Post-processing device and image formation device

Abstract

To enable a sheet to be loaded onto a discharge tray smoothly even if a lower curl occurs in a sheet bundle loaded on the discharge tray.SOLUTION: A controller causes a rear end pressing member 7 to press a rear end of a pring sheet on a discharge tray 5 when print setting for the print sheet does not meet lower curl conditions. Further, the controller determines whether the lower curl amount of the print sheet 101 on the discharge tray 5 is larger than or equal to a predetermined first threshold value when the print setting meets the lower curl conditions. If the lower curl amount is larger than or equal to the first threshold value, the controller provides a tray-full notice of the discharge tray 5.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a post-processing device and an image forming apparatus.

Background Art

[0002] A certain image forming apparatus includes a member that holds the rear end of a stack of sheets loaded on a discharge tray (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a downward curl (a curl in which the inner side of the sheet curvature faces downward) occurs in a stack of sheets loaded on the discharge tray, if the rear end of the stack of sheets is held as described above, the curvature of the downward curl becomes stronger, and the difference between the highest position of the stack of sheets and the position of the discharge port in the height direction becomes smaller. When subsequent sheets are discharged onto the discharge tray, problems (such as rounding of the leading edge of the subsequent sheet due to contact of the subsequent sheet with the top sheet of the stack of sheets, popping out of the top sheet, etc.) may occur.

[0005] The present invention has been made in view of the above problems, and an object thereof is to obtain a post-processing device and an image forming apparatus that can satisfactorily stack sheets on a discharge tray even when a downward curl occurs in a stack of sheets loaded on the discharge tray.

Means for Solving the Problems

[0006] The post-processing device according to the present invention includes a processing tray on which a printed sheet is placed for post-processing, an intermediate roller that conveys the printed sheet to the processing tray, a discharge tray on which the printed sheet after the post-processing is placed, a discharge roller that discharges the printed sheet to the discharge tray, a rear-end pressing member, and a controller that causes the rear-end pressing member to press the rear end of the printed sheet on the discharge tray when the print setting for the printed sheet does not satisfy the downward curl condition. When the print setting satisfies the downward curl condition, the controller determines whether the amount of downward curl indicating the degree of downward curl of the printed sheet on the discharge tray is equal to or greater than a predetermined first threshold value, and if the amount of downward curl is equal to or greater than the first threshold value, the controller issues a tray full notification for the discharge tray.

[0007] The image processing apparatus according to the present invention includes the above-described post-processing apparatus, and supplies a printed sheet after printing is performed by an inkjet method to the post-processing apparatus.

Advantages of the Invention

[0008] According to the present invention, a post-processing device and an image forming apparatus capable of satisfactorily stacking sheets on a discharge tray even when downward curl occurs in a stack of sheets stacked on the discharge tray can be obtained.

[0009] The above or other objects, features, and advantages of the present invention will become more apparent from the following detailed description together with the accompanying drawings.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a side view showing the mechanical configuration of a post-processing apparatus according to an embodiment of the present invention. The post-processing apparatus shown in FIG. 1 may be a single apparatus or may be incorporated in an image forming apparatus such as a multifunction machine. The post-processing apparatus is supplied with a print sheet after printing by a print engine, and performs predetermined post-processing (such as stapling processing and sorting processing on a plurality of print sheets) on the print sheet.

[0013] The post-processing apparatus shown in FIG. 1 includes an intermediate roller 1, a stopper guide 2, a processing tray 3, a discharge roller 4, a discharge tray 5, a discharge guide 6, and a trailing edge pressing member 7.

[0014] The intermediate roller 1 conveys the print sheet to be post-processed to above the processing tray 3. The intermediate roller 1 is driven by a motor (not shown) or the like.

[0015] The stopper guide 2 is disposed at one end side of the processing tray 3, and the end of the print sheet on the processing tray 3 abuts thereon.

[0016] The processing tray 3 is a substantially plate-shaped member that is inclined, and the print sheet to be post-processed is placed thereon. Post-processing (such as stapling processing and sorting processing) is performed on one or a plurality of print sheets placed on the processing tray 3.

[0017] In this embodiment, after the rear end portion of the printed sheet passes through the intermediate roller 1, it is guided to the processing tray 3 while receiving contact from a sheet contact member (not shown), and is brought into contact with the stopper guide 2 by a draw paddle (not shown) for alignment.

[0018] The discharge roller 4 is movable by the discharge guide 6, and is separated from each other until the post-processing is completed so that the printed sheet placed on the processing tray 3 and the printed sheet newly conveyed to the processing tray 3 can move through the gap of the discharge roller 4. After the completion of the post-processing, the printed sheet is nipped and conveyed (discharged) onto the discharge tray 5. When the post-processing is not performed, the discharge roller 4 nips the printed sheet conveyed by the intermediate roller 1 and conveys (discharges) it onto the discharge tray 5.

[0019] The discharge tray 5 is a member on which the printed sheet after the post-processing is placed and is capable of moving up and down.

[0020] The rear end pressing member 7 is a member for pressing the rear end of the printed sheet (sheet bundle) stacked on the discharge tray 5, and is fixed to the rotation shaft 7a so as to be rotatable between a first position (retracted position) and a second position (sheet pressing position).

[0021] FIG. 2 is a block diagram showing the electrical configuration of the post-processing apparatus according to the embodiment of the present invention. As shown in FIG. 2, the post-processing apparatus according to this embodiment further includes a motor 21 that drives the intermediate roller 1, the discharge roller 4, etc., a rotation mechanism 22 such as a motor that rotates the rear end pressing member 7, a controller 23 that controls the motor 21 and the rotation mechanism 22, and an operation panel 24.

[0022] The controller 23 includes an ASIC (Application Specific Integrated Circuit) or a computer, and uses the ASIC or the computer to control the motor 21, the rotation mechanism 22, a stapling mechanism (not shown), a sorting mechanism (not shown) that moves the processing tray 3 in the sheet width direction (perpendicular to the conveyance direction), etc., to execute post-processing of a type specified by the user. Further, the controller 23 adjusts the height of the discharge tray 5 according to the thickness of the entire printed sheet (i.e., the stack of sheets) placed on the discharge tray 5, and controls the rotation mechanism 22 to perform trailing edge pressing of the stack of sheets on the discharge tray 5 by the trailing edge pressing member 7 as necessary.

[0023] Further, the operation panel 24 is installed on the housing of the post-processing device, and includes a display device that displays various messages and operation screens for the user and an input device that detects user operations.

[0024] FIG. 3 is a diagram for explaining the position of the trailing edge pressing member 7 when the print setting for the printed sheet does not satisfy the undercurl condition. FIG. 4 is a diagram for explaining the position of the trailing edge pressing member 7 when the trailing edge pressing is not performed when the print setting for the printed sheet satisfies the undercurl condition.

[0025] For example, as shown in FIG. 3, when the print setting for the printed sheet 101 does not satisfy the undercurl condition, the controller 23 causes the trailing edge pressing member 7 to press the trailing edge of the printed sheet 101 on the discharge tray 5. The print setting is obtained, for example, from an inkjet printing engine for the printed sheet 101 or a previous inkjet image forming apparatus.

[0026] Here, the above-mentioned undercurl condition is set for the printing coverage of the print on the printed sheet 101 and the characteristics of the printed sheet 101 (size, sheet type, basis weight, paper texture, color, moisture content, etc.). That is, the undercurl condition is set so that undercurl occurs in the printed sheet 101 when the undercurl condition is satisfied.

[0027] On the other hand, for example, as shown in FIG. 4, when the print settings for the printed sheet 101 satisfy the downward curl condition, the controller 23 determines whether to hold down the rear end of the printed sheet 101 on the discharge tray 5 by the rear end holding member 7 according to the type of post-processing specified.

[0028] Specifically, in this case, when the type of post-processing is stapling, the controller 23 determines not to hold down the rear end of the printed sheet 101 on the discharge tray 5 by the rear end holding member 7. Also, in this case, when the type of post-processing is sorting, for example, as shown in FIG. 4, the controller 23 determines to hold down the rear end of the printed sheet 101 on the discharge tray 5 by the rear end holding member 7.

[0029] Note that when the controller 23 discharges the printed sheet to the discharge tray 5 without performing post-processing in the case where the above-described print settings satisfy the downward curl condition, the controller 23 determines to hold down the rear end of the printed sheet 101 on the discharge tray 5 by the rear end holding member 7.

[0030] Furthermore, when the above-described print settings satisfy the above-described downward curl condition, the controller 23 determines whether the amount of downward curl indicating the degree of downward curl of the printed sheet 101 on the discharge tray 5 is equal to or greater than a predetermined first threshold value. If the amount of downward curl is equal to or greater than the first threshold value, a tray full notification of the discharge tray 5 is given.

[0031] This amount of downward curl is derived from the printing rate of the printed sheet 101, the number of printed sheets 101 on the discharge tray 5, and the like. For example, for each printed sheet 101, an individual curl amount of one printed sheet 101 is derived based on the printing rate, and the sum of the individual curl amounts of the printed sheets 101 on the discharge tray 5 is derived as the above-described amount of downward curl. Note that the individual curl amount corresponding to the printing rate is set in advance and can be changed by the user.

[0032] Further, the tray full notification is a notification that prompts the removal of the printed sheet 101 on the discharge tray 5. For example, a message indicating this is displayed on the display device of the operation panel 24. Note that after the tray full notification, the post-processing for the subsequent printed sheet 101 may be temporarily stopped or may continue to be performed.

[0033] In this embodiment, when the above-described print setting satisfies the downward curl condition, the controller 23 determines whether to press the rear end of the printed sheet on the discharge tray 5 against the rear end pressing member 7 according to the type of post-processing specified in the job request. When it is determined based on the type of post-processing that the rear end of the printed sheet 101 on the discharge tray 5 is not to be pressed, the controller 23 determines whether the amount of downward curl is equal to or greater than the first threshold value. If the amount of downward curl is equal to or greater than the first threshold value, the above-described tray full notification is performed.

[0034] Further, even when the controller 23 determines that the rear end pressing member 7 is to press the rear end of the printed sheet 101 on the discharge tray 5, when the amount of downward curl based on the print setting is equal to or greater than a predetermined second threshold value, the rear end pressing member 7 is not made to press the rear end of the printed sheet 101 on the discharge tray 5. In this case, it is determined whether the amount of downward curl is equal to or greater than the first threshold value. If the amount of downward curl is equal to or greater than the first threshold value, the above-described tray full notification is performed. Note that the second threshold value may be the same as the first threshold value, may be larger than the first threshold value, or may be smaller than the first threshold value.

[0035] Next, the operation of the above post-processing device will be described.

[0036] When receiving a request for a post-processing job, the controller 23 first raises the discharge guide 6, opens the discharge port 4a, identifies the width of the printed sheet 101 based on the request, and arranges a width alignment cursor (not shown) at a position corresponding to the width of the printed sheet 101. Further, the controller 23 adjusts the height position of the discharge tray 5 according to the presence or absence of the printed sheet 101 on the discharge tray 5.

[0037] Then, the intermediate roller 1 conveys the printed sheet printed by an inkjet method from the preceding device (such as a print engine or a separate image forming device).

[0038] When post-processing is to be executed, after the rear end of the printed sheet has passed through the intermediate roller 1, the printed sheet 101 is placed on the processing tray 3 by a sheet contact member or a drawing paddle. A plurality of printed sheets are sequentially placed on the processing tray 3. At this time, the post-processing specified by the user is executed on the plurality of printed sheets, and then, by the discharge roller 4, the printed sheet after the post-processing is discharged to the discharge tray 5.

[0039] When post-processing is not executed, the printed sheet conveyed by the intermediate roller 1 is discharged to the discharge tray 5 by the discharge roller 4.

[0040] In this way, the printed sheets 101 are stacked on the discharge tray 5. At this time, the controller 23 determines whether to perform the rear end pressing of the printed sheet 101 on the discharge tray 5 by the rear end pressing member 7, and according to the determination result, retracts the rear end pressing member 7 and does not perform the rear end pressing, or rotates the rear end pressing member 7 to perform the rear end pressing.

[0041] FIG. 5 is a flowchart for explaining the control of the rear end pressing member 7 in the post-processing device shown in FIGS. 1 and 2.

[0042] First, the controller 23 determines whether the print setting satisfies the downward curl condition (step S1).

[0043] If it is determined that the print setting satisfies the downward curl condition, the controller 23 determines whether the post-processing type is stapling (step S2). If the post-processing type is stapling, the controller 23 does not perform the rear end pressing (step S3), derives the downward curl amount, and determines whether the downward curl amount is equal to or greater than the first threshold value (step S4).

[0044] When the amount of downward curl is greater than or equal to the first threshold value, the controller 23 determines whether to immediately give a tray full notification according to the settings by the user or the like (step S5). If it is determined to immediately give a tray full notification, the above-mentioned tray full notification is immediately given (step S6). On the other hand, if it is determined not to immediately give a tray full notification, the controller 23 monitors whether the current post-processing job has been completed (step S7), and when the current post-processing job is completed, the above-mentioned tray full notification is given (step S6).

[0045] On the other hand, when the amount of downward curl is less than the first threshold value, the controller 23 does not give a tray full notification.

[0046] Also, in step S2, when the post-processing type is not stapling (such as when the post-processing type is sorting), the controller 23 derives the amount of downward curl and determines whether the amount of downward curl is greater than or equal to the second threshold value (step S8). When the amount of downward curl is greater than or equal to the second threshold value, the controller 23 does not execute the trailing edge hold (step S3) and performs the processing after step S4. On the other hand, when the amount of downward curl is less than the second threshold value, the controller 23 executes the trailing edge hold (step S9).

[0047] Note that when it is determined in step S2 that the print settings do not satisfy the downward curl condition, the controller 23 executes the trailing edge hold (step S9).

[0048] As described above, according to the above embodiment, when the print settings for the print sheet 101 do not satisfy the downward curl condition, the controller 23 causes the trailing edge hold member 7 to hold the trailing edge of the print sheet 101 on the discharge tray 5. Further, when the print settings satisfy the downward curl condition, the controller 23 determines whether the amount of downward curl of the print sheet 101 on the discharge tray 5 is greater than or equal to a predetermined first threshold value. If the amount of downward curl is greater than or equal to the first threshold value, a tray full notification for the discharge tray 5 is given.

[0049] Accordingly, when the rear end pressing is not performed and the amount of downward curl is large, a tray full notification is issued, and before a problem caused by the downward curl occurs on the printed sheet 101 on the discharge tray 5, the printed sheet 101 on the discharge tray 5 is removed by the user who has received the tray full notification. Therefore, even if downward curl occurs in the sheet bundle stacked on the discharge tray 5, the sheets can be stacked on the discharge tray 5 satisfactorily. Here, when the printed sheet 101 is discharged to the discharge tray 5 one by one as in the case of sorting or without post-processing, the rear end pressing is appropriately performed, and when the downward curl is suppressed by post-processing such as stapling, the rear end pressing is not performed.

[0050] Various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing the intended advantages. That is, it is intended that such changes and modifications be included in the claims.

Industrial Applicability

[0051] The present invention is applicable to, for example, a post-processing device of an image forming apparatus.

Explanation of Signs

[0052] 1 Intermediate roller 2 Stopper guide 3 Processing tray 4 Discharge roller 5 Discharge tray 7 Rear end pressing member 23 Controller

Claims

1. A processing tray on which a printed sheet is placed for post-processing, An intermediate roller that conveys the printed sheet to the processing tray, A discharge tray on which the printed sheet after the post-processing is placed, A discharge roller that discharges the printed sheet to the discharge tray, A rear-end pressing member, And a controller that causes the rear-end pressing member to press the rear end of the printed sheet on the discharge tray when the print setting for the printed sheet does not satisfy the undercurl condition. When the print setting satisfies the undercurl condition, the controller determines whether or not the undercurl amount indicating the degree of undercurl of the printed sheet on the discharge tray is equal to or greater than a predetermined first threshold value. If the undercurl amount is equal to or greater than the first threshold value, the controller performs a tray full notification for the discharge tray. A post-processing apparatus characterized by the above.

2. When the print setting satisfies the undercurl condition, the controller determines whether or not to cause the rear-end pressing member to press the rear end of the printed sheet on the discharge tray according to the type of post-processing. When it is determined not to cause the rear-end pressing member to press the rear end of the printed sheet on the discharge tray, the controller determines whether or not the undercurl amount is equal to or greater than the first threshold value. If the undercurl amount is equal to or greater than the first threshold value, the controller performs a tray full notification for the discharge tray. The post-processing apparatus according to claim 1, characterized by the above.

3. Even when the controller determines to cause the rear-end pressing member to press the rear end of the printed sheet on the discharge tray, when the undercurl amount is equal to or greater than a predetermined second threshold value, the controller determines whether or not the undercurl amount is equal to or greater than the first threshold value. If the undercurl amount is equal to or greater than the first threshold value, the controller performs a tray full notification for the discharge tray. The post-processing apparatus according to claim 1, characterized by the above.

4. The post-processing device according to claim 1, wherein the lower curl condition is set with respect to the printing rate of printing on the print sheet and the characteristics of the print sheet.

5. The post-processing device according to claim 1, wherein the controller derives an individual curl amount from the printing rate of printing for each print sheet on the discharge tray and derives the sum of the individual curl amounts as the lower curl amount.

6. An image forming apparatus comprising the post-processing device according to any one of claims 1 to 5, feeding a print sheet after printing is performed by an inkjet method to the post-processing device, characterized by the above.

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