JP6031968B2 - Paper conveying apparatus and image forming system - Google Patents

Description

The present invention relates to a sheet conveying device and an image forming system . More specifically, the present invention relates to a sheet conveying apparatus and an image forming system that automatically discharges a sheet out of the conveying path when a jam occurs by providing a door that can be opened and closed on the conveying path having a downward curved portion.

  In recent years, in order to improve productivity in an image forming apparatus, paper conveyance control is performed with a gap between sheets narrowed. However, when conveyance control is performed with a gap between sheets narrowed, there is a problem that a jam is likely to occur. In order to avoid this problem, a paper that stays in the transport path is provided by providing a gate switching section on the transport path and switching the gate switch section to a retreat path (bypass path) when a jam occurs on the transport path. An image forming apparatus that discharges the toner out of the conveyance path has been developed.

  However, in the configuration in which the gate switching unit is provided, if the gate switching unit is jammed, it becomes impossible to perform gate switching. Therefore, the paper accumulated on the transport path cannot be discharged to the outside. There was a problem. As a result, it has not been possible to flexibly cope with the occurrence of a jam.

  Therefore, an image forming apparatus that performs jam processing by a method other than the gate switching has been proposed. For example, in Patent Document 1, a guide unit that can be opened and closed by an elastic member is provided in the transport path, and when a paper transport abnormality is detected, the transport roller on the upstream side of the guide unit is rotated forward to the downstream side of the guide unit. A paper conveyance device is disclosed in which a guide portion is opened by pressing a bent paper, and the paper is discharged out of the conveyance path by rotating the conveyance roller in reverse.

JP 2009-18923 A

  However, the paper conveying apparatus disclosed in Patent Document 1 has the following problems. That is, the guide portion is configured to be opened by pressing the paper, and is not configured to automatically open and close. Therefore, the user and the serviceman have to remove the paper exposed from the conveyance path by the pressing. For this reason, for example, when multiple sheets of paper are stagnant on the upstream side of the transport path and a serviceman or the like removes the sheets one by one, the plurality of sheets are discharged out of the transport path efficiently and quickly. There is a problem that cannot be made. There is also a problem that the work load on the worker increases.

The present invention has been made in view of the above problems, when the conveyance failure of the sheet occurs, automatically the sheet conveying apparatus and which can be discharged to the outside of the conveyance path the paper To provide an image forming system .

In order to solve the above-described problems, a paper transport device according to the present invention includes a paper transport path having a downwardly curved portion, and a door that is provided along the paper transport path and can be opened and closed at a position corresponding to the curved section. And a control unit that controls the operation of the door. When a paper conveyance failure occurs in the paper conveyance path, the control unit remains in the paper conveyance path by opening the door. The paper is discharged out of the paper transport path. In addition, an image forming system according to the present invention includes a first image forming apparatus that forms an image on a sheet, and the first image forming apparatus that is positioned downstream of the first image forming apparatus in the sheet conveying direction. The above-described sheet conveying apparatus that conveys the sheet on which the image is formed is positioned on the downstream side of the sheet conveying apparatus in the sheet conveying direction and forms an image on the sheet conveyed from the sheet conveying apparatus. 2 image forming apparatuses.

  In the present invention, when a paper conveyance failure occurs, the door of the paper conveyance unit is opened. The paper staying in the paper transport path is transported to the door section of the paper transport section, and is discharged out of the paper transport path from the door section opened by its own weight. By providing the downward curved portion in the conveyance path, the paper is bent along the curved portion, so that the paper can be easily discharged from the paper conveyance path by its own weight.

  According to the present invention, when a paper conveyance failure occurs by providing a downwardly curved portion in the paper conveyance path and making the paper conveyance portion at a position corresponding to this curved portion a door that can be opened and closed, The paper staying in the transport path can be automatically discharged out of the transport path.

1 is a diagram illustrating a configuration example of an image forming system according to a first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration example of a sheet conveying device. FIG. 3 is a diagram illustrating a block configuration example of an image forming apparatus and a sheet conveying apparatus. 6 is a flowchart illustrating an operation example of the sheet conveying device when a jam occurs. FIG. 10 is a diagram for explaining an operation example of the sheet conveying device when a jam occurs (part 1); FIG. 10 is a diagram for explaining an operation example of the sheet conveying device when a jam occurs (part 2); FIG. 10 is a diagram for explaining an operation example of the sheet conveying device when a jam occurs (part 3); FIG. 10 is a diagram for explaining an operation example of the sheet conveying device when a jam occurs (part 4); FIG. 10 is a diagram for explaining an operation example of the sheet conveying device when a jam occurs (part 5); FIG. 10 is a diagram for explaining an operation example of the sheet conveying device when a jam occurs (No. 6); It is a figure which shows the structural example of the image forming system which concerns on the 2nd Embodiment of this invention.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
<1. First Embodiment>
[Configuration example of image forming system]
First, the image forming system GS1 according to the present invention will be described. FIG. 1 shows an example of a schematic configuration of an image forming system GS1 according to the present invention. As shown in FIG. 1, the image forming system GS1 includes an image forming apparatus 100, a sheet conveying apparatus 200, and a post-processing apparatus 300.

  The image forming apparatus 100 forms an image on a sheet P by an electrophotographic method, and includes an image forming unit 110, a paper feeding unit 120, and a fixing unit 130. A document set on a document table or document feed tray (not shown) is read by a reading unit. The read image information is converted into a digital signal, and then subjected to predetermined image processing and output to the image forming unit 110 as an image signal.

  The image forming unit 110 includes a photosensitive drum 112, a charging unit (not shown), an exposure unit (writing unit), a developing unit, and a cleaning unit. The charging unit charges the peripheral surface of the photosensitive drum 112. The exposure unit (writing unit) writes an image composed of a latent image on the photosensitive drum 112 based on an image signal output from an image processing unit (not shown). The developing unit develops an image formed on the photosensitive drum 112 to form a toner image.

  The paper feed unit 120 has paper feed trays 120A and 120B on which paper P corresponding to each size such as A3 and A4 is set. The predetermined paper P set in each of the paper feed trays 120A and 120B is taken out one by one when the image forming process is started and fed to the photosensitive drum 112 of the image forming unit 110.

  A transfer unit 116 including a photoconductive drum 112 and a transfer roller 114 arranged to face the photoconductive drum 112 is an image (toner) formed on the photoconductive drum 122 on the surface side of the paper P fed from the paper feed unit 120. Transfer the image. The fixing unit 130 fixes the toner image on the paper P by performing pressure and heat treatment on the paper P on which the image is transferred by the transfer unit N. The paper P on which the fixing process has been performed by the fixing unit 130 is transported to the subsequent paper transport device 200 by the paper discharge roller 140.

  The paper transport device (relay device) 200 is connected to the downstream side in the paper transport direction D of the image forming apparatus 100, and synchronizes the transport speed of the paper P transported from the image forming apparatus 100, and a post-processing device in the subsequent stage. Carry to 300. In addition to synchronizing, the paper transport apparatus 200 has a function of automatically discharging the paper P staying in the transport path to the outside of the transport path when a jam occurs in the transport path of the image forming system GS. It has. The details of the sheet conveying apparatus 200 will be described later.

  The post-processing device 300 is connected to the downstream side in the paper transport direction D of the paper transport device 200, and has a function of performing various processes such as punching, folding, glue application, cutting, and bookbinding. Further, although not shown in the figure, the post-processing device 300 is provided with a paper detection sensor for detecting a jam at a predetermined position on the transport path. The number of paper detection sensors to be installed is arbitrary. The detection result of the jam by the paper detection sensor is used as jam information generated in the transport path downstream of the purge doors 222a and 222b.

  In this example, the image forming apparatus 100 that forms a monochrome image has been described. However, the present invention is not limited to this, and can also be applied to an image forming apparatus that forms a color image. In this case, the image forming apparatus uses Y (yellow), M (magenta), C (cyan), and K (black) image forming units, or intermediate transfer that forms a color image by superimposing these toner images. A belt is provided.

[Configuration example of paper transport unit]
Next, the sheet conveying apparatus 200 will be described. FIG. 2 shows a configuration example of the sheet conveying apparatus 200, FIG. 2A shows a state in which the purge doors 222a and 222b are closed, and FIG. 2B shows a state in which the purge doors 222a and 222b are opened. . As shown in FIGS. 2A and 2B, the sheet transport apparatus 200 includes a transport path R, upstream transport rollers 202, 204, 206, 208, and downstream transport rollers 210, 212, 214. , Guide members 220 and 222, a paper discharge tray 230, and a purge paper detection sensor 244.

  The transport path R is a relay path for transporting the paper P transported from the image forming apparatus 100 to the post-processing apparatus 300 in the subsequent stage, and a U-shaped curved portion protruding downward is partially formed on the path. I have. In this example, the conveyance path R is configured to be bent in a substantially U shape, but it is sufficient that at least a part of the conveyance path R protrudes downward and is bent. Thus, by making the conveyance path R into a U-shape projecting downward, the sheet P can be inclined and curved, so that the conveyance path R is formed horizontally compared to the case where the conveyance path R is formed horizontally. Thus, the paper P can be easily dropped (slidably) by its own weight. In particular, it is effective for paper having a light weight (self-weight).

  The guide members 220 and 222 are made of, for example, a flat plate made of a metal material, and are arranged to face each other along the transport path R. For this reason, the guide members 220 and 222 are also formed in a U shape like the transport path R. The guide members 220 and 222 constitute an example of a paper transport unit.

  In this example, the guide member 222 disposed outside the curved portion protruding downward in the transport path R is configured by purge doors (door portions) 222a and 222b that can be opened and closed in the left and right (front and rear) directions. Specifically, one end of the purge door 222a on the upstream side in the sheet conveyance direction D is rotatably supported by the rotation shaft 224a. One end portion of the purge door 222b on the downstream side in the sheet conveyance direction D is rotatably supported by the rotation shaft 224b. As a result, as shown in FIG. 2B, when the jam occurs, the purge doors 222a and 222b are opened, so that the paper P staying on the transport path R is moved along the transport path R by its own weight. Discharged to the outside. At normal times, as shown in FIG. 2A, the purge doors 222a and 222b are closed, and function as a guide unit for transporting the paper P along the transport direction.

  The upstream side conveyance rollers 202, 204, 206, 208 and the downstream side conveyance rollers 210, 212, 214 are composed of a driving roller and a driven roller disposed opposite thereto. One driven roller 208a of the upstream conveying roller 208 is attached to the purge door 222a and moves together with the opening / closing operation of the purge door 222a. The upstream transport rollers 202, 204, 206, 208 constitute an example of the first transport roller, and the downstream transport rollers 210, 212, 214 constitute an example of the second transport roller.

  The paper discharge tray 230 is a box having an upper end opened, and is disposed further below the curved portion protruding to the lower side of the conveyance path R. The paper discharge tray 230 accommodates the paper P discharged to the outside from the transport path R opened by the purge doors 222a and 222b. The paper discharge tray 230 is configured to be detachable from the paper transport device 200, for example, and the paper P can be taken out from the paper transport device 200 when the paper P in the paper discharge tray 230 becomes full. It can be done. The paper discharge tray 230 constitutes an example of a storage unit.

  The purge paper detection sensor 244 is constituted by, for example, a reflection type sensor (photo sensor) or a transmission type sensor, and is installed at a position slightly higher than the upper surface of the paper discharge tray 230. Specifically, it is installed at a height at which the door closing operation is affected by the paper P overflowing from the paper discharge tray 230. The purge sheet detection sensor 244 constitutes an example of a detection unit.

[Block Configuration Example of Image Forming Apparatus and Paper Conveying Device]
Next, block configuration examples of the image forming apparatus 100 and the sheet conveying apparatus 200 according to the present invention will be described. FIG. 3 shows an example of a block configuration of the image forming apparatus 100 and the sheet conveying apparatus 200.

  As illustrated in FIG. 3, the image forming apparatus 100 includes a control unit 150 that controls the operation of the entire image forming apparatus. The control unit 150 includes a CPU (Central Processing Unit) 152, a ROM (Read Only Memory) 154 that stores control software and data, and a RAM 156 (Random Access Memory) that forms a work area of the CPU 152. ing. The CPU 152 develops software and data read from the ROM 154 on the RAM 156, activates the software, and controls each unit of the image forming apparatus 100 to execute predetermined image forming processing.

  To the control unit 150, a communication unit 132, an operation display unit 170, an image forming unit 110, a paper feeding unit 120, and a fixing unit 130 are connected. The communication unit 132 is configured by a serial communication interface or the like, for example, and is connected to the communication unit 232 of the paper transport apparatus 200.

  When the paper P discharged into the paper discharge tray 230 overflows to the outside of the paper discharge tray 230 and obstructs the opening / closing operation of the purge doors 222a and 222b, the operation display unit 170 responds to an instruction from the control unit 250. Based on this, a warning message is displayed on the screen indicating that the paper P in the paper discharge tray 230 is to be taken out (that the purge doors 222a and 222b cannot be opened and closed). The operation display unit 170 constitutes an example of a notification unit.

  Although not shown, the image forming apparatus 100 is provided with a paper detection sensor for detecting a jam in the paper feeding unit 120, the registration roller 118, the fixing unit 130, and the paper discharge roller 140. The detection result of the jam by the paper detection sensor is supplied to the control unit 250 as jam information generated in the transport path upstream of the purge doors 222a and 222b.

  As shown in FIG. 3, the sheet conveying apparatus 200 includes a control unit 250 that controls the operation of the entire sheet conveying apparatus. The control unit 250 includes a CPU 252, a ROM 254, and a RAM 256. Based on the instruction information supplied from the control unit 150 of the main image forming apparatus 100, the control unit 250 relays the paper P and transports it to the post-processing apparatus 300 in the subsequent stage, or the image forming apparatus 100 when a jam occurs. And control to discharge the paper P staying in the transport path R of the paper transport apparatus 200 to the outside of the transport path R.

  The control unit 250 includes an upstream sheet detection sensor 240, a downstream sheet detection sensor 242, a purge sheet detection sensor 244, an upstream conveyance roller drive unit 270, a downstream conveyance roller drive unit 280, and a purge door drive. The unit 290 and the communication unit 232 are connected to each other. The communication unit 232 is configured by, for example, a serial communication interface or the like, and bi-directionally communicates information regarding image formation and jam occurrence with the image forming apparatus 100.

  The upstream sheet detection sensor 240 is configured by, for example, a reflection type sensor or a transmission type sensor, and is installed on the upstream side of the purge doors 222a and 222b in the transport path R. The upstream paper detection sensor 240 detects the passage of the paper P conveyed on the upstream conveyance path R of the paper conveyance device 200, and supplies a detection signal obtained by this detection to the control unit 250.

  The downstream side paper detection sensor 242 is configured by, for example, a reflection type sensor or a transmission type sensor, and is installed on the downstream side of the purge doors 222a and 222b in the transport path R. The downstream paper detection sensor 242 detects the passage of the paper P conveyed on the downstream conveyance path R of the paper conveyance device 200, and supplies a detection signal obtained by this detection to the control unit 250.

  The purge paper detection sensor 244 is constituted by, for example, a reflection type sensor or a transmission type sensor, and the height of the paper P stacked on the paper discharge tray 230 from the upper surface portion of the paper discharge tray 230 is determined by the purge doors 222a and 222b. It is detected whether or not it is at a level that does not disturb the opening and closing operation, and a detection signal obtained by the detection is supplied to the control unit 250.

  The upstream side conveyance roller driving unit 270 is configured by, for example, a stepping motor or the like, and is driven based on a drive signal from the control unit 250 to rotate the upstream side conveyance rollers 202, 204, 206, and 208 in a normal rotation or reverse rotation, Stop it.

  The downstream-side transport roller driving unit 280 is configured by, for example, a stepping motor and the like, and is driven based on a drive signal from the control unit 250 to cause the downstream-side transport rollers 210, 212, and 214 to rotate forward, reverse, or stop. Or

  The purge door drive unit 290 is constituted by, for example, a stepping motor, for example, and is driven based on a drive signal from the control unit 250 to open or close the purge doors 222a and 222b.

[Operation example of image forming apparatus]
Next, an operation example of the sheet conveying apparatus 200 according to the present invention will be described. FIG. 4 is a flowchart illustrating an example of the operation of the sheet conveying apparatus 200 when a jam occurs in the image forming system GS. 5 to 10 are diagrams for explaining an operation example of the sheet conveying apparatus 200 when a jam occurs. Hereinafter, a description will be given of a case where the control unit 250 of the paper transport apparatus 200 performs discharge control and the like based on an instruction from the control unit 150 of the main image forming apparatus 100.

  As shown in FIG. 4, in step S <b> 100, the control unit 250 determines whether or not a jam has occurred in the transport path in the image forming system GS. Whether or not a jam has occurred is determined based on the output results of the sheet detection sensors installed on the respective conveyance paths of the image forming apparatus 100, the sheet conveyance apparatus 200, and the post-processing apparatus 300. If the controller 250 determines that a jam has occurred in the image forming system GS, the control unit 250 proceeds to step S110. If the controller 250 determines that a jam has not occurred in the image forming system GS, the controller 250 determines whether a jam has occurred. Monitor continuously.

  In step S <b> 110, the control unit 250 determines whether a jam occurrence place has occurred on the upstream side or the downstream side in the paper transport direction D with respect to the purge doors 222 a and 222 b of the paper transport apparatus 200. For example, when the control unit 250 determines that a jam has been detected based on the output result of the paper detection sensor installed in the upstream conveyance path, the jam occurrence location is upstream of the purge doors 222a and 222b of the paper conveyance device 200. The process proceeds to step S170. On the other hand, when the control unit 250 determines that a jam is detected based on the output result of the paper detection sensor installed in the downstream conveyance path, the jam occurrence location is more than the purge doors 222a and 222b of the paper conveyance device 200. It judges that it is a downstream side, and progresses to step S120.

  When the jam occurrence location is upstream of the purge doors 222a and 222b, the control unit 250 normally discharges the paper P remaining on the downstream side of the purge doors 222a and 222b from the post-processing device 300 in step S170. . Specifically, the downstream conveyance rollers 210, 212, and 214 of the paper conveyance device 200 and the conveyance rollers (not shown) of the post-processing device 300 are driven to rotate forward without being stopped, so that they are externally connected from the discharge unit of the post-processing device 300. The paper P is discharged. As described above, since jamming has not occurred on the downstream side of the purge doors 222a and 222b, the paper P can be discharged along the paper transport direction D as usual.

  On the other hand, on the upstream side where the jam has occurred, the control unit 150 stops driving the upstream conveyance rollers 202, 204, 206, 208 of the paper conveyance device 200 and the conveyance rollers of the image forming apparatus 100. The conveyance of the paper P on the upstream side is stopped. In this case, for example, the service person or the user opens the doors of the housings of the image forming apparatus 100 and the paper transport apparatus 200 to remove the jammed paper P or the paper P staying on the transport path. If the paper P can be transported with respect to the paper P downstream of the jam occurrence location, the paper P may be discharged from the purge doors 222a and 222b to the outside of the transport path R, or the post-processing device 300. You may make it discharge from.

  On the other hand, if the jam occurrence location is downstream of the purge doors 222a and 222b, in step S120, the control unit 250 controls the downstream transport rollers 210, 212, and 214 of the paper transport device 200 and the transport rollers of the post-processing device 300. By stopping the rotation, the conveyance of the paper P on the downstream side where the jam has occurred is stopped. At this time, upstream of the purge doors 222a and 222b, the upstream conveying rollers 202, 204, 206, and 208 of the sheet conveying apparatus 200, the conveying rollers of the image forming apparatus 100, and the like are continuously driven without being stopped. State. When the rotation of the downstream side transport rollers 210, 212, 214, etc. is stopped, the process proceeds to step S130.

  In step S130, the control unit 250 drives the purge door drive unit 290 to open the purge doors 222a and 222b. Accordingly, as shown in FIGS. 5 and 6, for example, when the paper P stays in the state of being sandwiched between the upstream-side transport rollers 208 on the transport path R, the purge doors 222a and 222b are opened. The paper P is discharged to the outside of the transport path R by its own weight, and is stored in the lower paper discharge tray 230. Further, the plurality of sheets P staying in the transport path of the upstream image forming apparatus 100 are sequentially transported to the paper transport apparatus 200 by a transport roller or the like that is always rotating. The sheet P transported into the sheet transport apparatus 200 is transported to the lower side of the transport path R by the rotating upstream transport rollers 202, 204, 206, and 208, and is opened via the opened purge doors 222a and 222b. It is discharged to the outside of the transport path R by its own weight. The paper P discharged to the outside of the transport path R is collected in the lower paper discharge tray 230.

  In step S140, the control unit 250 determines whether or not the discharge of the sheet P on the upstream side in the sheet transport direction D from the purge doors 222a and 222b is completed. Based on the output results of the upstream paper detection sensor 240 installed on the upstream side of the paper transport apparatus 200, the paper detection sensor installed on the image forming apparatus 100, and the like, the control unit 250 controls the paper P in the upstream transport path. It is determined whether or not the discharge is completed. If the controller 250 determines that the upstream sheet P has been discharged, the process proceeds to step S150. On the other hand, when it is determined that the discharge of the upstream sheet P is not completed, the control unit 250 continuously monitors the output result of the upstream sheet detection sensor 240 and the like until the discharge of the sheet is completed.

  In step S150, the control unit 250 determines whether or not the paper P remains in the transport path R downstream of the purge doors 222a and 222b in the paper transport direction D. This is because the paper P may remain on the downstream conveyance path R because the rotation of the downstream conveyance rollers 210, 212, and 214 is stopped. The control unit 250 determines whether or not the paper P is staying in the downstream conveyance path based on the output result of the downstream paper detection sensor 242 installed on the downstream side. As illustrated in FIG. 7, when the control unit 250 determines that the paper P is staying in the downstream transport path R, the control unit 250 proceeds to step S <b> 160, and the paper P is staying in the downstream transport path R. If it is determined that there is not, the process proceeds to step S180.

  When it is determined that the paper P is staying in the downstream transport path R, the downstream transport rollers 210, 212, and 214 are rotated in the reverse direction. As a result, as shown in FIGS. 8 and 9, the paper P sandwiched between the downstream transport rollers 210 is transported in the direction opposite to the paper transport direction D, and is transported by its own weight from the opened purge doors 222a and 222b. It is discharged outside the path R. The paper P discharged to the outside of the transport path R is collected in the lower paper discharge tray 230.

  On the other hand, if it is determined that the sheet P is not staying on the downstream conveyance path, in step S180, the control unit 250 determines whether the opened purge doors 222a and 222b can be closed. As illustrated in FIG. 10, as a plurality of sheets P are stacked on the discharge tray 330, the sheets P accumulate on the discharge tray 330, and the sheets P protrude from the discharge tray 330, and the purge door. This is because the closing operation of 222a and 222b may be disturbed. When the controller 250 determines that the purge doors 222a and 222b can be closed based on the detection result of the purge paper detection sensor 244, the control unit 250 proceeds to step S190, and when the controller 250 determines that the purge doors 222a and 222b cannot be closed. Proceed to step S200.

  If the purge doors 222a and 222b can be closed, the control unit 250 drives the purge door drive unit 290 in step S190 to close the purge doors 222a and 222b.

  On the other hand, if the purge doors 222a and 222b cannot be closed, the control unit 250 in step S200 warns that the purge doors 222a and 222b cannot be closed by the paper P overflowing from the paper discharge tray 230. A message indicating that it is necessary to remove the paper P accumulated in the 330 is displayed on the screen of the operation display unit 170. When the purge paper detection sensor 244 detects that the opening / closing operation of the purge doors 222a and 222b is inhibited, the control unit 250 controls the operation of the purge door driving unit 290 to close the purge doors 222a and 222b. Stop. In this example, when a jam occurs, such a series of operations is repeatedly executed.

  As described above, according to the present embodiment, for example, when a jam occurs downstream of the purge doors 222a and 222b, the purge doors 222a and 222b are opened to open the purge doors 222a and 222b. In addition, the paper P staying in the upstream conveyance path can be continuously discharged without colliding with the outside of the conveyance path R through the opened purge doors 222a and 222b. In addition, the paper path P can be easily dropped by its own weight by configuring the transport path R with a U-shape protruding downward. Thereby, when a jam occurs, an unnecessary sheet can be discharged out of the conveyance path regardless of the stop position of the sheet P. Further, since the sheets P can be collected in one place of the sheet discharge tray 230, it is not necessary for the service person to open the housing and remove the sheets P one by one, thereby reducing the burden on the operator. it can.

  Further, for the preceding paper P downstream of the purge doors 222a and 222b, after the purge doors 222a and 222b are opened, the downstream transport rollers 210, 212, and 214 are stopped and reversely rotated to reverse the preceding paper P. By carrying it, the paper P can be discharged outside the carrying path R from the opened purge doors 222a and 222b. Thereby, it is possible to prevent the occurrence of jam other than the cause.

<2. Second Embodiment>
The second embodiment is different from the image forming system GS1 of the first embodiment in that it is applied to the serial tandem type image forming system GS2 with the paper conveying apparatus 200 of the present invention. . Note that other configurations and functions of the image forming apparatus and the sheet conveying apparatus are the same as those in the first embodiment, and therefore, common constituent elements are denoted by the same reference numerals and detailed description thereof is omitted.

  FIG. 11 shows an example of a schematic configuration of the image forming system GS2 according to the present invention. As shown in FIG. 11, the image forming system GS2 is configured by connecting two image forming apparatuses 100 and 400 in series via a sheet conveying apparatus 200. The preceding image forming apparatus 100 includes an image forming unit 110, a paper feeding unit 120, a fixing unit 130, and the like, forms a predetermined image on the front side of the paper P, and transports it to the paper transport device 200.

  The sheet conveying apparatus 200 includes a U-shaped conveying path R protruding downward, a pair of guide members 220 and 222, a plurality of conveying rollers, a plurality of sheet detecting sensors, and the like. The guide member 222 disposed at a position corresponding to the curved portion (lower part) protruding downward in the transport path R is configured by purge doors 222a and 222b that can be opened and closed. The sheet conveying apparatus 200 reverses the front and back of the sheet P conveyed from the preceding image forming apparatus 100 and conveys it to the subsequent image forming apparatus 400. In FIG. 11, the front / back reversing mechanism provided in the paper transport apparatus 200 is omitted for convenience. The front / back reversing mechanism may be provided on the upstream side of the transport path R or on the downstream side. Further, the front / back reversal of the paper P is performed in the paper transport apparatus 200. However, the front / back reversing mechanism may be provided in the image forming apparatus 100 to perform the reversal on the image forming apparatus 100 side.

  The latter-stage image forming apparatus 400 has the same configuration and functions as the former-stage image forming apparatus 100, and includes an image forming unit 410, a sheet feeding unit 420, a fixing unit 430, and the like. The rear-stage image forming apparatus 400 forms a predetermined image on the back side of the paper P that is conveyed with the front and back reversed, and discharges the paper P from the paper discharge roller 440 to the outside.

  As described above, also in the tandem type image forming system GS2 according to the second embodiment, the same effects as those in the first embodiment can be obtained by using the sheet conveying device 200. That is, when a jam occurs on the downstream side of the purge doors 222a and 222b of the sheet conveying apparatus 200, the image forming apparatus 100 on the upstream side of the purge doors 222a and 222b is opened by opening the purge doors 222a and 222b. The sheet P staying in the transport path can be continuously discharged to the outside of the transport path R through the opened purge doors 222a and 222b. In addition, the paper path P can be easily dropped by its own weight by configuring the transport path R with a U-shape protruding downward. Thereby, when a jam occurs, an unnecessary sheet can be discharged to the outside of the conveyance path regardless of the stop position of the sheet P. In addition, since the service person does not need to remove the paper P one by one, the burden on the operator can be reduced.

  Further, with respect to the preceding paper P downstream of the purge doors 222a and 222b, after the purge doors 222a and 222b are opened, the downstream transport rollers 210, 212, and 214 are stopped and reversely rotated to reverse the preceding paper P. By carrying it, the paper P can be discharged outside the carrying path R from the opened purge doors 222a and 222b. Thereby, it is possible to prevent the occurrence of a jam other than the cause.

  When a jam occurs on the upstream side of the purge doors 222a and 222b, as described in the first embodiment, the downstream side transport rollers 210, 212, and 214 of the paper transport device 200 and the subsequent image formation are performed. By rotating the transport roller of the apparatus 400, the paper P staying in the downstream transport path is normally discharged from the subsequent image forming apparatus 400.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In the above embodiment, when the opening / closing operation of the purge doors 222a and 222b is obstructed by the paper P accumulated in the paper discharge tray 230, a warning is displayed on the screen of the operation display unit 170. It is not limited to this. For example, an output unit capable of outputting sound and buzzer sound can be used as the notification unit, and the user can be notified that the paper P in the paper discharge tray 230 is removed by this output unit.

  In addition, the sheet conveying apparatus 200 described in the above embodiment can be provided in the image forming apparatuses 100 and 400 or in the post-processing apparatus 300. Accordingly, even when a jam occurs in the image forming apparatus 100 or the like, the staying paper P can be continuously discharged out of the conveyance path.

  In the above embodiment, when the purge doors 222a and 222b are not closed, a warning is displayed on the screen of the operation display unit 170 of the image forming apparatus 100. However, a network or the like is displayed on the image forming systems GS1 and GS2. A warning may be displayed on the screen of a computer connected via the computer.

  Further, in the above embodiment, it is detected whether or not the purge paper detection sensor 244 inhibits the closing when the purge doors 222a and 222b are closed, but the purge paper detection sensor 244 opens when the purge doors 222a and 222b are opened. It may be detected whether or not is inhibited. When the opening is inhibited, the control unit 250 displays a warning on the screen of the operation display unit 70 that the opening of the purge doors 222a and 222b is inhibited, and stops the opening operation of the purge doors 222a and 222b. .

100,400 Image forming apparatus 170 Operation display section (notification section)
200 Paper transport device 202, 204, 206, 208 Upstream transport roller (first transport roller)
210, 212, 214 Downstream transport roller (second transport roller)
220, 222 Guide member (paper transport section)
222a, 222b Purge door (door part)
230 Output tray (container)
250 Control unit 260 Purge paper detection sensor (detection unit)
GS1, GS2 Image forming system R Transport path (paper transport path)

Claims (8)

A paper transport path having a downwardly curved portion;
A paper transport unit provided along the paper transport path and having a door that can be opened and closed at a position corresponding to the curved portion;
A control unit for controlling the operation of the door unit,
The door portion can open a top portion located on the lowest side of the curved portion in the vertical direction,
The control unit discharges the paper remaining in the paper transport path to the outside of the paper transport path by opening the door when a paper transport failure occurs in the paper transport path. Paper transport device. A first transport roller provided upstream of the door in the paper transport direction from the door portion;
The control unit is configured to drive the first conveyance roller upstream without stopping the first conveyance roller when the defective conveyance portion of the sheet is downstream of the door portion in the sheet conveyance direction. The paper transport apparatus according to claim 1, wherein the remaining paper is discharged out of the paper transport path through the door. A second transport roller provided on the downstream side in the paper transport direction from the door,
The control unit causes the sheet remaining on the downstream side in the sheet conveying direction to be discharged out of the sheet conveying path through the door by rotating the second conveying roller in the reverse direction. The paper transport device described in 1. A storage section for storing paper discharged from the paper transport path;
A detection unit for detecting whether or not the opening / closing operation of the door unit is hindered by the paper stored in the storage unit;
The sheet conveying apparatus according to any one of claims 1 to 3, further comprising: A notification unit for notifying that the opening / closing operation of the door is inhibited when it is determined that the opening / closing operation of the door is inhibited based on a detection result of the detection unit. Item 5. The paper conveying device according to Item 4. The said control part stops the opening / closing operation | movement of the said door part, when it detects that the opening / closing operation | movement of the said door part is inhibited by the said detection part. The Claim 4 or Claim 5 characterized by the above-mentioned. Paper transport device. The length in the paper transport direction of the portion of the paper transport path where the door is provided is longer than the length of at least one paper transported in the paper transport path.
The sheet conveying apparatus according to any one of claims 1 to 6, wherein the sheet conveying apparatus is configured as described above. A first image forming apparatus for forming an image on a sheet;
8. The sheet according to claim 1, which is located downstream of the first image forming apparatus in a sheet conveying direction and on which an image is formed by the first image forming apparatus. A paper transport device,
A second image forming apparatus that is positioned downstream of the sheet conveying apparatus in the sheet conveying direction and forms an image on the sheet conveyed from the sheet conveying apparatus;
An image forming system comprising:

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