Sheet processing device

Abstract

To prevent a sheet which is not an object to be processed from being loaded on a preceding sheet, when a plurality of sheets are loaded and processed.SOLUTION: A sheet processing device includes processing means for sequentially receiving and loading each of a plurality of sheets, and processing the plurality of loaded sheets, and control means for controlling conveyance of the plurality of sheets, wherein when determining that a first sheet conveyed to the sheet processing device is not an object to be processed when the processing is performed by the processing means, but the first sheet must be conveyed to the processing means, the control means stops the conveyance of the first sheet on the upstream side by the processing means in the sheet conveyance direction.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a sheet processing apparatus for processing sheets. [Background technology]

[0002] 2. Description of the Related Art Image forming systems are currently in use, each of which includes an image forming apparatus that forms an image on a sheet, and a sheet processing apparatus that performs adhesive processing, stapling processing, etc. on a plurality of sheets on which the image has been formed by the image forming apparatus.

[0003] Patent Document 1 discloses a configuration for preventing the waste of sheets that can be used as deliverables among sheets that have already been conveyed into an image forming apparatus when a jam occurs. Specifically, Patent Document 1 discloses that, when a jam occurs, among sheets that are upstream of the jammed sheet and can be used as deliverables, they are discharged to a different destination. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-13430 Summary of the Invention [Problem to be solved by the invention]

[0005] Misprints can occur in image forming systems. For example, a misprint can occur when a sheet of a different size than the sheet to be used as the final product is mistakenly fed into the image forming device. Alternatively, a misprint can occur when a low-quality image is formed on a sheet due to poor sheet transport or the like.

[0006] When performing a process such as gluing on multiple sheets, the sheets to be processed are conveyed sequentially to a sheet processing apparatus and stacked as a sheet bundle within the sheet processing apparatus. The sheet processing apparatus then performs a predetermined process on the stacked sheet bundle. If a misprint occurs while stacking multiple sheets for processing, the misprinted sheet ends up being stacked on top of the preceding sheet bundle. Because the misprinted sheet is a sheet that should not be processed, the user must remove the misprinted sheet from the stacked sheets. However, in this case, there is a possibility that the user will remove a sheet other than the misprinted sheet. Furthermore, when processing a sheet bundle, a sheet bundle alignment process is usually performed, but there is a possibility that the alignment of the sheet bundle will be disrupted when the user removes the misprinted sheet.

[0007] Therefore, when a misprint occurs, it is desirable to dynamically change the discharge destination of the misprinted sheet so that the misprinted sheet is not stacked on top of the preceding sheet stack. However, depending on the timing at which the misprint is detected, it may already be impossible to change the discharge destination.

[0008] The present invention provides a technique for preventing a sheet that is not the target of processing from being stacked on top of a preceding sheet when multiple sheets are stacked and processed. [Means for solving the problem]

[0009] According to one aspect of the present invention, a sheet processing device includes a processing means that receives and stacks each of a plurality of sheets in sequence and processes the stacked sheets, and a control means that controls the transport of the plurality of sheets, and when the control means determines that a first sheet transported to the sheet processing device is not subject to the processing when the processing means performs the processing, but the first sheet must be transported toward the processing means, the control means stops the transport of the first sheet upstream of the processing means in the sheet transport direction. [Effects of the Invention]

[0010] According to the present invention, when a plurality of sheets are stacked and processed, it is possible to prevent a sheet that is not the target of the processing from being stacked on top of a preceding sheet. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a schematic configuration example of an image forming system according to some embodiments. [Figure 2] 10A-10C illustrate examples of adhesive images, according to some embodiments. [Figure 3] 1 is an illustration of a matching process, according to some embodiments. [Figure 4] 1 is an illustration of a bonding process, according to some embodiments. [Figure 5] FIG. 1 is a diagram showing an example of the hardware configuration of an image forming system according to some embodiments. [Figure 6] FIG. 1 is a functional block diagram of a finisher control unit according to some embodiments. [Figure 7] FIG. 10 is an illustration of a destination determination process according to some embodiments. [Figure 8] FIG. 10 is an illustration of a destination determination process according to some embodiments. [Figure 9] FIG. 10 is an illustration of a destination determination process according to some embodiments. [Figure 10] 10 is a flowchart of a process performed by a finisher control unit according to one embodiment. [Figure 11] 10A-10C illustrate example screens displayed for sheet removal, according to some embodiments. [Figure 12] 10 is a flowchart of a process performed by a finisher control unit according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0013] First Embodiment FIG. 1 shows a schematic configuration of an image forming system according to this embodiment. The image forming system includes an image forming apparatus 1 and a sheet processing apparatus 300. In the following description, the sheet processing apparatus 300 will be simply referred to as the "processing apparatus 300." The image forming apparatus 1 has four image forming units 7k, 7y, 7m, and 7c. The image forming units 7k, 7y, 7m, and 7c contain black, yellow, magenta, and cyan toner, respectively, and form black, yellow, magenta, and cyan toner images on the intermediate transfer belt 3. In this embodiment, black toner is also used as a powder adhesive in the adhesion process in the processing apparatus 300. In other words, if the image formed on the sheet for adhering the sheets is referred to as an adhesion image and the other images are referred to as user images, in this embodiment, black toner is used for both the adhesion image and the user image, and the other color toners are used only for the user image. Note that the toner used for the adhesion image may be a toner of a color other than black.

[0014] Image forming units 7k, 7y, 7m, and 7c have the same configuration except for the color of toner used. Therefore, the following description will focus on the configuration of image forming unit 7k. During image formation, photoconductor 73 rotates clockwise in the figure. Charging roller 71 charges the surface of photoconductor 73 to a uniform potential. Exposure unit 2 exposes photoconductor 73 to light to form an electrostatic latent image on photoconductor 73. Development unit 72 develops the electrostatic latent image formed on photoconductor 73 with toner to form a toner image on photoconductor 73. Primary transfer roller 74 outputs a primary transfer voltage to transfer the toner image on photoconductor 73 to intermediate transfer belt 3. By transferring the toner images formed on the photoconductors 73 of image forming units 7k, 7y, 7m, and 7c to the intermediate transfer belt 3 in a superimposed manner, different colors (black, yellow, magenta, and cyan) are reproduced.

[0015] The secondary transfer roller 5 outputs a secondary transfer voltage to transfer the toner image on the intermediate transfer belt 3 to the sheet S conveyed from the cassette 8 or the tray 20. The timing at which the registration roller 9 conveys the sheet S to the position opposite the secondary transfer roller 5 is determined based on the timing at which the registration sensor 37 detects the sheet S. The fixing unit 6 fixes the toner image to the sheet S by applying heat and pressure to the sheet S onto which the toner image has been transferred. When an image is formed on only one side (first side) of the sheet S, the sheet S onto which the toner image has been fixed is guided by a guide 33 to a conveying path provided with rollers 34. The rollers 34 then convey the sheet S to the processing device 300.

[0016] When forming images on both sides of the sheet S, the sheet S, on which the toner image has been fixed on its first side, is guided by a guide 33 to a conveying path provided with rollers 35. The rollers 35 reverse their rotation direction when the trailing edge of the sheet S reaches the rollers 35. Thus, the sheet S is conveyed again to a position facing the secondary transfer roller 5 via a double-sided conveying path 36, and the toner image is transferred onto its second side. The toner image formed on the second side of the sheet is fixed by a fixing unit 6. Thereafter, the sheet S is guided by a guide 33 to a conveying path provided with rollers 34, and is conveyed to the processing device 300.

[0017] The guide 22 of the processing device 300 is set to either a processing state or a non-processing state. In the processing state (first state), the guide 22 guides the sheet S to a conveying path provided with rollers 21. In the non-processing state (second state), the guide 22 guides the sheet S to a conveying path provided with rollers 23. The rollers 23 discharge and place the sheet S on the lower tray 303. The rollers 21 convey the sheet S downstream, and the rollers 29 convey the sheet S conveyed by the rollers 21 to the processing device 42. The processing device 42 receives and stacks the conveyed sheets in order, and performs alignment processing and bonding processing, which will be described later, on the stacked multiple sheets S. The processing device 42 discharges a booklet created by performing the alignment processing and bonding processing onto the upper tray 302 as a finished product.

[0018] An inlet sensor 27 that detects the sheet S is provided upstream of the guide 22 in the conveying direction of the sheet S. The inlet sensor 27 detects whether or not the sheet S is present at the detection position. In this embodiment, it is assumed that the state of the guide 22 needs to be changed before the inlet sensor 27 detects the leading edge of the sheet S. More specifically, when the guide 22 is set to the processing state, the guide 22 can be changed to the non-processing state and the sheet S can be discharged to the lower tray 303 until the leading edge of the sheet S is detected by the inlet sensor 27. On the other hand, when the guide 22 is set to the processing state, after the leading edge of the sheet S is detected by the inlet sensor 27, the sheet S must be conveyed toward the processing section 42. The same applies when the guide 22 is set to the non-processing state.

[0019] Furthermore, in the processing device 300, a pre-processing sensor 50 is provided between the roller 21 and the roller 29. Also, a door 24 for a user to remove the sheet S from the conveying path is provided on the housing of the processing device 300 facing a predetermined section of the conveying path between the roller 21 and the roller 29. Note that a door sensor 25 detects whether the door 24 is open or closed.

[0020] 2(A) and 2(B) show examples of adhesive images Tk. As shown in Fig. 2(A), by forming the adhesive image Tk on the edge of the long side of the sheet S, a long-length booklet can be produced by the adhesive process by the processing device 300. Also, as shown in Fig. 2(B), by forming the adhesive image Tk on a part of the edge of the long side of the sheet S, a corner-stitched booklet can be produced by the adhesive process by the processing device 300.

[0021] FIG. 3 is an explanatory diagram of the alignment process by the processing section 42. As shown in FIG. 3(A), the roller 29 transports the sheet S to the processing section 42. As shown in FIG. 3(B), the half-moon roller 40 performs vertical alignment by pushing the sheet S transported to the processing section 42 toward the vertical alignment reference plate 39. The conveying pressure of the half-moon roller 40 is adjusted so that the sheet S slips after it contacts the vertical alignment reference plate 39. As shown in FIG. 3(C), after the vertical alignment process is completed, the horizontal alignment jogger 41 moves the sheet S until it hits the horizontal alignment reference plate 500 (dotted line), thereby performing horizontal alignment. FIG. 3(D) shows the state after the alignment process is completed.

[0022] A plurality of sheets to be bonded are transported in order and stacked in the processing section 42. The alignment process is performed each time a sheet S is transported to the processing section 42. Furthermore, each time a predetermined number of sheets S are added to the processing section 42, the processing section 42 performs a bonding process (described later) using a thermocompression bonding unit 51. In the following description, the predetermined number is assumed to be five sheets, as an example. Therefore, when 15 sheets S are bonded together to form one booklet, the bonding process is performed three times to create one booklet. Furthermore, when 18 sheets S are bonded together to form one booklet, the bonding process is performed four times to create one booklet.

[0023] 4(A) and 4(B) are views of the processing unit 42 viewed in the direction in which the sheet S is conveyed by the rollers 29. A ceramic heater 501 incorporating a heating element is supported by a resin heater support 503 and heats an aluminum heating plate 502. The temperature of the ceramic heater 501 is controlled based on a temperature detected by a temperature sensor (not shown). The heating plate 502 also has a pressure unit A. A pressure lever 504 presses the heater support 503, the ceramic heater 501, and the heating plate 502 downward in FIG. 4, i.e., toward the direction in which the sheets S are stacked, via a rigid metal stay 505. As a result, the sheets S stacked in the processing unit 42 are heated and pressurized by the heating plate 502. A pressure plate 506 is provided on the opposite side of the sheet S from the heating plate 502 to receive the pressure from the heating plate 502. The pressure plate 506 is made of, for example, silicone rubber.

[0024] FIG. 4(A) shows a state in which five sheets S1-1 to S1-5 are stacked in the processing unit 42. As shown in FIG. 4(A), an adhesive image Tk is formed in an area that is heated and pressed by the heating plate 502. In the state shown in FIG. 4(A), the adhesive image Tk is melted and an adhesive process is performed by heating and pressing the five sheets S with the heating plate 502. FIG. 4(B) shows a state in which five new sheets S2-1 to S2-5 are stacked on top of the sheets S1-1 to S1-5 that have been subjected to the adhesive process. In the state shown in FIG. 4(B), the stacked sheets S are heated and pressed by the heating plate 502, and ten sheets S are adhered together.

[0025] 5 shows an example of a schematic hardware configuration of an image forming system. The image forming apparatus 1 has a printer control unit 100, and the processing device 300 has a finisher control unit 400. The printer control unit 100 and the finisher control unit 400 are connected to each other and cooperate to control the operation of the image forming system.

[0026] The printer control unit 100 has a central processing unit (CPU) 101 and a memory 102. The CPU 101 reads and executes programs stored in the memory 102 to perform overall control of the image forming apparatus 1. For example, the CPU 101 causes the printer unit 1e to perform an image formation operation. The printer unit 1e is a collective term for the components of the image forming apparatus 1 shown in FIG. 1. The memory 102 includes a non-volatile storage medium such as a read-only memory (ROM) and a volatile storage medium such as a random access memory (RAM), and serves as a storage location for programs and data as well as a workspace for the CPU 101 to execute the programs. The memory 102 is an example of a non-transitory computer-readable storage medium that stores programs for controlling the image forming apparatus.

[0027] The printer control unit 100 is connected to external devices such as a personal computer or a portable information device via an external interface (I / F) 104, and receives commands to execute a print job for the image forming system. The printer control unit 100 is also connected to an operation display unit 103, which is a user interface for the image forming system. The operation display unit 103 includes a display device such as a liquid crystal panel that presents information to the user, and an input device such as physical buttons and a touch panel function unit of the liquid crystal panel that accepts input operations by the user. The printer control unit 100 controls the display content of the display device and receives information input via the input device by communicating with the operation display unit 103.

[0028] The finisher control unit 400 has a central processing unit (CPU) 401, a memory 402, and an I / O port 403. The CPU 401 reads and executes programs stored in the memory 402 to control the processing device 300. The memory 402 includes a non-volatile storage medium such as a read-only memory (ROM) and a volatile storage medium such as a random access memory (RAM), and serves as a storage location for programs and data and as a workspace for the CPU 401 to execute the programs. The memory 402 is an example of a non-transitory computer-readable storage medium that stores programs for controlling the processing device 300. The CPU 401 and memory 402 are connected to the I / O port 403 via a bus 404, and the I / O port 403 inputs and outputs control signals to and from various components of the processing device 300.

[0029] The functions of the printer control unit 100 and the finisher control unit 400 may be implemented in hardware using an application-specific integrated circuit (ASIC) or the like. Alternatively, the functions of the printer control unit 100 and the finisher control unit 400 may be implemented in software, such as by a program executed by one or more processors. Alternatively, the functions of the printer control unit 100 and the finisher control unit 400 may be implemented by a combination of hardware and software. Furthermore, the printer control unit 100 may be configured to perform some or all of the functions of the finisher control unit 400 described below.

[0030] The I / O port 403 is connected to motors M1 to M6, the entrance sensor 27, the pre-processing sensor 50, the door sensor 25, the ceramic heater 501, and the solenoid 221. The motors M1 to M6 are drive sources for the rollers 21, 23, 29, the half-moon roller 40, the lateral alignment jogger 41, and the pressure lever 504, and the solenoid 221 is a drive source for the guide 22.

[0031] FIG. 6 shows functional blocks realized by the CPU 401 of the finisher control unit 400 executing a program stored in the memory 402. Note that FIG. 6 shows only functional blocks necessary for explaining the embodiment, and omits functional blocks not necessary for explaining the embodiment. The transport control unit 421 controls the transport of the sheet S, i.e., performs the transport process of the sheet S. The transport process of the sheet S includes a process of switching the destination of the sheet S by driving the guide 22 via the solenoid 221. The removal sheet determination unit 422 determines the sheet to be removed, which will be described later. The destination determination unit 423 determines the destination of the sheet to be removed. The notification unit 424 performs a process of presenting an instruction to the user to remove the sheet S whose transport has been stopped inside the processing device 300. The sheet length detection unit 425 detects the sheet length, which is the length of the sheet S in the transport direction. The information receiving unit 426 receives misprint information, which will be described later, from the image forming apparatus 1.

[0032] Next, misprints will be described. A misprint refers to an image formation defect that occurs when the size of the sheet S fed to the image forming apparatus 1 is different from the size of the sheet S on which an image is to be formed, or when the timing of conveying the sheet S is off. The printer control unit 100 of the image forming apparatus 1 can detect the sheet length using the registration sensor 37. The printer control unit 100 detects the occurrence of a misprint when the size of the fed sheet S is not within the allowable range for the size specified in the print job. When the printer control unit 100 detects the occurrence of a misprint, it notifies the information receiving unit 426 of misprint information indicating the occurrence of the misprint and the sheet S on which the misprint occurred. In this embodiment, the misprinted sheet S is referred to as a removal target sheet M. Therefore, in this embodiment, the removal sheet determination unit 422 determines the removal target sheet M based on the misprint information.

[0033] The destination determination unit 423 determines the destination of the removal target sheet M. The process performed by the destination determination unit 423 will be described below with reference to FIGS. 7 to 9. FIG. 7A shows an example of the state at the time when the information receiving unit 426 receives misprint information. According to FIG. 7A, multiple sheets S on which images were formed before the removal target sheet M are stacked as a sheet bundle S' in the processing unit 42. The leading edge of the removal target sheet M has not yet reached the detection position of the inlet sensor 27. In the case of FIG. 7A, the state of the guide 22 can be changed from the processing state to the non-processing state, and the removal target sheet M can be conveyed to the lower tray 303. Therefore, if the inlet sensor 27 has not detected the leading edge of the removal target sheet M at the time when the misprint is notified, the destination determination unit 423 determines that the removal target sheet M should be discharged to the lower tray 303. This prevents the removal target sheet M, which is not the target of processing in the processing unit 42, from being stacked on top of the sheet bundle S', as shown in FIG. 7B. Therefore, after printing is resumed, the sheets S to be processed in the processing section 42 are stacked in order on the sheet stack S' to form a booklet.

[0034] The state shown in Figure 7 can occur, for example, when an A4-sized sheet (sheet length: 297 mm) is to be processed, and an A5-sized sheet (sheet length: 210 mm), which is shorter than the sheet to be processed, is mistakenly fed to the image forming device 1.

[0035] FIG. 8A shows another example of the state at the timing when the information receiving unit 426 receives the misprint information. According to FIG. 8A, multiple sheets S on which images were formed before the removal target sheet M are stacked as a sheet bundle S' in the processing unit 42. The leading edge of the removal target sheet M has already reached the detection position of the entrance sensor 27. In the case of FIG. 8A, the removal target sheet M cannot be conveyed to the lower tray 303. In this case, the conveyance destination determination unit 423 conveys the removal target sheet M toward the processing unit 42, but determines that the conveyance of the removal target sheet M should be stopped at a predetermined removal position. FIG. 8B shows a state in which the conveyance of the removal target sheet M is stopped at the removal position. The removal position is a position within a predetermined range where the user can remove the removal target sheet M from the inside of the processing device 300 by opening the door 24. This prevents the removal target sheet M from being stacked on top of the sheet bundle S', as shown in FIG. 8B. Therefore, after printing is resumed, the sheets S to be processed in the processing section 42 are stacked in order on the sheet stack S' to form a booklet.

[0036] The state shown in Figure 8 can occur, for example, when an A4-size (sheet length: 297 mm) sheet is to be processed, and a legal-size (sheet length: 355.6 mm) sheet, which is longer than the sheet to be processed, is mistakenly fed to the image forming device 1.

[0037] FIG. 9A shows yet another example of the state at the timing when the information receiving unit 426 receives the misprint information. The difference from the example of FIG. 8A is that there is no sheet S on which an image has been formed before the removal target sheet M, and therefore no sheet bundle S' is stacked in the processing unit 42. In the case of FIG. 9A, since there is no preceding sheet bundle S', the removal target sheet M can be conveyed directly to the processing unit 42. Therefore, if there is no preceding sheet bundle S', the conveyance destination determination unit 423 determines whether to convey the removal target sheet M to the processing unit 42 or to discharge it to the upper tray 302 via the processing unit 42. Note that if there is no preceding sheet bundle S', the removal target sheet M can also be conveyed to the processing unit 42 instead of the lower tray 303, even if the inlet sensor 27 has not detected the leading edge of the sheet S when the information receiving unit 426 receives the misprint information.

[0038] FIG. 10 is a flowchart of the process performed by the finisher control unit 400. In S10, the finisher control unit 400 waits until the information receiving unit 426 receives print information from the printer control unit 100. When the information receiving unit 426 receives the print information from the printer control unit 100, the removal sheet determination unit 422 determines the removal target sheet M based on the print information. In S11, the conveyance destination determination unit 423 determines whether a preceding sheet stack S' is present in the processing unit 42. If no sheet stack S' is present, the conveyance destination determination unit 423 determines that the removal target sheet M should be conveyed to the upper tray 302 via the processing unit 42. In this case, in S16, the conveyance control unit 421 conveys the removal target sheet M to the upper tray 302 via the processing unit 42. Note that if the user can remove sheets stacked in the processing unit 42, the removal target sheet M may be conveyed to the processing unit 42 instead of the upper tray 302.

[0039] If a sheet stack S' is present, the transport destination determination unit 423 determines in S12 whether the removal target sheet M can be discharged to the lower tray 303. As described above, in this embodiment, if the entrance sensor 27 does not detect the leading edge of the removal target sheet M, the transport destination determination unit 423 determines that the removal target sheet M can be discharged to the lower tray 303. In this case, the transport control unit 421 changes the state of the guide 22 in S13 to discharge the removal target sheet M to the lower tray 303.

[0040] On the other hand, if the removal target sheet M cannot be discharged to the lower tray 303, the transport destination determination unit 423 transports the removal target sheet M toward the transport unit 42, but determines that the transport should stop at the removal position. In this case, in S14, the transport control unit 421 controls the transport of the removal target sheet M so that the removal target sheet M stops at the removal position. In addition, in S15, the notification unit 424 causes the printer control unit 100 to remove the removal target sheet M and to perform processing to notify the user of the procedure.

[0041] FIG. 11 shows an example of a procedure for removing the sheet M to be removed, which is displayed on the operation display unit 103. FIG. 11(A) shows that the door 24 is opened. FIG. 11(B) shows that the sheet M to be removed is removed, which is displayed after the door sensor 25 detects that the door 24 has been opened. The black circle in FIGS. 11(A) and 11(B) indicates the approximate position of the sheet M to be removed. FIG. 11(C) shows that the door 24 is closed after the sheet M to be removed. When the door sensor 25 detects that the door 24 has been closed, the notification unit 424 ends the notification process of S15.

[0042] As described above, according to this embodiment, when a removal target sheet M is conveyed to the processing device 300 while the guide 22 is set to a processing state for processing in the processing section 42, the processing device 300 controls the processing device 300 so that the removal target sheet M is not stacked on top of any sheets already stacked in the processing section 42. Specifically, the processing device 300 is configured to allow removal of the sheet S upstream of the processing section 42. When the removal target sheet M must be conveyed toward the processing section 42, the conveyance of the removal target sheet M is stopped at a position upstream of the processing section 42 where the sheet S can be removed. Note that if the removal target sheet M can be guided to a destination other than the processing section 42 when it is determined that the removal target sheet M is a removal target sheet, the removal target sheet M can be discharged to the destination. This configuration eliminates the need for the user to remove sheets that are not to be processed from the multiple sheets stacked in the processing section 42. This prevents the user from removing the wrong sheet or from disturbing the alignment of the multiple sheets stacked in the processing section 42. Note that the processing device 300 of this embodiment is configured so that the guide 22 allows the sheet S to be discharged without passing through the processing section 42. However, the present invention can also be applied to a processing apparatus 300 in which all of the conveyed sheets S must be conveyed toward the processing section 42.

[0043] 10, if there is no sheet bundle S' in S11, the removal target sheet M is discharged to the upper tray 302 even if it can be discharged to the lower tray 303. However, if the removal target sheet M can be discharged to the lower tray 303, it is possible to configure the removal target sheet M to be discharged to the lower tray 303 even if there is no preceding sheet bundle S' in the processing section 42. Furthermore, in the flowchart of FIG. 10, the transport of the removal target sheet M is stopped at the removal position only if the removal target sheet M cannot be discharged to the lower tray 303 and there is a preceding sheet bundle S' in the processing section 42. However, if the removal target sheet M cannot be discharged to the lower tray 303, it is possible to configure the transport of the removal target sheet M to be stopped at the removal position even if there is no preceding sheet bundle S' in the processing section 42.

[0044] Furthermore, in this embodiment, the removal target sheet M is a sheet whose sheet length is different from the sheet length of the sheet on which an image is to be formed. However, if a defect occurs in the sheet transport control, the quality of the image formed on the sheet may be reduced, so such a sheet can also be designated as the removal target sheet M. Note that a defect in the sheet transport control can be determined based on the timing at which a sensor (not shown) installed along the transport path of the image forming system detects the sheet. In other words, the removal target sheet M in this embodiment can be a sheet that is determined not to be used for processing in the processing unit 42 based on a predetermined criterion.

[0045] In addition, in this embodiment, the processing section 42 performs alignment processing and adhesive processing, but instead of adhesive processing, it may perform stapling or punching. More generally, this embodiment is applicable to a processing apparatus that stacks multiple sheets in order and includes a processing section 42 that performs some kind of processing on the stacked sheets.

[0046] Second Embodiment Next, the second embodiment will be described, focusing on the differences from the first embodiment. In the first embodiment, the image forming apparatus 1 detects the occurrence of a misprint, and the processing device 300 detects the occurrence of a misprint by receiving misprint information. In this embodiment, the sheet length detection unit 425 detects the misprint. The sheet length detection unit 425 detects the sheet length of the sheet S based on the time during which the inlet sensor 27 detects the sheet S and the conveying speed of the sheet S.

[0047] For example, the image forming apparatus 1 may be configured to determine a misprint if the difference between the measured sheet length and the sheet length of the sheet on which the image is to be formed exceeds 10 mm. In other words, the image forming apparatus 1 may be configured to tolerate a difference of up to 10 mm. On the other hand, the processing apparatus 300 may be configured to tolerate a difference of up to 5 mm to maintain the accuracy of the booklet to be produced. When the image forming system is configured in this manner, it is possible that only the processing apparatus 300 may detect a misprint. As an example, if the sheet on which the image is to be formed is A4 size (sheet length: 297 mm) and a sheet with a sheet length of 305 mm is fed, the image forming apparatus 1 will not detect the misprint, but the processing apparatus 300 will.

[0048] FIG. 12 is a flowchart of processing performed by the finisher control unit 400 in this embodiment. Note that processing steps similar to those in the flowchart of the first embodiment shown in FIG. 10 are assigned the same step numbers, and their description will be omitted. In S20, the finisher control unit 400 waits until the sheet length detection unit 425 detects a misprint. The sheet length detection unit 425 detects a misprint when it detects that the detected print length of the sheet S exceeds the allowable range, even if detection of the print length of the sheet S has not been completed. For example, if the sheet length of the target sheet to be processed in the processing unit 42 is 297 mm and the allowable range is ±5 mm, the sheet length detection unit 425 detects a misprint when the detected sheet length of the sheet S exceeds 302 mm, even if detection of the print length of the sheet S has not been completed.

[0049] In this embodiment, at the timing when the misprint is detected, the leading edge of the removal target sheet M has reached the detection position of the inlet sensor 27. Therefore, in this embodiment, the removal target sheet M cannot be discharged to the lower tray 303, and therefore S12 and S13 in Fig. 10 are omitted from the flowchart. That is, if there is no sheet stack S' in S11, the removal target sheet M is conveyed to the upper tray 302 via the processing unit 42. On the other hand, if there is a sheet stack S' in S11, the removal target sheet M is conveyed to the removal position in S14, and a notification process is performed in S15 to remove the removal target sheet M.

[0050] As described above, according to this embodiment, even if a sheet that is not a target for processing occurs when processing is performed in the processing section 42, it is possible to prevent the sheet from being stacked on top of another target sheet that is already transported to the processing section 42. Note that this embodiment can be combined with the first embodiment.

[0051] [Other embodiments] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0052] The disclosure of this embodiment includes the following configuration. (Configuration 1) A sheet processing apparatus, a processing unit that sequentially receives and stacks each of the plurality of sheets and processes the stacked sheets; a control unit for controlling the conveyance of the plurality of sheets; Equipped with The control means, when performing the processing by the processing means, determines that a first sheet transported to the sheet processing device is not subject to the processing, but the first sheet must be transported toward the processing means, stops the transport of the first sheet upstream of the processing means in the sheet transport direction. (Configuration 2) The sheet processing apparatus according to configuration 1, wherein the control means transports the first sheet to the processing means when the first sheet must be transported toward the processing means but a sheet preceding the first sheet is not loaded on the processing means. (Configuration 3) a tray on which sheets are placed; a guide that, in a first state, conveys the sheet conveyed to the sheet processing apparatus toward the processing means, and, in a second state, conveys the sheet conveyed to the sheet processing apparatus toward the tray; Furthermore, The sheet processing apparatus of configuration 1 or 2, wherein the control means determines that the first sheet must be transported toward the processing means if the state of the guide cannot be changed to the second state and the first sheet cannot be transported to the tray from the time when it is determined that the first sheet is not the target of the processing. (Configuration 4) 4. The sheet processing apparatus according to configuration 3, wherein the control unit, when it is possible to change the state of the guide based on the timing and transport the first sheet to the tray, changes the state of the guide and transports the first sheet to the tray. (Configuration 5) The sheet processing device according to configuration 4, wherein the control means, when a sheet preceding the first sheet is not loaded on the processing means, changes the state of the guide from the timing and transports the first sheet to the processing means regardless of whether the first sheet can be transported to the tray. (Configuration 6) a sensor for detecting the sheet upstream of the guide in the conveying direction; The sheet processing device of any one of configurations 3 to 5, wherein the control means, if the sensor has already detected the first sheet at the timing, changes the state of the guide and determines that the first sheet cannot be transported to the tray. (Configuration 7) the sheet processing device is configured so that a user can remove sheets that are in a predetermined range upstream of the processing means, 7. The sheet processing apparatus according to any one of configurations 1 to 6, wherein the control unit stops the transport of the first sheet in the predetermined range when the transport of the first sheet is stopped upstream of the processing unit. (Configuration 8) 8. The sheet processing apparatus according to configuration 7, wherein the housing of the sheet processing apparatus is provided with a door that allows a user to remove sheets that are in the predetermined range. (Configuration 9) 9. The sheet processing apparatus according to any one of configurations 1 to 8, wherein the control means, when stopping the transport of the first sheet upstream of the processing means, presents a procedure for removing the first sheet to a user. (Configuration 10) The sheet processing apparatus receives the sheet from an image forming apparatus that forms an image on the sheet, 10. The sheet processing apparatus according to any one of configurations 1 to 9, wherein the control unit determines whether a sheet conveyed from the image forming apparatus is a target for the processing based on information about the sheet received from the image forming apparatus. (Configuration 11) 10. The sheet processing apparatus according to any one of configurations 1 to 9, wherein the control unit determines whether or not the sheet is a target for the processing by measuring the size of the sheet.

[0053] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0054] 42: Processing section, 400: Finisher control section

Claims

1. A sheet processing apparatus, a processing unit that sequentially receives and stacks each of the plurality of sheets and processes the stacked sheets; a control unit for controlling the conveyance of the plurality of sheets; Equipped with The control means, when performing the processing by the processing means, determines that a first sheet transported to the sheet processing device is not subject to the processing, but the first sheet must be transported toward the processing means, stops the transport of the first sheet upstream of the processing means in the sheet transport direction.

2. 2. The sheet processing apparatus according to claim 1, wherein the control means transports the first sheet to the processing means when the first sheet must be transported toward the processing means but a sheet preceding the first sheet is not loaded on the processing means.

3. a tray on which sheets are placed; a guide that, in a first state, conveys the sheet conveyed to the sheet processing apparatus toward the processing means, and, in a second state, conveys the sheet conveyed to the sheet processing apparatus toward the tray; Furthermore, 2. The sheet processing apparatus according to claim 1, wherein the control means determines that the first sheet must be transported toward the processing means if the state of the guide cannot be changed to the second state and the first sheet cannot be transported to the tray from the time when it is determined that the first sheet is not the target of the processing.

4. The sheet processing apparatus according to claim 3 , wherein the control unit, when it is possible to change the state of the guide based on the timing and transport the first sheet to the tray, changes the state of the guide and transports the first sheet to the tray.

5. 5. The sheet processing apparatus according to claim 4, wherein the control means, when there is no sheet preceding the first sheet loaded on the processing means, changes the state of the guide from the timing to transport the first sheet to the processing means regardless of whether the first sheet can be transported to the tray.

6. a sensor for detecting the sheet upstream of the guide in the conveying direction; 4. The sheet processing apparatus according to claim 3, wherein the control unit determines that the first sheet cannot be conveyed to the tray by changing the state of the guide when the sensor has already detected the first sheet at the timing.

7. the sheet processing device is configured so that a user can remove sheets that are in a predetermined range upstream of the processing means, The sheet processing apparatus according to claim 1 , wherein the control unit stops the transport of the first sheet in the predetermined range when the control unit stops the transport of the first sheet upstream of the processing unit.

8. The sheet processing apparatus according to claim 7 , wherein a door is provided in the housing of the sheet processing apparatus to allow a user to remove the sheet in the predetermined range.

9. The sheet processing apparatus according to claim 1 , wherein the control unit, when stopping the conveyance of the first sheet upstream of the processing unit, presents a procedure for removing the first sheet to a user.

10. The sheet processing apparatus receives the sheet from an image forming apparatus that forms an image on the sheet, The sheet processing apparatus according to claim 1 , wherein the control unit determines whether a sheet conveyed from the image forming apparatus is a target of the processing based on information about the sheet received from the image forming apparatus.

11. The sheet processing apparatus according to claim 1 , wherein the control unit determines whether the sheet is a target of the processing by measuring a size of the sheet.

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