Image forming apparatus

Abstract

To eliminate the need to remove sheets present in the upstream and downstream areas of the location where jam is detected. [Solution] The sheet conveying device 3 includes a plurality of switching units 30, each having a plurality of branch paths 30a branching off from a standard conveying path and a plurality of sheet recovery units 30b that recover sheets downstream of the plurality of branch paths 30a. The plurality of switching units 30 can selectively perform a normal conveying process in which each of the plurality of sheets is conveyed along the standard conveying path, and an emergency conveying process in which each of the plurality of sheets is conveyed to each of the plurality of sheet recovery units 30b. When a jam is detected, the control device 8 causes the upstream terminal switching unit, which is located at the furthest downstream in the sheet conveying direction among the upstream switching units having a path branching off from the area downstream of the jam area in the sheet conveying direction, to perform the emergency conveying process, and causes the normal conveying process or the emergency conveying process to be performed by a unit other than the upstream terminal switching unit.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus capable of detecting a jam in a sheet conveyance path.

Background Art

[0002] An image forming apparatus includes a sheet conveyance device and a printing device. The sheet conveyance device sequentially conveys a plurality of sheets along a conveyance path. The printing device forms an image on each of the sheets at a printing position on the conveyance path.

[0003] Also, when a jam is detected in the conveyance path, it is known that the image forming apparatus selectively conveys a sheet that has passed through the printing position to one of a terminal portion of the main conveyance path and a branch path branched from the main conveyance path (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when a jam is detected, a sheet may remain in a region on the upstream side in the sheet conveyance direction with respect to the position where the jam is detected in the conveyance path.

[0006] An object of the present invention is to provide an image forming apparatus capable of omitting the trouble of removing sheets existing in regions on the upstream side and the downstream side in the sheet conveyance direction with respect to the position where a jam is detected in a sheet conveyance path.

Means for Solving the Problems

[0007] An image forming apparatus according to one aspect of the present invention comprises a standard transport path forming a sheet passage, a sheet supply device, a sheet transport device, a printing device, a jam detection device, and a control device. The sheet supply device sequentially supplies a plurality of sheets to the standard transport path. The sheet transport device transports each of the plurality of sheets along the standard transport path. The printing device forms an image on each of the plurality of sheets at a printing position in the standard transport path. The jam detection device detects jams in each of a plurality of detection areas in the standard transport path. The control device controls the sheet transport device. The sheet transport device comprises a plurality of switching units, each having a plurality of branch paths branching from a plurality of branching positions in the standard transport path, and a plurality of sheet retrieval units that retrieve sheets downstream of the plurality of branch paths. The plurality of switching units can selectively perform normal transport processing and emergency transport processing. The normal transport processing is the process of transporting each of the plurality of sheets along the standard transport path toward the exit of the standard transport path at each of the plurality of branching positions. The emergency transport process is a process of transporting each of the multiple sheets from the standard transport path through each of the multiple branch paths to each of the multiple sheet retrieval units at each of the multiple branching locations. When the jam is detected by the jam detection device, the control device performs upstream transport control for one or more upstream switching units which are part of the multiple switching units, and downstream transport control for one or more downstream switching units which are other part of the multiple switching units. The upstream switching unit has a path that branches off from the upstream region, which is the region upstream in the sheet transport direction from the jam area in the standard transport path where the jam was detected. The downstream switching unit has a path that branches off from the downstream region, which is the region downstream in the sheet transport direction from the jam area in the standard transport path. In the upstream transport control, the control device causes the upstream terminal switching unit, which is the downstreammost part of the upstream switching unit in the sheet transport direction, to perform the emergency transport process, and further causes the other upstream switching units to perform the normal transport process or the emergency transport process. In the downstream transport control described above, the control device causes the downstream switching unit to execute the normal transport process or the emergency transport process. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming apparatus that eliminates the effort of removing sheets located in the upstream and downstream regions in the sheet transport direction relative to the location where a jam is detected in the sheet transport path. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a configuration diagram of an image forming apparatus according to an embodiment. [Figure 2] Figure 2 is a diagram showing the configuration of a sheet supply unit in an image forming apparatus according to an embodiment. [Figure 3] Figure 3 is a diagram showing the configuration of the print unit in the image forming apparatus according to this embodiment. [Figure 4] Figure 4 is a diagram showing the configuration of a sheet processing unit in an image forming apparatus according to an embodiment. [Figure 5] Figure 5 is a block diagram showing the configuration of the control device in the image forming apparatus according to this embodiment. [Figure 6] Figure 6 is a flowchart showing an example of the jam-response control procedure in an image forming apparatus according to this embodiment. [Figure 7] Figure 7 is a flowchart showing an example of a first modified procedure for upstream transport control in an image forming apparatus according to an embodiment. [Figure 8] Figure 8 is a flowchart showing an example of a second modified procedure for upstream transport control in an image forming apparatus according to an embodiment. [Figure 9] Figure 9 is a flowchart showing an example of a first modified procedure for downstream transport control in an image forming apparatus according to an embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are merely examples of embodying the present invention and do not limit the technical scope of the present invention.

[0011] [Configuration of Image Forming Apparatus 10] The image forming apparatus 10 according to the embodiment includes a sheet feeding device 1, a standard conveyance path 2, a sheet conveyance device 3, and a printing device 4 (see FIG. 1). Further, the image forming apparatus 10 includes a sheet processing device 5 that processes a plurality of sheets 9 on which images are formed.

[0012] The sheet feeding device 1 sequentially feeds a plurality of sheets 9 to the standard conveyance path 2. The standard conveyance path 2 forms a passage for a plurality of sheets 9 that are sequentially fed.

[0013] The sheet conveyance device 3 conveys each of the plurality of sheets 9 along the standard conveyance path 2. The printing device 4 forms an image on each of the sheets 9 at a printing position P1 in the standard conveyance path 2. / /

[0014] The image forming apparatus 10 has a configuration in which a sheet feeding unit U1 including the sheet feeding device 1, a printing unit U2 including the printing device 4, and a sheet processing unit U3 including the sheet processing device 5 are connected in series (see FIG. 1). The standard conveyance path 2 is arranged across the sheet feeding unit U1, the printing unit U2, and the sheet processing unit U3.

[0015] The standard conveyance path 2 includes a main conveyance path 2b including the printing position P1, a sub-conveyance path 2c arranged in parallel with the main conveyance path 2b, a pre-conveyance path 2a arranged upstream of the main conveyance path 2b in the sheet conveyance direction, and a post-conveyance path 2d arranged downstream of the main conveyance path 2b in the sheet conveyance direction (see FIG. 1).

[0016] The sub-conveyance path 2c branches from a portion downstream of the printing position P1 in the main conveyance path 2b in the sheet conveyance direction and merges into a portion upstream of the printing position P1 in the main conveyance path 2b in the sheet conveyance direction.

[0017] Note that the sub-conveyor path 2c is a path through which the sheet 9 that has passed through the main conveyor path 2b is conveyed. In the present embodiment, each of the sub-conveyor path 2c and the post-conveyor path 2d is an example of a downstream portion in the sheet conveyance direction with respect to the printing position P1 in the standard conveyor path 2.

[0018] The pre-conveyor path 2a is arranged in the sheet supply unit U1, the main conveyor path 2b and the sub-conveyor path 2c are arranged in the printing unit U2, and the post-conveyor path 2d is arranged in the sheet processing unit U3 (see FIGS. 1 to 4).

[0019] In the present embodiment, the sheet supply device 1 is a cut-sheet supply device 1a that feeds the plurality of sheets 9 accommodated in the sheet storage portion 1x one by one to the pre-conveyor path 2a (see FIG. 2). Each of the sheets 9 accommodated in the sheet storage portion 1x is a cut sheet that has been cut into a standard size in advance.

[0020] Note that the sheet supply unit U1 may include a roll-sheet supply device 1b. The roll-sheet supply device 1b feeds out a roll sheet and sequentially generates a plurality of sheets 9 of a specific size by cutting the fed-out portion of the roll sheet. Further, the roll-sheet supply device 1b sequentially feeds the plurality of generated sheets 9 to the pre-conveyor path 2a.

[0021] The sheet conveyance device 3 conveys each of the plurality of sheets 9 supplied to the pre-conveyor path 2a along the pre-conveyor path 2a and the main conveyor path 2b. Further, the sheet conveyance device 3 conveys a part or all of the plurality of sheets 9 that are to be double-sided printed from the main conveyor path 2b to the sub-conveyor path 2c and conveys them again along the main conveyor path 2b.

[0022] Furthermore, after the sheet conveyance device 3 loads each of the plurality of sheets 9 from the main conveyor path 2b into the post-conveyor path 2d, it conveys them along the post-conveyor path 2d.

[0023] The sheet conveying device 3 includes multiple pairs of conveying rollers 31, each arranged along a standard conveying path 2, a first belt conveying device 32, a second belt conveying device 33, and multiple path switching mechanisms 34 (see Figures 2-4).

[0024] Each pair of conveyor rollers 31 rotates under the power of a motor (not shown) to convey each sheet 9. Some of the multiple pairs of conveyor rollers 31 convey each sheet 9 along the front conveyor path 2a, and further convey each sheet 9 from the front conveyor path 2a to the main conveyor path 2b.

[0025] The first belt conveyor 32 takes over the conveying of each sheet 9 from some of the multiple sets of conveyor roller pairs 31, and further conveys each sheet 9 along the main conveyor path 2b at the print position P1 (see Figure 3).

[0026] The second belt conveyor 33 takes over the conveying of each sheet 9 from the first belt conveyor 32 and further conveys each sheet 9 along the main conveying path 2b (see Figure 3). The remaining parts of the multiple sets of conveying roller pairs 31 take over the conveying of each sheet 9 from the second belt conveyor 33 and convey each sheet 9 along the rear conveying path 2d (see Figure 4).

[0027] Each of the multiple route switching mechanisms 34 switches the transport route of each sheet 9 at multiple branching points in the standard transport route 2. For example, some of the multiple route switching mechanisms 34 switch the transport route of some or all of the sheets 9 that have passed through the second belt transport device 33 from the main transport route 2b to the secondary transport route 2c (see Figure 3).

[0028] Furthermore, the sheet conveying device 3 is equipped with multiple normal path sheet detection devices 3a (see Figures 2-4). The multiple normal path sheet detection devices 3a detect each sheet 9 being conveyed along the standard conveying path 2 at multiple detection positions along the standard conveying path 2.

[0029] The printing device 4 forms an image on each of the sheets 9 at the printing position P1 on the main transport path 2b. In this embodiment, the printing device 4 is an inkjet recording device that forms an image on each of the sheets 9 transported by the first belt transport device 32 using an inkjet method (see Figure 3).

[0030] Therefore, the printing device 4 comprises a plurality of inkjet heads 41 that eject ink of different colors onto each sheet 9, and a plurality of ink supply units 42 that supply ink to each of the plurality of inkjet heads 41 (see Figure 3).

[0031] Furthermore, the printing device 4 is equipped with a drying device 43 that dries the ink image on each sheet 9 that is transported by the second belt conveying device 33 (see Figure 3).

[0032] The printing device 4 may also be a device that forms an image on each of the sheets 9 using another method, such as electrophotography.

[0033] The sheet processing device 5 performs sheet processing on a plurality of sheets 9 on which images have been formed. In this embodiment, the sheet processing device 5 is an orientation adjustment device 5a that adjusts the orientation of each sheet 9 (see Figure 4).

[0034] The orientation adjustment device 5a includes multiple adjustment transport paths R1, R2, multiple pairs of transport rollers 51, multiple path switching mechanisms 52, and multiple sheet position correction devices 53 (see Figure 4). The multiple adjustment transport paths R1, R2 are composed of a part of the rear transport path 2d and transport paths branched off from the rear transport path 2d.

[0035] In the example shown in Figure 4, the multiple adjustment transport paths R1 and R2 include a first adjustment transport path R1 and a second adjustment transport path R2. The multiple sheet position correction devices 53 include a first sheet position correction device 53a located on the first adjustment transport path R1 and a second sheet position correction device 53b located on the second adjustment transport path R2.

[0036] Multiple sets of transport rollers 51 are driven and rotated by a motor (not shown). By rotating, the multiple sets of transport rollers 51 transport each sheet 9 along one of the multiple adjustable transport paths R1, R2.

[0037] The multiple path switching mechanisms 52 alternately switch the transport paths of the multiple sheets 9 between the first adjusted transport path R1 and the second adjusted transport path R2.

[0038] The first adjustment transport path R1 includes the first forward transport path R11 and the first reverse transport path R12. The second adjustment transport path R2 includes the second forward transport path R21 and the second reverse transport path R22.

[0039] The first forward transport path R11 branches off from the downstream transport path 2d and leads to the first reverse transport path R12. The first reverse transport path R12 includes a portion that is connected to the first forward transport path R11 and a portion that branches off from the portion connected to the first forward transport path R11 and merges with the downstream transport path 2d.

[0040] The second forward transport path R21 branches off from the backward transport path 2d and leads to the second reverse transport path R22. The second reverse transport path R22 includes a portion that connects to the second forward transport path R21 and a portion that branches off from the portion that connects to the second forward transport path R21 and merges with the backward transport path 2d.

[0041] Multiple pairs of transport rollers 51 and multiple path switching mechanisms 52 selectively execute either a first adjustment transport process or a second adjustment transport process. The first adjustment transport process involves transporting the sheet 9 to a first forward transport path R11, and then inverting the leading and trailing ends of the sheet 9 to transport the sheet 9 along a first inversion transport path R12. The second adjustment transport process involves transporting the sheet 9 to a second forward transport path R21, and then inverting the leading and trailing ends of the sheet 9 to transport the sheet 9 along a second inversion transport path R22.

[0042] The first sheet position correction device 53a corrects the positional misalignment of each sheet 9 being transported along the first reversal transport path R12. The second sheet position correction device 53b corrects the positional misalignment of each sheet 9 being transported along the second reversal transport path R22.

[0043] The sheet processing unit U3 may also include a post-processing device 5b that processes some or all of the multiple sheets 9. For example, the post-processing device 5b may include some or all of a hole punching device, a stapling device, and a sheet folding device.

[0044] The punching device punches holes in each of the sheets 9. The stapling device performs a stapling process to bind multiple sheets 9 together. The sheet folding device performs a sheet folding process to fold one or more sheets 9.

[0045] The image forming apparatus 10 further comprises an operating device 801, a display device 802, and a control device 8 (see Figure 3). In the example shown in Figure 3, the operating device 801, the display device 802, and the control device 8 are provided in the print unit U2.

[0046] However, some or all of the operating device 801, display device 802, and control device 8 may be provided in the sheet supply unit U1 or the sheet processing unit U3.

[0047] The operating device 801 detects human operation. For example, the operating device 801 includes multiple operation buttons and a touch panel. The display device 802 can display various types of information. For example, the display device 802 is a panel display device such as a liquid crystal display panel.

[0048] The control device 8 controls the sheet supply device 1, the sheet transport device 3, the printing device 4, and the sheet processing device 5.

[0049] As shown in Figure 5, the control device 8 includes a CPU (Central Processing Unit) 80, RAM (Random Access Memory) 81, a secondary storage device 82, and a communication device 83, among others.

[0050] The CPU 80 performs various control and data processing by executing computer programs. The RAM 81 temporarily stores the computer programs executed by the CPU 80 and various data.

[0051] The secondary storage device 82 is a computer-readable, non-volatile storage device. The secondary storage device 82 stores the computer program executed by the CPU 80 and various data. For example, flash memory, a hard disk drive, or both may be used as the secondary storage device 82.

[0052] The communication device 83 communicates with other devices, such as the host device 7, via the network 70. The CPU 80 communicates with other devices via the communication device 83. The host device 7 is an information processing device that requests print processing from the image forming apparatus 10. The print processing is the process of forming an image on each of the sheets 9.

[0053] The CPU 80 includes a plurality of processing modules that are realized by executing the computer program. These plurality of processing modules include a state determination unit 8a, a transport control unit 8b, and a print control unit 8c (see Figure 5).

[0054] The state determination unit 8a determines the state of the image forming apparatus 10 according to the detection results of various detection devices, such as multiple normal path sheet detection devices 3a.

[0055] For example, the state determination unit 8a performs a jam detection process to detect jams in the standard transport path 2 according to the operating state of the sheet transport device 3 and the detection results of the normal path sheet detection device 3a. The jam is a blockage of sheet 9.

[0056] Here, one of the multiple sheets 9 that is subject to the jam detection process is referred to as the target sheet. Furthermore, two of the multiple normal path sheet detection devices 3a that are located at the position where the target sheet passes and at the position where the target sheet is scheduled to pass next are referred to as the first target detection device and the second target detection device, respectively.

[0057] The state determination unit 8a detects the jam if the second target detection device does not detect the target sheet within the standard transport time elapsed from the time the first target detection device detects the passage of the target sheet. In this case, the state determination unit 8a detects the jam in the region from the position of the first target detection device to the position of the second target detection device in the standard transport path 2.

[0058] Furthermore, the state determination unit 8a also detects the jam if the time for which the first target detection device continuously detects the target sheet exceeds the reference passage time. In this case, the state determination unit 8a detects the jam in a region corresponding to the length of the target sheet, including the position of the first target detection device in the standard transport path 2.

[0059] The standard transport time is set in accordance with the transport speed of each sheet 9 by the sheet transport device 3 and the path length from the first target detection device to the second target detection device. The standard passage time is set according to the transport speed of each sheet 9 by the sheet transport device 3 and the sheet length of the target sheet.

[0060] Multiple normal path sheet detection devices 3a and state determination unit 8a are an example of a jam detection device that detects jams in each of multiple detection areas in the standard transport path 2.

[0061] The transport control unit 8b controls the supply and transport of each sheet 9 by controlling the sheet supply device 1 and the sheet transport device 3. For example, the transport control unit 8b controls the transport timing of each sheet 9 to the print position P1 according to the detection result of one of the multiple normal path sheet detection devices 3a located before the print position P1.

[0062] The print control unit 8c causes the printing device 4 to perform the printing process in synchronization with the transport of each sheet 9. Furthermore, the print control unit 8c controls the power supply to the heaters provided in the drying device 43.

[0063] Incidentally, when the jam is detected, the sheet 9 may remain in the area upstream of the area where the jam was detected in the standard transport path 2, in the sheet transport direction.

[0064] The image forming apparatus 10 includes a configuration that eliminates the need to remove the sheets 9 present in the upstream and downstream areas in the sheet transport direction relative to the area where the jam is detected. The configuration will be described below.

[0065] The sheet conveying device 3 includes multiple switching units 30 (see Figures 2-3). Each of the multiple switching units 30 includes multiple branch paths 30a, multiple sheet collection units 30b, multiple path switching mechanisms 30c, and multiple pairs of collection rollers 30d (see Figures 2-4).

[0066] The multiple branch lines 30a are transport lines that branch off from multiple branching points PJ1 in the standard transport line 2. The multiple sheet collection sections 30b are sections that collect sheets 9 downstream of the multiple branch lines 30a. For example, each sheet collection section 30b is a collection tray that receives the sheets 9 or a collection box that houses the sheets 9.

[0067] Each of the sheet retrieval units 30b is positioned to be accessible either directly from outside the image forming apparatus 10 or by opening a cover formed on the exterior of the image forming apparatus 10. The user can access each of the sheet retrieval units 30b and remove the sheet 9 from each of them.

[0068] Each of the multiple route switching mechanisms 30c can switch between a normal state in which each of the multiple branching positions PJ1 guides each of the multiple sheets 9 along the standard transport path 2 and an emergency state in which it guides each of the multiple branching paths 30a from the standard transport path 2.

[0069] Multiple sets of recovery rollers 30d are driven and rotated by a motor (not shown). Each set of recovery rollers 30d transports the sheets 9 guided to multiple branch paths 30a to multiple sheet recovery sections 30b. As a result, the sheets 9 are collected in each of the sheet recovery sections 30b.

[0070] Each switching unit 30 can selectively perform normal transport processing and emergency transport processing at each branching position PJ1.

[0071] The aforementioned normal transport process involves transporting each sheet 9 along the standard transport path 2 toward the exit of the standard transport path 2 at each branching position PJ1. Each switching unit 30 executes the normal transport process by maintaining each route switching mechanism 30c in the normal state.

[0072] The emergency transport process involves transporting each sheet 9 from the standard transport path 2 through each branch path 30a to each sheet retrieval section 30b at each branch point PJ1. Each switching section 30 executes the emergency transport process by switching each route switching mechanism 30c to the emergency state.

[0073] In the example shown in Figure 3, the multiple sheet collection units 30b include a shared collection unit 30bx. The shared collection unit 30bx has one of the multiple switching units 30 having two branch paths 30a that branch off at two branching positions PJ1 and a shared collection unit 30bx corresponding to the two branch paths 30a.

[0074] In the example shown in Figure 3, one of the two branch paths 30a corresponds to one of the two branching locations PJ1. Furthermore, the two branch paths 30a that branch off at the two branching locations PJ1, along with a portion of the auxiliary transport path 2c, constitute the corresponding branch path 30a at the two branching locations PJ1.

[0075] The multiple switching units 30 include one or more pre-print switching units 30x and one or more post-print switching units 30y (see Figures 2-4).

[0076] The pre-print switching unit 30x has a path that branches off from a position upstream of the sheet transport direction relative to the print position P1 (see Figure 2). In this embodiment, the pre-print switching unit 30x, which has a path that branches off from the pre-transport path 2a, is located in the sheet supply unit U1.

[0077] The post-print switching unit 30y has a path that branches off from a position downstream of the print position P1 in the sheet transport direction (see Figures 3 and 4). In this embodiment, three post-print switching units 30y are arranged in the print unit U2 and the sheet processing unit U3.

[0078] One of the two post-print switching units 30y has a path from two branching points PJ1 in the secondary transport path 2c to the shared recovery unit 30bx (see Figure 3). The other of the two post-print switching units 30y has a path that branches off from one of the multiple branching points PJ1 in the post-transport path 2d (see Figure 4).

[0079] The image forming apparatus 10 further comprises a plurality of branch line sheet detection devices 3b that detect sheets 9 being transported along each of the plurality of branch lines 30a (see Figures 2-4). The sheets 9 detected by each branch line sheet detection device 3b are the sheets 9 that are collected in each of the sheet collection units 30b.

[0080] The state determination unit 8a executes the jam detection process when the sheet conveying device 3 is performing a continuous conveying process in which it sequentially conveys multiple sheets 9 along the standard conveying path 2. The conveying control unit 8b also performs jam response control when the sheet conveying device 3 is performing the continuous conveying process (see Figure 6).

[0081] [Jam-resistant control] Below, an example of the procedure for jam-responding control will be described with reference to the flowchart shown in Figure 6.

[0082] In the following description, S101, S102, ... represent identification codes for multiple processes in the jam-response control. In the jam-response control, the process of process S101 is executed first.

[0083] <Process S101> In step S101, the transport control unit 8b derives the number of transported sheets according to the detection results of the multiple normal path sheet detection devices 3a. The number of transported sheets is the number of multiple sheets 9 present in the image forming apparatus 10.

[0084] The transport control unit 8b executes the process of process S102 in conjunction with the process of process S101.

[0085] <Process S102> In step S102, the transport control unit 8b selects the following process according to the result of the jam detection process performed by the state determination unit 8a.

[0086] The transport control unit 8b repeats the processes of steps S101 and S102 if no jam is detected. On the other hand, the transport control unit 8b executes the process of step S103 if jam is detected.

[0087] The processes S103 to S110 shown below are executed when the jam is detected by the jam detection process performed by the state determination unit 8a.

[0088] <Process S103> In step S103, the transport control unit 8b instructs the sheet transport device 3 to stop transporting the sheet 9 in the jammed area. The jammed area is the area in the standard transport path 2 where the jam is detected.

[0089] The sheet conveying device 3 includes a conveying gear mechanism that transmits the rotation of one or more motors to multiple pairs of conveying rollers 31, a first belt conveying device 32, and a second belt conveying device 33, and a plurality of clutches provided on the conveying gear mechanism (not shown).

[0090] Each of the clutches blocks the transmission of rotation from the conveying gear mechanism to a portion of the multiple sets of conveying roller pairs 31, the first belt conveying device 32, and the second belt conveying device 33. In step S103, the conveying control unit 8b operates a portion of the multiple clutches that corresponds to the jam area.

[0091] The transport control unit 8b executes the process of process S104 following the process of process S103.

[0092] <Process S104> In step S104, the transport control unit 8b outputs jam occurrence information through either or both of the display device 802 and the communication device 83. For example, the transport control unit 8b outputs the jam occurrence information to the administrator's host device 7 through the communication device 83.

[0093] The jam occurrence information includes information indicating that the jam has been detected, and information representing the jam area. The display device 802 and the communication device 83 are examples of information output devices capable of outputting information.

[0094] The transport control unit 8b executes the process of process S105 following the process of process S104.

[0095] <Process S105> In process S105, the transport control unit 8b performs a process to classify the multiple switching units 30 into an upstream switching unit, a downstream switching unit, and an intermediate switching unit.

[0096] In the following description, the region upstream of the jam area in the standard transport path 2 in the sheet transport direction will be referred to as the upstream region. Similarly, the region downstream of the jam area in the standard transport path 2 in the sheet transport direction will be referred to as the downstream region.

[0097] The upstream switching section has a path branched from the upstream region of the standard transport path 2. The downstream switching section has a path branched from the downstream region of the standard transport path 2. The intermediate switching section has a path branched from the jam region of the standard transport path 2. The branched paths of the upstream switching section, the downstream switching section, and the intermediate switching section are one of a plurality of branch paths 30a.

[0098] The transport control unit 8b executes the process of step S106 when the multiple switching units 30 include the upstream switching unit and the downstream switching unit.

[0099] Furthermore, the transport control unit 8b executes the process of step S107 when the plurality of switching units 30 include one or more of the upstream switching units but do not include the downstream switching units.

[0100] Furthermore, the transport control unit 8b executes the process of step S108 when the multiple switching units 30 do not include the upstream switching unit but include one or more of the downstream switching units.

[0101] <Process S106> In step S106, the transport control unit 8b performs upstream transport control for one or more upstream switching units and downstream transport control for one or more downstream switching units.

[0102] Standard examples of the upstream transport control and the downstream transport control described above will be explained below.

[0103] In the upstream transport control according to the standard example described above, the transport control unit 8b causes all of the one or more upstream switching units to execute the emergency transport process. As a result, one or more sheets 9 located in the upstream region are transported to one of the multiple sheet retrieval units 30b via one of the multiple branch paths 30a that branches off from the region immediately downstream of the sheet transport direction relative to the sheet 9.

[0104] Here, the upstream terminal switching unit is defined as the one or more upstream switching units located at the downstream end in the sheet transport direction. In the standard example, if there are multiple upstream switching units, the transport control unit 8b causes the upstream terminal switching unit and the other upstream switching units to perform the emergency transport process.

[0105] On the other hand, in the downstream transport control according to the standard example, the transport control unit 8b causes all of the one or more downstream switching units to execute the emergency transport process. As a result, one or more sheets 9 located in the downstream area are transported to one of the multiple sheet retrieval units 30b via one of the multiple branch paths 30a that branches off from the area immediately downstream of the sheet transport direction relative to the sheet 9.

[0106] The transport control unit 8b executes the process of process S109 in conjunction with the process of process S106.

[0107] <Process S107> In step S107, the transport control unit 8b executes the upstream transport control for one or more of the upstream switching units. For example, the transport control unit 8b executes the upstream transport control according to the standard example.

[0108] The transport control unit 8b executes the process of process S109 in conjunction with the process of process S107.

[0109] <Process S108> In step S108, the transport control unit 8b executes the downstream transport control for one or more of the downstream switching units. For example, the transport control unit 8b executes the downstream transport control according to the standard example.

[0110] The transport control unit 8b executes the process of process S109 in conjunction with the process of process S108.

[0111] The transport control unit 8b terminates after continuing one of the processes S106 to S108 for a predetermined time.

[0112] <Process S109> In step S109, the transport control unit 8b derives the number of sheets to be collected in each of the multiple sheet collection units 30b. The transport control unit 8b derives the number of sheets to be collected according to the detection results of the multiple branch line sheet detection devices 3b when one or both of the upstream transport control and the downstream transport control are being executed.

[0113] In step S109, the transport control unit 8b derives the number of remaining sheets according to the number of transported sheets and the number of recovered sheets derived in step S101. The number of remaining sheets is the number of sheets 9 remaining on the standard transport path 2 after one or both of the upstream transport control and the downstream transport control have been executed.

[0114] Normally, the number of remaining sheets is the number of sheets 9 that jammed the standard transport path 2. Furthermore, if some of the multiple sheets 9 jammed while being transported by the upstream transport control or the downstream transport control, the number of jammed sheets 9 is also reflected in the number of remaining sheets.

[0115] The transport control unit 8b executes the process of process S110 following the process of process S109.

[0116] <Process S110> In process S110, the transport control unit 8b outputs sheet status notification information through either or both of the display device 802 and the communication device 83. The sheet status notification information includes information on the number of recovered sheets and information on the number of remaining sheets.

[0117] The transport control unit 8b terminates the jam response control after executing the process of step S110.

[0118] In the image forming apparatus 10, when the jam is detected, one or more sheets 9 present in the standard transport path 2 are discharged from the standard transport path 2.

[0119] In other words, one or more sheets 9 present in the standard transport path 2 are collected in one of the multiple sheet collection units 30b by either the upstream transport control or the downstream transport control, or discharged from the exit of the standard transport path 2.

[0120] By employing the image forming apparatus 10, the effort required to remove the sheets 9 present in the upstream and downstream regions is eliminated.

[0121] Furthermore, when the standard example of the upstream transport control is adopted, one or more sheets 9 located in the upstream region of the standard transport path 2 are transported to the sheet retrieval unit 30b located on the shortest path downstream in the sheet transport direction. This makes it less likely for jams to occur in the sheets 9 transported by the upstream transport control.

[0122] Similarly, when the standard example of downstream transport control is adopted, one or more sheets 9 located in the downstream region of the standard transport path 2 are transported to the sheet retrieval unit 30b located on the shortest path downstream in the sheet transport direction. This makes it less likely for jams to occur in the sheets 9 transported by the downstream transport control.

[0123] [First modified example of upstream transport control] Next, the procedure of the first modified example of the upstream transport control will be described with reference to the flowchart shown in Figure 7. The processing in this modified example is performed in process S106 or process S107 of the jam response control.

[0124] In the following description, S201 and S202 represent identification codes for two processes in the first modified example of the upstream transport control. In the first modified example of the upstream transport control, the process of process S201 is executed first.

[0125] <Process S201> In process S201, the transport control unit 8b identifies the upstream terminal switching unit, which is one or more of the upstream switching units.

[0126] The transport control unit 8b executes the process of process S202 following the process of process S201.

[0127] <Process S202> In process S202, the transport control unit 8b causes the normal transport process to be executed by the upstream switching unit, except for the upstream terminal switching unit, and causes the emergency transport process to be executed by the upstream terminal switching unit.

[0128] After executing the process in step S202, the transport control unit 8b terminates the upstream transport control.

[0129] When this modified configuration is adopted, when the jam is detected, all of the one or more sheets 9 present in the upstream region of the standard transport path 2 are transported to one of the multiple sheet retrieval units 30b included in the upstream terminal switching unit.

[0130] In other words, the upstream transport control causes all of the one or more sheets 9 discharged from the upstream region of the standard transport path 2 to be collected together in one place. This eliminates the need to remove the one or more sheets 9 discharged from the upstream region of the standard transport path 2 from the image forming apparatus 10.

[0131] [Second variation of upstream transport control] Next, the procedure for the second modified example of the upstream transport control will be described with reference to the flowchart shown in Figure 8. The processing in this modified example is performed in step S106 or step S107 of the jam response control.

[0132] In the following description, S301 to S303 represent identification codes for the three steps in the second modified example of the upstream transport control. In the second modified example of the upstream transport control, the processing of step S301 is performed first.

[0133] <Process S301> In step S301, the transport control unit 8b identifies the upstream terminal switching unit, which is one or more of the upstream switching units.

[0134] Furthermore, the transport control unit 8b selects the following processing depending on whether the upstream switching unit includes the post-print switching unit 30y or not.

[0135] If the upstream terminal switching section includes a path that branches off upstream of the print position P1 in the sheet transport direction, the upstream switching section does not include the post-print switching section 30y.

[0136] On the other hand, if the upstream terminal switching section includes a path that branches downstream of the print position P1 in the sheet transport direction, the upstream switching section includes a post-print switching section 30y.

[0137] The transport control unit 8b executes the process of step S302 when the upstream switching unit includes the post-print switching unit 30y. On the other hand, the transport control unit 8b executes the process of step S303 when the upstream switching unit does not include the post-print switching unit 30y.

[0138] Furthermore, the fact that the upstream switching unit includes the post-print switching unit 30y means that the upstream switching unit includes both the pre-print switching unit 30x and the post-print switching unit 30y. On the other hand, the fact that the upstream switching unit does not include the post-print switching unit 30y means that the upstream switching unit includes only the pre-print switching unit 30x.

[0139] <Process S302> In process S302, the transport control unit 8b performs pre-print upstream transport control for the pre-print switching unit 30x included in the upstream switching unit, and performs post-print upstream transport control for the post-print switching unit 30y included in the upstream switching unit.

[0140] In the upstream transport control before printing, the transport control unit 8b causes the pre-print switching unit 30x, which is included in the upstream switching unit, to perform the emergency transport process. As a result, one or more sheets 9 present in the upstream transport path 2a are collected in the sheet retrieval unit 30b of the pre-print switching unit 30x without being transported to the print position P1.

[0141] One or more sheets 9 present in the forward transport path 2a are collected in the sheet collection section 30b of the pre-print switching section 30x, thereby reducing the possibility of the sheets 9 being contaminated with developer. In this embodiment, the developer is ink.

[0142] On the other hand, in the post-print upstream transport control, the transport control unit 8b causes the normal transport process to be executed by the post-print switching unit 30y included in the upstream switching unit, excluding the upstream terminal switching unit, and causes the emergency transport process to be executed by the upstream terminal switching unit.

[0143] After executing the process in step S302, the transport control unit 8b terminates the upstream transport control.

[0144] <Process S303> In process S303, the transport control unit 8b executes the pre-print upstream transport control for the pre-print switching unit 30x included in the upstream switching unit.

[0145] After executing the process in step S303, the transport control unit 8b terminates the upstream transport control.

[0146] [First modified example of downstream transport control] Next, the procedure for the first modified example of the downstream transport control will be described with reference to the flowchart shown in Figure 9. The processing in this modified example is performed in step S106 or step S108 of the jam response control.

[0147] In the following description, S401 to S403 represent identification codes for the three steps in the first modified example of the downstream transport control. In the first modified example of the downstream transport control, the processing of step S401 is performed first.

[0148] <Process S401> In process S401, the transport control unit 8b identifies a downstream start switching unit, which is one or more of the downstream switching units.

[0149] The downstream starting point switching section is one of the one or more downstream switching sections located at the uppermost position in the sheet transport direction.

[0150] Furthermore, the transport control unit 8b selects the following processing depending on whether the downstream switching unit includes the pre-print switching unit 30x or not.

[0151] If the downstream starting switching section includes a path that branches upstream of the print position P1 in the sheet transport direction, the downstream switching section includes a pre-print switching section 30x.

[0152] On the other hand, if the downstream starting point switching section includes a path that branches downstream of the print position P1 in the sheet transport direction, the downstream switching section does not include the pre-print switching section 30x.

[0153] The transport control unit 8b executes the process of step S402 when the downstream switching unit includes the pre-print switching unit 30x. On the other hand, the transport control unit 8b executes the process of step S403 when the downstream switching unit does not include the pre-print switching unit 30x.

[0154] Furthermore, the fact that the downstream switching unit includes the pre-print switching unit 30x means that the downstream switching unit includes both the pre-print switching unit 30x and the post-print switching unit 30y. On the other hand, the fact that the downstream switching unit does not include the pre-print switching unit 30x means that the downstream switching unit includes only the post-print switching unit 30y.

[0155] <Process S402> In process S402, the transport control unit 8b performs pre-print downstream transport control for the pre-print switching unit 30x included in the downstream switching unit, and performs post-print downstream transport control for the post-print switching unit 30y included in the downstream switching unit.

[0156] In the downstream transport control before printing, the transport control unit 8b causes the pre-print switching unit 30x, which is included in the downstream switching unit, to perform the emergency transport process. As a result, one or more sheets 9 present in the forward transport path 2a are collected in the sheet retrieval unit 30b of the pre-print switching unit 30x without being transported to the print position P1.

[0157] One or more sheets 9 present in the forward transport path 2a are collected in the sheet collection section 30b of the pre-print switching section 30x, thereby reducing the possibility of the sheets 9 becoming contaminated with the developer.

[0158] On the other hand, in the downstream transport control after printing, the transport control unit 8b causes the post-print switching unit 30y, which is included in the downstream switching unit, to execute the normal transport process.

[0159] After executing the process in step S402, the transport control unit 8b terminates the upstream transport control.

[0160] <Process S403> In process S403, the transport control unit 8b executes the post-print downstream transport control for the post-print switching unit 30y included in the downstream switching unit.

[0161] After executing the process in step S403, the transport control unit 8b terminates the downstream transport control.

[0162] [Second modified example of downstream transport control] Next, the procedure for the second modified example of the downstream transport control will be described. The processing in this modified example is performed in step S106 or step S108 of the jam response control.

[0163] In the downstream transport control according to the second modified example, the transport control unit 8b causes all of the downstream switching units to perform the normal transport process. When this modified example is adopted, one or more sheets 9 located in the downstream region of the standard transport path 2 are discharged together to one location from the exit of the standard transport path 2.

[0164] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0165] <Note 1> Standard transport paths that form the aisles for the sheets, A sheet supply device that sequentially supplies multiple sheets to the standard transport path, A sheet conveying device that conveys each of the plurality of sheets along the standard conveying path, A printing device that forms an image on each of the plurality of sheets at the printing position in the standard transport path, A jam detection device for detecting jams in each of the multiple detection areas in the standard transport path, The system includes a control device for controlling the sheet transport device, The sheet conveying device comprises a plurality of switching units, each having a plurality of branch paths branching off from a plurality of branching points in the standard conveying path, and a plurality of sheet retrieval units that retrieve sheets downstream of the plurality of branch paths. The aforementioned multiple switching units are A normal transport process in which each of the multiple sheets is transported along the standard transport path toward the exit of the standard transport path at each of the multiple branching locations, At each of the multiple branching locations, an emergency transport process can be selectively performed, in which each of the multiple sheets is transported from the standard transport path through each of the multiple branching paths to each of the multiple sheet retrieval units. When the jam is detected by the jam detection device, the control device performs upstream transport control for one or more upstream switching units which are part of the plurality of switching units, and downstream transport control for one or more downstream switching units which are other part of the plurality of switching units. The upstream switching unit has a path that branches off from the upstream region, which is the region upstream in the sheet transport direction from the jam region in the standard transport path where the jam is detected, The downstream switching unit has a path that branches off from the downstream region, which is the region downstream in the sheet conveying direction from the jam region in the standard conveying path, In the upstream transport control described above, the control device causes the upstream terminal switching unit located at the furthest downstream in the sheet transport direction among the upstream switching units to execute the emergency transport process, and further causes the normal transport process or the emergency transport process to be executed by the other upstream switching units besides the upstream terminal switching unit. In the downstream transport control described above, the control device causes the downstream switching unit to execute the normal transport process or the emergency transport process, in an image forming apparatus.

[0166] <Note 2> The aforementioned multiple switching units are One or more pre-print switching units having a path that branches off from a position upstream of the print position in the sheet transport direction, The image forming apparatus according to Appendix 1, comprising one or more post-print switching units having a path branched from a position downstream of the print position in the sheet transport direction.

[0167] <Note 3> The image forming apparatus according to Appendix 2, wherein the upstream switching unit includes the pre-print switching unit and the post-print switching unit, and the control device causes the pre-print switching unit included in the upstream switching unit to perform the emergency transport process.

[0168] <Note 4> The image forming apparatus according to Appendix 2 or Appendix 3, wherein the downstream switching unit includes the pre-print switching unit and the post-print switching unit, and the control device causes the pre-print switching unit included in the downstream switching unit to perform the emergency transport process.

[0169] <Note 5> A branching path sheet detection device for detecting sheets being transported along each of the aforementioned multiple branching paths, It comprises an information output device capable of outputting information, The image forming apparatus according to any one of the appendices 1 to 4, wherein the control device derives the number of sheets to be collected in each of the plurality of sheet collection units according to the detection result of the branch line sheet detection device when the upstream transport control and the downstream transport control are executed, and causes the information output device to output notification information including information representing the number of sheets to be collected.

[0170] <Note 6> The system includes a normal path sheet detection device that detects sheets being transported along the standard transport path, The image forming apparatus according to Appendix 5, wherein the control device derives the number of remaining sheets in the standard transport path after the upstream transport control and the downstream transport control are executed in accordance with the detection result of the normal path sheet detection device and the number of recovered sheets, and causes the information output device to output the notification information including information representing the number of remaining sheets. [Explanation of Symbols]

[0171] 1: Sheet supply device 2: Standard transport route 3: Sheet conveying device 3a: Normal path sheet detection device 3b: Branch road sheet detection device 4: Printing device 5: Sheet processing device 8: Control device 10: Image forming apparatus 30: Switching section 30a: Branch road 30b: Sheet collection section 30bx: Shared collection area 30c: Route switching mechanism 30d: Recovery Roller vs. 30x: Pre-print switching section 30y: Post-print switching section 32: First belt conveying device 33: Second belt conveying device P1: Print position PJ1: Branching point U1: Sheet supply unit U2: Print Unit U3: Sheet processing unit

Claims

1. Standard transport paths that form the aisles for the sheets, A sheet supply device that sequentially supplies multiple sheets to the standard transport path, A sheet conveying device that conveys each of the plurality of sheets along the standard conveying path, A printing device that forms an image on each of the plurality of sheets at the printing position in the standard transport path, A jam detection device for detecting jams in each of the multiple detection areas in the standard transport path, The system includes a control device for controlling the sheet transport device, The sheet conveying device comprises a plurality of switching units, each having a plurality of branch paths branching off from a plurality of branching points in the standard conveying path, and a plurality of sheet retrieval units that retrieve sheets downstream of the plurality of branch paths. The aforementioned multiple switching units are A normal transport process in which each of the multiple sheets is transported along the standard transport path toward the exit of the standard transport path at each of the multiple branching locations, At each of the multiple branching locations, an emergency transport process can be selectively performed, in which each of the multiple sheets is transported from the standard transport path through each of the multiple branching paths to each of the multiple sheet retrieval units. When the jam is detected by the jam detection device, the control device performs upstream transport control for one or more upstream switching units which are part of the plurality of switching units, and downstream transport control for one or more downstream switching units which are other part of the plurality of switching units. The upstream switching unit has a path that branches off from the upstream region, which is the region upstream in the sheet transport direction from the jam region in the standard transport path where the jam is detected, The downstream switching unit has a path that branches off from the downstream region, which is the region downstream in the sheet conveying direction from the jam region in the standard conveying path, In the upstream transport control described above, the control device causes the upstream terminal switching unit located at the furthest downstream in the sheet transport direction among the upstream switching units to execute the emergency transport process, and further causes the normal transport process or the emergency transport process to be executed by the other upstream switching units besides the upstream terminal switching unit. In the downstream transport control described above, the control device causes the downstream switching unit to execute the normal transport process or the emergency transport process, in an image forming apparatus.

2. The aforementioned multiple switching units are One or more pre-print switching units having a path that branches off from a position upstream of the print position in the sheet transport direction, The image forming apparatus according to claim 1, comprising one or more post-print switching units having a path branched from a position downstream of the print position in the sheet transport direction.

3. The image forming apparatus according to claim 2, wherein, when the upstream switching unit includes the pre-print switching unit and the post-print switching unit, the control device causes the pre-print switching unit included in the upstream switching unit to perform the emergency transport process.

4. The image forming apparatus according to claim 2 or 3, wherein, when the downstream switching unit includes the pre-print switching unit and the post-print switching unit, the control device causes the pre-print switching unit included in the downstream switching unit to perform the emergency transport process.

5. A branching path sheet detection device for detecting sheets being transported along each of the aforementioned multiple branching paths, It comprises an information output device capable of outputting information, The image forming apparatus according to claim 1 or 2, wherein the control device derives the number of sheets to be collected in each of the plurality of sheet collection units according to the detection result of the branching path sheet detection device when the upstream transport control and the downstream transport control are executed, and causes the information output device to output notification information including information representing the number of sheets to be collected.

6. The system includes a normal path sheet detection device that detects sheets being transported along the standard transport path, The image forming apparatus according to claim 5, wherein the control device derives the number of remaining sheets in the standard transport path after the upstream transport control and the downstream transport control are executed in accordance with the detection result of the normal transport path sheet detection device and the number of recovered sheets, and causes the information output device to output the notification information including information representing the number of remaining sheets.

Images