Sheet conveyance apparatus

Abstract

To provide a sheet conveyance apparatus, when a jam is detected, which can remove a sheet remaining in a sheet feed part without causing deterioration in productivity.SOLUTION: A sheet conveyance apparatus comprises: resist rollers 14, after the abutting of a sheet P conveyed from a primary sheet feed part 12, for feeding out the sheet P at a predetermined time; a conveyance belt 133 for conveying the sheet P fed out from the resist rollers 14; a reversion part 50 for guiding the sheet P subjected to printing processing, executing reversion and thereafter feeding out the same to the conveyance belt 133 once more; and a control part 60, when sheet floating is detected, for switching a first switching part 90 into a state where the sheet P is guided toward the reversion part 50, reversely rotating the resist rollers 14 to reversely convey the sheet P, and feeding out the same toward the reversion part 50.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a sheet conveying device that conveys a sheet fed from a sheet feeding unit toward a conveying unit where printing processing is performed.

Background Art

[0002] Conventionally, an inkjet printing device has been proposed that performs printing processing by ejecting ink from an inkjet head onto a printing medium conveyed on a conveyance path.

[0003] For example, an inkjet printing device has been proposed in which a sheet fed from a sheet feeding unit is skew-corrected by a registration roller and then sent out from the registration roller to a conveying unit such as a conveying belt, and printing processing is performed during conveyance by the conveying unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, in the inkjet printing device as described above, when so-called paper floating or double feeding is detected during paper feeding and conveyance from the paper feeding unit toward the conveying unit, the conveyance operation of the paper is temporarily stopped. When the conveyance operation of the paper is stopped in this way, a plurality of papers remain in the device.

[0006] For example, when paper floating or double feeding is detected, even if the paper feeding unit is stopped to prevent further deterioration of the jam state and the jammed paper downstream of the conveying unit is discharged, paper remains from the paper feeding unit to the conveying unit, which is a very heavy burden on the user who removes the paper.

[0007] In particular, the sheets remaining in the paper feeding unit often reach the conveying unit and cannot be removed unless the conveying unit is lowered, resulting in waiting time until the lowering is completed or the need to open the front door and access the interior of the apparatus, which reduces productivity.

[0008] In Patent Document 1, when a jam occurs in the paper feeding unit, a method is proposed in which the registration roller rotates reversely to return the paper to the paper feeding unit.

[0009] However, when the paper returned to the paper feeding unit is re-fed, there is a possibility that paper dust on the roller adheres to the paper, so printing is performed on top of the paper dust, and the paper dust may move after printing, resulting in missing characters or the like.

[0010] Also, even if the paper returned by the reverse rotation of the registration roller is not re-fed, it is returned to the paper feed tray, so if the user does not remove it, new paper that has not been passed (paper without paper dust adhesion) cannot be fed, resulting in a decrease in productivity.

[0011] In view of the above circumstances, an object of the present invention is to provide a sheet conveying apparatus that can remove the sheets remaining in the paper feeding unit without causing a decrease in productivity when a jam is detected.

Means for Solving the Problems

[0012] The sheet conveyance device of the present invention includes a registration roller that abuts against an end portion of a sheet conveyed from a sheet feeding unit in the conveyance direction of the sheet, corrects the skew of the sheet by the abutment, and then feeds out the sheet at a predetermined timing, a conveyance unit that conveys the sheet fed out from the registration roller, a reversing unit that guides a sheet on which printing processing has been performed while being conveyed by the conveyance unit, reverses it, and then feeds out the reversed sheet again to the upstream side in the conveyance direction of the conveyance unit, a first switching unit that switches between a state of guiding the sheet fed out from the reversing unit toward the registration roller and a state of guiding the sheet reversely conveyed by the registration roller toward the reversing unit, a jam detection unit that detects a jam of the sheet, and a control unit that, when a jam is detected by the jam detection unit, switches the first switching unit to a state of guiding the sheet toward the reversing unit, reversely rotates the registration roller to reversely convey the sheet sandwiched between the registration rollers to the upstream side in the conveyance direction, and controls to feed it out toward the reversing unit.

Advantages of the Invention

[0013] According to the sheet conveyance device of the present invention, when a jam is detected, the registration roller is reversely rotated to reversely convey the sheet sandwiched between the registration rollers to the upstream side in the conveyance direction and control to feed it out toward the reversing unit. Therefore, it is possible to remove the paper remaining in the sheet feeding unit without causing a decrease in productivity.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0015] Hereinafter, an inkjet printing apparatus using an embodiment of the sheet conveying device of the present invention will be described in detail with reference to the drawings. The inkjet printing apparatus of the present embodiment is characterized by a method of conveying paper when a jam occurs. First, the overall configuration will be described. FIG. 1 is a diagram showing a schematic configuration of the inkjet printing apparatus 1 of the present embodiment. The up, down, left, and right directions shown in FIG. 1 are the up, down, left, and right directions of the inkjet printing apparatus 1 of the present embodiment. The front side of the paper surface in FIG. 1 is the front direction, and the back side of the paper surface is the back direction. Also, the right direction shown in FIG. 1 is the conveying direction of the sheet P, the left side is the upstream side in the conveying direction, and the right side is the downstream side in the conveying direction.

[0016] As shown in FIG. 1, the inkjet printing apparatus 1 of the present embodiment includes a side paper feeding unit 10, an internal paper feeding unit 20, a printing processing unit 30, a paper discharging unit 40, a reversing unit 50, and a control unit 60.

[0017] The printing processing unit 30, the internal paper feeding unit 20, and the control unit 60 are housed and installed in a housing formed of metal, resin, or the like. Also, the side paper feeding unit 10, the paper discharging unit 40, and the reversing unit 50 are installed in a state where a part is housed in the housing and a part protrudes outside the housing.

[0018] The side paper feeding unit 10 includes a paper feeding table 11 on which the sheet P is placed, a primary paper feeding unit 12 that feeds out only the sheet P at the uppermost position from the paper feeding table 11 and conveys it onto the paper feeding conveyance path FR, and a registration roller 14 that conveys the sheet P conveyed by the primary paper feeding unit 12 onto the circulation conveyance path CR.

[0019] The internal paper feeding unit 20 includes a paper feed table 21a on which the sheet P is placed, a primary paper feeding unit 22a that feeds out only the topmost sheet P from the paper feed table 21a and conveys it onto the paper feed conveyance path FR, a paper feed table 21b on which the sheet P is placed, a primary paper feeding unit 22b that feeds out only the topmost sheet P from the paper feed table 21b and conveys it onto the paper feed conveyance path FR, a paper feed table 21c on which the sheet P is placed, a primary paper feeding unit 22c that feeds out only the topmost sheet P from the paper feed table 21c and conveys it onto the paper feed conveyance path FR, a paper feed table 21d on which the sheet P is placed, and a primary paper feeding unit 22d that feeds out only the topmost sheet P from the paper feed table 21d and conveys it onto the paper feed conveyance path FR.

[0020] In this way, the sheet P is conveyed to the registration roller 14 from the side paper feeding unit 10 or the internal paper feeding unit 20, and further, the sheet P is also conveyed from the inversion unit 50 described later.

[0021] Therefore, in front of the registration roller 14 in the conveyance direction, there is a confluence point where the conveyance path of the sheet P fed from the internal paper feeding unit 20 and the conveyance path of the sheet P with one side printed thereon and conveyed from the inversion unit 50 merge. Based on this confluence point, the path on the paper feeding mechanism side is called the paper feed conveyance path FR, and the other paths are called the circulation conveyance path CR.

[0022] The registration roller 14 is a roller that contacts the downstream end of the sheet P conveyed from the primary paper feeding unit 12 in the conveyance direction, corrects the skew of the sheet P by this contact, and then feeds out the sheet P toward the conveyance belt 133 at a predetermined timing.

[0023] Near the upstream side in the conveyance direction of the registration roller 14, a registration sensor 15 is arranged. The registration sensor 15 is an optical sensor that detects the sheet P conveyed from the primary paper feeding unit 12. The detection signal from the registration sensor 15 is output to a control unit 60 described later. The control unit 60 controls the rotation speed and rotation start timing of the registration roller 14 based on the detection signal of the registration sensor 15.

[0024] Also, a double-feed detection sensor 16 is provided between the resist roller 14 and the conveyor belt 133, in the vicinity of the upstream side in the conveyance direction of the conveyor belt 133. The double-feed detection sensor 16 is a transmissive optical sensor, and detects the presence or absence of double-feed by detecting the thickness of the sheet P passing through the double-feed detection sensor 16. The detection signal of the double-feed detection sensor 16 is output to a control unit 60 described later. Based on the detection signal of the double-feed detection sensor 16, the control unit 60 stops the conveyance of the sheet P and notifies the fact to an operation panel (not shown) or the like.

[0025] Also, a sheet floating detection sensor 17 is provided on the conveyor belt 133 between the platen roller 133a disposed on the most upstream side in the conveyance direction and the printing processing unit 30. The sheet floating detection sensor 17 is an optical sensor, and detects the presence or absence of floating of the leading end portion of the sheet P by detecting the leading end portion of the sheet P passing through the sheet floating detection sensor 17. The detection signal of the sheet floating detection sensor 17 is output to a control unit 60 described later. Based on the detection signal of the sheet floating detection sensor 17, the control unit 60 stops the conveyance of the sheet P and notifies the fact to an operation panel (not shown) or the like.

[0026] In the present embodiment, the double-feed detection sensor 16 and the sheet floating detection sensor 17 correspond to the jam detection unit of the present invention, and double-feed detection and sheet floating detection correspond to jam detection. However, the jam detection in the present invention is not limited to these, and includes detection processing corresponding to other jam detections within the conveyance path of the sheet P.

[0027] The printing processing unit 30 includes a head unit 31 and an annular conveyor belt 133 provided to face the head unit 31. In the present embodiment, the conveyor belt 133 corresponds to the conveyance unit of the present invention.

[0028] The conveying belt 133 is formed of an annular endless belt, and a number of suction holes are formed therein. The conveying belt 133 extends in a direction perpendicular to the conveying direction, and is spanned over four platen rollers 133a arranged in parallel to the conveying direction and the vertical direction. The sheet P fed from the resist roller 14 is conveyed to the annular conveying belt 133. Then, the sheet P is adsorbed onto the conveying belt 133 by the suction of the suction fans 131 and 132 installed on the back side of the conveying road surface of the conveying belt 133, and is conveyed at a predetermined conveying speed. While the sheet P is being conveyed by the conveying belt 133, ink is ejected from the head unit 31 onto the sheet P, and thus printing processing is performed on the sheet P.

[0029] The head unit 31 includes four line heads 32a, 32b, 32c, 32d and a head holder 33 on which the four line heads 32a, 32b, 32c, 32d are installed. Each of the line heads 32a to 32d extends in a direction perpendicular to the conveying direction (moving direction) of the sheet P, and ejects ink onto the sheet P conveyed by the conveying belt 133. As shown in FIG. 1, the four line heads 32a to 32d are arranged at predetermined intervals along the conveying path of the sheet P. The four line heads 32a to 32d eject inks of different colors (for example, black, cyan, magenta, and yellow).

[0030] The head holder 33 is a member on which a plurality of inkjet heads constituting each of the line heads 32a to 32d are installed. The head holder 33 is composed of a box-shaped support member, and a plurality of installation holes into which the respective inkjet heads are fitted and installed are formed on the bottom surface of the head holder 33. The installation holes are through holes, and are formed such that the ink ejection surfaces of the respective inkjet heads are exposed outside the bottom surface of the head holder 33.

[0031] Each inkjet head has a plurality of nozzles for ejecting ink onto the sheet P, and the plurality of nozzles are arranged in a direction perpendicular to the conveying direction of the sheet P.

[0032] The sheet P printed by the printing processing unit 30 is conveyed on the circulation conveyance path CR by a conveyance roller or the like disposed on the circulation conveyance path CR. On the circulation conveyance path CR, there is provided a paper discharge switching unit 43 that switches between guiding the sheet P conveyed on the circulation conveyance path CR to the paper discharge unit 40 or recirculating it on the circulation conveyance path CR. Specifically, the paper discharge switching unit 43 switches between the conveyance path on the paper discharge unit 40 side and the conveyance path on the inversion unit 50 side.

[0033] The paper discharge unit 40 has a tray-shaped paper discharge table 41 protruding from the housing of the inkjet printing apparatus 1 and a pair of paper discharge rollers 42 for discharging the sheet P onto the paper discharge table 41. Then, the sheet P guided to the conveyance path on the paper discharge unit 40 side by the paper discharge switching unit 43 is discharged onto the paper discharge table 41 by the paper discharge rollers 42.

[0034] The inversion unit 50 includes an inversion table 51 for inverting the sheet P and an inversion roller 52 for guiding and conveying the sheet P that has been subjected to printing processing in the printing processing unit 30 described later from the circulation conveyance path CR to the inversion table 51 and then returning the sheet P conveyed to the inversion table 51 back onto the circulation conveyance path CR. A part of the inversion table 51 protrudes from the housing of the inkjet printing apparatus 1, and as will be described later, the sheet P conveyed to the inversion table 51 by the reverse rotation of the registration roller 14 when a jam is detected is configured to be removable by the user.

[0035] The sheet P guided to the inversion unit 50 by the paper discharge switching unit 43 is conveyed from the circulation conveyance path CR to the inversion table 51 by the inversion roller 52 and then returned from the inversion table 51 to the circulation conveyance path CR, so that it is conveyed on the circulation conveyance path CR with the front and back sides inverted. Then, the sheet P with the front and back sides inverted is conveyed again toward the printing processing unit 30 by a plurality of rollers such as a conveyance roller 53 provided on the circulation conveyance path CR.

[0036] Also, a lower paper discharge unit 70 for receiving the sheet P sent out from the resist roller 14 is provided on the lower side in the vertical direction of the conveyor belt 133. The lower paper discharge unit 70 includes a paper discharge path 71, a tray unit 72, and a sheet detection unit 73.

[0037] The paper discharge path 71 receives the sheet P sent out from the resist roller 14 and guides the sheet P separated from the resist roller 14 due to double feeding to the tray unit 72. Note that the separation of the sheet P due to double feeding will be described in detail later.

[0038] The tray unit 72 receives and stacks the sheet P guided by the paper discharge path 71. The sheet detection unit 73 detects that the sheet P has been stacked on the tray unit 72. The sheet detection unit 73 has, for example, a weight sensor or an optical sensor that detects the stacking of the sheet P. The detection signal of the sheet detection unit 73 is output to a control unit 60 described later. Based on the detection signal of the sheet detection unit 73, the control unit 60 notifies an operation panel (not shown) that the sheet P has been stacked on the tray unit 72.

[0039] Also, between the resist sensors 15 and the primary paper feed unit 12, a first switching unit 90 is provided for switching between a state of guiding the sheet P sent out from the inversion unit 50 toward the resist roller 14 and a state of guiding the sheet P reversely conveyed by the resist roller 14 toward the inversion unit 50. The configuration and operation of the first switching unit 90 will be described in detail later.

[0040] Also, between the resist roller 14 and the conveyor belt 133, a second switching unit 80 is provided for switching between a state of guiding the sheet P sent out from the resist roller 14 toward the conveyor belt 133 and a state of guiding the sheet P toward the paper discharge path 71 of the lower paper discharge unit 70. The configuration and operation of the second switching unit 80 will be described in detail later.

[0041] FIG. 2 is a block diagram showing a schematic configuration of a control system of the inkjet printing apparatus 1 according to the present embodiment.

[0042] The control unit 60 controls the entire inkjet printing apparatus 1 and includes a CPU (Central Processing Unit), a semiconductor memory, a hard disk, and the like. The control unit 60 controls the operations of the respective parts of the inkjet printing apparatus 1 by executing a program stored in advance in a storage medium such as a semiconductor memory or a hard disk and operating an electric circuit.

[0043] In particular, when double feed detection or sheet floating detection is performed by the control unit 60 of the present embodiment and the conveyance of the sheet P is stopped, the registration roller 14 is rotated reversely to convey the sheet P sandwiched between the registration rollers 14 toward the inversion unit 50 and to control so that the sheet P can be taken out from the inversion unit 50.

[0044] Hereinafter, the conveyance control of the sheet P when sheet floating detection or double feed detection is performed will be specifically described with reference to the drawings. FIG. 3 is a diagram for explaining the conveyance control of the sheet P when sheet floating detection is performed.

[0045] First, as shown in FIG. 3A, the floating of the leading end of the sheet P sent out from the registration roller 14 is detected by the sheet floating detection sensor 17.

[0046] When the sheet floating is detected by the sheet floating detection sensor 17, the control unit 60 once stops the sheet conveyance operation and then, as shown in FIG. 3B, rotates the registration roller 14 reversely to send out the sheet P upstream in the conveyance direction. At this time, since the primary paper feed unit 12 is in a stopped state, the feed amount due to the reverse rotation of the registration roller 14 is absorbed by the bending of the sheet P.

[0047] Then, as shown in FIG. 3B, when the sheet P is conveyed to a position where it is not detected by the double feed detection sensor 16, that is, when the end portion on the downstream side in the conveyance direction of the sheet P is sandwiched by the registration roller 14, the control unit 60 stops the reverse rotation of the registration roller 14.

[0048] Next, as shown in FIG. 3C, the control unit 60 controls the second switching unit 80 to switch from a state of guiding the sheet P sent out from the resist roller 14 toward the conveyor belt 133 to a state of guiding the sheet P toward the paper discharge path 71 of the lower paper discharge unit 70.

[0049] Then, the control unit 60 sends out the sheet P by rotating the resist roller 14 in the normal direction, and as shown in FIG. 3D, sends out the sheet P toward the lower paper discharge unit 70 until the sheet P is no longer detected by the resist sensor 15, that is, until the upstream end of the sheet P in the conveyance direction is clamped by the resist roller 14.

[0050] Next, when the sheet P is no longer detected by the resist sensor 15, the control unit 60 controls the first switching unit 90 to switch to a state of guiding the sheet P toward the reversing unit 50, as shown in FIG. 3E.

[0051] Then, as shown in FIG. 3F, the control unit 60 controls to rotate the resist roller 14 in the reverse direction again to send out the sheet P toward the reversing unit 50 side.

[0052] The sheet P sent out by the resist roller 14 is conveyed to the reversing table 51 by the conveyance roller 53 and the reversing roller 52 of the reversing unit 50, and the sheet P can be taken out by the user.

[0053] Next, FIG. 4 is a diagram for explaining the conveyance control of the sheet P when double feed detection is performed.

[0054] First, as shown in FIG. 4A, double feed of the sheet P sent out from the resist roller 14 is detected by the double feed detection sensor 16.

[0055] When double feed is detected by the double feed detection sensor 16, the control unit 60 temporarily stops the sheet conveyance operation, and then, as shown in FIG. 4B, reversely rotates the resist roller 14 to send out the sheet P upstream in the conveyance direction. At this time, since the primary paper feed unit 12 is stopped, the feed amount due to the reverse rotation of the resist roller 14 is absorbed by the bending of the sheet P.

[0056] Then, as shown in FIG. 4B, when the sheet P is conveyed to a position where it is not detected by the double feed detection sensor 16, that is, when the downstream end of the sheet P in the conveyance direction is clamped by the resist roller 14, the control unit 60 stops the reverse rotation of the resist roller 14.

[0057] Next, as shown in FIG. 4C, the control unit 60 controls the second switching unit 80 to switch from the state of guiding the sheet P sent out from the resist roller 14 toward the conveyance belt 133 to the state of guiding it toward the paper discharge path 71 of the lower paper discharge unit 70.

[0058] Then, the control unit 60 sends out the sheet P by rotating the resist roller 14 forward, and as shown in FIG. 4D, sends out the sheet P toward the lower paper discharge unit 70 until the sheet P is no longer detected by the resist sensor 15, that is, until the upstream end of the sheet P in the conveyance direction is clamped by the resist roller 14.

[0059] Next, when the sheet P is no longer detected by the resist sensor 15, the control unit 60 controls the first switching unit 90 to switch to the state of guiding the sheet P toward the inversion unit 50, as shown in FIG. 4E.

[0060] Then, as shown in FIG. 4F, the control unit 60 controls to reversely rotate the resist roller 14 again to send out the sheet P toward the inversion unit 50 side.

[0061] The sheet P sent out by the resist roller 14 is conveyed to the reversing table 51 by the conveying roller 53 and the reversing roller 52 of the reversing unit 50, and the user can take out the sheet P.

[0062] Next, when double feeding is detected by the double feed detection sensor 16, the operation when the double feed width is large will be described with reference to FIG. 5. Note that a large double feed width means that the deviation width between the sheets overlapping due to double feeding is large.

[0063] When double feeding is detected by the double feed detection sensor 16, as described with reference to FIG. 4, the second switching unit 80 is switched to a state in which the sheet P is sent out toward the lower paper discharge unit 70, and as shown in FIG. 5A, the sheet P is sent out from the resist roller 14 toward the lower paper discharge unit 70.

[0064] Then, as shown in FIG. 5A, the control unit 60 conveys the sheet P until the sheet P is no longer detected by the resist sensor 15. At this time, when the double feed width is large, among the plurality of double-fed sheets P, some sheets P are nipped by the resist roller 14, but some other sheets P may be detached from the resist roller 14.

[0065] For the sheet P thus detached from the resist roller 14, as shown in FIG. 5B, it falls downward by its own weight, is guided by the paper discharge path 71, and is stacked on the tray unit 72.

[0066] When the sheet P is stacked on the tray unit 72, it is detected by the sheet detection unit 73, and the control unit 60 notifies the user to that effect. The user can take out the sheet P from the tray unit 72, for example, by opening the front door of the housing.

[0067] According to the inkjet printing apparatus 1 of the above embodiment, when jams such as sheet floating or double feeding are detected, the registration roller 14 is rotated reversely to reversely convey the sheet P sandwiched between the registration rollers 14 upstream in the conveyance direction and control it to be sent out toward the reversing unit 50. Therefore, without causing a decrease in productivity, the paper remaining between the side paper feeding unit 10 and the conveyance belt 133 can be removed.

[0068] In addition, when all the jams in the apparatus are removed, it is possible to automatically return from the jam state and end the job without the user's intervention.

[0069] Also, when a jam occurs, by collecting the sheet P at the reversing unit 50, the location to access is limited and the sheet P can be removed without the user getting lost.

[0070] Moreover, usually, all the sheet P remaining in the apparatus can be removed without opening the front door of the housing. Also, since no sheet P remains on the conveyance belt 133, operations for removing the sheet P, such as the lowering operation of the conveyance belt 133, become unnecessary, and the time required for recovery can be shortened.

[0071] Further, in the inkjet printing apparatus 1 of the above embodiment, the lower paper discharging unit 70 is provided. After once sending out the sheet to the lower paper discharging unit 70, the registration roller 14 is rotated reversely to send out the sheet P toward the reversing unit 50. Therefore, the sheet P can be reversely conveyed toward the reversing unit 50 more efficiently.

[0072] Furthermore, in the inkjet printing apparatus 1 of the above embodiment, among the multiple double-fed sheets P, the sheet P separated from the registration roller 14 is allowed to fall by its own weight to the lower paper discharging unit 70 and loaded on the tray unit 72. When it is detected that the sheet P is loaded on the tray unit 72, the user is notified. Therefore, even the sheet P that has not been reversely conveyed by the reversing unit 50 can be taken out from the lower paper discharging unit 70.

[0073] Note that the present invention is not limited to the above-described embodiments, and the components can be modified and embodied without departing from the gist thereof at the implementation stage. Also, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments. For example, all the components shown in the embodiments may be appropriately combined. Needless to say, various modifications and applications are possible within the scope not departing from the gist of the invention.

[0074] Regarding the present invention, the following additional remarks are further disclosed.

[0075] (Supplementary Note 1) The sheet conveyance device of the present invention includes a registration roller that abuts against an end portion in the conveyance direction of a sheet conveyed from a sheet feeding unit, corrects the skew of the sheet by the abutment, and then feeds out the sheet at a predetermined timing; a conveyance unit that conveys the sheet fed out from the registration roller; a reversing unit that guides and reverses a sheet on which printing processing has been performed while being conveyed by the conveyance unit, and then feeds out the reversed sheet again to the upstream side in the conveyance direction of the conveyance unit; a first switching unit that switches between a state of guiding the sheet fed out from the reversing unit toward the registration roller and a state of guiding the sheet reversely conveyed by the registration roller toward the reversing unit; a jam detection unit that detects a jam of the sheet; and a control unit that, when a jam is detected by the jam detection unit, switches the first switching unit to a state of guiding the sheet toward the reversing unit, reversely conveys the sheet sandwiched between the registration rollers upstream in the conveyance direction by reversely rotating the registration roller, and controls to feed it out toward the reversing unit.

[0076] (Supplementary Note 2) In the sheet conveying device described in Supplementary Note 1, there is further provided a lower paper discharge unit that is provided below the conveying unit in the vertical direction and receives the sheet sent out from the resist roller, and a second switching unit that switches between a state of guiding the sheet sent out from the resist roller toward the conveying unit and a state of guiding the sheet toward the lower paper discharge unit. When a jam is detected by the jam detection unit, the control unit reversely rotates the resist roller to reversely convey the sheet pinched by the resist roller to the upstream side in the conveying direction. When the end of the sheet on the downstream side in the conveying direction is pinched by the resist roller, the second switching unit is switched to a state of guiding the sheet toward the lower paper discharge unit, and the resist roller is rotated forward to convey the sheet toward the lower paper discharge unit. When the end of the sheet on the upstream side in the conveying direction is pinched by the resist roller, the first switching unit is switched to a state of guiding the sheet toward the reversing unit, and the resist roller can be reversely rotated to send out the sheet toward the reversing unit.

[0077] (Supplementary Note 3) In the sheet conveying device described in Supplementary Note 2, the lower paper discharge unit includes a tray unit that receives and stacks the sheet, and a sheet detection unit that detects that the sheet has been stacked on the tray unit, and the control unit can notify the detection result by the sheet detection unit.

Explanation of Reference Numerals

[0078] 1 Inkjet printing device 10 Side paper feeding unit 11 Paper feeding table 12 Primary paper feeding unit 14 Resist roller 15 Resist sensor 16 Double feed detection sensor 17 Sheet floating detection sensor 20 Internal paper feeding unit 21a~21d Paper feeding table 22a~22d Primary paper feeding unit 30 Printing processing unit 31 Head unit 32a~32d Line head 33 Head holder 40 - sheet discharging section 41 - sheet discharging table 42 - sheet discharging roller 43 - sheet discharging switching section 50 - reversing section 51 - reversing table 52 - reversing roller 53 - conveying roller 60 - control section 70 - lower sheet discharging section 71 - sheet discharging path 72 - tray section 73 - sheet detection section 80 - second switching section 90 - first switching section 131, 132 - suction fan 133 - conveying belt 133a - platen roller CR - circulation conveying path FR - paper feeding conveying path P - sheet

Claims

1. A registration roller that abuts on an end portion of a sheet conveyed from a sheet feeding unit in the conveying direction, corrects the skew of the sheet by the abutment, and then feeds out the sheet at a predetermined timing; A conveying unit that conveys the sheet fed out from the registration roller; An inversion unit that guides and inverts a sheet that has been subjected to printing processing while being conveyed by the conveying unit, and then feeds out the inverted sheet to the upstream side in the conveying direction of the conveying unit again; A first switching unit that switches between a state of guiding the sheet fed out from the inversion unit toward the registration roller and a state of guiding the sheet reversely conveyed by the registration roller toward the inversion unit; A jam detection unit that detects a jam of a sheet; A control unit that, when a jam is detected by the jam detection unit, switches the first switching unit to a state of guiding the sheet toward the inversion unit, reversely conveys the sheet sandwiched between the registration rollers upstream in the conveying direction by reversely rotating the registration rollers, and controls to feed out the sheet toward the inversion unit. A sheet conveying apparatus comprising:

2. A lower paper discharge unit provided below the conveying unit in the vertical direction and receiving the sheet fed out from the registration roller; A second switching unit that switches between a state of guiding the sheet fed out from the registration roller toward the conveying unit and a state of guiding the sheet toward the lower paper discharge unit; and When a jam is detected by the jam detection unit, the control unit reversely conveys the sheet sandwiched between the registration rollers upstream in the conveying direction by reversely rotating the registration rollers, and when the end portion on the downstream side in the conveying direction of the sheet is sandwiched between the registration rollers, switches the second switching unit to a state of guiding the sheet toward the lower paper discharge unit, conveys the sheet toward the lower paper discharge unit by rotating the registration rollers forward, and when the end portion on the upstream side in the conveying direction of the sheet is sandwiched by the registration rollers, switches the first switching unit to a state of guiding the sheet toward the inversion unit, and reversely rotates the registration rollers to feed out the sheet toward the inversion unit. The sheet conveying apparatus according to Claim 1.

3. The lower paper discharge unit includes a tray unit that receives and stacks the sheets, and a sheet detection unit that detects that the sheets are stacked on the tray unit. The sheet conveying device according to claim 2, wherein the control unit notifies the detection result by the sheet detection unit.

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