Post-processing apparatus and image forming apparatus

Abstract

When performing post-processing on multiple sheet bundles consecutively, this suppresses delays in post-processing for subsequent sheet bundles. [Solution] The controller performs simultaneous transport of the sheet bundle and subsequent sheets after post-processing. During simultaneous transport, (a) when the sheet bundle is discharged through the discharge port 24a, the transport roller 12 is controlled to transport the subsequent sheets to the discharge roller 24 so that they partially overlap the sheet bundle and protrude from the discharge port 24a, and (b) after the rear end of the sheet bundle has passed through the discharge port 24a, the discharge roller 24 is reversed to transport the subsequent sheets to the processing tray 23.

Description

Technical Field

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

Background Art

[0002] A certain post-processing device includes a storage conveyance path for storing sheets in addition to a processing tray on which a sheet bundle is placed when performing a specific post-processing. The sheets conveyed from a preceding device (such as an image forming apparatus main body) are overlapped with the sheets stored in the storage conveyance path, and both sheets are conveyed to the processing tray (see, for example, Patent Document 1). Further, in this post-processing device, when conveying a sheet or a sheet bundle from the storage conveyance path to the processing tray, the leading end portion of the sheet or the sheet bundle is projected from the discharge port, and then the sheet or the sheet bundle is switched back and conveyed to the processing tray.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, since the conveyance path when conveying a sheet or a sheet bundle from the storage conveyance path to the processing tray partially overlaps with the conveyance path when conveying the sheet bundle on the processing tray to the discharge tray after post-processing, after the post-processed sheet bundle is discharged, the subsequent sheet or sheet bundle is conveyed from the storage conveyance path to the processing tray. Therefore, the post-processing for the subsequent sheet bundle is delayed.

[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 suppress a delay in post-processing for a subsequent sheet bundle when continuously performing post-processing on a plurality of sheet bundles. [Means for solving the problem]

[0006] The post-processing device according to the present invention comprises a processing unit that performs post-processing on a sheet bundle on a processing tray, a discharge roller that discharges the sheet bundle after the post-processing through a discharge port, a temporary transport path that can temporarily move subsequent sheets during the post-processing of the sheet bundle, a transport roller that pulls subsequent sheets into the temporary transport path and transports the subsequent sheets from the temporary transport path to the processing tray, and a controller that controls the processing unit, the discharge roller, and the transport roller. The controller then performs simultaneous transport of the sheet bundle and the subsequent sheets after the post-processing, and in the simultaneous transport, (a) when the sheet bundle is discharged through the discharge port, the transport roller is controlled to transport the subsequent sheets to the discharge roller so that the subsequent sheets partially overlap the sheet bundle and protrude from the discharge port, and (b) after the rear end of the sheet bundle has passed the discharge port, the discharge roller is reversed to transport the subsequent sheets to the processing tray.

[0007] The image forming apparatus according to the present invention comprises the above-described post-processing device and an image forming apparatus main body that outputs each sheet of the sheet bundle and the subsequent sheets to the post-processing device. [Effects of the Invention]

[0008] According to the present invention, a post-processing device and an image forming apparatus are obtained that suppress delays in post-processing for subsequent sheet bundles when post-processing is performed on multiple sheet bundles in succession.

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

[0010] [Figure 1] Figure 1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. [Figure 2]Figure 2 is a side view showing the mechanical configuration of the post-processing device 1b in Figure 1. [Figure 3] Figure 3 is a block diagram showing the electrical configuration of the post-processing device 1b in Figure 1. [Figure 4] Figure 4 illustrates the transport of the sheet to the processing tray 23 (1 / 2). [Figure 5] Figure 5 illustrates the transport of the sheet to the processing tray 23 (2 / 2). [Figure 6] Figure 6 is a diagram illustrating simultaneous transport (1 / 3). [Figure 7] Figure 7 illustrates simultaneous transport (2 / 3). [Figure 8] Figure 8 illustrates simultaneous transport (3 / 3). [Figure 9] Figure 9 illustrates the operation of the sheet transport and cursor unit when the post-processing is stapling. [Figure 10] Figure 10 is a flowchart illustrating the sheet transport operation of the post-processing device 1b shown in Figures 1 to 3. [Figure 11] Figure 11 is a diagram showing an example of the criteria for determining whether or not to perform simultaneous transport in Embodiment 2. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the figures.

[0012] Embodiment 1.

[0013] Figure 1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 shown in Figure 1 is a multifunction device having a printing function, an image reading function, a facsimile function, and the like.

[0014] As shown in FIG. 1, the image forming apparatus 1 includes an image forming apparatus main body (hereinafter also referred to as the apparatus main body) 1a and a post-processing apparatus 1b. The apparatus main body 1a includes, in addition to an operation panel, an image reading apparatus, a printing apparatus, a storage apparatus, a controller, etc. For example, it prints an image on a print sheet (hereinafter also simply referred to as a sheet) by an electrophotographic method and outputs the print sheet to the post-processing apparatus 1b. The post-processing apparatus 1b performs post-processing (stapling processing, sorting processing, etc.) on the print sheet conveyed from the apparatus main body 1a.

[0015] FIG. 2 is a side view showing the mechanical configuration of the post-processing apparatus 1b in FIG. 1. The post-processing apparatus 1b shown in FIG. 2 includes a conveyance roller 11, a conveyance roller 12, a path switching member 13, an intermediate roller 21, a stopper guide 22, a processing tray 23, a discharge roller 24, a discharge tray 25, and a processing unit 26.

[0016] Furthermore, the post-processing apparatus 1b includes a main conveyance path 10a and a bypass conveyance path 10b. The main conveyance path 10a is a conveyance path for conveying the sheet output from the image forming apparatus main body 1a (front-stage apparatus) by the conveyance roller 11. The bypass conveyance path 10b is a conveyance path capable of bypassing subsequent sheets during the post-processing of the sheet bundle on the processing tray 23.

[0017] The conveyance roller 11 moves the sheet conveyed to the post-processing apparatus 1b along the main conveyance path 10a.

[0018] The conveyance roller 12 is a conveyance roller that (together with the intermediate roller 21) draws the sheet conveyed in the main conveyance path 10a into the bypass conveyance path 10b and conveys the sheet from the bypass conveyance path 10b to the processing tray 23.

[0019] The intermediate roller 21 conveys the sheet conveyed in the main conveyance path 10a above the processing tray 23.

[0020] Note that the conveyance rollers 11, 12 and the intermediate roller 21 are driven by a motor (motor 42 described later) not shown.

[0021] The stopper guide 22 is positioned on one end of the processing tray 23, and the edge of the sheet on the processing tray 23 makes contact with it.

[0022] The processing tray 23 is an inclined, roughly plate-shaped member on which one or more sheets (sheet bundles) to be processed are placed. Post-processing (stapling, sorting, etc.) is performed on the sheet bundles placed on the processing tray 23.

[0023] When the sheets are transported to the processing tray 23, specifically, after the rear end of the sheet passes through the intermediate roller 21, the sheet is guided to the processing tray 23 by contact from a sheet contact member (not shown), and is brought into contact with the stopper guide 22 by a retraction paddle (not shown) to align. In this way, the sheet bundle is aligned in the transport direction by the stopper guide 22. In the direction perpendicular to the transport direction, the sheet bundle on the processing tray 23 is aligned by a cursor unit (not shown). The cursor unit aligns the sheet bundle by driving, for example, a contact member (cursor) with a motor or actuator to bring it into contact with the side of the sheet bundle.

[0024] The discharge rollers 24 are spaced apart from each other until post-processing is complete, so that the sheet bundle on the processing tray 23 and subsequent sheets can move through the gap between the discharge rollers 24 (discharge port 24a). After post-processing is complete, the sheet bundle is nipped and transported (discharged) onto the discharge tray 25 via the discharge port 24a.

[0025] The discharge tray 25 is a component on which the sheet bundles after post-processing are placed, and is capable of being raised and lowered.

[0026] The processing unit 26 performs post-processing on the sheet stack on the processing tray 23. Post-processing includes stapling and sorting. In other words, the processing unit 26 is equipped with a stapler and the aforementioned cursor unit, and performs stapling with the stapler and sorting with the cursor unit.

[0027] Figure 3 is a block diagram showing the electrical configuration of the post-processing device 1b in Figure 1. As shown in Figure 3, the post-processing device 1b further comprises a controller 41 and a motor 42 that drives the transport rollers 11, 12, intermediate roller 21, discharge roller 24, etc.

[0028] The controller 41 operates according to commands from the image forming apparatus main body 1a, controlling the motors 42 (i.e., transport rollers 11, 12, intermediate roller 21, discharge roller 24, etc.) to transport sheets from the image forming apparatus main body 1a, and controlling the processing unit 26 to perform post-processing.

[0029] Figures 4 and 5 illustrate the transport of sheets to the processing tray 23.

[0030] When using the evacuated transport path 10b, the controller 41 controls the transport rollers 11, 12 and the intermediate roller 21 to sequentially transport the sheets 101 and 102 that have been transported on the main transport path 10a to the evacuated transport path 10b, for example, as shown in Figure 4.

[0031] For example, when post-processing is performed for every three sheets, as shown in Figure 4, two sheets 101 and 102 are moved to the temporary transport path 10b. Then, as shown in Figure 5, when the third sheet 103 is transported on the main transport path 10a, the controller 41 uses the transport rollers 12 and intermediate rollers 21 to overlap the two sheets 101 and 102 on the temporary transport path 10b with sheet 103, and transports sheets 101, 102, and 103 onto the processing tray 23. As a result, the three sheets 101, 102, and 103 are placed on the processing tray 23.

[0032] Figures 6 to 8 illustrate simultaneous transport.

[0033] Furthermore, the controller 41 performs simultaneous transport of the sheet bundle 111 after post-processing and subsequent sheets (sheet bundle 211 such as the sheets 101-103 described above) as shown in Figures 6 to 8. During simultaneous transport, the controller 41 (a) when discharging the sheet bundle 111 after post-processing through the discharge port 24a, it controls the transport roller 12 to transport the subsequent sheets (sheet bundle 211) to the discharge roller 24 so that they partially overlap the sheet bundle, as shown in Figure 6, and cause them to protrude from the discharge port 24a, and (b) after the rear end of the sheet bundle 111 has passed the discharge port 24a, as shown in Figure 7, it reverses the discharge roller 24 to transport the subsequent sheets (sheet bundle 211) to the processing tray 23, as shown in Figure 8, for example.

[0034] Figure 9 illustrates the operation of the sheet transport and cursor unit when the post-processing is stapling.

[0035] Furthermore, the controller 41 controls the cursor unit to (a) cause the cursor unit to align the sheet bundles on the processing tray 23 before post-processing, and (b) cause the cursor unit to release the sheet bundles on the processing tray 23 after post-processing and before the sheet bundles are discharged.

[0036] For example, when stapling is performed on three sheet bundles of three sheets each, as shown in Figure 9, when the first bundle of three sheets is transported to the processing tray 23 as described above, the first bundle of sheets is aligned at the cursor unit before stapling is performed. Note that when the first bundle of sheets is transported to the processing tray 23, there are no sheet bundles in the processing tray 23, so simultaneous transport does not occur.

[0037] Immediately after post-processing (stapling), the cursor unit releases the sheet bundle, and simultaneously, the first sheet bundle is discharged into the discharge tray 25, while the second bundle of three sheets is transported to the processing tray 23.

[0038] Then, the second sheet bundle is aligned at the cursor unit before stapling is performed. Immediately after post-processing (stapling), the cursor unit releases the sheet bundle, and simultaneously, the second sheet bundle is discharged into the discharge tray 25, while the three sheets of the third bundle are transported to the processing tray 23.

[0039] Then, the third sheet bundle is aligned at the cursor unit before stapling is performed. Immediately after post-processing (stapling), the cursor unit releases the sheet bundle, and the third sheet bundle is discharged into the discharge tray 25. Note that when the third (i.e., final) sheet bundle is transported to the discharge tray 25, there are no subsequent sheets, so simultaneous transport does not occur.

[0040] Furthermore, the controller 41 (a) determines whether or not to move the subsequent sheet to the retraction transport path 10b based on commands from the main unit 1a, (b1) if the subsequent sheet is to be moved to the retraction transport path 10b, it performs the simultaneous transport described above, and (b2) if the subsequent sheet is not to be moved to the retraction transport path 10b, it does not perform simultaneous transport, discharges the sheet bundle after post-processing with the discharge roller 24, and then transports the subsequent sheet to the processing tray 23 with the intermediate roller 21 without going through the retraction transport path 10b.

[0041] Next, the sheet transport operation of the post-processing device 1b will be described. Figure 10 is a flowchart illustrating the sheet transport operation of the post-processing device 1b shown in Figures 1 to 3.

[0042] The controller 41 performs the following processing each time a sheet is transported to the post-processing device 1b.

[0043] First, the controller 41 determines whether or not to use the evacuating transport path 10b (step S1). If the evacuating transport path 10b is not used, the controller 41 transports the sheet to the processing tray 23 (step S2).

[0044] On the other hand, when using the evacuated transport path 10b, the controller 41 determines whether the number of sheets on the evacuated transport path 10b is a predetermined number (step S3). For example, if post-processing is performed every three sheets as described above, this predetermined number will be two. In other words, the predetermined number is one less than the number of sheets in the sheet bundle subject to post-processing.

[0045] If the number of sheets on the siding transport path 10b is not the predetermined number, the controller 41 determines whether the current sheet is the last sheet in the sheet bundle to be processed (step S4). If the current sheet is not the last sheet, the controller 41 transports the current sheet to the siding transport path 10b (step S5).

[0046] Then, in step S4, if the current sheet is the final sheet, and in step S3, if there is a predetermined number of sheets on the siding transport path 10b, the controller 41 determines whether or not there is a sheet bundle (previous sheet bundle) on the processing tray 23 (step S6). If there is no sheet bundle on the processing tray 23, the controller 41 transports the current sheet to the processing tray 23 together with the sheets on the siding transport path 10b (step S2).

[0047] On the other hand, if there is a sheet bundle (previous sheet bundle) on the processing tray 23, the controller 41 performs simultaneous transport, discharges the previous sheet bundle, and transports the current sheet, along with the sheet on the siding transport path 10b, to the processing tray 23 (step S7).

[0048] As described above, according to Embodiment 1, the processing unit 26 performs post-processing on the sheet bundle on the processing tray 23. The discharge roller 24 discharges the sheet bundle after post-processing through the discharge port 24a. The retraction transport path 10b is a transport path that can retract subsequent sheets during the post-processing of the sheet bundle. The transport roller 12 pulls subsequent sheets into the retraction transport path 10b and transports the subsequent sheets from the retraction transport path 10b to the processing tray 23. The controller 41 then performs simultaneous transport of the sheet bundle after post-processing and the subsequent sheets. In simultaneous transport, (a) when discharging the sheet bundle through the discharge port 24a, the transport roller 12 is controlled to transport the subsequent sheets to the discharge roller 24 so that they partially overlap the sheet bundle and protrude from the discharge port 24a, and (b) after the rear end of the sheet bundle has passed the discharge port 24a, the discharge roller 24 is reversed to transport the subsequent sheets to the processing tray 23.

[0049] As a result, simultaneous transport suppresses delays in the transport of subsequent sheets, thus reducing delays in post-processing for subsequent sheet bundles when performing post-processing on multiple sheet bundles consecutively.

[0050] Embodiment 2.

[0051] Figure 11 is a diagram showing an example of the criteria for determining whether or not to perform simultaneous transport in Embodiment 2.

[0052] For example, as shown in Figure 11, the controller 41 (a) does not perform simultaneous transport if the sheet size of the subsequent sheet is different from the sheet size of the sheet bundle after post-processing, and (b) performs simultaneous transport if the sheet size of the subsequent sheet is the same as the sheet size of the sheet bundle after post-processing, the type of post-processing applied to the subsequent sheet is the same as the type of post-processing applied to the sheet bundle after post-processing, and the subsequent sheet is to be moved to the evacuated transport path 10b. Note that the normal transport in Figure 11 is sheet transport in which the subsequent sheet is transported to the processing tray 23 after the discharge of the sheet bundle after post-processing is completed.

[0053] The other configurations and operations of the post-processing device according to Embodiment 2 are the same as those of Embodiment 1, so their description will be omitted.

[0054] Furthermore, various changes and modifications to the embodiments described above will be obvious to those skilled in the art. Such changes and modifications may be made without deviating from the spirit and scope of the subject matter and without diminishing the intended advantages. In other words, such changes and modifications are intended to be included in the claims. [Industrial applicability]

[0055] The present invention can be applied, for example, to a post-processing device for an image forming apparatus such as a multifunction printer. [Explanation of symbols]

[0056] 1. Image forming apparatus 1a Image forming apparatus main unit 1b Post-processing device 10a Main transport path 10b Evacuation transport route 12 Conveyor rollers 21 Intermediate Roller 23 Processing trays 24 discharge rollers 24a Outlet 26 Processing Unit 41 Controllers

Claims

1. A processing unit that performs post-processing on a stack of sheets on a processing tray, A discharge roller that discharges the sheet bundle after the aforementioned post-processing through a discharge port, A retraction transport path that allows subsequent sheets to be moved aside during the post-processing of the aforementioned sheet bundle, A conveying roller that pulls the subsequent sheet into the aforementioned evacuating conveying path and conveys the subsequent sheet from the evacuating conveying path to the processing tray, The processing unit, the discharge roller, and the controller for controlling the transport roller are provided. The controller performs simultaneous transport of the sheet bundle and the subsequent sheet after the post-processing, and in the simultaneous transport, (a) when the sheet bundle is discharged through the discharge port, the transport roller is controlled to transport the subsequent sheet to the discharge roller so that the subsequent sheet partially overlaps the sheet bundle and protrudes from the discharge port, and (b) after the rear end of the sheet bundle has passed the discharge port, the discharge roller is reversed to transport the subsequent sheet to the processing tray. A post-processing device characterized by the following.

2. The system further includes a cursor unit for aligning the sheet stack on the processing tray, The controller controls the cursor unit to (a) cause the cursor unit to align the sheet bundle before the post-processing, and (b) cause the cursor unit to release the sheet bundle after the post-processing and before the sheet bundle is discharged. A post-processing apparatus according to claim 1, characterized by the following:

3. It is further equipped with intermediate rollers that transport the sheets that are transported from the preceding device, The controller (a) determines whether or not to move the subsequent sheet to the temporary transport path, (b1) if the subsequent sheet is to be moved to the temporary transport path, executes the simultaneous transport, and (b2) if the subsequent sheet is not to be moved to the temporary transport path, does not execute the simultaneous transport, discharges the sheet bundle after the post-processing using the discharge roller, and then transports the subsequent sheet to the processing tray by the intermediate roller without going through the temporary transport path. A post-processing apparatus according to claim 1, characterized by the following:

4. The post-processing device according to claim 1, characterized in that (a) if the sheet size of the subsequent sheet is different from the sheet size of the sheet bundle, the controller does not perform the simultaneous transport, and (b) if the sheet size of the subsequent sheet is the same as the sheet size of the sheet bundle, and the type of post-processing for the subsequent sheet is the same as the type of post-processing for the sheet bundle, and the subsequent sheet is to be moved to a siding transport path.

5. A post-processing device according to any one of claims 1 to 4, An image forming apparatus main body that outputs each sheet of the sheet bundle and the subsequent sheets to the post-processing device, An image forming apparatus characterized by comprising:

Images