a skewing amount or a lateral displacement amount exceeding that value. However, if only the first correction control is executed, a normal correction may still be performed by subsequently performing a second correction control.

[0112] Next, a second correction control is started, wherein a skewing amount of a sheet is detected by the leading edge registration sensors SN3L and SN3R (S7), and a lateral displacement amount of the sheet is detected by the image sensors SN1L and SN1R (S8). In this state, whether the detected skewing amount and lateral displacement amount are correctable by the skew correction and the lateral registration displacement correction by the registration unit 210 is determined (S16). If they are correctable (S16: YES), similar to the first embodiment described above, a correction profile is created based on the detected skewing amount and lateral displacement amount (S9), and a second correction control for fine adjustment is executed (S10).

[0113] Meanwhile, it may be determined that at least either one of the skewing amount and the lateral displacement amount is not correctable by the second correction control (S16: NO). In that case, either the uncorrectable one of the amounts or both amounts are set based on an upper limit value correctable by the registration unit 210. Next, a correction profile is created by combining a skew correction profile and a lateral registration displacement correction profile, at least one of which is created by the upper limit value (S17).

[0114] In summary, when executing the second correction control, there may be a case where at least one of the detected skewing amount of the sheet and the width direction position of the sheet is a value uncorrectable even by controlling the registration unit 210 based on a correctable upper limit control amount. In that case, the correction profile serving as the second control amount is set to a correction profile set based on an upper limit value serving as the upper limit control amount.

[0115] In that case, since correction cannot be performed normally by the second correction control, the image formed on the sheet may be inclined or laterally displaced, such that image formation failure occurs. Therefore, the controller 260 handles the sheet as a sheet where an error has occurred. At first, the controller 260 outputs a signal notifying error to the operation portion 290 or an external computer not shown in step S17, that is, executes a notification of error.

[0116] Then, even after executing the notification of error, the second correction control is executed by controlling the registration driving motors M1L and M1R and the steering motors M2L and M2R according to a correction profile created by the upper limit value as described above (S10). Thereby, the skewing and lateral displacement, i.e., position, of the sheet can be corrected as much as possible, and occurrence of sheet jamming can be reduced. If sheet jamming does not occur, the inkjet recording system 1 will not be stopped suddenly, and for example, the sheet may be conveyed to the top tray 720 or the supporting portion 750 to complete sheet discharge. Especially, by setting the top tray 720 as an error tray onto which a sheet to which error has occurred is discharged, sheets subjected to image formation failures may be easily excluded. By performing the control described above, operation load of sheet jam processing can be reduced, and the productivity of the inkjet recording system 1 can be improved without causing the system to stop suddenly.

[0117] In the first correction control described above, if a correction profile is created based on an upper limit value (refer to S15), it is not handled as an error, but the present technique is not limited thereto, and similar to step S17, the sheet may be handled as a sheet to which an error has occurred. Especially, in the second correction control, the sheet is being conveyed toward the recording unit 230, such that skew correction and lateral registration displacement correction are fine adjustments, and compared to the rough adjustment as in the case of the first correction control, the correctable upper limit value may be small. Therefore, in a case where skewing or lateral displacement cannot be corrected by the first correction control, they may also be uncorrectable by the second correction control, such that the sheet may be handed as an error in the stage of first correction control.

[0118] In the second correction control, a case has been described where whether the detected skewing amount and the lateral displacement amount are correctable by the skew correction and the lateral registration displacement correction by the registration unit 210 is determined, and where the upper limit value is set in the correctable range. However, according to the present embodiment, when performing the second correction control, the side edges Sa of the sheets S is detected by a same single sensor chip 51 and fine adjustment of the position of the sheets S is performed. Specifically, regarding the upper limit value of the lateral displacement amount, a value falling within a range detectable by the same sensor chip 51, that is, the range of size of the sensor chip 51 in the width direction, may be set as the upper limit value. Thereby, when a side edge Sa of the sheet S is detected by other sensor chips 51, the sheet may be handled as a sheet to which an error has occurred, and the sheet that will have an image formed to a position that is not good may be excluded. In a case where the upper limit value is set as described above, the position that is detected by the sensor chip 51 according to product design in the width direction differs according to various regular size sheets (refer to FIG. 16B), such that the upper limit values may be set individually according to the respective sheet sizes. That is, the position at which the side edge Sa of a B3-size sheet S passes the sensor chip 51 according to product design is close to the spacing between adjacent sensor chips 51 (refer to FIG. 16B), such that it may be possible to set the upper limit value smaller than in the case of an A4-sized sheet.

[0119] The configurations, operations, and effects of the second embodiment other than those described above are similar to those of the first embodiment, such that descriptions thereof are omitted.Third Embodiment

[0120] Next, a third embodiment in which a portion of the first embodiment has been varied will be described with reference to FIGS. 18 and 19. FIG. 18A is a top view illustrating a state in which skew correction has been performed at a skew correction portion of a registration unit according to a third embodiment. FIG. 18B is a top view illustrating a state in which shifting has been performed by a registration roller pair of the registration unit according to the third embodiment. FIG. 19A is a top view illustrating a positional relationship between a side edge of a sheet and a CIS sensor chip in a state where skew correction has been performed at the skew correction portion of the registration unit according to the third embodiment. FIG. 19B is a top view illustrating a positional relationship between a side edge of a sheet and a CIS sensor chip in a state where shifting has been performed by the registration roller pair of the registration unit according to the third embodiment. In the description of the third embodiment, similar components as the first embodiment are denoted with the same reference numbers, and descriptions thereof are omitted.

[0121] According to the first embodiment described above, a case has been illustrated where skew correction and lateral registration displacement correction are performed while conveying the sheet S by the registration roller pairs 240L and 240R of the registration unit 210 in the sheet conveyance unit 200A. In comparison, according to the third embodiment, in a registration unit 1210 of the sheet conveyance unit 200A, a sheet S is abutted against a reference member 31 by obliquely conveying roller pairs 32-1, 32-2, and 32-3 to perform skew correction. Thereafter, in the registration unit 1210, the sheet S is subjected to lateral registration displacement correction by a registration roller pair 35 serving as a width direction moving unit.

[0122] Specifically, as illustrated in FIGS. 18A and 18B, the registration unit 1210 includes, in order from upstream to downstream in a sheet conveyance direction, a conveyance unit 1210A, a skew correction portion 1210B, and a registration roller pair 35. Further, the registration unit 1210 includes image sensors SN5 and SN7 serving as width position detection units for detecting a position of an edge portion of a sheet in a width direction orthogonal to a sheet conveyance direction. The image sensors SN5 and SN7 are formed of the CIS 50, similar to the image sensors SN1L and SN1R according to the first embodiment.

[0123] Further, the registration unit 1210 includes a slide mechanism 40 that moves a conveyance roller pair 34-3 among conveyance roller pairs 34-1, 34-2, 34-3, and 34-4 of the conveyance unit 1210A in a width direction orthogonal to the sheet conveyance direction. The conveyance unit 1210A conveys a sheet in a sheet conveyance direction by the conveyance roller pairs 34-1, 34-2, 34-3, and 34-4, and performs a lateral registration displacement correction by which a width direction position of the sheet S is moved by the conveyance roller pair 34-3.

[0124] In the present embodiment, a configuration is illustrated in which the slide mechanism 40 is disposed on the conveyance roller pair 34-3. However, the slide mechanism 40 can be disposed on the conveyance roller pair 34-4, for example, that is, the conveyance roller pair moved to slide by the slide mechanism 40 may be any conveyance roller pair, as long as the lateral registration displacement correction may be performed according to a result detected by the image sensor SN5.

[0125] In the present embodiment, a configuration is illustrated in which the image sensor SN5 is disposed at a position between the conveyance roller pair 34-2 and the conveyance roller pair 34-3. However, the image sensor SN5 may be arranged at any position capable of detecting an edge portion in a width direction of a sheet conveyed in the conveyance unit 1210A, such that the image sensor SN5 may be arranged at a position between the conveyance roller pair 34-1 and the conveyance roller pair 34-2, for example.

[0126] The skew correction portion 1210B includes obliquely conveying roller pairs 32-1, 32-2, and 32-3 serving as obliquely conveying rotary member pairs, and the reference member 31 serving as an abutment portion. The reference member 31 has a reference surface extending in a sheet conveyance direction disposed on one side thereof when viewed from a conveyance center line in the width direction, against which a side edge Sa of a sheet is abutted.

[0127] In the vicinity of the conveyance roller pair 34-3 is arranged a pre-registration sensor SN6 that detects reaching of a leading edge of a sheet by detecting the presence of a sheet. A reflection-type photoelectric sensor including a light emitting portion and a light receiving portion can be adopted as the pre-registration sensor SN6. In that case, a light emitted by the light emitting portion is reflected on a sheet having arrived at a detection position, and by having the light receiving portion detect the reflected light, a sheet passing timing is detected. In the present embodiment, the pre-registration sensor SN6 is arranged between the conveyance roller pair 34-3 and the conveyance roller pair 34-4 in the sheet conveyance direction.

[0128] The obliquely conveying roller pairs 32-1, 32-2, and 32-3 respectively rotate about an axis inclined with respect to the width direction. Therefore, by abutting against the sheet S and rotating, the obliquely conveying roller pairs 32-1, 32-2, and 32-3 move the sheet S such that the sheet S approaches the reference member 31 in the width direction as the sheet S travels downstream in a conveyance direction V. Then, the obliquely conveying roller pairs 32-1, 32-2, and 32-3 cause the side edge Sa of the sheet S to be abutted against the reference member 31. Thereby, the sheet S is moved to a set position, which is a position abutted against the reference member 31. That is, the skew correction portion 1210B constitutes a set position moving unit for moving a position of a sheet to a set position by the obliquely conveying roller pairs 32-1, 32-2, and 32-3 and the reference member 31 according to the present embodiment.

[0129] Further, the image sensor SN7 serving as a width position detection unit is arranged on the other side of the conveyance center line in the width direction with respect to the reference member 31. That is, the image sensor SN7 detects a position of a side edge Sa, on the other side from the reference member 31, of the sheet S abutted against the reference member 31. A slide mechanism 41 capable of sliding the registration roller pair 35 in the width direction is disposed on the registration roller pair 35. That is, the registration roller pair 35 and the slide mechanism 41 constitute a width direction moving unit capable of moving the position of a sheet that has been moved to a set position according to the present embodiment.

[0130] Further, a registration sensor SN8 for detecting an arrival of a leading edge of a sheet by detecting the presence of a sheet is arranged in a vicinity of the area upstream of the registration roller pair 35 in the conveyance direction V. Similar to the pre-registration sensor SN6, the registration sensor SN8 may adopt a reflection-type photoelectric sensor including a light emitting portion and a light receiving portion. In that case, the light emitted by the light emitting portion is reflected on a sheet having reached a detection position, and by having the light receiving portion detect the reflected light, a passing timing of the sheet is detected.

[0131] Thereafter, an operation of the registration unit 1210 will be described. In a state where the sheet S is conveyed to the registration unit 1210, the sheet S is conveyed by the conveyance roller pairs 34-1, 34-2, 34-3, and 34-4. The side edge Sa on one side of the sheet S in a width direction, i.e., the side edge Sa on the side of the reference member 31, is detected by the image sensor SN5, that is, the position of the sheet in the width direction is detected. Then, the sheet S is subjected to lateral registration displacement correction in the width direction by the slide mechanism 40 and the conveyance roller pair 34-3 so as to be conveyed toward the obliquely conveying roller pair 32-3.

[0132] Next, as illustrated in FIG. 18A, the obliquely conveying roller pairs 32-1, 32-2, and 32-3 cause the sheet S to be obliquely sent in an arrow K direction such that the side edge Sa of the sheet S is abutted against the reference member 31. Then, after the sheet S has been abutted against the reference member 31, skewing of the sheet S is corrected by moving the side edge Sa of the sheet S along the reference member 31.

[0133] A leading edge of the sheet S subjected to skew correction by the reference member 31 is detected by the registration sensor SN8, and after the elapse of a predetermined, it is detected that the sheet S has arrived at the registration roller pair 35. In this state, at a timing at which the leading edge of the sheet S has been detected by the registration sensor SN8, the side edge Sa of the sheet S is detected by the image sensor SN7. By detecting the width direction size of the sheet S by the image sensor SN7, the target position for performing lateral registration displacement correction of the sheet S in the width direction by the registration roller pair 35 is computed. The details of this computation is described below.

[0134] Thereafter, the registration roller pair 35 slides and moves the sheet S while nipping the sheet S by the slide mechanism 41 in the width direction Z, which is an arrow W direction. That is, the registration roller pair 35 moves the sheet S having the side edge Sa thereof abutted against the reference member 31 to correspond to a position of an image formed at the recording unit 230 of the printing module 200. In summary, the sheet S is moved such that a width direction center of the sheet S that has been subjected to skew correction and lateral registration displacement correction in the registration unit 1210 corresponds to a width direction center of the image formed at the recording unit 230.Lateral Registration Displacement Correction according to Third Embodiment

[0135] Next, a lateral registration displacement correction according to the third embodiment will be described. A tolerance exists in the width direction size of the sheet S conveyed to the registration unit 1210. For example, according to Japanese Industrial Standard, the tolerance of the width direction size is 2 mm. Therefore, it may be possible that, after having the side edge of the sheet S abut against the reference member 31 by the obliquely conveying roller pairs 32-1, 32-2, and 32-3, even if the sheet S is moved in the width direction for a predetermined distance, the center of the sheet S may not always correspond to the conveyance center line.

[0136] Therefore, according to the present third embodiment, as illustrated in FIG. 19A, in a state where the sheet S is abutted against the reference member 31, the position of the side edge Sa on a side opposite to the reference member 31 is detected by the image sensor SN7. That is, in a case where a first sheet S11, a second sheet S12, and a third sheet S13 are conveyed, it is assumed that there is a tolerance in each of the sheets S. Then, on an opposite side in the width direction from the reference member 31, a side edge Sa11 of the sheet S11, a side edge Sa12 of the sheet S12, and side edge Sa13 of the sheet S13 are dispersed according to tolerance. Therefore, by detecting the side edges Sa of the sheets S by the image sensor SN7, the width direction size of the sheets S can be measured accurately.

[0137] However, in the image sensor SN7, if the side edges Sa of a plurality of sheets S are detected by different sensor chips 51, similar to the first embodiment described above, the accuracy may be deteriorated due to the error in the spacing of the sensor chips 51. Therefore, according to the present third embodiment, as illustrated in FIG. 19A, even if the sheets have tolerances, the image sensor SN7 is arranged such that the side edges Sa of the sheets can be detected by the same single sensor chip 51, when regular size sheets are abutted against the reference member 31. In other words, the image sensor SN7 is arranged such that the range of dispersion of the side edges Sa of the sheets S including tolerances falls within a detection range of a same single sensor chip 51, that is, such that the side edges Sa of regular size sheets S are not positioned in the spacing of the sensor chips. Then, a width direction size, or distance, of the sheet S is computed based on the side edge Sa of the sheet S detected in this manner, and as illustrated in FIG. 19B, lateral registration displacement correction, i.e., width movement process, is performed by the registration roller pair 35 such that a center of the sheet S corresponds to the conveyance center line.

[0138] Thereby, in a lateral registration displacement correction, i.e., width movement process, according to the third embodiment, a detection result of the positions of side edges Sa of a plurality of sheets S with a preferable accuracy that are not detected across different sensor chips 51, and therefore, does not contain spacing errors of the sensor chips 51, can be obtained. Therefore, lateral registration displacement correction of a plurality of sheets S can be performed with a preferable accuracy, such that the position of the sheets S in the width direction Z can be corrected preferably, and positional accuracy of the image printed thereafter on the sheet S can also be made preferable.

[0139] The other configurations, operations, and effects of the third embodiment described above are similar to those of the first embodiment described above, such that descriptions thereof are omitted.Other Embodiments

[0140] According to the first to third embodiments described above, an example has been illustrated where the registration unit 210 or 1210 performs skew correction at a position upstream in a conveyance direction of the recording unit 230 serving as an image forming unit. However, the present technique is not limited thereto, and for example, any apparatus that performs skew correction at a position upstream in the conveyance direction, such as an image reading unit that reads images on sheets, a punching unit that punches holes on sheets, and a folding unit that folds the sheets, may be adopted. In summary, the sheet conveyance apparatus that carries out skew correction can be any apparatus or can be assembled to any apparatus.

[0141] According further to the first and second embodiments, an example in which the skewing amount of the sheet is detected using the leading edge registration sensors SN2L and SN2R and the leading edge registration sensors SN3L and SN3R has been described. However, the present technique is not limited thereto, and it may be possible to adopt any configuration, such as a configuration for imaging and analyzing image, as long as the skewing amount of the sheet can be detected. Furthermore, the leading edge registration sensors SN2L and SN2R and the leading edge registration sensors SN3L and SN3R as sensors for detecting the skewing amount of the sheet are not limited to the arrangement illustrated in FIG. 2, and they may be arranged at any position.

[0142] According further to the first and second embodiments, an example in which side edges Sa on either side of the sheet S are detected by arranging the image sensors SN1L and SN1R, but the present technique is not limited thereto, and an image sensor may be arranged only on one side to detect only one of the side edges Sa.

[0143] According further to the first to third embodiments, an example in which both skew correction and lateral registration displacement correction are carried out has been described. However, the present technique is not limited thereto, and it may be possible to have only the lateral registration displacement correction performed. Further, lateral registration displacement correction means correcting the position of the sheet in the width direction, but the present technique is not limited thereto, and the position of the sheet may be moved, or shifted. In other words, according to the first and second embodiments, instead of performing the first correction control and the second correction control, it may be possible to execute the first movement process and the second movement process that perform movement only in the width direction. Further, according to the third embodiment, the technique is not limited to abutting the sheet against the reference member 31 by skew correction, and it may be a technique of performing a width movement process in which the sheet S is moved only in the width direction, such as conveying the sheet while having one side of the sheet guided along a conveyance guide.

[0144] According to the first and second embodiments, an example has been illustrated where the arrangement of the CIS 50 is set such that, in a state where the first correction control is executed, the side edges Sa of regular size sheets S that have been moved to have the center of the sheet S correspond to the conveyance center line do not overlap with the nodes of the sensor chips 51 of the CIS 50. However, the present technique is not limited thereto, and the sheets S may be moved according to the first correction control to a target position such that the side edges Sa of the sheet S fall within a detection range of the sensor chip 51. In that case, it may be possible to perform the second correction control to detect the side edges Sa of the regular size sheets S by the same single sensor chip 51, and to move the sheets S using the detection result such that the center of the sheets S correspond to the conveyance center line. Further, even if the center of the sheet S is not moved to correspond to the conveyance center line according to the second correction control, it may be possible to have the position in which the image is formed on the sheet S adjusted by the recording heads 230H.

[0145] According to the present disclosure, the positional accuracy of the sheets moved by the sheet moving unit can be improved.Other Embodiments

[0146] Embodiment(s) of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and / or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and / or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

[0147] While the present disclosure has been described with reference to embodiments, it is to be understood that the present disclosure is not limited to the disclosed 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.

[0148] This application claims the benefit of Japanese Patent Application No. 2025-008421, filed Jan. 21, 2025 which is hereby incorporated by reference herein in its entirety.

Claims

1. A sheet conveyance apparatus comprising:a moving unit including a roller configured to convey a sheet, the moving unit being configured to move a position of the sheet in a width direction orthogonal to a conveyance direction;a width position detection unit including a plurality of sensor chips aligned in the width direction, the width position detection unit being configured to detect a position of an edge portion of the sheet in the width direction; anda control unit configured to control the moving unit according to a detection result of the width position detection unit,wherein each sensor chip constituting the plurality of sensor chips includes a plurality of light receiving elements aligned in the width direction,wherein, among the plurality of light receiving elements on the sensor chip, a first element is arranged closest to one side in the width direction,wherein, among the plurality of light receiving elements on the sensor chip, a second element is arranged closest to the other side in the width direction,wherein the control unit is configured to execute a first movement process and a second movement process with respect to all regular size sheets conveyable in the sheet conveyance apparatus,wherein in the first movement process, the control unit is configured to move a position of a regular size sheet by the moving unit such that an edge portion of the regular size sheet is positioned between the first element and the second element of one of the plurality of sensor chips according to a detection result of the width position detection unit, andwherein in the second movement process, the control unit is configured to move the position of the regular size sheet by the moving unit according to a detection result of the width position detection unit after execution of the first movement process.

2. The sheet conveyance apparatus according to claim 1,wherein the regular size sheets includes a first regular size sheet,wherein the plurality of sensor chips includes a first sensor chip positioned corresponding to the first regular size sheet and a second sensor chip that differs from the first sensor chip,wherein in the first movement process, the control unit is configured to move a position of the first regular size sheet by the moving unit such that an edge portion of the first regular size sheet is positioned between the first element and the second element of the first sensor chip according to a detection result of the width position detection unit, andwherein in the first movement process, the control unit is configured to move the position of the first regular size sheet by the moving unit such that an edge portion of the first regular size sheet is in a range between the first element and the second element on the first sensor chip according to a detection result of the width position detection unit after execution of the first movement process,wherein, in a case where the edge portion of the first regular size sheet is detected by the second sensor chip prior to execution of the first movement process, the control unit is configured to move, in the first movement process, the edge portion of the first regular size sheet by the moving unit from a position detected by the second sensor chip to a position detected by the first sensor chip.

3. The sheet conveyance apparatus according to claim 1,wherein, in the first movement process, the control unit is configured to move a position of the regular size sheet by the moving unit by setting a position where a center of the sheet in the width direction is at a width direction center of a sheet conveyance path as a target position.

4. The sheet conveyance apparatus according to claim 1,wherein the width position detection unit is configured such that an edge portion of the regular size sheet after execution of the first movement process is not positioned in a spacing between adjacent sensor chips.

5. The sheet conveyance apparatus according to claim 4,wherein the width position detection unit is a first width position detecting sensor disposed on one side in the width direction with respect to a center of a conveyance path in the width direction,wherein the sheet conveyance apparatus further comprises a second width position detecting sensor disposed on the other side in the width direction with respect to the center of the conveyance path, the second width position detecting sensor including a plurality of sensor chips aligned in the width direction, each sensor chip including a plurality of light receiving elements, the second width position detecting sensor being configured to detect a position of an edge portion of the sheet in the width direction, andwherein the second width position detecting sensor is configured such that an edge portion of the regular size sheet after execution of the first movement process is not positioned in a spacing between adjacent sensor chips of the second width position detecting sensor.

6. The sheet conveyance apparatus according to claim 1,further comprising a skew detection unit configured to detect a skewing amount of a sheet conveyed to the moving unit,wherein the moving unit is a correction unit configured to execute, while conveying the sheet, a correction control including a skew correction of correcting skewing of a sheet and a width position correction of correcting a position of the sheet in the width direction, andwherein the control unit is configured to execute, as the first movement process, a first correction control serving as the correction control by the correction unit according to a detection result of the skew detection unit and the width position detection unit, and configured to execute, as the second movement process, a second correction control serving as the correction control by the correction unit after executing the first correction control.

7. The sheet conveyance apparatus according to claim 6,wherein the skew detection unit includesa first skewing amount detection unit configured to detect a skewing amount of a sheet passing through the correction unit, anda second skewing amount detection unit arranged downstream of the first skewing amount detection unit in the conveyance direction and configured to detect a skewing amount of the sheet passing through the correction unit,wherein the width position detection unit is configured to detect the position of the sheet passing through the correction unit in the width direction, andwherein the control unit is configured toexecute a first correction control by the correction unit according to a position of the regular size sheet in the width direction detected by the width position detection unit and a skewing amount of the regular size sheet detected by the first skewing amount detection unit, andexecute a second correction control by the correction unit according to a position of the regular size sheet in the width direction detected by the width position detection unit and a skewing amount of the regular size sheet detected by the second skewing amount detection unit.

8. The sheet conveyance apparatus according to claim 7,wherein the correction unit includesa first skew correction roller configured to turn about an axis in an intersecting direction intersecting the conveyance direction and the width direction and to convey a sheet,a first rotational driving motor configured to drive the first skew correction roller to rotate,a first turning motor configured to drive the first skew correction roller to turn,a second screw correction roller configured to turn in the intersecting direction and to convey the sheet,a second rotational driving motor configured to drive the second screw correction roller to rotate, anda second turning motor configured to drive the second screw correction roller to turn, andwherein the control unit is configured toperform the skew correction by generating a velocity difference by the first skew correction roller driven by the first rotational driving motor to rotate and by the second screw correction roller driven by the second rotational driving motor to rotate, andperform the width position correction by turning the first skew correction roller by the first turning motor and turning the second screw correction roller by the second turning motor.

9. The sheet conveyance apparatus according to claim 8,wherein the control unit is configured to execute the second correction control after executing the first correction control and before a trailing edge of a sheet passes through the first skew correction roller and the second screw correction roller.

10. The sheet conveyance apparatus according to claim 6,wherein the control unit is configured toset a first control amount of the correction unit configured to execute the first correction control based on a skewing amount of the regular size sheet detected by the skew detection unit and a position of the regular size sheet in the width direction detected by the width position detection unit, andset the first control amount to an upper limit control amount, when executing the first correction control, if at least either one of the skewing amount of the sheet detected by the skew detection unit and the position of the regular size sheet in the width direction detected by the width position detection unit is a value uncorrectable even by controlling the correction unit based on the upper limit control amount correctable by the correction unit.

11. The sheet conveyance apparatus according to claim 10,wherein the control unit is configured toset a second control amount of the correction unit configured to execute the second correction control based on a skewing amount of the regular size sheet detected by the skew detection unit and a position of the regular size sheet in the width direction detected by the width position detection unit, andset the second control amount to the upper limit control amount, when executing the second correction control, if at least either one of the skewing amount of the regular size sheet detected by the skew detection unit and the position of the regular size sheet in the width direction detected by the width position detection unit is a value uncorrectable even by controlling the correction unit based on the upper limit control amount correctable by the correction unit.

12. The sheet conveyance apparatus according to claim 11,wherein the control unit is configured to execute notification of an error in a state where the second control amount is set to the upper limit control amount.

13. The sheet conveyance apparatus according to claim 1,wherein the width position detection unit is composed of a contact image sensor.

14. A sheet conveyance apparatus comprising:a first moving unit including an abutment portion arranged on one side in a width direction with respect to a sheet being conveyed, and an obliquely conveying rotary member pair configured to obliquely convey the sheet toward the abutment portion;a second moving unit including a roller configured to convey the sheet, the second moving unit being configured to move a position of the sheet in a width direction orthogonal to a conveyance direction;a width position detection unit including a plurality of sensor chips aligned in the width direction, the width position detection unit being configured to detect a position of an edge portion of the sheet in the width direction; anda control unit configured to control the second moving unit according to a detection result of the width position detection unit,wherein each sensor chip constituting the plurality of sensor chips includes a plurality of light receiving elements aligned in the width direction,wherein, among the plurality of light receiving elements on the sensor chip, a first element is arranged closest to one side in the width direction,wherein, among the plurality of light receiving elements on the sensor chip, a second element is arranged closest to the other side in the width direction,wherein, with respect to all regular size sheets conveyable in the sheet conveyance apparatus, the control unit is configured to executea process of abutting an edge portion of a regular size sheet against the abutment portion by the first moving unit so that the edge portion of the regular size sheet is positioned between the first element and the second element of one of the plurality of sensor chips, anda process of moving a position of the regular size sheet according to a position of the edge portion of the regular size sheet in the width direction detected by the width position detection unit in a state in which the edge portion of the regular size sheet abuts against the abutment portion.

15. The sheet conveyance apparatus according to claim 14,wherein the control unit is configured to move the regular size sheet by the second moving unit such that a center of the regular size sheet in the width direction corresponds to a width direction center of a sheet conveyance path according to the position of the edge portion of the regular size sheet moved by the first moving unit detected by the width position detection unit.

16. An image forming apparatus comprising:the sheet conveyance apparatus according to claim 1, andan image forming unit configured to form an image on a sheet conveyed by the sheet conveyance apparatus.

17. An image forming system comprising:the image forming apparatus according to claim 16, anda processing apparatus configured to subject a sheet on which an image has been formed by the image forming apparatus to processing.

Images