Sheet processing apparatus and image forming system

Abstract

To appropriately perform processing on a sheet bundle without setting an upper limit number of sheets of the sheet bundle in advance.SOLUTION: A sheet processing apparatus includes a conveyance unit configured to convey a sheet to a stacking tray, a bonding unit configured to perform a bonding process of bonding a plurality of stacked sheets stacked on the stacking tray to each other by a bonding image formed on the plurality of stacked sheets, and a control unit configured to control the bonding process by the bonding unit to create a sheet bundle including a designated number of sheets designated by a job.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a sheet processing apparatus that bonds sheets together with toner, and an image forming system that includes the sheet processing apparatus. [Background technology]

[0002] Patent Document 1 discloses an image forming system in which sheets on which adhesive images are formed are stacked and heated and pressurized to bond the sheets together. In Patent Document 1, toner is used as the adhesive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-209859 Summary of the Invention [Problem to be solved by the invention]

[0004] The multiple sheets adhered together by the adhesive process are discharged from the image forming system as a sheet bundle. If the sheet bundle becomes too thick, a jam may occur when the sheet bundle is discharged. To prevent a jam, a configuration may be adopted in which an upper limit is set on the number of sheets that can be included in the sheet bundle. This upper limit may be set, for example, based on the maximum thickness of sheets that can be used in the image forming system. Therefore, when forming a sheet bundle using thin sheets, this upper limit will be smaller than the number of sheets that can actually be included in the sheet bundle without causing a jam.

[0005] The present disclosure provides a technique for appropriately processing a sheet bundle without setting an upper limit on the number of sheets in the sheet bundle in advance. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a sheet processing apparatus includes: a conveying unit that conveys a sheet to a stacking table; The device includes an adhesive means that performs an adhesive process to adhere multiple stacked sheets loaded on the loading tray to each other using adhesive images formed on the multiple stacked sheets, and a control means that controls the adhesive process by the adhesive means to create a sheet bundle of a specified number of sheets specified in a job, and the control means does not perform the adhesive process on the multiple stacked sheets if the thickness of the multiple stacked sheets exceeds a first threshold value. [Effects of the Invention]

[0007] According to the present disclosure, processing of a sheet bundle can be performed appropriately without setting an upper limit on the number of sheets in the sheet bundle in advance. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view of an imaging system, according to some embodiments. [Figure 2] 1 is a schematic cross-sectional view of a bonding device, according to some embodiments. [Figure 3] FIG. [Figure 4] FIG. 10 is a diagram showing an example of an adhesion image. [Figure 5] FIG. 1 is a diagram showing a schematic hardware configuration of an image forming system according to some embodiments. [Figure 6] FIG. 2 is a functional block diagram of a main controller, according to some embodiments. [Figure 7] FIG. 10 is an explanatory diagram of a limit on the thickness of a sheet bundle. [Figure 8] 10 is a flowchart of a process for creating a sheet bundle according to one embodiment. [Figure 9] 10 is a flowchart of a process for creating a sheet bundle according to one embodiment. [Figure 10] 10 is a flowchart of a process for creating a sheet bundle according to one embodiment. [Figure 11] 10 is a flowchart of a process for creating a sheet bundle according to one embodiment. [Figure 12]10A and 10B are diagrams illustrating jamming caused by curling of a sheet stack. [Figure 13] 10A and 10B are diagrams showing examples of the relationship between sheet types and sizes and adjustment values. [Figure 14] 10 is a flowchart of a process for creating a sheet bundle according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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.

[0010] First Embodiment FIG. 1 is a cross-sectional view showing 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 4. The image forming apparatus 1 has an image forming cartridge 8 equipped with a photosensitive member 9. An exposure device 15 exposes the charged photosensitive member 9 to light to form an electrostatic latent image on the photosensitive member 9. The image forming cartridge 8 develops the electrostatic latent image on the photosensitive member 9 with toner to form a toner image on the photosensitive member 9. A transfer roller 10 transfers the image formed on the photosensitive member 9 to a sheet conveyed from a cassette 6. A fixing unit 11 fixes the image transferred to the sheet by applying heat and pressure to the sheet.

[0011] When an image is formed on only one side of the sheet, the sheet that has passed through the fixing unit 11 is conveyed to the horizontal conveying path 14. When images are formed on both sides of the sheet, the sheet that has passed through the fixing unit 11 is conveyed toward the reversing conveying path 12. The flapper 53 is a guide member that guides the sheet to the horizontal conveying path 14 or the reversing conveying path 12. The sheet conveyed toward the reversing conveying path 12 is then conveyed toward the double-sided conveying path 16 by reversing the rotation direction of the reversing roller 54. The sheet conveyed toward the double-sided conveying path 16 is conveyed again to a position facing the transfer roller 10, where the image is transferred to the other side of the sheet. After the image transferred to the other side of the sheet is fixed by the fixing unit 11, the sheet is conveyed to the horizontal conveying path 14.

[0012] In this embodiment, toner is used as an adhesive in the adhesion process in the sheet processing device 4. In the following description, of the images formed on the photoreceptor 9 and the sheet, an image formed as an adhesive in the adhesion process in the sheet processing device 4 will be referred to as an adhesion image, and other images will be referred to as user images. The adhesion image is formed within an adhesion area determined by the configuration of an adhesion device 167 of the sheet processing device 4, which will be described later.

[0013] Furthermore, the image forming apparatus 1 of this embodiment is a monochrome image forming apparatus that forms monochrome images using a single color toner, such as black, and therefore uses black toner for both the user image and the adhesive image. However, the image forming apparatus 1 may also be a color image forming apparatus that forms color images using multiple colors of toner, such as yellow, cyan, magenta, and black. In this case, a configuration may be adopted in which each of the multiple colors of toner is used to form the user image, and one or more of the multiple colors of toner is used to form the adhesive image. Furthermore, a configuration may be adopted in which one of the multiple toners is used only to form the adhesive image, and the remaining toners are used only to form the user image. The toner used only to form the adhesive image may be transparent.

[0014] The sheet transported to the horizontal transport path 14 is transported to the sheet processing device 4. The sheet transported to the sheet processing device 4 is transported toward the reversing transport path 17 by transport rollers 21 and 22. When the sheet is not to be subjected to adhesive processing, the sheet transported to the reversing transport path 17 is discharged onto the upper tray 25 by the discharge rollers 24. When the sheet is to be subjected to adhesive processing, the sheet transported to the reversing transport path 17 is transported toward the processing transport path 18 by the reverse rotation of the discharge rollers 24. The sheet transported to the processing transport path 18 is transported to the stacking table 39 and stacked.

[0015] The bonding device 167 having the bonding unit 61 aligns and bonds a plurality of sheets stacked on the stacking table 39. The sheet bundle formed by the bonding process is pushed by the bundle discharge guide 34 between the upper guide 63 and the lower guide 64 toward the discharge roller pair 36. The bundle discharge guide 34 is driven by the guide drive unit 35. The discharge roller pair 36 discharges the sheet bundle onto the lower tray 37.

[0016] The sheet processing device 4 may be configured to transport and stack sheets one by one onto the stacking tray 39. Alternatively, the sheet processing device 4 may be configured to stack multiple sheets upstream of the stacking tray 39 by a buffer process described below, and then transport and stack the multiple stacked sheets together onto the stacking tray 39. Furthermore, the sheet processing device 4 may be configured to be selectively settable between an operation mode in which buffering process is performed and an operation mode in which buffering process is not performed.

[0017] For example, when performing buffer processing, the rotation of the conveying rollers 26 is stopped to stop the conveyance of the first sheet in the processing conveying path 18. Then, in synchronization with the timing at which the second sheet following the first sheet is conveyed to the reversing conveying path 17, the conveying rollers 26 also convey the first sheet to the reversing conveying path 17. As a result, the first sheet and the second sheet are superimposed on each other in the reversing conveying path 17. The superimposed first and second sheets are conveyed by the discharge rollers 24 toward the processing conveying path 18. When three or more sheets are superimposed, the above process is repeated. When a predetermined number of sheets have been superimposed, the predetermined number of superimposed sheets are conveyed to the stacking tray 39.

[0018] FIG. 2 is a schematic diagram of the bonding device 167. The bonding unit 61 is configured to be movable toward and away from the loading platform 39. In the following description, the movement direction of the bonding unit 61 is defined as the Z direction as shown in FIG. 2. The conveyance direction of the sheet or sheet stack in the vicinity of the bonding device 167 is defined as the Y direction. In this embodiment, the Z direction is a direction perpendicular to the Y direction. Furthermore, the direction perpendicular to both the Z direction and the Y direction is defined as the X direction. The Z direction, Y direction, and X direction are also referred to as the height direction, length direction, and width direction, respectively.

[0019] The motor 177 rotates the pinion gear 179. The rack gear 175, which meshes with the pinion gear 179, moves in the Z direction as the pinion gear 179 rotates. The adhesive unit 61 is configured to move in the Z direction in conjunction with the movement of the rack gear 175. The home position (HP) sensor 62 detects whether the adhesive unit 61 is at a predetermined position in the Z direction. In the following description, this predetermined position will be referred to as the "home position." The home position is also the standby position of the adhesive unit 61. The receiving plate 180 is made of an elastic material such as silicone rubber. The adhesive unit 61 is configured to be movable in the -Z direction to a position where it contacts the receiving plate 180.

[0020] The bonding device 167 performs alignment and bonding processes on sheets stacked on the stacking tray 39. The alignment process is a process of aligning the positions of the sheets stacked on the stacking tray 39 in the X and Y directions. The bonding process is a process of bonding the sheets stacked on the stacking tray 39 together using a bonding image formed in the bonding area by heating and pressurizing the bonding area of ​​the sheets stacked on the stacking tray 39 with the bonding unit 61. The bonding device 167 performs the bonding process one or more times to form a sheet bundle of a specified number of sheets specified in a print job. For example, assume that a sheet bundle of P sheets (P is an integer greater than or equal to 2) is formed. The bonding device 167 performs the bonding process on the sheets stacked on the stacking tray 39 when S sheets (S is an integer greater than or equal to 1) (additional sheets) are newly stacked on the stacking tray 39, or when the last sheet (additional sheet) of the sheet bundle is stacked on the stacking tray 39. Therefore, if P≦S, a sheet bundle is formed in one bonding process. If P>S, a sheet bundle is formed through multiple gluing processes. The number of gluing processes is calculated as an integer obtained by dividing P by S and rounding up the decimal point. In this example, the value of S is kept constant while one sheet bundle is formed, but it is also possible to configure the value of S to change dynamically while one sheet bundle is formed.

[0021] In the following description, the sheets stacked on the stacking tray 39 will be referred to as "stacked sheets." Even if multiple stacked sheets are stacked on the stacking tray 39, the entire stack of multiple stacked sheets will be simply referred to as "stacked sheets." Furthermore, in the following description, "thickness of stacked sheets" will mean the overall thickness (length in the Z direction) of the stacked sheets stacked on the stacking tray 39.

[0022] 3(A) to 3(C) are detailed cross-sectional views of the bonding device 167 when viewed in the Y direction in FIG. 2. FIG. 3(A) shows a state in which the bonding unit 61 is in its home position. FIG. 3(B) shows a state in which the bonding unit 61 has been moved in the -Z direction from the state in FIG. 3(A) and has come into contact with the backing plate 180. FIG. 3(C) shows a state in which the rack gear 175 has been further moved in the -Z direction from the state in FIG. 3(B), causing the bonding unit 61 to press the backing plate 180. Note that, for simplification of the drawings, reference numerals for some components have been omitted in FIGS. 3(B) and 3(C).

[0023] Although sheets are not shown in FIGS. 3A to 3C, when sheets are loaded on the loading tray 39, some of the sheets are loaded on the loading tray 39 so as to cover the receiving plate 180. The number of sheets that can be loaded on the loading tray 39 can be limited so that the sheets loaded on the loading tray 39 do not come into contact with the bonding unit 61 at the home position. The bonding unit 61 then heats and presses part or all of the area of ​​the sheet that covers the receiving plate 180. The area of ​​the sheet that is heated and pressed by the bonding unit 61 is the bonding area, and the bonding image is formed within this bonding area. For example, by forming an adhesive image 138 in the bonding area as shown in FIG. 4A, a long-edge-bound sheet bundle can be created. By forming an adhesive image 139 in the bonding area as shown in FIG. 4B, a corner-bound sheet bundle can be created.

[0024] Returning to FIG. 3 , the bonding unit 61 includes a pressure plate 169, a ceramic heater 102, a metal stay 170, and a thermistor (not shown). The pressure plate 169 is a pressure member that applies pressure to the stacked sheets. When viewed in the Z direction, the pressure plate 169 has a substantially rectangular shape with its longer side in the Y direction and its shorter side in the X direction. The pressure plate 169 is made of, for example, aluminum. The ceramic heater 102 is a heating unit that heats the pressure plate 169. A thermistor (not shown) detects the temperature of the ceramic heater 102. The pressure plate 169 and the ceramic heater 102 are held by the metal stay 170. The metal stay 170 is fixed to a lift plate 172. The lift plate 172 moves integrally with the bonding unit 61.

[0025] The rack gear 175 is configured to be movable in the Z direction by a cylindrical guide shaft 173 fixed to the frame of the bonding device 167. As described in Fig. 2, the rack gear 175 is engaged with a pinion gear 179, and the rotation of the pinion gear 179 causes the rack gear 175 to move in the Z direction.

[0026] The HP sensor 62 is, for example, a photointerrupter fixed to the frame of the bonding device 167. A flag 66 integrally molded with the rack gear 175 blocks light from the light-emitting element of the photointerrupter to the light-receiving element when the bonding unit 61 is in the home position. Furthermore, the flag 66 transmits light from the light-emitting element of the photointerrupter to the light-receiving element when the bonding unit 61 is not in the home position. The HP sensor 62 notifies the main control unit 101 (FIG. 5) of the image forming system of the light detection result of the light-receiving element. Therefore, the main control unit 101 can detect whether the bonding unit 61 is in the home position based on the light detection result notified by the HP sensor 62. The flag 66 may be configured to transmit light from the light-emitting element of the photointerrupter to the light-receiving element when the bonding unit 61 is in the home position and to block light when the bonding unit 61 is in any other position.

[0027] The contact detection sensor 65 is, for example, a photointerrupter, and is held integrally with the rack gear 175. The state detection sensor 65 notifies the main control unit 101 (FIG. 5) whether or not it has detected the rib 172e of the lift plate 172. A compression spring 174 is disposed between the rack gear 175 and the lower surface 172c of the lift plate 172 to generate a pressure force in the -Z direction on the pressure plate 169. Furthermore, the lift plate 172 has a width alignment member 172a that regulates the position in the X direction of the sheets stacked on the stacking table 39, thereby aligning the positions of the sheets stacked on the stacking table 39 in the X direction.

[0028] 3(A) and 3(B), while the adhesive unit 61 moves from the home position to contact with the receiving plate 180 (or the upper surface of the stacked sheets), the contact detection sensor 65 detects the rib 172e of the lift plate 172. In other words, the rib 172e blocks the optical path from the light-emitting element to the light-receiving element of the contact detection sensor 65. Even if the pinion gear 179 is further rotated from the state shown in FIG. 3(B), the movement of the adhesive unit 61 and the lift plate 172 in the -Z direction is restricted by the receiving plate 180, so only the rack gear 175 pushes down the compression spring 174 and moves in the -Z direction. When only the rack gear 175 moves in the -Z direction, the relative position between the state detection sensor 65 and the rib plate 172e changes, and the rib plate 172e no longer blocks the optical path from the light-emitting element to the light-receiving element of the contact detection sensor 65.

[0029] The main control unit 101 (FIG. 5) detects that the relative position between the rack gear 175 and the lift plate 172 has changed when the state detection sensor 65 no longer detects the rib 172e. This change in relative position occurs when the bonding unit 61 comes into contact with the top surface of the stacked sheets, and hereinafter, the timing at which the contact detection sensor 65 detects the change in relative position is referred to as the "sheet contact timing." The main control unit 101 (FIG. 5) stops the rotation of the pinion gear 179 when the rack gear 175 moves a predetermined distance in the -Z direction from the sheet contact timing (the state in FIG. 3(C)). In this state, the compression spring 174 generates a pressure force in the -Z direction on the pressure plate 169 toward the receiving plate 180 via the lift plate 172.

[0030] Fig. 5 is a block diagram showing the hardware configuration of the image forming system. Note that components not necessary for explaining this embodiment are omitted from Fig. 5. A video controller 119 controls an engine control unit 301 that controls the image forming apparatus 1 and a main control unit 101 that controls the sheet processing apparatus 4. The video controller 119 also controls a display unit 120. The display unit 120 provides an input interface and an output interface for a user of the image forming system.

[0031] The main control unit 101 has a CPU 306 which is a processor, a RAM 307 which is a volatile memory, a ROM 308 which is a non-volatile memory, a system timer 111, a communication unit 315, and an I / O port 310, all of which are connected to one another via a bus 309. The communication unit 315 performs communication processing with the video controller 119. The CPU 306 controls the entire sheet processing apparatus 4 by executing programs stored in the ROM 308. In doing so, the CPU 306 stores control data and the like required for controlling the sheet processing apparatus 4 in the RAM 307. The ROM 308 stores the programs executed by the CPU 306 and the control data used to control the sheet processing apparatus 4. The system timer 111 generates timing required for various controls.

[0032] The I / O port 310 acquires the detection result of the HP sensor 62 via the input circuit 311 and notifies the CPU 306. Furthermore, the I / O port 310 acquires the detection result of the status detection sensor 65 via the input circuit 311 and notifies the CPU 306. The CPU 306 also controls the drive circuit 314 via the I / O port 310, thereby controlling the rotation of the motor 177. The motor 177 is a drive source for the pinion gear 179.

[0033] FIG. 6 shows functional blocks realized by the main control unit 101 as the main control unit 101 executes a program. Note that FIG. 6 only shows functional blocks necessary for explaining this embodiment. The conveying unit 115 controls the sheet conveyance and discharge of the sheet stack in the sheet processing device 4. The thickness determination unit 116 determines the thickness of the stacked sheets. For example, the movement distance of the adhesive unit 61 from the home position until the adhesive unit 61 contacts the receiving plate 180 is set to D1 as shown in FIG. 7. D1 is a known value. The thickness determination unit 116 determines the movement distance D2 of the adhesive unit 61 from the home position (first position) to the position (second position) of the adhesive unit 61 at the sheet contact timing. This allows the thickness determination unit 116 to calculate the thickness T of the stacked sheets as D1-D2. Note that D2 can be determined from the rotation amount of the pinion gear 179, and therefore the rotation amount of the motor 177.

[0034] The sheet bundle formation control unit 118 performs processing to form a sheet bundle. Specifically, the sheet bundle formation control unit 118 controls the temperature of the ceramic heater 102 of the bonding unit 61, controls the movement of the bonding unit 61 in the Z direction, etc. The input / output processing unit 117 displays the progress of the print job to the user of the image forming system, and performs notification processing such as warnings.

[0035] For example, as shown in FIG. 7 , the distance between the upper guide 63 and the lower guide 64 is assumed to be L. In this case, if the thickness T of the stacked sheets is greater than L, a jam may occur when the sheet bundle is discharged. Therefore, in this embodiment, the thickness determination unit 116 determines the thickness T of the stacked sheets during the gluing process. If the thickness T of the stacked sheets exceeds a first threshold, the sheet bundle formation control unit 118 halts the sheet bundle formation process to prevent a jam from occurring when the sheet bundle is discharged. Note that the first threshold may be, for example, the distance L between the upper guide 63 and the lower guide 64. Alternatively, the first threshold may be a value obtained by subtracting a predetermined margin from the distance L between the upper guide 63 and the lower guide 64. The first threshold is determined in advance and stored in the ROM 308.

[0036] FIG. 8 is a flowchart of a process for forming one sheet bundle executed by the main control unit 101 in this embodiment. In S10, the conveying unit 115 conveys sheets to the stacking tray 39. When a predetermined number of sheets or the last sheet of the sheet bundle is conveyed to the stacking tray 39, the sheet bundle formation control unit 118 moves the adhesive unit 61 from the home position toward the sheets. In S11, the thickness determination unit 116 determines the thickness T of the stacked sheets based on the movement distance D2 of the adhesive unit 61. In S12, the sheet bundle formation control unit 118 compares the thickness T of the stacked sheets with a first threshold value. If the thickness T of the stacked sheets is equal to or less than the first threshold value, the sheet bundle formation control unit 118 performs adhesive processing in S13. In S14, the sheet bundle formation control unit 118 determines whether the formation of one sheet bundle has been completed. If the formation of one sheet bundle has not been completed, the sheet bundle formation control unit 118 repeats the process from S10. When the formation of one sheet bundle is completed, the conveying section 115 performs a process of discharging the sheet bundle to the outside of the image forming system in S15, and the process of FIG. 8 ends.

[0037] On the other hand, if the thickness T of the stacked sheets is greater than the first threshold value in S12, the sheet bundle formation control unit 118 halts the sheet bundle formation process in S16. The conveying unit 115 halts the conveying of sheets that have already been conveyed to the image forming system but have not yet reached the stacking table 39 due to the halt of the sheet bundle formation process to the stacking table 39. For example, the conveying unit 115 ejects sheets that have not yet reached the stacking table 39 at the time the sheet bundle formation process is halted onto the upper tray 25. Furthermore, the sheet bundle formation control unit 118 also instructs the video controller 119 to halt image formation of subsequent sheets in the image forming apparatus 1. Then, in S17, the sheet bundle formation control unit 118 notifies the input / output processing unit 117 of the halt of the sheet bundle formation process and the procedure for removing the stacked sheets. The notification destination can be, for example, the display unit 120 or a personal computer (PC) connected to the image forming system via a network.

[0038] If the first threshold value is the distance L between the upper guide 63 and the lower guide 64, the thickness T of the stacked sheets exceeds L at S12, and therefore the stacked sheets cannot be pushed toward the pair of discharge rollers 36. However, if the first threshold value is set to a value smaller than the distance L between the upper guide 63 and the lower guide 64, the thickness T of the stacked sheets at S12 can be prevented from exceeding L. In this case, the conveying unit 115 can be configured to discharge the stacked sheets to the lower tray 37.

[0039] As described above, according to this embodiment, the thickness of the stacked sheets is measured, and if the measured thickness of the stacked sheets exceeds the first threshold, the sheet bundle formation process is stopped. Therefore, jams caused by the thickness of the sheet bundle can be reduced without presetting an upper limit on the number of sheets in the sheet bundle. The first threshold is determined in advance based on the configuration of the image forming system. In this example, the first threshold is set to the length L in the thickness direction of the discharge path through which the sheet bundle on the stacking tray 39 is discharged, or a value that is shorter than the length L by a margin.

[0040] Note that this embodiment is not limited to preventing jams caused by the thickness of a sheet stack. For example, the first threshold value can be a value based on the thickness of stacked sheets that can be stacked on the stacking tray 39 or a value based on the thickness of stacked sheets that can be appropriately subjected to adhesive processing. By setting such a first threshold value, it is possible to prevent processing of stacked sheets, such as adhesive processing, from being inappropriately performed.

[0041] Second Embodiment Next, the second embodiment will be described, focusing on the differences from the first embodiment. In this embodiment, the thickness determination unit 116 also determines the thickness TS of a single sheet based on the thickness T of the stacked sheets. As an example, the thickness of the stacked sheets measured during the first adhesive process is T1, the thickness of the stacked sheets measured during the second adhesive process following the first adhesive process is T2, and the number of additional sheets newly transported to the stacking table 39 for the second adhesive process after the first adhesive process is completed is X1. In this case, the thickness determination unit 116 can calculate the thickness TS of a single sheet after the second adhesive process is performed as (T2-T1) / X1. Note that in the first adhesive process performed to form a sheet bundle, T1=0.

[0042] Based on the thickness TS of a single sheet, the thickness determination unit 116 can further estimate the thickness T3 of the stack of sheets in the third adhesive process performed after the second adhesive process. Specifically, if the number of additional sheets to be newly transported to the stacking tray 39 for the third adhesive process after the second adhesive process is X2, the thickness determination unit 116 can calculate the thickness T3 of the stack of sheets in the third adhesive process as T2 + TS × X2. Here, TS × X2 corresponds to the total thickness of the one or more additional sheets. In this embodiment, if the thickness T of the stack of sheets in the next adhesive process determined by the thickness determination unit 116 exceeds the first threshold, the sheet bundle formation control unit 118 stops the sheet bundle formation process.

[0043] FIG. 9 is a flowchart of a process for forming a single sheet bundle executed by the main control unit 101 in this embodiment. Note that the same step numbers are assigned to process steps similar to those in the flowchart of the first embodiment shown in FIG. 8 , and their descriptions are generally omitted. In this embodiment, after the completion of the gluing process in S13, the thickness determination unit 116 determines the thickness TS of one sheet in S20 and calculates the thickness T of the stack of sheets in the next gluing process, as described above. In S21, the sheet-bundle formation control unit 118 compares the thickness T of the stack of sheets in the next gluing process with a first threshold value. If the thickness T of the stack of sheets in the next gluing process is greater than the first threshold value, the sheet-bundle formation control unit 118 ends the sheet-bundle formation process in S16; otherwise, the process proceeds to S14. Note that, as in the first embodiment, when the sheet-bundle formation process ends in S16, sheets that have not yet been conveyed to the stacking tray 39 are discharged, for example, to the upper tray 25 rather than the stacking tray 39.

[0044] As described above, in this embodiment, during the bonding process, the thickness T of the stacked sheets in the next bonding process is determined, and if the thickness T of the stacked sheets in the next bonding process exceeds the first threshold, the sheet bundle formation process is stopped. Because the thickness T of the stacked sheets at this point is equal to or less than the first threshold, the conveying unit 115 can discharge the stacked sheets to the lower tray 37, and there is no need for the user to remove the stacked sheets.

[0045] Third Embodiment Next, the third embodiment will be described, focusing on the differences from the second embodiment. In a print job, the user may specify a sheet type. One of the reasons why the thickness T of the stacked sheets exceeds the first threshold is a mismatch between the type of sheets the user intended to use and the type of sheets stored in the cassette 6. For this reason, in this embodiment, the sheet bundle formation control unit 118 sets an allowable range for the thickness TS of a single sheet based on the sheet type specified by the user in the print job. The allowable range for the sheet thickness TS is a predetermined range that includes the nominal value of the thickness of sheets of the sheet type specified by the user. Then, if the thickness TS of a single sheet determined by the thickness determination unit 116 is outside the allowable range, the sheet bundle formation control unit 118 issues a warning to the user.

[0046] FIG. 10 is a flowchart of a process executed by the main control unit 101 in this embodiment to form a single sheet bundle. Note that the same step numbers are used for process steps similar to those in the flowchart of the second embodiment shown in FIG. 9 , and their descriptions are generally omitted. When the thickness determination unit 116 determines the thickness TS of a single sheet in S20, the sheet-bundle formation control unit 118 determines whether the sheet thickness TS is within the allowable range in S30. If the sheet thickness TS is within the allowable range, the sheet-bundle formation control unit 118 proceeds to S14. On the other hand, if the sheet thickness TS is outside the allowable range, the sheet-bundle formation control unit 118 causes the input / output processing unit 117 to issue a warning in S31. This warning may notify the user that a sheet of a different type than the sheet type specified in the print job may be stored in the cassette 6. Thereafter, the sheet-bundle formation control unit 118 ejects the stacked sheets in S15, and the process of FIG. 10 ends.

[0047] As described above, in this embodiment, it is possible to determine whether a sheet type different from the sheet type specified by the user in the print job is being used to form a sheet bundle and to issue an early warning to the user. This eliminates unnecessary processing and improves usability. In this embodiment, if the sheet thickness TS is outside the allowable range, a warning is issued in S31 and the stacked sheets are ejected in S15. However, in S15, the user may be prompted to input whether or not to continue forming the sheet bundle. If the user selects to continue, the sheet bundle formation continues. If the user selects to cancel, the sheet bundle formation is stopped. The user can change the type of sheets stored in the cassette 6 before inputting the command to continue forming the sheet bundle in response to the warning. Furthermore, this embodiment can be combined with the second embodiment.

[0048] <Fourth embodiment> Next, the fourth embodiment will be described, focusing on the differences from the second embodiment. As described above, the number of sheets to be included in the sheet bundle (the specified number) is specified in the print job. Therefore, the thickness determination unit 116 can determine the thickness TF of the final sheet bundle by determining the thickness TS of a single sheet. For example, if the thickness of the current stack of sheets is T1 and the difference between the specified number and the current number of sheets is X3, the thickness TF of the sheet bundle can be calculated as T1 + X3 × TS. In this embodiment, when the sheet bundle formation control unit 118 determines that the thickness TF of the sheet bundle exceeds the first threshold, it interrupts the sheet bundle formation process and prompts the user to change settings or displays a message inquiring whether to cancel the sheet bundle formation process.

[0049] FIG. 11 is a flowchart of processing for forming one sheet bundle executed by the main control unit 101 in this embodiment. Note that processing steps similar to those in the flowchart of the second embodiment shown in FIG. 9 are assigned the same step numbers, and their descriptions are generally omitted. In S40, the thickness determination unit 116 determines the thickness TF of the sheet bundle based on the thickness TS of one sheet determined in S20. In S41, the sheet bundle formation control unit 118 compares the thickness TF of the sheet bundle with a first threshold value. If the thickness TF of the sheet bundle is equal to or less than the first threshold value, the sheet bundle formation control unit 118 proceeds to S14. On the other hand, if the thickness TF of the sheet bundle is greater than the first threshold value, the sheet bundle formation control unit 118 interrupts the sheet bundle formation processing in S42.

[0050] Then, the sheet bundle formation control unit 118 controls the input / output processing unit 117 to notify the user that the thickness TF of the sheet bundle exceeds the limit, and to prompt the user to change the number of sheets to be made into a sheet bundle to a smaller value. Note that the sheet bundle formation control unit 118 can also present to the user the number of sheets that can be made into a sheet bundle or the upper limit of the remaining number of sheets that can be stacked on top of the currently stacked sheets, based on the thickness T of the currently stacked sheets and the thickness TS of a single sheet.

[0051] For example, if the user inputs a new value that reduces the number of sheets to be included in the sheet bundle, the sheet bundle formation control unit 118 repeats the process from S10 to form a sheet bundle with that number of sheets. For example, if the document is divided into chapters, by inputting the new number of sheets corresponding to the position of the chapter boundary as the new number of sheets in the sheet bundle, it is possible to form a sheet bundle up to the chapter boundary. This makes it possible to provide a sheet processing apparatus with excellent usability.

[0052] The sheet bundle formation control unit 118 can also control the input / output processing unit 117 to prompt the user to change to thinner sheets. At this time, the sheet bundle formation control unit 118 determines the allowable thickness of a single sheet based on the difference between the thickness T of the currently stacked sheets and the first threshold value and the number of remaining sheets to be stacked on top of the currently stacked sheets to form a sheet bundle, and can thereby present usable sheet types to the user. When the user changes the sheets in the cassette 6 and inputs a change in sheet type, the sheet bundle formation control unit 118 repeats the process from S10. Because it can be determined that the thickness TF of the sheet bundle exceeds the first threshold value early after the start of the print job, the user can complete the sheet bundle formation process by changing the sheets to thinner sheets.

[0053] Furthermore, the sheet bundle formation control unit 118 can also control the input / output processing unit 117 to present the user with the option of suspending the sheet bundle formation process. If the user selects to suspend the sheet bundle formation process, the sheet bundle formation control unit 118 proceeds to S15 assuming that S14 is Yes. Note that this embodiment can also be combined with the second embodiment, the third embodiment, or both.

[0054] Fifth Embodiment Next, the fifth embodiment will be described, focusing on the differences from the first embodiment. FIG. 12A shows a state in which the length of the stacked sheets in the Y direction is longer than the bonding unit 61, and therefore a curl occurs in the portion of the sheets that is not pressurized or heated by the bonding unit 61. The thickness T of the stacked sheets in FIG. 12A is less than or equal to L, but the thickness T+M1 taking the curl into account exceeds L. Hereinafter, a curl that occurs in the edge of the stacked sheets on the upper guide 63 and lower guide 64 side in the Y direction (lengthwise direction) will be referred to as a "lengthwise curl." FIG. 12B shows a state in which a curl occurs in the edge of the sheets on the opposite side from the side pressed by the bonding unit 61 in the X direction (widthwise direction). In FIG. 12B, the thickness T of the stacked sheets is also less than L, but the thickness T+M2 taking the curl into account exceeds L. Hereinafter, a curl that occurs in the edge of the stacked sheets on the opposite side from the bonding area in the X direction (widthwise direction) will be referred to as a "widthwise curl."

[0055] As shown in Figures 12(A) and 12(B), considering that curling may occur at the edge of a sheet, a jam may occur when the sheet bundle is discharged depending on the amount of curl, even if the thickness T of the stacked sheets is equal to or less than the first threshold. The amount of curl may vary depending on the size and type of sheet. For this reason, in this embodiment, the sheet bundle formation control unit 118 sets the second threshold based on the size and type of sheet, or both.

[0056] As an example, as shown in FIG. 13, the maximum width-direction curl amount and the maximum length-direction curl amount are determined in advance for a combination of sheet type and size. Then, as shown in FIG. 13, the larger of the maximum width-direction curl amount and the maximum length-direction curl amount is set as the adjustment value. The ROM 308 of the main control unit 101 stores adjustment value information indicating the relationship between the combination of sheet type and size and the adjustment value. The sheet bundle formation control unit 118 determines the adjustment value based on the type and size of the sheets to be bundled, and sets the second threshold value to a value obtained by subtracting the adjustment value from the first threshold value. The type and size of the sheets to be bundled are specified in the print job. For example, as shown in FIG. 13, if the sheets are plain paper and A4 size, the adjustment value is 2.9 mm. Therefore, the sheet bundle formation control unit 118 sets the second threshold value to a value obtained by subtracting 2.9 from the first threshold value.

[0057] 14 is a flowchart of processing for forming one sheet bundle executed by the main control unit 101 in this embodiment. Note that processing steps that are the same as those in the flowchart of the first embodiment shown in FIG. 8 are assigned the same step numbers, and descriptions thereof will generally be omitted. In this embodiment, if the thickness T of the stacked sheets is greater than a first threshold value in S12, it is determined in S50 whether the thickness T of the stacked sheets is greater than a second threshold value. If the thickness T of the stacked sheets is greater than the second threshold value, the sheet-bundle formation control unit 118 proceeds to S16, and if the thickness T of the stacked sheets is equal to or less than the second threshold value, the sheet-bundle formation control unit 118 proceeds to S13.

[0058] Note that, in S50, if the thickness T of the stacked sheets is greater than the second threshold, a warning may be issued to the user instead of halting the sheet-bundle formation process in S16. For example, the user may be asked to confirm whether or not a curl has occurred, and prompted to input whether or not to halt the sheet-bundle formation process. For example, if the user confirms that no curl has occurred, the user may input a command to continue the sheet-bundle formation process, and if the user confirms that a curl has occurred, the user may input a command to halt the sheet-bundle formation process.

[0059] Furthermore, while the first threshold value in the first to fourth embodiments was a predetermined value, it is also possible to replace the first threshold value in the first to fourth embodiments with the second threshold value in this embodiment. That is, a reference value based on the configuration of the image forming system, for example, the distance L between the upper guide 63 and the lower guide 64, can be determined in advance, and the reference value reduced by an adjustment value can be used as the first threshold value in the first to fourth embodiments. That is, it is possible to dynamically set the first threshold value in the first to fourth embodiments based on the type and size of the sheet specified in the print job.

[0060] In this example, the adjustment value is determined based on both the sheet type and size. However, the adjustment value may be determined based only on the sheet type or only on the sheet size. Furthermore, the amount of curl may vary depending on the sheet thickness, the density of the image formed on the sheet, and whether the image is formed on one side or both sides. Therefore, the adjustment value may be determined based on a combination of one or more parameters including the sheet type, sheet size, sheet thickness, the density of the image formed on the multiple sheets in the sheet stack, and whether the image is formed on both sides. The engine controller 119 determines the image density and whether the image is formed on both sides based on the print job and notifies the main control unit 101.

[0061] [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. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0062] The disclosure of this embodiment includes the following configuration. (Configuration 1) a conveying means for conveying the sheet to the stacking table; an adhesive means for performing an adhesive process to adhere a plurality of stacked sheets stacked on the stacking table to each other by adhesive images formed on the plurality of stacked sheets; a control unit that controls the gluing process by the gluing unit to create a sheet bundle of a specified number of sheets specified in a job; Equipped with The control means is configured to not perform the adhesive process on the stack of sheets when the thickness of the stack of sheets exceeds a first threshold value. (Configuration 2) The sheet processing device described in configuration 1, wherein the control means, when performing the bonding process, moves the bonding means from a predetermined first position that does not contact the plurality of stacked sheets to a second position that contacts the plurality of stacked sheets, and determines the thickness of the plurality of stacked sheets based on the distance from the first position to the second position. (Configuration 3) the control means performs the bonding process a plurality of times to create the sheet bundle; After the first bonding process is completed, one or more additional sheets are stacked on the first stack of sheets in the first bonding process, which then become the second stack of sheets in the second bonding process following the first bonding process; The sheet processing device of configuration 1 or 2, wherein the control means determines the thickness of the second stack of sheets after the first adhesive process is completed and before the one or more additional sheets are stacked on top of the first stack of sheets, and does not perform the second adhesive process if the thickness of the second stack of sheets exceeds the first threshold value. (Configuration 4) The sheet processing device of configuration 3, wherein the control means determines the thickness of the second stack of sheets by determining the total thickness of the one or more additional sheets based on the thickness of the stack of sheets in the bonding process already performed to create the sheet bundle. (Configuration 5) The sheet processing apparatus according to configuration 3 or 4, wherein the control means controls the transport of the one or more additional sheets so that the one or more additional sheets are not stacked on top of the multiple first stack sheets when the thickness of the multiple second stack sheets exceeds the first threshold value. (Configuration 6) the control means performs the bonding process a plurality of times to create the sheet bundle; After the first bonding process is completed, one or more additional sheets are stacked on the first stack of sheets in the first bonding process, which then become the second stack of sheets in the second bonding process following the first bonding process; The sheet processing apparatus according to any one of configurations 1 to 5, wherein, after the first adhesive process is completed, the control means determines the thickness of one sheet based on the thicknesses of the plurality of stacked sheets in the adhesive process already performed to create the sheet bundle, and if the thickness of the one sheet is not within a range determined based on the sheet type specified in the job, the control means issues a warning to a user. (Configuration 7) 7. The sheet processing apparatus according to claim 6, wherein the control means does not perform the second bonding process when the thickness of the single sheet is not within the range. (Configuration 8) the control means performs the bonding process a plurality of times to create the sheet bundle; After the first bonding process is completed, one or more additional sheets are stacked on the first stack of sheets in the first bonding process, which then become the second stack of sheets in the second bonding process following the first bonding process; The sheet processing apparatus according to any one of configurations 1 to 7, wherein the control means determines the thickness of the sheet stack after the first adhesive process is completed, and if the thickness of the sheet stack exceeds the first threshold, performs a message notification process to a user before starting the second adhesive process. (Configuration 9) The sheet processing device of configuration 8, wherein the control means determines the thickness of a single sheet based on the thicknesses of the plurality of stacked sheets in the adhesive process already performed to create the sheet bundle, and determines the thickness of the sheet bundle based on the difference between the number of the first plurality of stacked sheets and the specified number and the thickness of the single sheet. (Configuration 10) 10. The sheet processing apparatus according to configuration 8 or 9, wherein the message is a message that prompts the user to change the specified number of sheets to a smaller value. (Configuration 11) 10. The sheet processing apparatus according to claim 8, wherein the message is a message that prompts the user to change the sheets used to create the sheet bundle to a type having a smaller thickness. (Configuration 12) 10. The sheet processing apparatus according to configuration 8 or 9, wherein the message is a message that prompts the user to input whether or not to stop creating the sheet bundle. (Configuration 13) 13. The sheet processing apparatus of any one of configurations 1 to 12, wherein the first threshold is a predetermined value. (Configuration 14) The sheet processing device described in any one of configurations 1 to 13, wherein the control means calculates a second threshold value by reducing the first threshold value by an adjustment value based on at least one of the type, thickness, and size of the sheets specified in the job, and issues a warning to a user if the thickness of the multiple stacked sheets exceeds the second threshold value. (Configuration 15) 13. The sheet processing apparatus according to any one of configurations 1 to 12, wherein the control means calculates the first threshold value by reducing a predetermined reference value by an adjustment value based on at least one of the type, thickness, and size of the sheet specified in the job. (Configuration 16) The sheet processing device according to any one of configurations 1 to 12, an image forming apparatus that forms an image including the adhesive image on a sheet based on the job; Including, The conveying unit conveys the sheet from the image forming apparatus to the stacking table. (Configuration 17) the control means determines the first threshold value by decreasing a predetermined reference value by an adjustment value; 17. The image forming system according to configuration 16, wherein the adjustment value is a value based on the density of an image formed by the image forming apparatus on the specified number of sheets constituting the sheet stack. (Configuration 18) the control means determines the first threshold value by decreasing a predetermined reference value by an adjustment value; 18. The image forming system according to claim 16, wherein the adjustment value is a value based on whether or not images are formed by the image forming device on both sides of the specified number of sheets that make up the sheet stack.

[0063] 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]

[0064] 115: conveying section, 61: adhesive unit, 116: thickness determining section, 118: sheet bundle forming control section

Claims

1. a conveying means for conveying the sheet to the stacking table; an adhesive means for performing an adhesive process to adhere a plurality of stacked sheets stacked on the stacking table to each other by adhesive images formed on the plurality of stacked sheets; a control unit that controls the gluing process by the gluing unit to create a sheet bundle of a specified number of sheets specified in a job; Equipped with The control unit is configured to not perform the adhesive process on the stack of sheets when the thickness of the stack of sheets exceeds a first threshold value.

2. 2. The sheet processing apparatus according to claim 1, wherein the control means, when performing the bonding process, moves the bonding means from a predetermined first position that does not contact the plurality of stacked sheets to a second position that contacts the plurality of stacked sheets, and determines the thickness of the plurality of stacked sheets based on the distance from the first position to the second position.

3. the control means performs the bonding process a plurality of times to create the sheet bundle; After the first bonding process is completed, one or more additional sheets are stacked on the first stack of sheets in the first bonding process, which then become the second stack of sheets in the second bonding process following the first bonding process; 2. The sheet processing apparatus according to claim 1, wherein the control means determines the thickness of the second stack of sheets after the first adhesive process is completed and before the one or more additional sheets are stacked on top of the first stack of sheets, and does not perform the second adhesive process if the thickness of the second stack of sheets exceeds the first threshold value.

4. 4. The sheet processing apparatus according to claim 3, wherein the control means determines the thickness of the second stack of sheets by determining the total thickness of the one or more additional sheets based on the thickness of the stack of sheets in the bonding process already performed to create the sheet bundle.

5. 4. The sheet processing apparatus according to claim 3, wherein the control means controls the transport of the one or more additional sheets so that the one or more additional sheets are not stacked on top of the plurality of first stacked sheets when the thickness of the plurality of second stacked sheets exceeds the first threshold value.

6. the control means performs the bonding process a plurality of times to create the sheet bundle; After the first bonding process is completed, one or more additional sheets are stacked on the first stack of sheets in the first bonding process, which then become the second stack of sheets in the second bonding process following the first bonding process; 2. The sheet processing apparatus according to claim 1, wherein, after the first adhesive process is completed, the control means determines the thickness of a single sheet based on the thicknesses of the plurality of stacked sheets in the adhesive process already performed to create the sheet bundle, and if the thickness of the single sheet is not within a range determined based on the sheet type specified in the job, the control means issues a warning to a user.

7. The sheet processing apparatus according to claim 6 , wherein the control unit does not perform the second adhesive process when the thickness of the one sheet is not within the range.

8. the control means performs the bonding process a plurality of times to create the sheet bundle; After the first bonding process is completed, one or more additional sheets are stacked on the first stack of sheets in the first bonding process, which then become the second stack of sheets in the second bonding process following the first bonding process; 2. The sheet processing apparatus according to claim 1, wherein the control means determines the thickness of the sheet stack after the first adhesive process is completed, and if the thickness of the sheet stack exceeds the first threshold, performs a message notification process to a user before starting the second adhesive process.

9. 9. The sheet processing apparatus according to claim 8, wherein the control means determines the thickness of a single sheet based on the thicknesses of the plurality of stacked sheets in the gluing process already performed to create the sheet bundle, and determines the thickness of the sheet bundle based on the difference between the number of the first plurality of stacked sheets and the specified number and the thickness of the single sheet.

10. The sheet processing apparatus according to claim 8 , wherein the message is a message that prompts the user to change the designated number of sheets to a smaller value.

11. The sheet processing apparatus according to claim 8 , wherein the message is a message that prompts the user to change the sheets used to create the sheet bundle to a type having a smaller thickness.

12. The sheet processing apparatus according to claim 8 , wherein the message prompts the user to input whether or not to stop creating the sheet bundle.

13. The sheet processing apparatus according to claim 1 , wherein the first threshold value is a predetermined value.

14. 13. A sheet processing apparatus according to claim 1, wherein the control means calculates the second threshold by reducing the first threshold by an adjustment value based on at least one of the type, thickness, and size of the sheets specified in the job, and issues a warning to the user if the thickness of the multiple stacked sheets exceeds the second threshold.

15. The sheet processing apparatus according to claim 1 , wherein the control unit calculates the first threshold value by reducing a predetermined reference value by an adjustment value based on at least one of the type, thickness, and size of the sheet specified in the job.

16. a sheet processing apparatus according to any one of claims 1 to 12; an image forming apparatus that forms an image including the adhesive image on a sheet based on the job; Including, The conveying unit conveys the sheet from the image forming apparatus to the stacking table.

17. the control means determines the first threshold value by decreasing a predetermined reference value by an adjustment value; 17. The image forming system according to claim 16, wherein the adjustment value is a value based on the density of an image formed by the image forming apparatus on the specified number of sheets constituting the sheet bundle.

18. the control means determines the first threshold value by decreasing a predetermined reference value by an adjustment value; 17. The image forming system according to claim 16, wherein the adjustment value is a value based on whether or not images are formed on both sides of the specified number of sheets that make up the sheet bundle by the image forming apparatus.

Images