JP2023087526A - Sheet post-processing device - Google Patents

Abstract

To provide a sheet post-processing device for folding a sheet, which can independently improve productivity related to sheet conveyance.SOLUTION: A sheet folding part 100 is disposed in parallel with a first sheet conveyance path 3, and folds a sheet conveyed on the first sheet conveyance path 3. A standby conveyance path 9 branches from a third branch part 33 closer to the downstream side of the first sheet conveyance path 3 than the sheet folding part 100. A post-processing control unit conveys, when two unprocessed sheets subsequent to the processed sheet to be folded are sequentially conveyed, the preceding first unprocessed sheet of the two unprocessed sheets to the standby conveyance path 9 to wait during a period for folding the processed sheet, conveys the succeeding second unprocessed sheet of the two unprocessed sheets to the third branch part 33 at the timing of completing the folding, resumes conveyance of the first unprocessed sheet, and conveys the processed sheet and the two unprocessed sheets in a stacked manner at the third branch part 33.SELECTED DRAWING: Figure 7

Description

1. Field of the Invention The present invention relates to a sheet post-processing apparatus that folds a sheet on which an image has been formed by an image forming apparatus.

2. Description of the Related Art There is known a sheet post-processing apparatus that folds a sheet on which an image has been formed by an image forming apparatus such as a copier or printer.

Conventional image forming systems and image forming apparatuses disclosed in Japanese Patent Application Laid-Open Nos. 2005-200003 and 2005-200012 perform folding processing when forming and outputting an image on a sheet bundle including sheets to be folded and sheets not to be folded. The order of the sheets to be printed is changed, and images are formed and output earlier than the original order. Then, while the sheets are being folded, the sheets on which the images are formed later than the original order and are not to be folded are output ahead of the sheets to be folded. returned to their original order. Accordingly, when an image is formed on a sheet bundle including sheets to be folded and output, it is possible to suppress a decrease in productivity.

Japanese Patent Application Laid-Open No. 2004-20882 Japanese Patent Application Laid-Open No. 2004-348028

However, in the conventional technique, it is necessary to change the order of the sheets in advance on the side of the image forming apparatus main body that performs image formation, and there is concern that the control of the image forming apparatus main body will be burdened. In other words, the conventional technology has a problem in that the sheet post-processing device for folding the sheet alone cannot improve the productivity related to sheet conveyance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet post-processing apparatus capable of improving the productivity associated with sheet conveyance by the sheet post-processing apparatus that folds sheets alone. With the goal.

In order to solve the above problems, the sheet post-processing apparatus of the present invention includes a sheet conveying path, a sheet folding section, a shunting conveying path, a tray section, and a control section. A sheet is conveyed through the sheet conveying path. The sheet folding section is arranged in parallel with the sheet conveying path, performs folding processing on the sheet conveyed from the sheet conveying path, and returns the sheet to the sheet conveying path. The shunting conveying path branches and extends from a shunting branch portion located downstream of the sheet folding portion in the sheet conveying direction of the sheet conveying path. The tray section is positioned downstream of the retraction branch section in the sheet conveying direction of the sheet conveying path, and the sheets are stacked thereon. The control section controls operations of the sheet conveying path, the sheet folding section, and the retraction branch section. When the control unit sequentially conveys two unprocessed sheets, which are not subjected to the folding process, to the tray unit on the sheet transport path, following the sheet to be processed which is subjected to the folding process in the sheet folding unit, During the period in which the sheet to be processed leaves the sheet conveying path when the folding process is performed in the sheet folding section, the first non-processing sheet, which precedes the two non-processing sheets, is transferred to the escape conveying path. Conveyed through the sheet conveying path and made to stand by, the following second non-processed sheet out of the two non-processed sheets is moved to the escape branch portion in synchronization with the completion timing of the folding process for the processed sheet. Conveyance of the first non-processing sheet is restarted while conveying the first non-processing sheet through the sheet conveying path, and the to-be-processed sheet, the first non-processing sheet and the second non-processing sheet are superimposed on each other at the shunting branch portion. Convey toward the tray section.

According to the configuration of the present invention, it is possible to advance the conveyance of subsequent non-processed sheets while the process-target sheets are being folded. Accordingly, it is possible to improve productivity related to sheet conveyance only by the sheet post-processing device that folds the sheet.

1 is a schematic cross-sectional front view of a sheet post-processing apparatus according to one embodiment of the present invention; FIG. FIG. 4 is a schematic front view of a Z-folded sheet; 2 is a partial cross-sectional front view showing the periphery of a sheet folding portion of the sheet post-processing apparatus of FIG. 1; FIG. FIG. 4 is a cross-sectional front view showing the periphery of the sheet folding portion in FIG. 3 , showing the first stage of transition of the Z-folding process of the sheet; FIG. 4 is a cross-sectional front view showing the periphery of the sheet folding portion in FIG. 3 , showing a second stage of transition of Z-folding of the sheet; FIG. 4 is a cross-sectional front view showing the periphery of the sheet folding portion in FIG. 3 , showing a third stage of transition of the Z-folding process of the sheet; FIG. 4 is a cross-sectional front view showing the periphery of the sheet folding portion in FIG. 3 , showing a fourth stage of transition of the Z-folding process of the sheet; FIG. 10 is an explanatory diagram showing timings and paths of sheet conveyance in a sheet post-processing apparatus of a comparative example; FIG. 4 is an explanatory diagram showing the sheet conveying timing and path in the sheet post-processing apparatus of the embodiment;

Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following contents.

FIG. 1 is a schematic cross-sectional front view of a sheet post-processing apparatus 1 according to an embodiment. The sheet post-processing apparatus 1 is detachably connected to, for example, a side surface of an image forming apparatus (not shown). The sheet post-processing apparatus 1 performs post-processing on sheets on which images have been formed (printed) by the image forming apparatus.

As shown in FIG. 1, the sheet post-processing apparatus 1 includes a sheet inlet 2, a first sheet conveying path (sheet conveying path) 3, a first sheet discharge portion 4, a second sheet conveying path 5, a second A second sheet discharge section 6 , a third sheet conveying path 7 , a third sheet discharging section 8 , a shunting conveying path 9 , a post-processing section 10 , and a post-processing control section (control section) 11 are provided.

The sheet inlet 2 is provided on a side surface of the sheet post-processing device 1 facing an image forming apparatus (not shown) and opens. A sheet conveyed from the image forming apparatus toward the sheet post-processing apparatus 1 is carried into the sheet post-processing apparatus 1 through the sheet inlet 2 .

The first sheet conveying path 3 extends substantially horizontally from the sheet inlet 2 to the first sheet discharge portion 4 in a direction away from the image forming apparatus (leftward in FIG. 1). In this description, the direction from the sheet inlet 2 to the first sheet discharge portion 4 is called the sheet conveying direction in the first sheet conveying path 3 . The sheet inlet 2 is located at the upstream end of the first sheet conveying path 3 in the sheet conveying direction.

The first sheet conveying path 3 has a plurality of conveying roller pairs 3r. The first sheet conveying path 3 conveys the sheet conveyed into the sheet post-processing apparatus 1 from the sheet inlet 2 toward the downstream side in the sheet conveying direction by the conveying roller pair 3r. Further, the conveying roller pair 3r can be reversely rotated to convey the sheet toward the upstream side in the sheet conveying direction.

The first sheet conveying path 3 has a first branch portion (folding branch portion) 31 , a second branch portion 32 , and a third branch portion (shelter branch portion) 33 . The first branch portion 31 , the second branch portion 32 , and the third branch portion 33 are arranged in order from the upstream side in the sheet conveying direction of the first sheet conveying path 3 . A first switching guide 311, a second switching guide 321, and a third switching guide 331 for switching the sheet conveying direction are individually provided in the first branching portion 31, the second branching portion 32, and the third branching portion 33, respectively. be done.

The first sheet discharge portion 4 is provided on the side of the sheet post-processing apparatus 1 opposite to the side facing the image forming apparatus. The first sheet discharge section 4 is arranged at the downstream end of the first sheet conveying path 3 in the sheet conveying direction. The first sheet discharge section 4 has a first discharge port 41 , a first discharge roller pair 42 and a first discharge tray 43 .

The first discharge port 41 is positioned at the downstream end of the first sheet conveying path 3 in the sheet conveying direction. The first discharge roller pair 42 is arranged at the first discharge port 41 . The first discharge tray 43 is positioned downstream of the first discharge port 41 in the sheet conveying direction. A sheet conveyed through the first sheet conveying path 3 and reaching the first discharge port 41 is discharged onto the first discharge tray 43 through the first discharge port 41 by the first discharge roller pair 42 . The first discharge tray 43 is one of the final discharge locations for sheets post-processed by the sheet post-processing apparatus 1 .

The second sheet conveying path 5 branches from a second branch portion 32 on the first sheet conveying path 3 and extends laterally in a direction away from the image forming apparatus (to the left in FIG. 1) to the second sheet discharge portion 6. , and extends upward. In this description, the direction from the second branch portion 32 to the second sheet discharge portion 6 is called the sheet conveying direction in the second sheet conveying path 5 . The second branch portion 32 is positioned at the upstream end of the second sheet conveying path 5 in the sheet conveying direction.

The second sheet conveying path 5 has a plurality of conveying roller pairs 5r. The second sheet conveying path 5 conveys the sheet separated from the first sheet conveying path 3 at the second branch portion 32 toward the downstream side in the sheet conveying direction by the conveying roller pair 5r. Further, the conveying roller pair 5r can be reversely rotated to convey the sheet toward the upstream side in the sheet conveying direction.

The second switching guide 321 of the second branch portion 32 switches the sheet conveyed on the first sheet conveying path 3 from the sheet inlet 2 side to the downstream end of the first sheet conveying path 3 in the sheet conveying direction (the first sheet). 4) and the second position (solid line P2 in FIG. 4) leading to the second sheet conveying path 5. As shown in FIG. Further, the second switching guide 321 is moved to the third position (broken line P3 in FIG. 4) for guiding the sheet that has undergone the folding process and passed through the second folding conveying path 106 to the second sheet conveying path 5 to the second sheet conveying path 5 . ). The second switching guide 321 is connected to a driving mechanism (not shown) and its operation is controlled by the post-processing control section 11 .

The second sheet discharge portion 6 is provided above the first sheet discharge portion 4 on the side of the sheet post-processing apparatus 1 opposite to the side facing the image forming apparatus. The second sheet discharge portion 6 is arranged at the downstream end of the second sheet conveying path 5 in the sheet conveying direction. The second sheet discharge section 6 has a second discharge port 61 , a second discharge roller pair 62 and a second discharge tray 63 .

The second discharge port 61 is positioned at the downstream end of the second sheet conveying path 5 in the sheet conveying direction. A second discharge roller pair 62 is arranged at the second discharge port 61 . The second discharge tray 63 is positioned downstream of the second discharge port 61 in the sheet conveying direction. The sheet conveyed through the second sheet conveying path 5 and reaching the second discharge port 61 is discharged onto the second discharge tray 63 through the second discharge port 61 by the second discharge roller pair 62 . The second discharge tray 63 is one of the final discharge locations for sheets post-processed by the sheet post-processing apparatus 1 . In addition, sheets that have not undergone post-processing, small-sized sheets, and the like may also be discharged to the second discharge tray 63 .

The third sheet conveying path 7 branches from a first branch portion 31 on the first sheet conveying path 3 and extends downward to the third sheet discharge portion 8 . In this description, the direction from the first branch portion 31 to the third sheet discharge portion 8 is called the sheet conveying direction in the third sheet conveying path 7 . The first branch portion 31 is positioned upstream in the sheet conveying direction of the second branch portion 32 on the first sheet conveying path 3 and is positioned at the upstream end of the third sheet conveying path 7 in the sheet conveying direction.

The third sheet conveying path 7 has a plurality of conveying roller pairs 7r. The third sheet conveying path 7 conveys the sheet separated from the first sheet conveying path 3 at the first branch portion 31 toward the downstream side in the sheet conveying direction by the conveying roller pair 7r. Further, the conveying roller pair 7r can be reversely rotated to convey the sheet toward the upstream side in the sheet conveying direction.

The first switching guide 311 of the first branch portion 31 switches the sheet conveyed on the first sheet conveying path 3 from the sheet inlet 2 side to the downstream end of the first sheet conveying path 3 in the sheet conveying direction (the first sheet). The first position leads to the discharge section 4 side or the second sheet discharge section 6 side) and the second position leads to the third sheet conveying path 7 . The first switching guide 311 is connected to a drive mechanism (not shown) and its operation is controlled by the post-processing control section 11 .

The third sheet discharge portion 8 is provided below the first sheet discharge portion 4 on the side of the sheet post-processing apparatus 1 opposite to the side facing the image forming apparatus. In other words, the third sheet discharge section 8 is arranged near the bottom of the sheet post-processing apparatus 1 . The third sheet discharge section 8 has a third discharge port 81 , a third discharge roller pair 82 and a third discharge tray 83 .

The third discharge port 81 is positioned at the downstream end of the third sheet conveying path 7 in the sheet conveying direction. A third discharge roller pair 82 is arranged at the third discharge port 81 . The third discharge tray 83 is located downstream of the third discharge port 81 in the sheet conveying direction. The sheet conveyed through the third sheet conveying path 7 and reaching the third discharge port 81 is discharged onto the third discharge tray 83 through the third discharge port 81 by the third discharge roller pair 82 . The third discharge tray 83 is one of the final discharge locations for sheets post-processed by the sheet post-processing apparatus 1 .

The shunting conveying path 9 branches off from a third branching portion (shunting branching portion) 33 on the first sheet conveying path 3, and extends below a sheet folding portion 100, which will be described later, in a direction toward the image forming apparatus (rightward direction in FIG. 1). ) and downward. That is, the shunting conveying path 9 extends toward the upstream side in the sheet conveying direction of the first sheet conveying path 3 at the third branch portion 33 . The third branching portion 33 is positioned downstream of the first branching portion 31 and the second branching portion 32 in the sheet conveying direction of the first sheet conveying path 3 and downstream of the sheet folding portion 100 . do.

In other words, the shunting conveying path 9 branches and extends from the third branch portion (shunting branch portion) 33 located downstream of the sheet folding portion 100 in the sheet conveying direction of the first sheet conveying path 3 . The shunting conveying path 9 has a pair of conveying rollers 9r for conveying sheets.

The third switching guide 331 of the third branch portion 33 switches the sheet conveyed on the first sheet conveying path 3 from the sheet inlet 2 side to the downstream end of the first sheet conveying path 3 in the sheet conveying direction (the first sheet). and a second position for guiding the sheet passing through the third branch 33 and switched back from the first sheet discharging portion 4 side to the shunting conveying path 9 . The third switching guide 331 is connected to a driving mechanism (not shown) and its operation is controlled by the post-processing control section 11 .

Post-processing section 10 performs predetermined post-processing on a sheet having an image formed by an image forming apparatus and carried into sheet post-processing apparatus 1 . The post-processing section 10 includes a punching section 10 a , a stapling section 10 b , a binding section 10 c , and a sheet folding section 100 .

The punching part 10 a is arranged immediately downstream of the sheet inlet 2 in the first sheet conveying path 3 . The punching section 10a can perform punching processing on the sheet conveyed on the first sheet conveying path 3 to form punch holes.

The stapling section 10b is arranged in the vicinity of the first sheet discharging section 4 at the downstream portion of the first sheet conveying path 3 in the sheet conveying direction. The stapling unit 10b can perform stapling processing (binding processing) on a sheet bundle formed by stacking a plurality of sheets to bind the sheet bundle.

A processing tray 10d is arranged downstream of the stapling unit 10b in the sheet conveying direction. Sheets conveyed through the first sheet conveying path 3 are stacked on the processing tray 10d, and predetermined processing including stapling is performed on the sheets. The "tray section" of the present invention includes the first discharge tray 43 and the processing tray 10d. That is, the tray portion is positioned downstream of the third branch portion 33 with respect to the sheet conveying direction of the first sheet conveying path 3, and the sheets are stacked thereon.

The binding section 10 c is arranged in the vicinity of the third sheet discharging section 8 at the downstream portion of the third sheet conveying path 7 in the sheet conveying direction. The binding portion 10c has a center-folding portion 10e and a center-stitching portion 10f. The binding unit 10c can form a booklet by subjecting a sheet bundle formed by stacking a plurality of sheets to center-folding and saddle-stitching by folding and binding approximately the central portion in the sheet conveying direction.

The sheet folding section 100 is arranged in the first sheet conveying path 3 downstream of the punching section 10a and upstream of the staple section 10b. In other words, the sheet folding section 100 is arranged in parallel with the first sheet conveying path 3 and positioned upstream of the third branching section 33 of the first sheet conveying path 3 in the sheet conveying direction. The sheet folding unit 100 can perform folding processing on one sheet to form folds.

The sheet folding unit 100 performs folding processes such as two-fold, Z-fold, outward three-fold, inward three-fold, and four-fold on the sheet conveyed from the first sheet conveying path 3 . can be returned to For example, FIG. 2 is a schematic front view of a sheet S that is Z-folded.

2, the downstream portion of the sheet S in the sheet conveying direction in the first sheet conveying path 3 is folded into a Z shape when viewed from the sheet width direction perpendicular to the sheet conveying direction. How to fold. In Z-folding, the downstream portion Sd of the sheet S on the downstream side of the first fold line F1 with respect to the sheet conveying direction in the first sheet conveying path 3 and the upstream portion Su of the sheet S on the upstream side of the second fold line F2 are The two fold lines F1 and F2 are vertically opposed across an intermediate portion Sc. The lengths of the downstream portion Sd and the intermediate portion Sc of the sheet S with respect to the sheet conveying direction are substantially the same and shorter than the length of the upstream portion Su.

A detailed configuration of the sheet folding unit 100 will be described later.

The post-processing control section 11 includes a CPU, an image processing section, a storage section, and other electronic circuits and electronic components (all not shown). Post-processing control section 11 is communicably connected to a body control section of an image forming apparatus (not shown). The post-processing control unit 11 receives commands from the body control unit, and uses the CPU to control the operation of each component provided in the sheet post-processing apparatus 1 based on control programs and data stored in the storage unit. Then, processing related to the functions of the sheet post-processing apparatus 1 is performed. First sheet conveying path 3, first sheet discharging section 4, second sheet conveying path 5, second sheet discharging section 6, third sheet conveying path 7, third sheet discharging section 8, escape conveying path 9, and post-processing Each of the units 10 individually receives a command from the post-processing control unit 11 and performs post-processing on the sheet in conjunction. Note that the function of the post-processing control unit (control unit) 11 may be provided by the main body control unit of the image forming apparatus.

Next, the configuration of the sheet folding section 100 will be described with reference to FIG. 3 . FIG. 3 is a partial cross-sectional front view showing the periphery of the sheet folding unit 100 of the sheet post-processing apparatus 1 of FIG. The sheet folding section 100 includes a first folding branching section (folding branching section) 101, a first folding conveying path 102, a first pair of folding rollers 103, a first folding guide (first switching guide 311), a second A folding and branching portion 105 , a second folding conveying path 106 , a second folding roller pair 107 , and a second folding guide 108 are provided.

The first folding branch portion 101 is arranged on the first sheet conveying path 3 . More specifically, the first folding branch portion 101 is located on the first branch portion 31 downstream in the sheet conveying direction from the arrangement location of the punching portion 10a (see FIG. 1) on the first sheet conveying path 3. To position.

The first folding conveying path 102 is configured as an upstream portion of the third sheet conveying path 7 in the sheet conveying direction. That is, the first folding conveying path 102 branches off from the first folding branch portion 101 (first branch portion 31 ) on the first sheet conveying path 3 and extends. As shown in FIG. 3, in the present embodiment, the first folding conveying path 102 extends downward from the first folding branch portion 101 substantially vertically. The first folding conveying path 102 receives the sheet conveyed on the first sheet conveying path 3 into the sheet folding section 100 .

The first folding roller pair 103 is arranged on the first folding conveying path 102 at the first folding branch portion 101 . The first folding roller pair 103 is composed of a first roller 111 and a second roller 112 . The first folding roller pair 103 forms a first folding nip portion N1 by one of the first roller 111 and the second roller 112 being urged toward the other and coming into contact with each other. The sheet entering the first folding conveying path 102 passes through the first folding nip portion N<b>1 and is conveyed toward the lower side of the first folding roller pair 103 .

Note that the second roller 112 is also used as one of the rollers constituting one transport roller pair 3 r on the first sheet transport path 3 .

The first switching guide 311 of the first folding branch portion 101 (first branch portion 31) functions as a first folding guide. A first switching guide 311, which is a first folding guide, is arranged to face the first folding nip portion N1 at the first folding branch portion 101. As shown in FIG. Specifically, the first switching guide 311 is arranged on the upstream side of the first folding conveying path 102 in the sheet conveying direction with respect to the first folding nip portion N1, that is, on the upper side of the first folding nip portion N1 in FIG. . When the sheet is not to be folded, the first switching guide 311 is retracted in a direction away from the first folding nip portion N1 relative to the first sheet transport path 3, that is, above the first sheet transport path 3 in FIG. . As a result, the sheet passing through the first sheet conveying path 3 does not contact the first switching guide 311 .

The first switching guide 311 is connected to a drive mechanism (not shown) and is capable of reciprocating in directions approaching and separating from the first folding nip portion N1. The first switching guide 311 guides the sheet conveyed on the first sheet conveying path 3 to the first folding nip portion N1.

The second folding branch portion 105 is arranged on the first folding conveying path 102 . More specifically, the second folding branch portion 105 is located downstream of the first folding roller pair 103 in the sheet conveying direction on the first folding conveying path 102 and further than the first folding nip portion N1. located on the lower side.

The second folding conveying path 106 branches off from the second folding branch portion 105 on the first folding conveying path 102 and extends. The second folding conveying path 106 extends from the second folding branch portion 105 to the side surface of the sheet post-processing apparatus 1 where the first sheet discharge portion 4 is provided, that is, toward the left side in FIG. In other words, the second folding conveying path 106 extends in substantially the same direction as the extending direction of the first sheet conveying path 3 .

The first sheet conveying path 3 has a confluence portion 34 . The confluence portion 34 is located downstream of the second branch portion 32 and upstream of the third branch portion 33 in the sheet conveying direction. The second folding conveying path 106 merges with the first sheet conveying path 3 at the junction 34 and returns the sheet folded in the sheet folding section 100 to the first sheet conveying path 3 . In other words, the merging portion 34 is located downstream of the second branch portion 32 of the first sheet conveying path 3 in the sheet conveying direction, and the sheets folded by the sheet folding portion 100 merge.

Specifically, in the present embodiment, the merging portion 34 is positioned near the second switching guide 321 . As shown in FIG. 3 , the second switching guide 321 guides the sheet conveyed on the first sheet conveying path 3 from the sheet inlet 2 side to the second sheet conveying path 5 at the second position at the junction 34 . The folded sheet joining the first sheet conveying path 3 is guided to the downstream end side of the first sheet conveying path 3 in the sheet conveying direction. The second switching guide 321 closes the upstream side of the first sheet conveying path 3 in the sheet conveying direction at the junction 34 when it is at the second position.

The second folding roller pair 107 is arranged on the second folding conveying path 106 at the second folding branch portion 105 . The second folding roller pair 107 is composed of a first roller 111 and a third roller 113 . The second folding roller pair 107 forms a second folding nip portion N2 by one of the first roller 111 and the third roller 113 being biased toward the other and coming into contact with each other. The sheet entering the second folding conveying path 106 passes through the second folding nip portion N2 and is conveyed toward the merging portion 34 side, that is, toward the left side of the second folding roller pair 107 in FIG.

The second folding guide 108 is arranged to face the second folding nip portion N2 at the second folding branch portion 105 . Specifically, the second folding guide 108 is arranged on the upstream side of the second folding conveying path 106 in the sheet conveying direction with respect to the second folding nip portion N2, that is, on the right side of the second folding nip portion N2 in FIG. . When the sheet is not to be folded, the second folding guide 108 retreats in a direction away from the second folding nip portion N2 relative to the first folding conveying path 102, that is, to the right of the first folding conveying path 102 in FIG. . As a result, the sheet passing through the first folding conveying path 102 does not contact the second folding guide 108 .

The second folding guide 108 is connected to a driving mechanism (not shown) and is capable of reciprocating in the directions of approaching and separating from the second folding nip portion N2. The second folding guide 108 guides the sheet conveyed on the first folding conveying path 102 to the second folding nip portion N2.

Next, the operation of the sheet folding section 100 will be described with reference to FIGS. 4, 5, 6 and 7. FIG. 4, 5, 6, and 7 are cross-sectional front views showing the periphery of the sheet folding unit 100 in FIG. and a fourth stage. The operation of the sheet folding unit 100 will be described by taking Z-folding shown in FIG. 2 as an example.

As shown in FIG. 4, the sheet S1 conveyed from the sheet inlet 2 (see FIG. 1) to the first sheet conveying path 3 has its downstream portion in the sheet conveying direction transferred from the second branch portion 32 to the second sheet conveying path 5. be guided. The second switching guide 321 of the second branch portion 32 is positioned at a second position P2 for guiding the sheet S1 conveyed on the first sheet conveying path 3 from the sheet inlet 2 side to the second sheet conveying path 5. .

In the first folding/branching portion 101, the first switching guide 311, which is the first folding guide, is arranged in the direction away from the first folding nip portion N1 rather than the first sheet conveying path 3, that is, in the direction of the first sheet conveying path in FIG. It is retreating above 3.

Next, when the portion corresponding to the first fold line F1 (see FIG. 2) of the sheet S1 reaches the first folding branch portion 101, each pair of conveying rollers 3r of the first sheet conveying path 3 and the second sheet conveying path 5 , the rotation of each transport roller pair 5r is stopped, and the transport of the sheet S1 is stopped. Then, the pair of conveying rollers 3r on the sheet conveying direction downstream side of the first folding branch portion 101 (the left side of the first folding branch portion 101 in FIG. 4) of the first sheet conveying path 3 and the second sheet conveying path 5 , the rotation of each transport roller pair 5r is reversed. As a result, the portion of the sheet S1 on the downstream side in the sheet conveying direction of the first folding/branching portion 101 moves upstream (to the right in FIG. 4), and the sheet S1 is flexed at the first folding/branching portion 101. occur.

Subsequently, the first switching guide 311, which is the first folding guide, is moved in the direction of approaching the first folding nip portion N1 and comes into contact with the sheet S1. By contacting the first switching guide 311 , the bent portion of the sheet S<b>1 is guided to the first folding nip portion N<b>1 of the first folding roller pair 103 . Then, as shown in FIG. 5, a first fold line F1 is formed on the sheet S1 that has passed through the first folding nip portion N1.

The timing of forming the first fold line F1 on the sheet S1 is determined by the detection timing of the downstream end of the sheet S1 in the first sheet conveying path 3 in the sheet conveying direction by a sheet detection sensor (not shown) and the timing of detecting the sheet conveying direction downstream end of the sheet S1 in the first sheet conveying path 3. It is measured based on the total length and the conveying speed of the sheet S1. The same applies to the timing of forming a second fold line F2, which will be described later.

At the second folding branch portion 105, the second folding guide 108 retreats in the direction away from the second folding nip portion N2 relative to the first folding conveying path 102, that is, to the right of the first folding conveying path 102 in FIG. are doing.

The sheet S1 that has passed through the first folding nip portion N1 is moved along the first folding conveying path 102 by the first folding rollers in a state in which two areas extending along the sheet conveying direction are overlapped with the first folding line F1 at the top. Transported away from pair 103 . The upstream portion in the conveying direction of the sheet S1 that has passed through the first folding conveying path 102 temporarily enters the third sheet conveying path 7 .

Next, when the portion corresponding to the second fold line F2 (see FIG. 2) of the sheet S1 reaches the second folding branch portion 105, each pair of conveying rollers 3r of the first sheet conveying path 3 and the second sheet conveying path 5 The rotation of each transport roller pair 5r, the first folding roller pair 103, and each transport roller pair 7r of the third sheet transport path 7 is stopped, and the transport of the sheet S1 is stopped.

Subsequently, the second folding guide 108 is moved toward the second folding nip portion N2 and contacts the sheet S1. By contacting the second folding guide 108, the portion corresponding to the second folding line F2 of the sheet S1 is guided to the second folding nip portion N2 of the second folding roller pair 107 as shown in FIG. Then, a second fold line F2 is formed on the sheet S1 that has passed through the second folding nip portion N2 (see FIG. 7).

As shown in FIG. 7, the sheet S1 that has passed through the second folding nip portion N2 is second-folded and conveyed in a state in which three areas extending along the sheet conveying direction are overlapped with the second folding line F2 at the top. It is transported along the path 106 away from the second pair of folding rollers 107 . In this manner, the sheet folding section 100 Z-folds the sheet S<b>1 conveyed through the first sheet conveying path 3 .

Then, the sheet post-processing apparatus 1 of the present embodiment conveys a non-processed sheet to be folded in the sheet folding section 100 followed by a non-processed sheet to the tray section on the first sheet conveying path 3 . In this case, the shunting conveying path 9 is used to carry out sheet conveying with improved productivity.

Therefore, prior to explaining the sheet conveying of the sheet post-processing apparatus 1 of the present embodiment, the sheet conveying of the sheet post-processing apparatus of the comparative example will be explained. FIG. 8 is an explanatory diagram showing timings and paths of sheet conveyance in a sheet post-processing apparatus of a comparative example. The upper part of FIG. 8 shows a timing chart of sheet transport, and the lower part shows a sheet transport path.

Note that in the description using FIG. 8, the first sheet to be processed S1 is Z-folded to A3 size, and the second and third sheets are not folded to A4 size (landscape). Suppose that the first non-processed sheet S2 and the second non-processed sheet S3 are conveyed. Note that "horizontally placed" means that a rectangular sheet is arranged and conveyed with respect to the sheet conveying path such that the short side direction of the rectangular sheet is along the sheet conveying direction and the long side direction is along the sheet width direction.

As shown in FIG. 8, in the sheet post-processing apparatus of the comparative example, a first sheet to be processed S1 to be subjected to Z-folding of A3 size is carried into the apparatus through the sheet inlet 2, and passes through the first sheet conveying path. 3 is transported. The sheet to be processed S1 is branched from the first sheet conveying path 3 and conveyed to the sheet folding section 100, where it is subjected to Z-folding. Note that "Td" in the timing chart at the top of FIG. 8 represents the period during which the sheet to be processed S1 is conveyed from the first sheet conveying path 3 to the sheet folding section 100 (the same applies to FIG. 9 described later).

Subsequently, the processed sheet S<b>1 subjected to the Z-folding process joins the first sheet conveying path 3 at the joining portion 34 . Note that "Tm" in the timing chart at the top of FIG. 8 represents a period during which the sheet to be processed S1 joins the first sheet conveying path 3 from the sheet folding section 100 (the same applies to FIG. 9 described later). Then, the sheet S1 to be processed is carried out from the first sheet conveying path 3 toward the first discharge tray 43 or the processing tray 10d, which is a tray portion.

After the sheet to be processed S1 is carried out toward the tray portion, the second first non-processed sheet S2 is then carried into the apparatus from the sheet inlet 2 and carried on the first sheet carrying path 3. . Further, the first non-processed sheet S2 is carried out from the first sheet conveying path 3 toward the tray section. Subsequently, the third non-processed sheet S<b>3 is carried into the apparatus from the sheet inlet 2 and conveyed on the first sheet conveying path 3 . Further, the second non-processed sheet S3 is carried out from the first sheet conveying path 3 toward the tray section.

In this manner, in the sheet post-processing apparatus of the comparative example, the first sheet to be processed S1 to be Z-folded is loaded, folded, and unloaded, and the second and third sheets are not folded. Carry-in and carry-out of the first non-processed sheet S2 and the second non-processed sheet S3 are performed in order. According to FIG. 8, in the sheet post-processing apparatus of the comparative example, it takes time T0 to complete the conveyance of the three sheets S1, S2, and S3.

Next, sheet conveyance of the sheet post-processing apparatus 1 of this embodiment will be described. FIG. 9 is an explanatory diagram showing the timing and path of sheet conveyance in the sheet post-processing apparatus 1 of the embodiment. The upper part of FIG. 9 shows a timing chart of sheet transport, and the lower part shows a sheet transport path.

In the description using FIG. 9, similarly to FIG. 8 of the comparative example, the sheet to be processed S1 to be Z-folded to A3 size is conveyed as the first sheet, and the second and third sheets are A4 size ( It is assumed that the first unprocessed sheet S2 and the second unprocessed sheet S3 that are not subjected to the folding process (horizontally placed) are conveyed.

As shown in FIG. 9, in the sheet post-processing apparatus 1 of the embodiment, a first sheet to be processed S1 to be subjected to Z-folding of A3 size is carried into the apparatus from the sheet inlet 2, and the first sheet is conveyed. Transported on road 3. The sheet to be processed S1 is branched from the first sheet conveying path 3 and conveyed to the sheet folding section 100, where it is subjected to Z-folding.

At this time, at the timing when the first sheet to be processed S1 is conveyed to the sheet folding unit 100, the second sheet to be processed S2 is conveyed from the sheet inlet 2 in the sheet post-processing apparatus 1 of the embodiment. The sheet is carried into the apparatus and conveyed on the first sheet conveying path 3 . The second first non-processed sheet S2 is folded in the sheet folding section 100 while the first processed sheet S1 leaves the first sheet conveying path 3 when the first processed sheet S1 is Z-folded. It passes above the first sheet conveying path 3 .

Then, the second first unprocessed sheet S<b>2 is switched back at the third branching portion 33 and conveyed to the shunting conveying path 9 . The second first unprocessed sheet S2 waits in the vicinity of the third branch portion 33 on the shunting conveying path 9 . Note that "Td" relating to the first non-processed sheet S2 in the timing chart at the top of FIG. It represents the period during which the first non-processed sheet S2 waits in the shunting conveying path 9 .

FIG. 7 shows that the second non-processed sheet S2 is positioned above the sheet folding section 100 while the first sheet to be processed S1 is Z-folded by the sheet folding section 100. 1 passes through the first sheet conveying path 3 and is conveyed to the shunting conveying path 9. FIG.

Subsequently, at the timing when the Z-folding process for the first processed sheet S1 is completed, the third non-processed sheet S3 is carried into the apparatus from the sheet inlet 2, and is placed on the first sheet conveying path 3. transported above. Note that the processed sheet S1 and the first non-processed sheet S2 stop and wait until the third non-processed sheet S3 reaches the confluence portion 34 and the third branch portion 33 .

Then, at the timing when the third second non-process sheet S3 reaches the merging portion 34 and the third branch portion 33, the to-be-processed sheet S1 and the first non-process sheet S2 are started to be conveyed. The first sheet to be processed S<b>1 and the third sheet to be processed S<b>3 are vertically overlapped at the confluence portion 34 . The first sheet to be processed S1, the second first non-processed sheet S2, and the third second non-processed sheet S3 are vertically overlapped at the third branch portion 33, and are stacked in the tray. The sheet is carried out from the first sheet conveying path 3 toward the section.

In this manner, in the sheet post-processing apparatus 1 of the embodiment, the post-processing control section 11 conveys the non-processed sheet S2, which is not subjected to the folding process, following the processed sheet S1 which is subjected to the folding process in the sheet folding section 100. In this case, while the sheet to be processed S1 is being folded by the sheet folding unit 100, the subsequent non-processed sheet S2 is conveyed to the shunting conveying path 9 and made to wait, and is synchronized with the completion timing of the folding process for the sheet to be processed S1. Then, the sheet to be processed S1 and the sheet to be processed S2 are overlapped at the third branching portion 33 and transported toward the tray portion.

According to this configuration, it is possible to advance the conveyance of the subsequent non-processed sheet S2 while performing the folding process on the processed sheet S1. As a result, it is possible to improve the productivity related to sheet conveyance by the sheet post-processing device that folds the sheet S alone.

9, in the sheet post-processing apparatus 1 of the embodiment, the post-processing control section 11 sequentially feeds the two non-processing sheets S2 and S3 following the sheet S1 to the tray section. In the case of conveying on the one-sheet conveying path 3, when the processing sheet S1 leaves the first sheet conveying path 3 when the processing sheet S1 undergoes the Z-folding process in the sheet folding section 100, two non-printing sheets are separated. The first non-processed sheet S2, which precedes the processing sheets, is transported to the shunting transport path 9 via the first sheet transport path 3 and waited. of the non-processed sheets, the second non-processed sheet S3 is conveyed to the third branching portion 33 via the first sheet conveying path 3, and the conveyance of the first non-processed sheet S2 is resumed, and the third branching portion At 33, the sheet to be processed S1, the first non-processed sheet S2 and the second non-processed sheet S3 are superimposed and conveyed toward the tray section.

According to FIG. 9, in the sheet post-processing apparatus 1 of the embodiment, it takes time T1 to complete the conveyance of the three sheets S1, S2, and S3. This is significantly shorter than the time T0 (see FIG. 8) for the sheet post-processing apparatus of the comparative example. Therefore, it is possible to greatly improve the productivity of sheet transport by advancing the transport of the subsequent non-processed sheets S2 and S3 while performing the Z-folding process on the to-be-processed sheet S1. .

Further, the sheet folding section 100 branches off from the first sheet conveying path 3 at the first branching section 31 to join the first folding conveying path 102 for receiving the sheet S1 to be processed, and joins the first sheet conveying path 3 at the joining section 34 . and a second folding conveying path 106 for returning the processed sheet S<b>1 to the first sheet conveying path 3 . In the sheet post-processing apparatus 1 of the embodiment, the post-processing control unit 11 conveys the first non-processed sheet S2 to the shunting conveying path 9 and makes it wait while the Z-folding process is performed on the sheet to be processed S1. The second non-processed sheet S3 is conveyed to the upstream side of the confluence portion 34 on the first sheet conveying path 3 in accordance with the completion timing of the folding process, and the processed sheet S1 whose Z-folding process has been completed 2 unprocessed sheets S3 are stacked, and at the third branch portion 33, the processed sheets S1, the first unprocessed sheets S2 and the second unprocessed sheets S3 are stacked. With this configuration, the three sheets S1, S2, and S3 can be preferably stacked.

In addition, the shunting conveying path 9 extends toward the upstream side (right side in FIG. 3) in the sheet conveying direction of the first sheet conveying path 3 at the third branch portion 33 . Then, the post-processing control section 11 conveys the first non-processed sheet S<b>2 to the downstream side of the third branching section 33 in the sheet conveying direction of the first sheet conveying path 3 to pass the third branching section 33 . After that, it is switched back and conveyed into the shunting conveying path 9 via the third branch portion 33 .

According to the above configuration, when the non-processed sheet S2 is transported toward the tray portion when the transport of the non-processed sheet S2 is resumed in accordance with the completion timing of the Z-folding process for the processed sheet S1, a quick response can be achieved. can. Therefore, it is possible to improve the productivity related to sheet conveyance.

Further, in the folding process for the sheet to be processed S1, the downstream portion of the sheet to be processed S1 with respect to the sheet conveying direction of the first sheet conveying path 3 is folded into a Z shape when viewed from the sheet width direction orthogonal to the sheet conveying direction. This is Z-folding. According to this configuration, when the non-processed sheets S2 and S3 are conveyed following the processed sheet S1 to be Z-folded, the sheet post-processing apparatus alone can improve productivity related to sheet conveyance. is possible.

In this embodiment, the folding process for the sheet S1 to be processed is the Z-folding process, but is not limited to the Z-folding process. The folding process may be, for example, two folds, three folds, or the like.

Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the gist of the invention.

For example, the shunting conveying path 9 is not limited to the configuration in which the sheet is switched back to enter. The shunting conveying path 9 may be formed in a U shape downward from the third branch portion 33, for example, so that the sheet enters and exits without switching back. Also, the second sheet conveying path 5 may be configured to be used as a shunting conveying path.

INDUSTRIAL APPLICABILITY The present invention can be used in a sheet post-processing device of an image forming apparatus.

REFERENCE SIGNS LIST 1 sheet post-processing device 2 sheet inlet 3 first sheet conveying path (sheet conveying path)
9 escape transport path 10d processing tray (tray section)
11 post-processing control unit (control unit)
31 first bifurcation (folding bifurcation)
33 third branch (shelter branch)
34 confluence section 43 first discharge tray (tray section)
100 sheet folding portion 101 first folding branch portion (folding branch portion)
102 first folding conveying path 106 second folding conveying path S sheet S1 processed sheet S2 first non-processed sheet (non-processed sheet)
S3 Second non-processed sheet (non-processed sheet)

Claims (4)

a sheet conveying path through which the sheet is conveyed;
a sheet folding unit arranged in parallel with the sheet conveying path for folding the sheet conveyed from the sheet conveying path and returning the sheet to the sheet conveying path;
a shunting conveying path that branches off from a shunting branch portion located downstream of the sheet folding portion with respect to the sheet conveying direction of the sheet conveying path;
a tray portion positioned downstream of the retraction branch portion in the sheet conveying direction of the sheet conveying path and on which the sheets are stacked;
a control unit that controls operations of the sheet conveying path, the sheet folding unit, and the evacuation branch unit;
with
When the control unit sequentially conveys two unprocessed sheets, which are not subjected to the folding process, to the tray unit on the sheet transport path, following the sheet to be processed which is subjected to the folding process in the sheet folding unit, During the period in which the sheet to be processed leaves the sheet conveying path when the folding process is performed in the sheet folding section, the first non-processing sheet, which precedes the two non-processing sheets, is transferred to the escape conveying path. Conveyed through the sheet conveying path and made to stand by, the following second non-processed sheet out of the two non-processed sheets is moved to the escape branch portion in synchronization with the completion timing of the folding process for the processed sheet. Conveyance of the first non-processing sheet is restarted while conveying the first non-processing sheet through the sheet conveying path, and the to-be-processed sheet, the first non-processing sheet and the second non-processing sheet are superimposed on each other at the shunting branch portion. A sheet post-processing apparatus characterized by conveying a sheet toward a tray section. the sheet conveying path has a folding branch portion and a merging portion arranged in order from the upstream side of the retraction branch portion in the sheet conveying direction;
The sheet folding section
a first folding conveying path that branches from the sheet conveying path at the folding branch portion and receives the sheet to be processed conveyed on the sheet conveying path;
a second folding conveying path that merges with the sheet conveying path at the confluence portion and returns the processed sheet subjected to the folding process to the sheet conveying path;
has
The control unit conveys the first non-processing sheet to the shunting conveying path to wait while the folding process is performed on the sheet to be processed, and adjusts the second non-processing sheet to the completion timing of the folding process. The sheet is conveyed to the upstream side of the merging portion on the sheet conveying path, the to-be-processed sheet for which the folding processing has been completed and the second non-processing sheet are overlapped at the merging portion, and the to-be-processed sheet is placed at the shunting branch portion. 2. The sheet post-processing apparatus according to claim 1, wherein the sheet, the first non-process sheet, and the second non-process sheet are stacked. The shunting conveying path extends toward the upstream side of the sheet conveying path in the sheet conveying direction at the shunting branch,
The control unit causes the first non-processed sheet to be conveyed to a downstream side of the shunting branch in the sheet conveying direction of the sheet conveying path, to pass through the shunting branch, and then switch back. 3. The sheet post-processing apparatus according to claim 1, wherein the sheet is conveyed into the evacuation conveying path through the evacuation branch. The folding process is a Z-folding process in which a downstream portion of the sheet to be processed is folded into a Z shape when viewed from a sheet width direction orthogonal to the sheet conveying direction with respect to the sheet conveying direction. The sheet post-processing apparatus according to any one of claims 1 to 3.

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