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] When the transport of sheets from the preceding device is interrupted, the controller determines whether or not to perform simultaneous transport based on the presence or absence of a sheet bundle on the processing tray 23 and the presence or absence of subsequent sheets in the siding transport path 10b. In simultaneous transport, the controller (a) when the sheet bundle is discharged through the discharge port 24a, controls the transport roller 12 to transport the subsequent sheets to the discharge roller 24 so that the subsequent sheets 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, reverses the discharge roller 24 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, and overlaps a sheet conveyed from a preceding device (such as an image forming apparatus main body) with a sheet stored in the storage conveyance path, and conveys both sheets 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 protruded 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 sheet bundle after post-processing 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 is a post-processing device that performs post-processing on a sheet bundle of sheets conveyed from a preceding device, and comprises a processing unit that performs the post-processing on the 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 determines whether to perform simultaneous transport based on the presence or absence of the sheet bundle on the processing tray and the presence or absence of the subsequent sheets in the temporary transport path when the transport of sheets from the preceding device is interrupted. In the simultaneous transport described above, the controller (a) when the sheet bundle is discharged through the discharge port, controls the transport roller 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 through the discharge port, reverses the discharge roller to transport the subsequent sheet to the processing tray.

[0007] The image forming apparatus according to the present invention comprises the above-described post-processing device and the image forming apparatus main body as the preceding 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 when sheet transport is interrupted. [Modes for carrying out the invention]

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

[0012] 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.

[0013] 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., and prints an image on a print sheet (hereinafter also simply referred to as a sheet) by, for example, 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 sheet bundle of the sheets conveyed from the preceding apparatus (here, the apparatus main body 1a).

[0014] 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.

[0015] 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 (preceding 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.

[0016] The conveyance roller 11 moves the sheet conveyed to the post-processing apparatus 1b along the main conveyance path 10a.

[0017] The conveyance roller 12 is a conveyance roller that draws the sheet conveyed in the main conveyance path 10a (together with the intermediate roller 21) into the bypass conveyance path 10b and conveys the sheet from the bypass conveyance path 10b to the processing tray 23.

[0018] The intermediate roller 21 conveys the sheet conveyed in the main conveyance path 10a above the processing tray 23.

[0019] The transport rollers 11 and 12 and the intermediate roller 21 are driven by a motor (motor 42, described later) or the like (not shown).

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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, a motor 42 that drives the transport rollers 11, 12, intermediate roller 21, discharge roller 24, etc., and a communication device 43 that performs data communication with the main device body 1a.

[0027] The controller 41 receives commands and notifications from the main unit 1a via the communication device 43, operates according to those commands, controls the motors 42 (i.e., transport rollers 11, 12, intermediate roller 21, discharge roller 24, etc.) to transport sheets from the main unit 1a of the image forming apparatus, and controls the processing unit 26 to perform post-processing.

[0028] Figures 4 and 5 illustrate the transport of sheets to the processing tray 23.

[0029] 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.

[0030] 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.

[0031] Figures 6 to 8 illustrate simultaneous transport.

[0032] 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.

[0033] Figure 9 illustrates the operation of the sheet transport and cursor unit when the post-processing is stapling.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Furthermore, if the transport of sheets from the preceding device (device body 1a) is temporarily interrupted due to events such as paper emptying or toner emptying, the controller 41 determines whether or not to perform the simultaneous transport described above based on the presence or absence of sheet bundles on the processing tray 23 and the presence or absence of subsequent sheets in the siding transport path 10b.

[0040] The presence or absence of sheet bundles on the processing tray 23 and the presence or absence of subsequent sheets in the retraction transport path 10b may be determined by providing sheet sensors on the processing tray 23 and the retraction transport path 10b and determining the presence or absence of subsequent sheets based on the output of the sheet sensors, or by determining the presence or absence of sheets based on the current sheet transport status within the post-processing device 1b.

[0041] Furthermore, the controller 41 detects that the sheet transport from the preceding device (device body 1a) has been temporarily interrupted, based on a notification from the preceding device (device body 1a) received by the communication device 43. In other words, when an event occurs within the preceding device (device body 1a) that should temporarily interrupt the output of the printed sheet, such as paper empty or toner empty, the preceding device (device body 1a) sends a notification to the post-processing device 1b indicating the interruption of sheet transport.

[0042] In this embodiment, if the transport of sheets from the preceding device is interrupted as described above, the controller 41 determines that simultaneous transport should be performed if there is a bundle of sheets on the processing tray 23 and there are subsequent sheets in the siding transport path 10b.

[0043] Furthermore, in this embodiment, if the transport of sheets from the preceding device is interrupted as described above, and there are no sheet bundles on the processing tray 23 and there are subsequent sheets in the siding transport path 10b, the controller 41 does not perform simultaneous transport, but immediately controls the transport rollers 12 to transport the subsequent sheets from the siding transport path 10b to the processing tray 23.

[0044] Then, when sheet transport from the preceding device is interrupted and then resumed, the controller 41 controls the transport rollers 12 to transport the sheets that are being transported when transport resumes (at least the first sheets transported after the restart) to the processing tray 23 without transporting them to the siding transport path 10b. In other words, the sheets that make up the sheet bundle together with the sheets that were transported from the siding transport path 10b to the processing tray during the interruption are transported directly to the processing tray 23 when transport resumes. The restart of sheet transport is also detected by notification from the main unit 1a of the device.

[0045] Furthermore, in this embodiment, if the transport of sheets from the preceding device is interrupted as described above, the controller 41 will not perform simultaneous transport if there is a sheet bundle on the processing tray 23 and there are no subsequent sheets in the siding transport path 10b, and will determine whether or not post-processing has already been performed on the sheet bundle on the processing tray 23.

[0046] If post-processing has been performed on the sheet bundle on the processing tray 23, the controller 41 immediately controls the discharge roller 24 to discharge the sheet bundle through the discharge port 24a. On the other hand, if post-processing has not been performed on the sheet bundle on the processing tray 23, the controller 41 does not immediately discharge the sheet bundle (specifically, the sheet bundle is discharged after post-processing has been performed following the interruption and resumption).

[0047] Next, we will explain the sheet transport operation of the post-processing device 1b.

[0048] When the sheet is transported to the post-processing device 1b, the controller 41 performs the following processing.

[0049] The controller 41 (a) moves one less sheet than the number of sheets in the sheet bundle corresponding to the post-processing to be performed to the temporary transport path 10b, (b) transports the temporary sheet and the next sheet together to the processing tray 23, and (c) causes the processing unit 26 to perform the post-processing on those sheets (i.e., the sheet bundle).

[0050] Then, in parallel with the post-processing, the controller 41 moves the subsequent sheets to the siding transport path 10b, simultaneously transports the sheets for the next sheet bundle and the sheet bundle after post-processing, discharges the sheet bundle after post-processing to the discharge tray 25, and transports the next sheet bundle to the processing tray 23.

[0051] In this way, post-processing is performed on multiple sheet bundles in succession.

[0052] Next, we will explain the sheet transport operation of the post-processing device 1b when sheet transport is interrupted in the preceding device. Figure 10 is a flowchart illustrating the sheet transport operation of the post-processing device 1b shown in Figures 1 to 3 when sheet transport is interrupted.

[0053] When the controller 41 receives a notification from the main unit 1a that sheet transport has been interrupted, it determines whether or not there is a sheet bundle on the processing tray 23 (step S1). If it determines that there is a sheet bundle on the processing tray 23, it determines whether or not there is a sheet on the siding transport path 10b (step S2).

[0054] Then, if there is a sheet in the evacuation transport path 10b, the controller 41 performs the simultaneous transport operation as described above (step S3).

[0055] In this case, when sheet transport from the main unit 1a is resumed, there are sheets on the processing tray 23. If the number of sheets matches the number of sheets in the processing unit for post-processing (for example, 3 sheets in the case of stapling in batches of 3), the subsequent sheets when sheet transport is resumed will be transported to the siding transport path 10b, and post-processing will be performed on the sheets (sheet bundle) on the processing tray 23. Otherwise, the subsequent sheets when sheet transport is resumed will be transported directly to the processing tray 23 instead of the siding transport path 10b.

[0056] On the other hand, if it is determined in step S1 that there is no sheet bundle on the processing tray 23, the controller 41 determines whether there is a sheet in the siding transport path 10b (step S4). If it is determined that there is a sheet in the siding transport path 10b, the controller 41 controls the transport rollers 12 and intermediate rollers 21 (because there is no sheet bundle on the processing tray 23) to transport the sheet in the siding transport path 10b to the processing tray 23 (step S5).

[0057] In this case as well, when sheet transport from the main unit 1a is resumed, there are sheets on the processing tray 23. If the number of sheets matches the number of sheets in the processing unit for post-processing, the subsequent sheets when sheet transport is resumed will be transported to the siding transport path 10b, and post-processing will be performed on the sheets (sheet bundle) on the processing tray 23. Otherwise, the subsequent sheets when sheet transport is resumed will be transported directly to the processing tray 23 instead of the siding transport path 10b.

[0058] On the other hand, if step S4 determines that there is no sheet in the evacuation transport path 10b, the controller 41 does not perform any transport operation.

[0059] In this case, since there are no sheets in either the processing tray 23 or the evacuating transport path 10b, subsequent sheets when processing resumes after sheet transport may be transported directly to the processing tray 23, or they may be transported to the evacuating transport path 10b first, and then transported together to the processing tray 23.

[0060] Furthermore, if it is determined in step S2 that there are no sheets in the evacuating transport path 10b, the controller 41 determines whether or not post-processing has been performed on the sheet bundle on the processing tray 23 (step S6). If post-processing has been performed on the sheet bundle on the processing tray 23, it controls the discharge roller 24, etc., to transport the sheet bundle to the discharge tray 25 (step S7).

[0061] In this case as well, since there are no sheets in either the processing tray 23 or the evacuating transport path 10b, subsequent sheets when processing resumes after sheet transport may be transported directly to the processing tray 23, or they may be transported to the evacuating transport path 10b first, and then transported together to the processing tray 23.

[0062] On the other hand, if post-processing has not been performed on the sheet bundle on the processing tray 23, the controller 41 does not perform any transport operation and leaves the sheet bundle as it is.

[0063] In this case, when sheet transport from the main unit 1a is resumed, there are sheets on the processing tray 23. If the number of sheets matches the number of sheets required for post-processing, the subsequent sheets when sheet transport is resumed will be transported to the siding transport path 10b, and post-processing will be performed on the sheets (sheet bundle) on the processing tray 23. Otherwise, the subsequent sheets when sheet transport is resumed will be transported directly to the processing tray 23 instead of the siding transport path 10b.

[0064] As described above, according to the above embodiment, when the transport of sheets from the preceding device is interrupted, the controller 41 determines whether or not to perform simultaneous transport based on the presence or absence of a sheet bundle on the processing tray 23 and the presence or absence of subsequent sheets in the escaping transport path 10b. In simultaneous transport, the controller 41 (a) when discharging the sheet bundle through the discharge port 24a, controls the transport roller 12 to transport the subsequent sheets to the discharge roller 24 so that the subsequent sheets 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, reverses the discharge roller 24 to transport the subsequent sheets to the processing tray 23.

[0065] 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. Furthermore, even if sheet transport from the preceding device is temporarily interrupted, post-processing can be smoothly resumed when sheet transport is restarted.

[0066] 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]

[0067] 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]

[0068] 1. Image forming apparatus 1a Image forming apparatus main unit (an example of a pre-stage device) 1b Post-processing device 10b Waiting transport path 12 Conveyor rollers 24 discharge rollers 24a Outlet 25 Discharge Trays 26 Processing Unit 41 Controllers

Claims

1. In a post-processing device that performs post-processing on sheet bundles of sheets conveyed from a preceding device, A processing unit that performs the post-processing on the sheet bundle on the 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, when the transport of sheets from the preceding device is interrupted, determines whether or not to perform simultaneous transport based on the presence or absence of the sheet bundle on the processing tray and the presence or absence of the subsequent sheets in the evacuating transport path. In the simultaneous transport described above, the controller (a) when the sheet bundle is discharged through the discharge port, controls the transport roller 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 through the discharge port, reverses the discharge roller to transport the subsequent sheet to the processing tray. A post-processing device characterized by the following.

2. The post-processing device according to claim 1, characterized in that the controller determines to perform simultaneous transport when the transport of sheets from the preceding device is interrupted, and there is a bundle of sheets on the processing tray and a subsequent sheet in the evacuating transport path.

3. The post-processing device according to claim 1, characterized in that, when the transport of sheets from the preceding device is interrupted, and there are no sheets on the processing tray and there are subsequent sheets in the siding transport path, the controller does not perform the simultaneous transport and immediately controls the transport rollers to transport the subsequent sheets to the processing tray.

4. The post-processing device according to claim 4, characterized in that, when the transport of sheets from the preceding device is interrupted and then resumed, the controller controls the transport rollers to transport the sheets to the processing tray without transporting them to the siding transport path when the transport is resumed.

5. The post-processing device according to claim 1, characterized in that, when the transport of sheets from the preceding device is interrupted, and there is a sheet bundle on the processing tray and no subsequent sheets in the evacuating transport path, the controller does not perform the simultaneous transport, (a) determines whether the post-processing on the sheet bundle on the processing tray has been completed, (b1) if the post-processing on the sheet bundle on the processing tray has been completed, it immediately controls the discharge roller to discharge the sheet bundle through the discharge port, and (b2) if the post-processing on the sheet bundle on the processing tray has not been completed, it does not immediately discharge the sheet bundle.

6. A post-processing device according to any one of claims 1 to 5, The image forming apparatus main body, which serves as the preceding device, An image forming apparatus characterized by comprising:

Images