Sheet conveying device

Abstract

This disclosure provides a sheet conveying apparatus, comprising: a supply unit, an image forming unit, a first conveying unit, and a second conveying unit. The first conveying unit includes a first skew correction unit and a pair of shifting rollers. The first skew correction unit includes a first abutment portion configured to correct sheet skew by abutting the leading edge of the sheet against the first abutment portion. The shifting roller pair is disposed downstream of the first skew correction unit in the sheet conveying direction and configured to move the sheet in a width direction orthogonal to the sheet conveying direction while clamping the sheet. The second conveying unit includes a second skew correction unit, which includes a second abutment portion configured to correct sheet skew by abutting the leading edge of the sheet against the second abutment portion.

Description

Technical Field

[0001] This disclosure relates to a sheet conveying device for conveying sheet materials. Background Technology

[0002] Japanese Patent Application Publication No. 2024-110456 discloses an image forming apparatus that includes an alignment section for correcting sheet skew. The alignment section includes a conveying section for conveying the sheet in a sheet conveying direction and a skew correction section for conveying the sheet at an angle relative to the sheet conveying direction. The skew correction section includes a reference member and an inclined conveying roller for conveying the sheet at an angle toward the reference member. The sheet is conveyed while abutting against the reference member via the inclined conveying roller, thereby correcting the skew of the sheet.

[0003] The alignment section described in Japanese Patent Application Publication No. 2024-110456 corrects skew using a so-called side alignment system. Therefore, a long and linear transport path is required in the alignment section. Thus, it is desirable to be able to correct sheet skew and positional deviation with high precision using a method different from the side alignment system. Summary of the Invention

[0004] According to a first aspect of this disclosure, a sheet conveying apparatus includes: a supply unit configured to supply a sheet; an image forming unit configured to form an image on the sheet supplied by the supply unit at an image forming position; a first conveying unit disposed between the supply unit and the image forming position in a sheet conveying direction and configured to convey the sheet; and a second conveying unit disposed between the first conveying unit and the image forming position in the sheet conveying direction and configured to convey the sheet. The first conveying unit includes a first skew correction section and a pair of shifting rollers. The first skew correction section includes a first abutment portion configured to correct skewness of the sheet by abutting the leading edge of the sheet against the first abutment portion. The shifting roller pair is disposed downstream of the first skew correction section in the sheet conveying direction and configured to move the sheet in a width direction orthogonal to the sheet conveying direction while clamping the sheet. The second conveying unit includes a second skew correction section, which includes a second abutment portion configured to correct skewness of the sheet by abutting the leading edge of the sheet against the second abutment portion.

[0005] According to a second aspect of this disclosure, a sheet conveying apparatus includes: a supply unit configured to supply a sheet; an image forming unit configured to form an image on the sheet supplied by the supply unit at an image forming position; and a conveying unit disposed between the supply unit and the image forming position in a sheet conveying direction, and configured to convey the sheet. The conveying unit includes: a skew correction unit and a pair of shifting rollers; the skew correction unit includes an abutment portion configured to correct skew of the sheet by abutting the leading edge of the sheet against the abutment portion; and the pair of shifting rollers disposed downstream of the skew correction unit in the sheet conveying direction, and configured to move the sheet in a width direction orthogonal to the sheet conveying direction while clamping the sheet.

[0006] According to a third aspect of this disclosure, a sheet conveying apparatus includes: a supply unit configured to supply a sheet; an image forming unit configured to form an image on the sheet supplied by the supply unit at an image forming position; a first conveying unit disposed between the supply unit and the image forming position in a sheet conveying direction and configured to convey the sheet; and a second conveying unit disposed between the first conveying unit and the image forming position in the sheet conveying direction and configured to convey the sheet. The first conveying unit is configured to perform a first skew correction process to correct skewness of the sheet, and a movement process to move the sheet that has undergone the first skew correction process in a width direction orthogonal to the sheet conveying direction. The second conveying unit is configured to perform a second skew correction process to correct skewness of the sheet that has undergone the first skew correction process and the movement process by the first conveying unit. The supply unit includes: a sheet support section configured to support a sheet; an air blowing section configured to blow air toward the edge of the sheet supported by the sheet support section to make the sheet float; and a suction supply section configured to suction and supply the sheet that has been floated by the air blowing section.

[0007] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is by way of example. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating the overall image forming system of this embodiment.

[0009] Figure 2 These are sectional views and plan views showing the alignment unit.

[0010] Figure 3 This is a block diagram showing the control box of the image forming system.

[0011] Figure 4 This is a flowchart illustrating the sheet feeding control.

[0012] Figure 5This is a flowchart illustrating the sheet material conveying control.

[0013] Figure 6 It is a cross-sectional view and a plan view showing the state of the sheet having reached the gap of the first alignment roller pair.

[0014] Figure 7 It is a cross-sectional view and a plan view showing the state in which the sheet has reached the position directly in front of the first shift roller.

[0015] Figure 8 These are cross-sectional and plan views showing the state after the first movement of the sheet.

[0016] Figure 9 It is a cross-sectional view and a plan view showing the state of the sheet having reached the gap of the second alignment roller pair.

[0017] Figure 10 These are cross-sectional and plan views showing the second lateral deviation of the sheet.

[0018] Figure 11 These are cross-sectional views and plan views showing the state in which the sheet has been displaced in the width direction. Detailed Implementation

[0019] This embodiment will be described in detail below with reference to the accompanying drawings. Figure 1 As shown, the image forming system 10, which serves as a sheet feeding device, includes an image forming apparatus 1 and a sheet feeding device 2. Examples of the image forming apparatus 1 include printers, copiers, fax machines, and multifunction printers. The image forming apparatus 1 forms an image on a sheet used as a recording medium based on image information sent from an external personal computer (PC) or image information read from a document. In this embodiment, an electrophotographic full-color laser printer is used as the image forming apparatus 1. It should be noted that although an electrophotographic full-color laser printer is used as the image forming apparatus 1 in this embodiment, the image forming apparatus may include an inkjet image forming unit, rather than an electrophotographic system.

[0020] Overview of an image forming apparatus Image forming apparatus 1 can be a print-on-demand (POD) machine capable of printing for tasks other than general office work. The recording medium can be various types of sheet material, including paper such as sheets or envelopes for any purpose, glossy paper, plastic film such as overhead projector paper (OHT), and cloth. The main body 1A of image forming apparatus 1 houses a supply unit 40H and an image forming unit 513. The supply unit 40H serves as the main supply unit for supplying sheet material S, and the image forming unit 513 forms an image on the sheet material S supplied from the supply unit 40H. The image forming unit 513 has a tandem intermediate transfer system and includes four processing units PY, PM, PC, and PK, and an intermediate transfer belt 506 as an intermediate transfer component. The four processing units PY, PM, PC, and PK respectively form toner images of yellow, magenta, cyan, and black. The processing units PY, PM, PC, and PK are electrophotographic units that each include photosensitive drums 1Y, 1M, 1C, and 1K as photosensitive components.

[0021] Processing units PY, PM, PC, and PK have the same structure except that the color of the toner used for development differs from each other. Therefore, the structure of the processing unit and the toner image formation process (i.e., image formation operation) will be described using the yellow-colored processing unit PY as an example. In addition to the photosensitive drum 1Y, processing unit PY also includes an exposure unit 511, a developing unit 510, and a drum cleaner 509. The photosensitive drum 1Y is a drum-shaped photosensitive member with a photosensitive layer formed on its outer periphery, and it rotates in the direction of rotation along the intermediate transfer belt 506. The surface of the photosensitive drum 1Y receives charge from a charged part, such as a charged roller, and becomes charged.

[0022] Exposure unit 511 forms an electrostatic latent image on the surface of photosensitive drum 1Y by emitting a laser beam modulated according to image information and scanning the surface of the photosensitive drum 1Y with the laser beam using an optical system including a reflector 512. Development unit 510 stores developer containing toner and develops the electrostatic latent image into a toner image by supplying developer to the photosensitive drum 1Y. The toner image formed on the photosensitive drum 1Y is transferred in one pass by primary transfer roller 507 to intermediate transfer belt 506. Any remaining toner on the photosensitive drum 1Y after transfer is removed by drum cleaner 509.

[0023] The intermediate transfer belt 506 is wound around the drive roller 504, the driven roller 505, the secondary transfer inner roller 503, and multiple primary transfer rollers 507, and is driven by the drive roller 504. Figure 1The image forming operation is performed in parallel within processing units PY to PK, and multiple transfers are performed to superimpose the four-color toner images onto each other. Therefore, a full-color toner image is formed on the intermediate transfer belt 506. This toner image is conveyed to the secondary transfer roller gap N1 while being carried by the intermediate transfer belt 506. The secondary transfer roller gap N1 is formed by the secondary transfer roller 56 and the secondary transfer inner roller 503. The secondary transfer roller 56 is subjected to a bias voltage with a polarity opposite to that of the toner, causing the toner image to be transferred a second time onto the sheet S at the image forming position. In other words, the secondary transfer roller 56 is an example of a transfer section that transfers the image formed on the intermediate transfer belt 506 onto the sheet S. Any remaining toner on the intermediate transfer belt 506 after the transfer is removed by the belt cleaner 508.

[0024] The sheet S, on which a toner image has already been transferred, is moved by the pre-fixing transport unit 57 to the fixing unit 58. The fixing unit 58 includes a pair of fixing rollers that hold and transport the sheet S, as well as a heat source such as a halogen heater, and applies pressure and heat to the toner image carried on the sheet S. As a result, the toner particles melt and solidify, making it possible to obtain an image fixed on the sheet S.

[0025] The sheet transport system of the image forming apparatus Next, the structure and operation of the sheet transport system will be described. The sheet transport system supplies the sheet S stored in the supply box 50H of the supply unit 40H and discharges the sheet S with an image already formed on it to the outside of the image forming apparatus 1. Generally, the sheet transport system includes the supply unit 40H, the transport unit 54, the alignment unit 100, the branch transport section 59, and the re-transport section 550.

[0026] The supply unit 40H includes a supply box 50H, a tray 52H, an air blowing unit 51H, and a suction supply unit 53H. The supply box 50H is installed on the device body 1A in such a way that it can be pulled out of the device body 1A. The tray 52H is supported by the supply box 50H in such a way that it can be raised and lowered. The tray 52H can be raised and lowered relative to the supply box 50H to maintain the height of the top sheet in the stack of sheets piled on the tray 52H at a predetermined height. The air blowing unit 51H blows air towards the top of the stack of sheets piled on the tray 52H. That is, the air blowing unit 51H blows air towards the edge of the sheet S to make the sheet S float.

[0027] The suction supply unit 53H includes: a suction belt with multiple holes formed therein; and a suction fan that operates to create negative pressure inside the suction belt. The uppermost sheet S, which is lifted by the air blowing unit 51H, is sucked in by the suction belt of the suction supply unit 53H and supplied one by one as the suction belt rotates. It should be noted that the method of supplying the sheet through the supply unit 40H is not limited to the belt suction system described above; a friction separation system using rollers or pads can also be used.

[0028] The conveying unit 54 is an example of a conveying section in which a supply path 54a is formed from the supply box 50H toward the image forming section 513, and the conveying unit conveys the sheet in the supply path 54a. The sheet S supplied from the supply unit 40H is conveyed along the supply path 54a and the vertical path 111 continuous with the supply path 54a, and is transferred to the alignment unit 100.

[0029] In the alignment unit 100, which serves as the second conveying unit, the sheet S is skewed and corrected. Afterward, the sheet S is fed to the secondary transfer roller gap N1. The construction and operation of the alignment unit 100 will be described below.

[0030] In the secondary transfer roller gap N1, the toner image is transferred onto the sheet S, and the image is fixed onto the sheet S by the fixing unit 58. Afterwards, the sheet S is conveyed to the branch conveyor section 59, which includes a switching component capable of switching the conveying path of the sheet S. Once image formation on the sheet S is complete, the sheet S is discharged via the discharge roller pair of the branch conveyor section 59 to the discharge tray 500 located outside the device body 1A.

[0031] When the sheet S is discharged to the discharge tray 500 with the printed surface as the bottom surface of the sheet S, the sheet S is temporarily conveyed to the reverse conveyor 501 and flipped (switch-back), and then discharged to the discharge tray 500.

[0032] When an image is to be formed on the back side of sheet S, sheet S is conveyed to re-transport unit 550. Re-transport unit 550 includes reversing transport unit 501 and double-sided transport unit 502. Furthermore, re-transport unit 550 reverses the front and back sides of the sheet on which the image has been formed by image forming unit 513, and conveys the sheet into vertical path 111. Re-transport unit 550 includes reversing path 54d and re-transport path 54e. Reversing path 54d is a reversing path for reversing the transport direction of sheet S, and re-transport path 54e is a double-sided transport path. Re-transport path 54e conveys the sheet S conveyed from reversing path 54d into vertical path 111.

[0033] The sheet S, conveyed from the branch conveyor 59, is transferred via a reversing conveyor 501, including a reversing path 54d, to a double-sided conveyor 502, including a re-conveyor path 54e. The reversing conveyor 501 includes a pair of reversing rollers capable of rotating in both the forward and reverse directions, flipping the sheet S and transferring it to the double-sided conveyor 502. The leading edge of the sheet S conveyed to the double-sided conveyor 502 is detected by a detection unit 4, which is positioned in the re-conveyor path 54e to detect the leading edge of the sheet S. In this case, the sheet S stops in the re-conveyor path 54e until it is re-conveyed (awaiting double-sided printing) to form an image on the second side of the sheet.

[0034] The detection unit 4 can be an optical sensor. The double-sided conveying unit 502 conveys the sheet S toward the alignment unit 100 in sync with the moment an image is formed on the second side of the sheet. That is, the re-conveying unit 550 temporarily stops the sheet in the re-conveying path 54e, and then begins to convey the sheet S toward the alignment unit 100. After the image is formed on the back side of the sheet S, the sheet S is discharged into the discharge tray 500.

[0035] Sheet feeding device like Figure 1 As shown, the sheet supply device 2 is located upstream of the inlet path 110 of the image forming apparatus 1 and is connected to the image forming apparatus 1. The sheet supply device 2 includes three supply units 40L, 40M, and 40U, which have the same structure as the supply unit 40H of the image forming apparatus 1 and are arranged side-by-side in the vertical direction. Specifically, the supply unit 40L includes a supply table 50L, a tray 52L, an air blowing section 51L, and a suction supply section 53L. The supply table 50L is mounted to the apparatus body 2A of the sheet supply device 2 in a manner that allows it to be pulled out from the apparatus body 2A. The supply unit 40M includes a supply table 50M, a tray 52M, an air blowing section 51M, and a suction supply section 53M. The supply table 50M is mounted to the apparatus body 2A of the sheet supply device 2 in a manner that allows it to be pulled out from the apparatus body 2A. The supply unit 40U includes a supply table 50U, a tray 52U, an air blowing unit 51U, and a suction supply unit 53U. The supply table 50U is installed on the device body 2A of the sheet supply device 2 in such a way that the supply table 50U can be pulled out from the device body 2A. The tray 52U serves as a sheet support.

[0036] Each air blowing unit 51L, 51M, and 51U blows air onto multiple sheets stacked on corresponding trays. That is, each air blowing unit 51L, 51M, and 51U causes the sheet S to float by blowing air onto its edges. Each suction supply unit 53L, 53M, and 53U includes: a suction belt with multiple holes formed therein; and a suction fan that operates to create negative pressure on the inner side of the corresponding suction belt. The uppermost sheet S, floated by each air blowing unit 51L, 51M, and 51U, is sucked by the suction belt of one of the corresponding suction supply units 53L, 53M, and 53U, and supplied sequentially as the suction belt rotates.

[0037] As in the image forming apparatus 1, the sheet S is supplied by the supply units 40L, 40M, and 40U synchronously with the image formation time of the image forming apparatus 1. The sheet supply device 2 includes an alignment unit 240, through which the sheet S supplied from the supply units 40L, 40M, and 40U is conveyed to the inlet path 110 of the image forming apparatus 1.

[0038] More specifically, the sheet S supplied from the supply stage 50M of the supply unit 40M or the supply stage 50U of the supply unit 40U is conveyed through the alignment unit 240 and via the upper transport path 241 to the inlet path 110 of the image forming apparatus 1. The sheet S supplied from the supply stage 50L is conveyed through the alignment unit 240 and via the lower transport path 242 to the inlet path 110 of the image forming apparatus 1.

[0039] Furthermore, the horizontal path 270 extends horizontally from the confluence of the upper conveying path 241 and the lower conveying path 242, and a first pre-displacement sensor S2 for detecting the leading edge of the sheet S is disposed in the horizontal path 270. The first pre-displacement sensor S2 may be an optical sensor. If the leading edge of the sheet S is detected by the first pre-displacement sensor S2, the alignment unit 240 temporarily stops the sheet S.

[0040] Then, the alignment unit 240, as the first transport unit, supplies the sheet S again synchronously with the image formation time of the image forming apparatus 1, and transports the sheet S to the image forming apparatus 1. Therefore, variations in transport timing caused by the supply units 40L, 40M, and 40U can be corrected in this way. It should be noted that the supply units 40L, 40M, and 40U of the sheet supply device 2 and the alignment unit 240 can be controlled by the control unit 9 of the image forming apparatus 1. The structure of the alignment unit 240 will be described in detail below.

[0041] The sheet S conveyed in the horizontal path 270 is transferred to the inlet path 110 of the image forming apparatus 1. The vertical path 111 merges with the inlet path 110. The conveying path from the horizontal path 270 of the sheet supply device 2 to the discharge tray 500 extends linearly in a generally horizontal direction. Therefore, the conveying resistance of the sheet can be reduced, and the load and damage to the sheet can be reduced.

[0042] Alignment unit Next, refer to Figure 2 The structure of the alignment unit 240 of the sheet supply device 2 and the structure of the alignment unit 100 of the image forming device 1 are described. Figure 2 This is a cross-sectional view and a plan view showing alignment unit 240 and alignment unit 100.

[0043] First, the structure of the alignment unit 240 of the sheet supply device 2 will be described. For example... Figure 2 As shown, the alignment unit 240 includes an upper conveying path 241, a lower conveying path 242, and a horizontal path 270. The upper conveying path 241 is formed by a bending guide 301b and a swing guide 301a. The bending guide 301b serves as a first guide, and the swing guide 301a faces the bending guide 301b, which bends along the upper conveying path 241, and serves as a second guide. The bending guide 301b and the swing guide 301a constitute a guide portion that guides the sheet towards a first alignment roller pair 243, which serves as a skew correction portion and a first skew correction portion, while bending the sheet.

[0044] The swing guide 301a is capable of swinging about the swing axis 301c and is pushed to the standby position by the spring 301d. In the standby position, the swing guide 301a, together with the bending guide 301b, forms the upper conveying path 241. When the swing guide 301a swings from the standby position to the retracted position against the thrust of the spring 301d, the swing guide 301a forms an annular space SP1 in the upper conveying path 241.

[0045] The lower conveying path 242 is formed by a pair of curved guides 302a and 302b. A portion of the curved guide 302a protrudes outward relative to the curved guide 302b and forms an annular space SP2.

[0046] The horizontal path 270 is formed by mutually facing guides 303a and 303b, mutually facing guides 304a and 304b, mutually facing guides 305a and 305b, and mutually facing guides 306a and 306b. Guides 303a and 303b are positioned upstream of the first alignment roller pair 243 in the sheet transport direction D. Guides 304a and 304b, as well as guides 305a and 305b, are positioned between the first alignment roller pair 243 and the first shift roller pair 244 in the sheet transport direction D. Guides 306a and 306b are positioned downstream of the first shift roller pair 244 in the sheet transport direction D. A portion of guide 304a protrudes upward relative to guide 304b, forming an annular space SP3.

[0047] The alignment unit 240 further includes an upper conveying roller pair 245 disposed on the upper conveying path 241, a lower conveying roller pair 246 disposed on the lower conveying path 242, and a first alignment roller pair 243 and a first shifting roller pair 244 disposed on the horizontal path 270. Furthermore, the alignment unit 240 includes a first pre-alignment sensor S1, a first pre-shifting sensor S2, and a first line sensor S3 disposed in the horizontal path 270.

[0048] The first pre-alignment sensor S1 is positioned upstream of the first alignment roller pair 243 and downstream of the confluence of the upper conveying path 241 and the lower conveying path 242 in the sheet conveying direction D. The first pre-displacement sensor S2 and the first line sensor S3 are positioned between the first alignment roller pair 243 and the first displacement roller pair 244 in the sheet conveying direction D. The first pre-alignment sensor S1 and the first pre-displacement sensor S2 are positioned at the center of the horizontal path 270 in the width direction W, orthogonal to the sheet conveying direction D, and detect the sheet S. The first line sensor S3 is positioned on one side of the horizontal path 270 in the width direction W, relative to the center, and detects the position of the side edge SE of the sheet S in the width direction W. For example, the first line sensor S3 is a contact image sensor.

[0049] Next, the configuration of the alignment unit 100 of the image forming apparatus 1 will be described. The alignment unit 100 includes a horizontal path 541 that extends substantially horizontally from the confluence of the vertical path 111 and the entry path 110. The horizontal path 541 is formed by guides 120, 121, and 122. Guide 120 is disposed in the sheet transport direction D between the transport roller pair 101 and the second alignment roller pair 102, which serves as a second skew correction section, forming an annular space SP4. Guides 121 and 122 are disposed in the sheet transport direction D between the second alignment roller pair 102 and the secondary transfer roller gap N1.

[0050] The alignment unit 100 also includes a conveying roller pair 101 and a second alignment roller pair 102. The conveying roller pair 101 is disposed downstream of the confluence portion 540 in the sheet conveying direction D and conveys the sheet S toward the second alignment roller pair 102. The second alignment roller pair 102 is disposed on the horizontal path 541.

[0051] Furthermore, the alignment unit 100 includes a second pre-alignment sensor S4, a second line sensor S5, and a leading edge sensor S6 disposed in the horizontal path 541. The second pre-alignment sensor S4 and the second line sensor S5 are disposed between the conveying roller pair 101 and the second alignment roller pair 102 in the sheet conveying direction D. The leading edge sensor S6 is disposed between the second alignment roller pair 102 and the secondary transfer roller gap N1 in the sheet conveying direction D.

[0052] The second alignment sensor S4 and the leading edge sensor S6 are disposed at the center of the horizontal path 541 in the width direction W, and detect the sheet S. Specifically, the leading edge sensor S6 detects the leading edge of the sheet S. Similar to the first line sensor S3, the second line sensor S5 is disposed on one side of the horizontal path 541 in the width direction W relative to the center, and detects the position of the side edge SE of the sheet S in the width direction W. For example, the second line sensor S5 is a contact image sensor.

[0053] Control box Figure 3 This is a block diagram showing the control block of the image forming system 10. For example... Figure 1 and Figure 3 As shown, the image forming apparatus 1 of the image forming system 10 includes a control unit 9. The control unit 9 includes a central processing unit (CPU) 91, a read-only memory (ROM) 92, and a random access memory (RAM) 93. The CPU 91 reads various programs stored in the ROM 92 and executes these programs. The RAM 93 serves as the working area of ​​the CPU 91.

[0054] The control unit 9 is connected to the operation unit 94, which includes a touch panel or physical keys. The user can input various settings for the image forming system 10, start commands for print jobs, etc., through the operation unit 94. The input side of the control unit 9 is connected to the first alignment sensor S1, the first shift sensor S2, the first line sensor S3, the second alignment sensor S4, the second line sensor S5, and the leading edge sensor S6.

[0055] The output side of the control unit 9 is connected to the supply motor 250, the first upper roller drive motor MD1U, the first upper roller separation motor MA1U, the first lower roller drive motor MD1L, the first lower roller separation motor MA1L, the first alignment drive motor MD2, and the first alignment separation motor MA2. Furthermore, the output side of the control unit 9 is connected to the first shift drive motor MD3, the first shift separation motor MA3, the first shift motor MS3, the second roller drive motor MD4, the second roller separation motor MA4, the second alignment drive motor MD5, the second alignment separation motor MA5, and the second shift motor MS5.

[0056] The supply motor 250 can drive the suction belts of each suction supply unit. It should be noted that the fans of each air blowing unit and the suction fans of each suction supply unit can be driven by the driving force from the supply motor 250, or they can be driven by other motors.

[0057] like Figure 2 and Figure 3 As shown, the upper conveyor roller pair 245, which is the upstream conveyor roller pair, is driven by the first upper roller drive motor MD1U, and the roll gap of the upper conveyor roller pair 245 is released by the first upper roller separation motor MA1U. It should be noted that, in the following description, "drive roller pair" means driving the drive roller in the roller pair (which consists of a drive roller and a driven roller) by using a motor drive force applied to the drive roller. Furthermore, in the following description, "releasing the roll gap of the roller pair" means releasing the roll gap of the roller pair by separating the driven roller in the roller pair from the drive roller.

[0058] The lower conveying roller pair 246 is driven by the first lower roller drive motor MD1L, and the roll gap of the lower conveying roller pair 246 is released by the first lower roller separation motor MA1L. The first alignment roller pair 243 is driven by the first alignment drive motor MD2, and the roll gap NP1 of the first alignment roller pair 243 is released by the first alignment separation motor MA2. The first shifting roller pair 244 is driven by the first shifting drive motor MD3, and the roll gap of the first shifting roller pair 244 is released by the first shift separation motor MA3. Furthermore, when the sheet S is held in the roll gap by the first shifting roller pair 244, the first shifting roller pair 244 can move in the width direction W by the first shifting motor MS3.

[0059] The conveyor roller pair 101 is driven by the second roller drive motor MD4, and the roll gap of the conveyor roller pair 101 is released by the second roller release motor MA4. The second alignment roller pair 102 is driven by the second alignment drive motor MD5, and the roll gap NP2 of the second alignment roller pair 102 is released by the second alignment release motor MA5. Furthermore, when the sheet S is held in the roll gap NP2 by the second alignment roller pair 102, the second alignment roller pair 102 can move in the width direction W by the second shift motor MS5.

[0060] Skew correction control Next, refer to Figures 4 to 11 Describe the sheet transport control of the image forming system 10. Figure 4 and Figure 5 This is a flowchart illustrating the sheet feeding control. Figure 6 This is a cross-sectional view and a plan view showing the state in which the sheet S has reached the roll gap NP1 of the first alignment roller pair 243. Figure 7 It is a cross-sectional view and a plan view showing the state in which the sheet S has reached the position directly in front of the first shift roller pair 244. Figure 8 These are cross-sectional and plan views showing the state of the sheet S after the first moving process. Figure 9 This is a cross-sectional view and a plan view showing the state in which the sheet S has reached the roll gap NP2 of the second alignment roller pair 102. Figure 10 This is a cross-sectional view and a plan view showing the second lateral deviation Δ2 of the sheet S. Figure 11 These are cross-sectional and plan views showing the state in which the sheet S has been shifted in the width direction W.

[0061] like Figure 4 As shown, if the control unit 9 receives a print job as a task from an external computer connected to the operation unit 94 or the image forming system 10, the control unit 9 begins sheet transport control. The print job includes the number of copies to be printed and the size of the sheet to be printed, as specified by the user.

[0062] If sheet transport control is initiated, the control unit 9 supplies sheet S from the supply source specified according to the printing job (step S11). The image forming system 10 includes a supply box 50H and supply tables 50L, 50M, and 50U as the supply source. Hereinafter, the case of supplying sheet S from supply table 50U will be described, for example. The sheet S supplied from supply table 50U passes through the upper transport path 241 and is transported by the upper transport roller pair 245 toward the first alignment roller pair 243.

[0063] Then, as Figure 6As shown, the leading edge of the sheet S is detected by the first alignment sensor S1. Then, the sheet S reaches the roll gap NP1 of the first alignment roller pair 243, which is in a state where the drive of the first alignment roller pair 243 is stopped (step S12). Then, the control unit 9 performs a first skew correction process (step S13). Assume that when the sheet S has reached the roll gap NP1 of the first alignment roller pair 243, the sheet S is skewed at an angle θ1 relative to the sheet conveying direction D.

[0064] In the first skew correction process, the control unit 9 stops the first alignment roller pair 243 by stopping the first alignment drive motor MD2, and in this state, the control unit 9 drives the first upper roller drive motor MD1U based on the detection result of the first alignment pre-sensor S1. Through this operation, the leading edge of the sheet S abuts against the roll gap NP1 of the first alignment roller pair 243, and the sheet S is further conveyed by the upper conveying roller pair 245, causing the sheet S to form an annular shape. The roll gap NP1 is an example of the abutment portion where the leading edge of the sheet abuts and the first abutment portion.

[0065] If an annular structure is formed on the sheet S, the oscillating guide 301a is pressed against the surface of the sheet S forming the annular structure, causing the oscillating guide 301a to move from the ready position to the retracted position. Therefore, an annular space SP1 is formed in the upper conveying path 241, and the leading edge of the sheet S is aligned with the roller gap NP1, thus correcting the skewness of the sheet S. In other words, the sheet S in… Figure 6 The counterclockwise pivot angle θ1.

[0066] After the skewness of sheet S is corrected, the control unit 9 drives the first alignment drive motor MD2 to cause the first alignment roller pair 243 to transport sheet S in the sheet transport direction D. After the first alignment roller pair 243 has transported sheet S a predetermined distance, the control unit 9 releases the gap of the upper conveying roller pair 245 by driving the first upper roller separation motor MA1U.

[0067] Then, based on the detection result of the first pre-shift sensor S2, the control unit 9 stops the sheet S in front of the first shift roller pair 244 (step S14). Afterwards, the control unit 9 transports the sheet S again synchronously with the moment the photosensitive drum is exposed by the exposure unit 511. It should be noted that the control unit 9 may also choose not to stop the sheet S in front of the first shift roller pair 244, but instead control the transport speed of the sheet S based on the moment the image is transferred to the sheet S in the secondary transfer roller gap N1.

[0068] The position of the side edge SE of sheet S in the width direction W is detected by the first line sensor S3, which serves as both a side edge detection unit and a first side edge detection unit (step S15). For example... Figure 7As shown, the control unit 9 calculates the first lateral deviation Δ1 of the side edge SE of the sheet S relative to the reference position ST1 in the width direction W based on the detection result of the first line sensor S3. It should be noted that the reference position ST1 for each size of the sheet S is pre-stored in the ROM 92.

[0069] Then, as Figure 8 As shown, after the sheet S is conveyed a predetermined distance by the first shift roller pair 244, the control unit 9 releases the gap NP1 of the first alignment roller pair 243 by driving the first alignment separation motor MA2 (step S16). It should be noted that the release time of the gap of the upper conveying roller pair 245 can be synchronized with the release time of the gap NP1 of the first alignment roller pair 243. That is, as long as the gap of the conveying roller pair 245 is released after the sheet S is clamped by the first alignment roller pair 243, the release time of the gap of the conveying roller pair 245 can be any time. Furthermore, as long as the gap NP1 of the first alignment roller pair 243 is released after the sheet S is clamped by the first shift roller pair 244, the release time of the gap NP1 of the first alignment roller pair 243 can be any time.

[0070] Then, the control unit 9 performs a first movement process (i.e., movement processing) (step S17). Specifically, the control unit 9 drives the first shift motor MS3 to move (or shift) the first shift roller pair 244, which holds the sheet S and serves as a shift roller pair, in the width direction W by a first lateral deviation Δ1. In this case, since the upper conveying path 241 is curved, the so-called skew may recur, such as... Figure 9 As shown. If the skewness recurs, the sheet S pivots and skews relative to the sheet conveying direction D. It should be noted that in this embodiment, the first shift roller pair 244 moves in the width direction W simultaneously with the first shift drive motor MD3 and the first shift motor MS3. However, this disclosure is not limited to this. For example, the first shift roller pair 244 can move in the width direction W with the first shift motor MS3 while the first shift drive motor MD3 is stopped.

[0071] Then, the sheet S is transferred to the inlet path 110 of the image forming apparatus 1 via the first shift roller pair 244, and is conveyed toward the second alignment roller pair 102 via the first shift roller pair 244 and the conveyor roller pair 101 (step S18). Then, the control unit 9 performs a second skew correction process (step S19). Assuming... Figure 9 As shown, when the sheet S has reached the gap NP2 of the second alignment roller pair 102, the sheet S is tilted at an angle θ2 relative to the sheet conveying direction D.

[0072] In the second skew correction process, the control unit 9 stops the second alignment roller pair 102 by stopping the second alignment drive motor MD5, and in this state, the control unit 9 drives the second roller drive motor MD4 based on the detection result of the second pre-alignment sensor S4. Through this operation, the leading edge of the sheet S abuts against the roll gap NP2 of the second alignment roller pair 102, and the sheet S is further conveyed by the conveying roller pair 101, causing the sheet S to form an annular shape. The annular shape formed by the sheet S can enter the annular space SP4 formed by the guide 120. In addition, the leading edge of the sheet S is aligned with the roll gap NP2, so that the skew of the sheet S is corrected. That is, the sheet S in Figure 9 The clockwise pivot angle θ2.

[0073] The position of the side edge SE of the sheet S (whose skewness has been corrected in the second skewness correction process) in the width direction W is detected by the second line sensor S5, which serves as the second side edge detection unit (step S20). Figure 10 As shown, the control unit 9 calculates the second lateral deviation Δ2 of the side edge SE of the sheet S relative to the reference position ST1 in the width direction W based on the detection result of the second line sensor S5.

[0074] Then, as Figure 5 As shown, the control unit 9 determines whether sheet S is the first sheet in the printing operation (step S21). If the control unit 9 determines that sheet S is the first sheet in the printing operation (step S21: Yes), the control unit 9 stops sheet S in the state where the leading edge of sheet S abuts against the roll gap NP2 of the second alignment roller pair 102 (step S22). In this state, the second alignment drive motor MD5 stops. Roll gap NP2 is an example of the second abutment portion abutted by the leading edge of the sheet.

[0075] Then, the control unit 9 sets the position where the photosensitive drum is exposed by the exposure unit 511 to a shifted position that has moved by a second lateral deviation amount Δ2 from the normal position (step S23). That is, the exposure unit 511 adjusts the position in which the electrostatic latent image is formed in the width direction W based on the detection result of the second line sensor S5. It should be noted that the normal position refers to the position where the transport center of each horizontal path 270 and 541 becomes consistent with the center of the image formed in the normal position.

[0076] In this printing operation, after the operation, the position where the photosensitive drum is exposed by the exposure unit 511 is a shifted position. That is, in this printing operation, the image on the second side of the first sheet and the images on the second and subsequent sheets are formed at the shifted position. In addition, the reference position of the second line sensor S5 becomes reference position ST2 (not shown), which is moved from the reference position ST1 by a second lateral deviation Δ2 in the width direction W. It should be noted that the exposure unit 511 can form an image on the photosensitive drum before step S22 (corresponding to step S23). That is, as long as the position of the side edge SE of the sheet S in step S20 is detected by the second line sensor S5 and the exposure unit 511 forms an image on the photosensitive drum, the exposure unit 511 can form an image on the photosensitive drum at any time.

[0077] Then, as Figure 10 As shown, the control unit 9 drives the second alignment roller pair 102 by driving the second alignment drive motor MD5, thereby conveying the sheet S again (step S24). After the sheet S has been conveyed a predetermined distance by the second alignment roller pair 102, the control unit 9 releases the gap of the first shift roller pair 244 by driving the first shift separation motor MA3, and releases the gap of the conveying roller pair 101 by driving the second roller separation motor MA4 (step S25).

[0078] On the other hand, if the control unit 9 determines in step S21 that the sheet S is not the first sheet in the printing operation (step S21: No), then the control unit 9 drives the second alignment drive motor MD5 (step S27). Through this operation, the sheet S, whose skewness has been corrected in the second skew correction process, is conveyed again by the second alignment roller pair 102. Then, as in step S25, the control unit 9 releases the gap of the first shift roller pair 244 by driving the first shift separation motor MA3, and releases the gap of the conveyor roller pair 101 by driving the second roller separation motor MA4 (step S28).

[0079] Then, the control unit 9 calculates the displacement between the updated reference position ST2 and the position of the side edge SE of the sheet S in the width direction W detected by the second line sensor S5 in step S20. That is, the control unit 9 calculates the deviation between the reference position ST2 and the detected position of the side edge SE of the sheet S. Then, the control unit 9 performs a second movement process (step S29). Specifically, the control unit 9 drives the second shift motor MS5 to move the second alignment roller pair 102 holding the sheet in the width direction W by the aforementioned deviation (step S29). Through this operation, the sheet S moves by the deviation in the width direction W. However, since the deviation is very small, the recurrence of the skewing of the sheet S caused by the movement process in step S29 is almost impossible.

[0080] It should be noted that the skewing and positional deviation (in the width direction W) of the conveyed sheet S are often caused by wear of the conveying roller pair, tolerances of the guide members guiding the sheet, etc. That is, the skewing and positional deviation in the width direction W occurring in the first sheet of the printing operation often occur by the same amount as the skewing and positional deviation in the width direction W of each sheet in the second and subsequent sheets of the printing operation. Therefore, in the printing operation, the images for the second side of the first sheet and the second sheet are formed at the shifted position as described above. Therefore, the amount of sheet S shifted in the width direction W by the second alignment roller pair 102 in step S29 can be reduced, thereby reducing the recurrence of skewing caused by sheet shift. Furthermore, for the second sheet S of the printing operation, the image is formed at the shifted position based on the position of the side edge SE of the first sheet of the printing operation detected by the second line sensor S5. Therefore, the exposure unit 511 can form an image on the photosensitive drum earlier than the moment when the first sheet in the printing operation forms an image on the photosensitive drum, thereby shortening the time when the sheet S is stopped as in step S22. This improves productivity.

[0081] After steps S25 and S29, the control unit 9 controls the conveying speed of the sheet S by controlling the speed of the second alignment roller pair 102 based on the detection result of the leading edge sensor S6 and according to the moment when the image is transferred in the secondary transfer roller gap N1 (step S26).

[0082] like Figure 11 As shown, the toner image is transferred to the sheet S in the secondary transfer roller gap N1 (step S30). Then, the control unit 9 releases the roller gap NP2 of the second alignment roller pair 102 by driving the second alignment separation motor MA5 (step S31). Furthermore, the control unit 9 fixes the toner image to the sheet S in the fixing unit 58 (step S32) and discharges the sheet S to the discharge tray 500 (step S33). With this operation, the sheet transport control ends.

[0083] In double-sided printing, when an image is formed on the second side of the sheet S, the sheet S is conveyed from the vertical path 111 to the alignment unit 100 without passing through the alignment unit 240 of the sheet supply device 2. Therefore, the sheet S undergoing double-sided printing is... Figure 4 , Figure 5 The processing of steps S18 to S21 and steps S27 to S33 in the flowchart.

[0084] The above describes an example of supplying sheet S from supply station 50U. Similarly, in the case of supplying sheet S from supply station 50M, the following process is also performed. Figure 4 and Figure 5The control described above is shown in the flowchart. Furthermore, when sheet S is supplied from the supply table 50L, the control described above is performed similarly, except that sheet S is conveyed by the lower conveyor roller 246 via the lower conveyor path 242 instead of the upper conveyor path 241.

[0085] Furthermore, when the sheet S is supplied from the supply cassette 50H of the image forming apparatus 1, as in the case of forming an image on the second side of the sheet S in duplex printing, the sheet S is conveyed from the vertical path 111 to the alignment unit 100, and skew correction and movement (displacement) of the sheet S in the width direction W are performed in the alignment unit 100. In other words, the sheet S supplied from the supply unit 40H of the image forming apparatus 1 is conveyed by the alignment unit 100 without passing through the alignment unit 240, and then an image is formed on the sheet S by the image forming unit 513.

[0086] As described above, in this embodiment, the sheet S supplied from the supply stages 50L, 50M, or 50U of the sheet supply device 2 undergoes a first skew correction process and a first movement process via the alignment unit 240 of the sheet supply device 2. Furthermore, the sheet S undergoes at least a second skew correction process via the alignment unit 100 of the image forming apparatus 1. Therefore, significant skew and positional deviation in the width direction W are corrected in the first skew correction process and the first movement process.

[0087] Furthermore, after the first movement process, a recurrence of skewness, which causes the sheet S to become skewed, may occur. This recurrence is particularly noticeable when a portion of the sheet S to be moved is on a curved conveyor path (e.g., upper conveyor path 241 or lower conveyor path 242). However, even if skewness recurs and the sheet S becomes skewed again, the skewness of the sheet S is corrected in the second skewness correction process. Therefore, the skewness and positional deviation of the sheet S can be corrected with high precision.

[0088] Furthermore, in this embodiment, the so-called side alignment system that corrects the skewness of sheet S while it abuts against the reference component is not used. Specifically, the skewness of sheet S is corrected by having sheet S abut against the gap NP1 of the first alignment roller pair 243 and the gap NP2 of the second alignment roller pair 102. Therefore, the long and linear transport path used in the side alignment system is not necessary, allowing the device to be miniaturized. For example, the upper transport path 241 and lower transport path 242 traversed by sheet S supplied from the supply table 50L, 50M, or 50U can be curved, thereby reducing the horizontal dimension of the sheet supply device 2.

[0089] Furthermore, in this embodiment, the sheet S is supplied by an air blowing unit and a suction supply unit. Because this supply unit with an air supply system is used, it can supply various types of sheet S and increase the types of media that the supply unit can handle. When using a supply unit with an air supply system, the sheet S may become skewed or deviate from its position during supply. However, in this embodiment, because at least a first skew correction process, a first movement process, and a second skew correction process are performed, the skewness and position deviation of the sheet S can be corrected with high precision. In other words, in this embodiment, the image forming system 10 can handle various types of media, can be miniaturized, and can correct skewness and position deviation in the width direction W with high precision.

[0090] The alignment unit 240 of the sheet supply device 2 corrects the skewness of the sheet using the first alignment roller pair 243 and moves the sheet S in the width direction W using the first shift roller pair 244. In this embodiment, the lower transport path 242 of the sheet supply device 2 is significantly curved. For example, when supplying thin paper with a low basis weight, the sheet may buckle when it abuts against the gap NP1 of the first alignment roller pair 243 and forms an annular shape in the annular space SP2 of the lower transport path 242. Therefore, when supplying thin paper, the first alignment roller pair 243 may not perform the first skew correction process, the first shift roller pair 244 may not perform the first movement process, while the second alignment roller pair 102 of the image forming apparatus 1 can perform the second skew correction process and the second movement process.

[0091] Furthermore, when supplying thick paper with a large basis weight, since the annular space SP4 is smaller than the annular space SP2, it may not be possible to properly form an annular shape in the annular space SP4 at the second alignment roller pair 102, thus the skewness of the sheet may not be corrected. Therefore, when supplying thick paper, the first alignment roller pair 243 can perform the first skew correction process, the first shift roller pair 244 can not perform the first shift process, and the second alignment roller pair 102 of the image forming apparatus 1 can perform the second shift process without performing the second skew correction process. Therefore, since the first alignment roller pair 243 and the first shift roller pair 244 are separately arranged in the alignment unit 240 of the sheet supply apparatus 2, the sheet can be properly processed according to its basis weight.

[0092] Other embodiments It should be noted that although the alignment unit 240 in the above embodiments includes a first alignment roller pair 243 and a first shifting roller pair 244, this disclosure is not limited thereto. For example, the first shifting roller pair 244 may not be provided, while the first alignment roller pair 243 may perform a first skew correction process and a first movement process. Furthermore, although the alignment unit 100 in the above embodiments includes a second alignment roller pair 102 capable of performing a second skew correction process and a second movement process, this disclosure is not limited thereto. For example, the alignment unit 100 may include an alignment roller pair performing a second skew correction process and a shifting roller pair performing a second movement process.

[0093] Furthermore, although in the above embodiments, skew correction is performed by bringing the leading edge of the sheet against the gap of the alignment roller pair, this disclosure is not limited thereto. For example, a baffle including an abutment surface may be disposed upstream of the gap of the alignment roller pair in the sheet conveying direction. In this case, skew correction can be performed by bringing the leading edge of the sheet against the abutment surface of the baffle.

[0094] Furthermore, although the position of the photosensitive drum exposed by the exposure unit 511 is adjusted based on the detection result of the second line sensor S5 in the above embodiment, this disclosure is not limited thereto. For example, the position of the photosensitive drum exposed by the exposure unit 511 may not be changed.

[0095] Furthermore, although in the above embodiments the alignment unit 240 is disposed in the sheet supply device 2 and the alignment unit 100 is disposed in the image forming apparatus 1, this disclosure is not limited thereto. For example, both the alignment unit 240 and 100 may be disposed in the sheet supply device 2 or the image forming apparatus 1.

[0096] Furthermore, although an air supply system that supplies the sheet via an air blowing section and a suction supply section was used in the above embodiments, this disclosure is not limited thereto. For example, a friction separation system utilizing rollers or pads can be used.

[0097] Furthermore, although in the above embodiment the first line sensor S3 is disposed upstream of the first shift roller pair 244 in the sheet conveying direction D, this disclosure is not limited thereto. For example, the first line sensor S3 may be disposed downstream of the first shift roller pair 244 in the sheet conveying direction D. Similarly, although in the above embodiment the second line sensor S5 is disposed upstream of the second alignment roller pair 102 in the sheet conveying direction D, this disclosure is not limited thereto. For example, the second line sensor S5 may be disposed downstream of the second alignment roller pair 102 in the sheet conveying direction D.

[0098] In the above embodiment, the position of the side edge SE of the first sheet S in the printing job is detected by the second line sensor S5; and the exposure position of the image of the second side of the first sheet in the printing job and the exposure position of the image of the second and subsequent sheets in the printing job are adjusted by using the detection result. However, the position of the side edge SE of each sheet S being transported can also be detected by the second line sensor S5, and the position of the photosensitive drum exposed by the exposure unit 511 is adjusted by using the detection result of the second line sensor S5 on each sheet.

[0099] Furthermore, although the first sheet S of the printing job is not subjected to a second movement process by the second alignment roller 102 in the above embodiment, this disclosure is not limited thereto. For example, a second movement process as in step S29 may be performed after step S25.

[0100] This disclosure enables high-precision correction of sheet skewing and positional deviation.

[0101] Other embodiments The embodiments of the present invention can also be implemented by the following method: providing software (including computer program products of computer programs) that performs the functions of the above embodiments to a system or device via a network or various storage media, and the computer (central processing unit (CPU) or microprocessor unit (MPU) of the system or device) reads out and executes the computer program.

[0102] While this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A sheet conveying device, comprising: A supply unit configured to supply sheet material; An image forming unit configured to form an image at an image forming position on a sheet supplied by the supply unit; A first conveying unit is disposed between the supply unit and the image forming position in the sheet conveying direction, and the first conveying unit is configured to convey the sheet. as well as A second conveying unit is disposed between the first conveying unit and the image forming position in the sheet conveying direction, and the second conveying unit is configured to convey the sheet. The first conveying unit includes: A first skew correction unit, the first skew correction unit including a first abutment portion, the first abutment portion being configured to correct the skewness of the sheet by abutting against the leading edge of the sheet; and A pair of shifting rollers is disposed downstream of the first skew correction section in the sheet conveying direction, and the pair of shifting rollers is configured to move the sheet in a width direction orthogonal to the sheet conveying direction while clamping the sheet. The second conveying unit includes a second skew correction section, which includes a second abutment section. The second abutment section is configured to correct the skewness of the sheet by abutting the leading edge of the sheet against the second abutment section.

2. The sheet conveying device according to claim 1, wherein the sheet conveying device comprises: An image forming apparatus, the image forming apparatus including a second transport unit and the image forming section; as well as A sheet supply device, comprising the supply unit and the first conveying unit, wherein the sheet supply device is connected to the image forming apparatus.

3. The sheet conveying device according to claim 2, wherein, The image forming apparatus includes a body supply unit configured to supply a sheet, and In this process, after the sheet supplied by the main supply unit is conveyed by the second conveying unit without passing through the first conveying unit, the image forming unit forms an image on the sheet.

4. The sheet conveying device according to any one of claims 1 to 3, wherein, The first conveying unit includes a side edge detection unit configured to detect the position of the side edge of the sheet in the width direction, and The shifting rollers are configured to move the sheet in the width direction based on the detection result of the side edge detection unit.

5. The sheet conveying device according to claim 4, wherein, The first conveying unit includes: Upstream conveyor roller pair, the upstream conveyor roller pair being disposed upstream of the first skew correction section in the sheet conveying direction; and A guide portion is configured to guide the sheet toward the first abutment portion of the first skew correction portion while bending the sheet conveyed by the upstream conveyor rollers.

6. The sheet conveying device according to claim 5, wherein, The guide section includes: First guide element; and The second guide faces the first guide and can be moved away from the first guide by being pressed by a sheet that has abutted the first abutment portion.

7. The sheet conveying device according to any one of claims 1 to 3, wherein, The supply unit includes: A sheet support portion, wherein the sheet support portion is configured to support a sheet; An air blowing section, configured to blow air toward the edge of a sheet supported by the sheet support section to cause the sheet to float; and A suction supply unit is configured to suction and supply the sheet material that has been floated by the air blowing unit.

8. The sheet conveying device according to claim 4, wherein, The second skew correction part is configured to move the sheet in the width direction while clamping it after correcting the skew of the sheet by having the leading edge of the sheet abut against the second abutment part.

9. The sheet conveying device according to claim 8, wherein, The side edge detection unit is the first side edge detection unit. The second conveying unit includes a second side edge detection unit, which is configured to detect the position of the side edge of the sheet in the width direction. The second skew correction unit moves the sheet in the width direction while clamping it, based on the detection result of the second side edge detection unit.

10. The sheet conveying device according to claim 9, wherein, The image forming unit includes: Photosensitive components; An exposure unit configured to form an electrostatic latent image on a photosensitive element by exposing the photosensitive element; and The developing unit is configured to develop the electrostatic latent image into a toner image, and The exposure unit is configured to adjust the position of the electrostatic latent image in the width direction based on the detection result of the second side edge detection unit.

11. The sheet conveying device according to claim 8, wherein, The second skew correction unit is configured to prevent the first sheet of the operation, which is supplied by the supply unit, from moving in the width direction, and is configured to allow the second and subsequent sheets of the operation to move in the width direction.

12. The sheet conveying device according to any one of claims 1 to 3, wherein, The first skew correction section includes a first alignment roller pair, which is configured to form a roller gap serving as the first abutment portion. The second skew correction section includes a second alignment roller pair, which is configured to form a roller gap serving as the second abutment section.

13. A sheet conveying device, comprising: A supply unit configured to supply sheet material; An image forming unit configured to form an image at an image forming position on a sheet supplied by the supply unit; as well as A conveying unit is disposed between the supply unit and the image forming position in the sheet conveying direction, and the conveying unit is configured to convey the sheet. The conveying unit includes: A skew correction unit, the skew correction unit including an abutment portion configured to correct the skewness of the sheet by abutting against the leading edge of the sheet; and A pair of shifting rollers is disposed downstream of the skew correction section in the sheet conveying direction, and the pair of shifting rollers is configured to move the sheet in a width direction orthogonal to the sheet conveying direction while clamping the sheet.

14. A sheet conveying device, comprising: A supply unit configured to supply sheet material; An image forming unit configured to form an image at an image forming position on a sheet supplied by the supply unit; A first conveying unit is disposed between the supply unit and the image forming position in the sheet conveying direction, and the first conveying unit is configured to convey the sheet. as well as A second conveying unit is disposed between the first conveying unit and the image forming position in the sheet conveying direction, and the second conveying unit is configured to convey the sheet. The first conveying unit is configured to perform a first skew correction process to correct the skewness of the sheet, and a movement process to move the sheet, which has undergone the first skew correction process, in a width direction orthogonal to the sheet conveying direction. The second conveying unit is configured to perform a second skew correction process, which corrects the skewness of the sheet that has already undergone the first skew correction process and the moving process by the first conveying unit. The supply unit includes: A sheet support portion, wherein the sheet support portion is configured to support a sheet; An air blowing section, configured to blow air toward the edge of a sheet supported by the sheet support section to cause the sheet to float; and A suction supply unit is configured to suction and supply the sheet material that has been floated by the air blowing unit.

15. The sheet conveying device according to claim 14, wherein, The movement process is the first movement process, and The second conveying unit is configured to perform a second movement process, which moves the sheet that has undergone the second skew correction process in the width direction.

Images