POSTPROCESSING APPARATUS AND IMAGE FORMING APPARATUS

Abstract

A processing unit performs a postprocess for a sheet bunch on a processing tray. In a waiting transportation path, a subsequent sheet can wait while the postprocess is performed for the sheet bunch. If sheet transportation is suspended, a controller determines whether concurrent transportation is performed or not on the basis of whether there is the sheet bunch on the processing tray and whether there is the subsequent sheet in the waiting transportation path. In the concurrent transportation, when the sheet bunch is outputted through an ejection port, the controller transports the subsequent sheet to an output roller and causes the subsequent sheet to protrude from the ejection port such that the subsequent sheet partially overlaps the sheet bunch, and after a rear end of the sheet bunch passes through the ejection port, the controller reverses the output roller and transports the subsequent sheet to the processing tray.

Claims

1. A postprocessing apparatus configured to perform a postprocess for a sheet bunch of a sheet transported from a previous-stage device, comprising: a processing unit configured to perform the postprocess for the sheet bunch on a processing tray; an output roller configured to output the sheet bunch after the postprocess through an ejection port; a waiting transportation path in which a subsequent sheet can wait while the postprocess is performed for the sheet bunch; a transportation roller configured to draw the subsequent sheet to the waiting transportation path and transport the subsequent sheet from the waiting transportation path to the processing tray; and a controller configured to control the processing unit, the output roller, and the transportation roller; wherein if transportation of a sheet is suspended, the controller determines whether concurrent transportation is performed or not on the basis of (a) whether there is the sheet bunch on the processing tray or not and (b) whether there is the subsequent sheet in the waiting transportation path or not; and in the concurrent transportation, (a) when the sheet bunch is outputted through the ejection port, the controller controls the transportation roller and thereby transports the subsequent sheet to the output roller and causes the subsequent sheet to protrude from the ejection port such that the subsequent sheet partially overlaps the sheet bunch, and (b) after a rear end of the sheet bunch passes through the ejection port, the controller reverses the output roller and transports the subsequent sheet to the processing tray.

2. The postprocessing apparatus according to claim 1, wherein if there is the sheet bunch on the processing tray and there is the subsequent sheet in the waiting transporting path when the transportation is suspended, then the controller performs the concurrent transportation.

3. The postprocessing apparatus according to claim 1, wherein if there is not the sheet bunch on the processing tray and there is the subsequent sheet in the waiting transporting path when the transportation is suspended, then the controller does not perform the concurrent transportation and controls the transportation roller and thereby immediately transports the subsequent sheet to the processing tray.

4. The postprocessing apparatus according to claim 3, wherein when the transportation is resumed after suspended, the controller controls the transportation roller and thereby does not transport a sheet incoming when the transportation is resumed to the waiting transportation path but transports the sheet to the processing tray.

5. The postprocessing apparatus according to claim 1, wherein if there is the sheet bunch on the processing tray and there is not the subsequent sheet in the waiting transporting path when the transportation is suspended, then the controller does not perform the concurrent transportation and (a) determines whether the postprocess has been performed for the sheet bunch on the processing tray or not, (b1) if the postprocess has been performed for the sheet bunch on the processing tray, controls the output roller and thereby immediately outputs the sheet bunch to the ejection port, and (b2) if the postprocess has not been performed for the sheet bunch on the processing tray, does not perform immediate output of the sheet bunch.

6. An image forming apparatus, comprising: a postprocessing apparatus configured to perform a postprocess for a sheet bunch of a sheet transported from a previous-stage device; and an image forming apparatus main body as the previous-stage device; wherein the postprocessing apparatus comprises: a processing unit configured to perform the postprocess for the sheet bunch on a processing tray; an output roller configured to output the sheet bunch after the postprocess through an ejection port; a waiting transportation path in which a subsequent sheet can wait while the postprocess is performed for the sheet bunch; a transportation roller configured to draw the subsequent sheet to the waiting transportation path and transport the subsequent sheet from the waiting transportation path to the processing tray; and a controller configured to control the processing unit, the output roller, and the transportation roller; wherein if transportation of a sheet is suspended, the controller determines whether concurrent transportation is performed or not on the basis of (a) whether there is the sheet bunch on the processing tray or not and (b) whether there is the subsequent sheet in the waiting transportation path or not; and in the concurrent transportation, (a) when the sheet bunch is outputted through the ejection port, the controller controls the transportation roller and thereby transports the subsequent sheet to the output roller and causes the subsequent sheet to protrude from the ejection port such that the subsequent sheet partially overlaps the sheet bunch, and (b) after a rear end of the sheet bunch passes through the ejection port, the controller reverses the output roller and transports the subsequent sheet to the processing tray.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 shows a perspective-view diagram that indicates an image forming apparatus according to an embodiment of the present disclosure;

[0009] FIG. 2 shows a side-view diagram that indicates a mechanical configuration of a postprocessing apparatus 1b shown in FIG. 1;

[0010] FIG. 3 shows a block diagram that indicates an electronic configuration of the postprocessing apparatus 1b shown in FIG. 1;

[0011] FIG. 4 shows a diagram that explains transportation of a sheet to a processing tray 23 (1/2);

[0012] FIG. 5 shows a diagram that explains transportation of a sheet to a processing tray 23 (2/2);

[0013] FIG. 6 shows a diagram that explains concurrent transportation (1/3);

[0014] FIG. 7 shows a diagram that explains concurrent transportation (2/3);

[0015] FIG. 8 shows a diagram that explains concurrent transportation (3/3);

[0016] FIG. 9 shows a diagram that explains sheet transportation and a behavior of a cursor unit when the postprocess is a stapling process.

[0017] FIG. 10 shows a flowchart that explains a sheet transportation operation of the postprocessing apparatus 1b shown in FIGS. 1 to 3 when sheet transportation suspension occurs.

DETAILED DESCRIPTION

[0018] Hereinafter, an embodiment according to an aspect of the present disclosure will be explained with reference to drawings.

[0019] FIG. 1 shows a perspective-view diagram that indicates an image forming apparatus according to an embodiment of the present disclosure. The image forming apparatus 1 shown in FIG. 1 is a multi function peripheral that has a printing function, an image scanning function, a facsimile function and the like.

[0020] As shown in FIG. 1, the image forming apparatus 1 includes an image forming apparatus main body (hereinafter, also called apparatus main body) 1a, and a postprocessing apparatus 1b. The apparatus main body 1a includes not only an operation panel but an image scanning device, a printing device, a storage device, a controller and the like, and prints an image on a print sheet (hereinafter, also simply called sheet) and outputs the print sheet to the postprocessing apparatus 1b. The postprocessing apparatus 1b performs a postprocess (i.e. a stapling process, a sorting process or the like) for print sheets transported from a previous-stage device (here, the apparatus main body 1a).

[0021] FIG. 2 shows a side-view diagram that indicates a mechanical configuration of a postprocessing apparatus 1b shown in FIG. 1. The postprocessing apparatus 1b includes a transportation roller 11, a transportation roller 12, a path changing member 13, an intermediate roller 21, a stopper guide 22, a processing tray 23, an output roller 24, an output tray 25, and a processing unit 26.

[0022] Further, the postprocessing apparatus 1b includes a main transportation path 10a and a waiting transportation path 10b. The main transportation path 10a is a transportation path to transport a sheet outputted from the image forming apparatus main body 1a (previous-stage device). The waiting transportation path 10b is a transportation path in which a subsequent sheet can wait while the postprocess is performed for a sheet bunch on the processing tray 23.

[0023] The transportation roller 11 causes a sheet transported to the postprocessing apparatus 1b to move along the main transportation path 10a.

[0024] The transportation roller 12 is a transportation roller that draws a sheet transported by the main transportation path 10a to the waiting transportation path 10b (with the intermediate roller 21) and transports the sheet from the waiting transportation path 10b to the processing tray 23.

[0025] The intermediate roller 21 transports a sheet transported by the main transportation path 10a to (a position over) the processing tray 23.

[0026] The transportation rollers 11 and 12 and the intermediate roller 21 are driven by an unshown motors (motors 42 mentioned below or the like).

[0027] The stopper guide 22 is arranged at an end of the processing tray 23, and an end of a sheet on the processing tray 23 contacts with the stopper guide 22.

[0028] The processing tray 23 is a member of a slanted planer shape, and a single sheet or plural sheets (a sheet bunch) as a target of the postprocess is/are put on the processing tray 23. The postprocess (stapling process, sorting process or the like) is performed for a sheet bunch put on the processing tray 23.

[0029] When a sheet is transported to the processing tray 23, specifically, after a rear end of the sheet passes through the intermediate roller 21, the sheet is guided to the processing tray 23 while making contact with a sheet contact member (not shown), and is caused to contact with the stopper guide 22 by a drawing paddle (not shown) and thereby the sheet is aligned. In this manner, the sheet bunch is aligned in its transportation direction by the stopper guide 22. In a perpendicular to the transportation direction, the sheet bunch on the processing tray 23 is aligned by a cursor unit (not shown). For example, the cursor unit drives contact members (cursors) using a motor, an actuator or the like and causes the contact members to contact with sides of the sheet bunch and thereby aligns the sheet bunch.

[0030] The output rollers 24 are apart from each other until the postprocess is finished such that the sheet bunch on the processing tray 23 and the subsequent sheet can move through a gap between the output rollers 24 (i.e. the ejection port 24a), and after finishing the postprocess, nip the sheet bunch and transport (output) the sheet bunch through the ejection port 24a onto the output tray 25.

[0031] The output tray 25 is a member on which the sheet bunch after the postprocess is put and is enabled to be lifted and lowered.

[0032] The processing unit 26 performs a postprocess for the sheet bunch on the processing tray 23. The postprocess is a stapling process, a sorting process, or the like. Specifically, the processing unit 26 includes a stapler, the aforementioned cursor unit, and the like, and performs the stapling process using the stapler or performs the sorting process using the cursor unit.

[0033] FIG. 3 shows a block diagram that indicates an electronic configuration of the postprocessing apparatus 1b shown in FIG. 1. As shown in FIG. 3, this postprocessing apparatus 1b further includes a controller 41, and motors 42 that drives the transportation rollers 11 and 12, the intermediate roller 21, the output roller 24, a communication device 43 that performs data communication with the apparatus main body 1a, and the like.

[0034] The controller 41 receives an instruction and a notification from the image forming apparatus main body 1a using the communication device 43, operates in accordance with the instruction, and controls the motors 42 (i.e. controls the transportation rollers 11 and 12, the intermediate roller 21, the output roller 24 and the like), and thereby performs transportation of a sheet from the image forming apparatus main body 1a, and controls the processing unit 26 and thereby causes the processing unit 26 to perform the postprocess.

[0035] FIGS. 4 and 5 show diagrams that explain transportation of a sheet to the processing tray 23.

[0036] If the waiting transportation path 10b is used, the controller 41 controls the transportation rollers 11 and 12 and the intermediate roller 21, and thereby, as shown in FIG. 4, for example, transports sheets 101 and 102 transported by the main transportation path 10a to the waiting transportation path 10b in turn.

[0037] For example, if the postprocess is performed for every three sheets, then as shown in FIG. 4, for example, after two sheets 101 and 102 is moved to the waiting transportation path 10b, when transporting the third sheet 103 using the main transportation path 10a as shown in FIG. 5, for example, the controller 41 causes the sheet 103 to overlap the two sheets 101 and 102 in the waiting transportation path 10b and transports the sheets 101 to 103 onto the processing tray 23 using the transportation roller 12 and the intermediate roller 21. Consequently, the three sheets 101 to 103 are put on the processing tray 23.

[0038] FIGS. 6 to 8 show diagrams that explain concurrent transportation.

[0039] Further, as shown in FIGS. 6 to 8, for example, the controller 41 performs concurrent transportation of a sheet bunch 111 after the postprocess and a subsequent sheet (a sheet bunch 211 like the aforementioned sheets 101 to 103). In the concurrent transportation, the controller 41 (a) as shown in FIG. 6, for example, when the sheet bunch 111 after the postprocess is outputted through the ejection port 24a, controls the transportation roller 12 and thereby transports the subsequent sheet (sheet bunch 211) to the output roller 24 and causes the subsequent sheet to protrude from the ejection port 24a such that the subsequent sheet (sheet bunch 211) partially overlaps the sheet bunch 111, and (b) after a rear end of the sheet bunch 111 passes through the ejection port 24a as shown in FIG. 7, for example, reverses the output roller 24 and transports the subsequent sheet (sheet bunch 211) to the processing tray 23 as shown in FIG. 8, for example.

[0040] FIG. 9 shows a diagram that explains sheet transportation and a behavior of a cursor unit when the postprocess is a stapling process.

[0041] Further, the controller 41 controls the aforementioned cursor unit and thereby (a) causes the cursor unit to perform alignment of the sheet bunch on the processing tray 23 before the postprocess, and (b) causes the cursor unit to release the sheet bunch before starting to output the sheet bunch after the postprocess.

[0042] For example, if the stapling process is performed for each of three copies of three sheets per copy, then as shown in FIG. 9, for example, after three sheets of the first copy are transported to the processing tray 23 as mentioned, a sheet bunch of the first copy is aligned by the cursor unit and then stapling of it is performed. When the sheets of the first copy are transported to the processing tray 23, the concurrent transportation is not performed because there is not a sheet bunch on the processing tray 23.

[0043] After the postprocess (stapling), the cursor unit immediately releases the sheet bunch, and in the concurrent transportation, the sheet bunch of the first copy is outputted to the output tray 25 and three sheets of the second copy are transported to the processing tray 23.

[0044] Subsequently, a sheet bunch of the second copy is aligned and then stapling of it is performed. After the postprocess (stapling), the cursor unit immediately releases the sheet bunch, and in the concurrent transportation, the sheet bunch of the second copy is outputted to the output tray 25 and three sheets of the third copy are transported to the processing tray 23.

[0045] Subsequently, a sheet bunch of the third copy is aligned and then stapling of it is performed. After the postprocess (stapling), the cursor unit immediately releases the sheet bunch, and in the concurrent transportation, the sheet bunch of the third copy is outputted to the output tray 25. When the sheets of the third (i.e. the last) copy is transported to the output tray 25, the concurrent transportation is not performed because there are no subsequent sheets.

[0046] Further, if transportation of a sheet from the previous-stage device (apparatus main body 1a) is temporarily suspended due to a specific event such as paper empty or toner empty, the controller 41 determines whether concurrent transportation is performed or not on the basis of (a) whether there is the sheet bunch on the processing tray 23 or not and (b) whether there is the subsequent sheet in the waiting transportation path 10b or not.

[0047] Regarding (a) whether there is the sheet bunch on the processing tray 23 or not and (b) whether there is the subsequent sheet in the waiting transportation path 10b or not, sheet sensors may be installed to the processing tray 23 and the waiting transportation path 10b and these may be determined on the basis of outputs of the sheet sensors, or these may be determined on the basis of a current status of sheet transportation in the postprocessing apparatus 1b.

[0048] Further, on the basis of a notification received by the communication device 43 from the previous-stage device (apparatus main body 1a), the controller 41 detects that transportation of a sheet from the previous-stage device is temporarily suspended. If a specific event such as paper empty or toner empty that should temporarily suspend output of a print sheet occurs in the previous-stage device (apparatus main body 1a), then the previous-stage device (apparatus main body 1a) transmits to the postprocessing apparatus 1b a notification that indicates suspension of the sheet transportation.

[0049] In this embodiment, if there is a sheet bunch on the processing tray 23 and there is a subsequent sheet in the waiting transportation path 10b when transportation of a sheet from the previous-stage device is suspended as mentioned, then the controller 41 determines that the concurrent transportation should be performed.

[0050] Further, in this embodiment, if there is not a sheet bunch on the processing tray 23 and there is a subsequent sheet in the waiting transportation path 10b when transportation of a sheet from the previous-stage device is suspended as mentioned, then the controller 41 does not perform the concurrent transportation but controls the transportation roller 12 and thereby immediately transports the subsequent sheet from the waiting transportation path 10b to the processing tray 23.

[0051] Further, when transportation of a sheet from the previous-stage device is resumed after the suspension, the controller 41 controls the transportation roller 12 and thereby does not transport a sheet incoming when the transportation is resumed to the waiting transportation path 10b but transports this sheet to the processing tray 23. Thus, a sheet that forms a sheet bunch together with a sheet that has transported to the processing tray 23 when the suspension occurs is directly transported to the processing tray 23 when the transportation is resumed. Resuming the sheet transportation is also detected on the basis of a notification from the apparatus main body 1a.

[0052] Further, in this embodiment, if there is the sheet bunch on the processing tray 23 and there is not the subsequent sheet in the waiting transporting path 10b when the transportation is suspended as mentioned, then the controller 41 does not perform the concurrent transportation, and determines whether the postprocess has been performed for the sheet bunch on the processing tray or not.

[0053] If the postprocess has been performed for the sheet bunch on the processing tray 23, then the controller 41 controls the output roller 24 and thereby immediately outputs the sheet bunch to the ejection port 24a. Contrarily, if the postprocess has not been performed for the sheet bunch on the processing tray 23, the controller 41 does not perform immediate output of the sheet bunch (specifically, output of the sheet bunch is performed after the postprocess is performed after the sheet transportation is resumed).

[0054] The following part explains a sheet transportation operation of the postprocessing apparatus 1b.

[0055] When a sheet is transported to the postprocessing apparatus 1b, the controller 41 performs the following process.

[0056] The controller 41 (a) moves to the waiting transportation path 10b one or more sheets of a number smaller by 1 than the number of sheets in a sheet bunch as a target of the postprocess to be performed, (b) transports the waiting sheet(s) and its subsequent sheet together to the processing tray 23, and (c) causes the processing unit 26 to perform the postprocess for these sheets (i.e. a sheet bunch).

[0057] Further, in parallel to the postprocess, the controller 41 moves a subsequent sheet to the waiting transportation path 10b, and performs the concurrent transportation for the sheet bunch after the postprocess and sheets of a next sheet bunch, and thereby outputs the sheet bunch after the postprocess to the output tray 25 and transports the next sheet bunch to the processing tray 23.

[0058] As mentioned, the postprocess is continuously performed for plural sheet bunches in turn.

[0059] The following part explains a sheet transportation operation behavior of the postprocessing apparatus 1b when sheet transportation suspension occurs in the previous-stage device. FIG. 10 shows a flowchart that explains a sheet transportation operation of the postprocessing apparatus 1b shown in FIGS. 1 to 3 when sheet transportation suspension occurs.

[0060] When receiving a suspension notification of the sheet transportation from the apparatus main body 1a, the controller 41 determines whether there is a sheet bunch on the processing tray 23 or not (in Step S1), and if it is determined that there is a sheet bunch on the processing tray 23, determines whether there is a sheet in the waiting transportation path 10b or not (in Step S2).

[0061] Subsequently, if there is a sheet in the waiting transportation path 10b, the controller 41 performs operation of the concurrent transportation as mentioned (in Step S3).

[0062] In this case, there is a sheet on the processing tray 23 when the sheet transportation from the apparatus main body 1a is resumed, and therefore, if the number of the sheet(s) on the processing tray 23 is equal to the number of sheets as unit of the postprocess (for example, if the postprocess is a stapling process for every three sheets, the unit is 3), then a subsequent sheet incoming when the sheet transportation is resumed is transported to the waiting transportation path 10b and the postprocess is performed for sheets (a sheet bunch) on the processing tray 23, and otherwise if not, a subsequent sheet incoming when the sheet transportation is resumed is directly transported to the processing tray 23 rather than to the waiting transportation path 10b.

[0063] Contrarily, if in Step S1 it is determined that there is not a sheet bunch on the processing tray 23, the controller 41 determines whether there is a sheet in the waiting transportation path 10b or not (in Step S4); and if it is determined that there is a sheet bunch on the processing tray 23, the controller 41 controls the transportation roller 12 and the intermediate roller 21 and thereby transports the sheet(s) in the waiting transportation path 10b to the processing tray 23 (because there is not a sheet bunch on the processing tray 23) (in Step S5).

[0064] In this case, as well, since there is a sheet on the processing tray 23 when the sheet transportation from the apparatus main body 1a is resumed, if the number of the sheet(s) on the processing tray 23 is equal to the number of sheets as unit of the postprocess, a subsequent sheet incoming when the sheet transportation is resumed is transported to the waiting transportation path 10b and the postprocess is performed for sheets (a sheet bunch) on the processing tray 23; and otherwise if not, a subsequent sheet incoming when the sheet transportation is resumed is directly transported to the processing tray 23 rather than to the waiting transportation path 10b.

[0065] Contrarily, if in Step S4 it is determined that there is not a sheet in the waiting transportation path 10b, the controller 41 does not perform the transportation operation.

[0066] In this case, since there are no sheets both on the processing tray 23 and in the waiting transportation path 10b, a subsequent sheet incoming when the sheet transportation is resumed may be directly transported to the processing tray 23 or may be transported to the waiting transportation path 10b at first and then may be transported to the processing tray 23 together with another sheet.

[0067] If in Step S2 it is determined that there is not a sheet in the waiting transportation path 10b, the controller 41 determines whether the postprocess has been performed for a sheet bunch on the processing tray 23 or not (in Step S6); and if the postprocess has been performed for a sheet bunch on the processing tray 23, the controller 41 controls the output roller 24 and the like and thereby transports the sheet bunch to the output tray 25 (in Step S7).

[0068] In this case, as well, since there are no sheets both on the processing tray 23 and in the waiting transportation path 10b, a subsequent sheet incoming when the sheet transportation is resumed may be directly transported to the processing tray 23 or may be transported to the waiting transportation path 10b at first and then may be transported to the processing tray 23 together with another sheet.

[0069] Contrarily, if the postprocess has not been performed for a sheet bunch on the processing tray 23, then the controller 41 does not perform the transportation operation and keeps the sheet bunch as it is.

[0070] In this case, since there is a sheet on the processing tray 23 when the sheet transportation from the apparatus main body 1a is resumed, if the number of the sheet(s) on the processing tray 23 is equal to the number of sheets as unit of the postprocess, a subsequent sheet incoming when the sheet transportation is resumed is transported to the waiting transportation path 10b and the postprocess is performed for sheets (a sheet bunch) on the processing tray 23; and otherwise if not, a subsequent sheet incoming when the sheet transportation is resumed is directly transported to the processing tray 23 rather than to the waiting transportation path 10b.

[0071] As mentioned, in the aforementioned embodiment, if transportation of a sheet from a previous-stage device is suspended, the controller 41 determines whether concurrent transportation is performed or not on the basis of (a) whether there is the sheet bunch on the processing tray 23 or not and (b) whether there is the subsequent sheet in the waiting transportation path 10b or not. In the concurrent transportation, (a) when the sheet bunch is outputted through the ejection port 24a, the controller 41 controls the transportation roller 12 and thereby transports the subsequent sheet to the output roller 24 and causes the subsequent sheet to protrude from the ejection port 24a such that the subsequent sheet partially overlaps the sheet bunch, and (b) after a rear end of the sheet bunch passes through the ejection port 24a, the controller 41 reverses the output roller 24 and transports the subsequent sheet to the processing tray 23.

[0072] Consequently, the concurrent transportation restrains transportation delay of the subsequent sheet and therefore when the postprocess is performed for plural continuous sheet bunches, delay on the postprocess for a subsequent sheet bunch is restrained. In addition, even if the sheet transportation from the previous-stage device is temporarily suspended, the postprocess is smoothly resumed when the sheet transportation is resumed.

[0073] It should be understood that various changes and modifications to the embodiments described herein 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 present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.