JP2000327208A - Sheet processing equipment - Google Patents

Abstract

(57) [Problem] To reduce the productivity in image formation without complicating the configuration, increasing the size, and increasing the cost. A switching claw as backflow prevention means is provided at a predetermined position of a conveyance path of a post-processing device.
Only the passage of the paper in the transport direction is allowed. If the post-processing unit 14 is not in a state of receiving the leading sheet of the next set without completing the post-processing of the previous set, the control unit 30 reversely rotates the conveying roller 22 and the conveying roller pair 18 and 20 to switch the switching claw. The leading sheet passing through 44 is made to wait in the branch path 46. Thereafter, the transport roller 22 and the transport roller pairs 18 and 20 are rotated forward, and the next transported paper and the standby paper are transported in a superimposed state, and are transported to the post-processing tray of the post-processing unit 14. Is discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine or a printer, or a sheet processing apparatus such as a post-processing apparatus provided in parallel with the image forming apparatus.

[0002]

2. Description of the Related Art In a post-processing apparatus, a printed sheet (paper) output from an image forming apparatus is conveyed in a conveying path by sheet conveying means including a plurality of conveying rollers, and is positioned downstream of the conveying path. After stacking while aligning with the processing tray, the binding process is performed by, for example, a stapler, and the bound sheet bundle is pushed up by a transport belt structure and discharged to a discharge tray. The stapler binding operation is performed by a staple signal from the control unit between the last sheet of the sheet bundle and the leading sheet of the next sheet bundle. In other words, when the number of sheets to be stapled is two or more, the image forming apparatus is configured to discharge the first sheet of the next sheet to the post-processing tray by the time the stapling and discharging of the post-processing tray is completed. Then, control is performed to lengthen the copy interval between the last sheet of one copy and the first sheet of the next copy.

As described above, there is a problem that productivity is low because the copying operation is stopped between copies. In order to cope with this problem, a bypass conveyance path is formed separately from the main conveyance path that guides the sheet to the post-processing tray, and a staple process of a front portion is performed by the post-processing tray. Paper that is output while the paper is being guided to the bypass transport path and waits, then merges with the next paper that is transported in the main transport path and stacks it on the post-processing tray in a superimposed state. Have been.

[0004]

In the bypass merging method, the same number of bypass conveying paths as the number of standby sheets is required. Therefore, when the image forming speed is high, the number of bypass conveying paths increases, and the configuration becomes complicated. , Which results in an increase in size. Further, in the case of a long-sized sheet, the length of the bypass conveyance path must be at least as long as the sheet length, and a correspondingly large number of conveyance rollers are required. Was.

Accordingly, an object of the present invention is to provide a sheet processing apparatus capable of avoiding a decrease in productivity in image formation without increasing the complexity, size, and cost of the configuration.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a post-processing tray provided inside an apparatus, and a conveyance for guiding a sheet toward the post-processing tray are provided. A sheet processing device having a sheet conveying means for conveying a sheet, stacking the sheets on the post-processing tray, performing a binding process or the like, and then discharging the sheets to a discharge tray. The sheet is formed so as not to be allowed to flow backward, and a branch path is formed downstream of the predetermined position, and the sheet conveying means may cause the sheet that has passed the predetermined position to flow backward and wait in the branch path. It is possible, and it is possible to convey one or a plurality of sheets and the next conveyed sheet waiting in the branch path to the post-processing tray in a superimposed state, It adopts a configuration say.

According to a second aspect of the present invention, in the configuration of the first aspect, a state in which the leading edge of the sheet in the transport direction is shifted so as to protrude in the transport direction when the sheet is stacked on the post-processing tray. It is configured to be superimposed.

According to the third aspect of the present invention, the first or second aspect is provided.
In the configuration described above, a configuration is adopted in which the driving sources on the upstream side and the downstream side of the predetermined position in the sheet conveying means are different, and only the downstream side is controlled so that the sheet flows backward.

According to a fourth aspect of the present invention, in the configuration of the first, second or third aspect, the branch path is configured to accommodate the sheet in a hanging state with only one end of the sheet held therebetween. I am taking it.

According to a fifth aspect of the present invention, in the configuration of the first, second, or third aspect, a backflow preventing means for preventing a backflow of the sheet is provided at the predetermined position, and the backflow preventing means prevents the sheet from passing. It is configured to be provided so as to be allowed by displacement due to elastic force.

According to a sixth aspect of the present invention, in the configuration of the first, second, or third aspect, a sheet detecting means is provided downstream of the predetermined position, and the branch path is determined based on information detected by the sheet detecting means. The standby operation and the transport operation in a superposed state are controlled.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. The sheet P output as a sheet from the image forming apparatus 2 enters a post-processing apparatus 6 as a sheet processing apparatus provided alongside the image forming apparatus 2 via a sheet transfer section 4.
In the vicinity of the sheet delivery site 4 in the post-processing device 6,
An entrance sensor S1 and an entrance roller pair 8 are provided. The sheet P taken into the post-processing device 6 by the pair of entrance rollers 8 is conveyed in the conveyance path 10 by the sheet conveying means 12 and sent to the post-processing unit 14. Sheet conveying means 1
2 is an inlet roller pair 8 and transport roller pairs 16, 18, 2
0 and a transport roller 22.

The paper P discharged in the direction of arrow A from the transport path 10 toward the post-processing tray (not shown) falls by its own weight in the direction of arrow B, and the sheet transport direction is aligned by the rear end fence 24. A sheet sensor S2 as a sheet detecting means is provided near the upstream side of the pair of conveying rollers 18. The sheet sensor S2 detects the rear end of the sheet P in advance, and after a time period in which the sheet conveying direction can be aligned, alignment is performed. Fence 2
6, the sheet width direction substantially orthogonal to the sheet conveyance direction is aligned. This operation is repeated for each sheet, and a predetermined number of sheets P are aligned and stacked on the post-processing tray. When the alignment of the final sheet is completed, the stapler 32 is driven by the staple signal from the control means 30, and the binding process is performed. When the binding process is completed, the discharge belt 34 is driven to rotate in the direction of arrow C, and the sheet bundle is pushed up in the direction of arrow D by the discharge claw 34 a attached to the discharge belt 34, and the discharge tray 36 is driven by the discharge roller 36 and the driven roller 38. It is discharged to 40. The above is the operation in the case of one copy.

The paper discharge tray 40 can be moved up and down by an elevating mechanism (not shown), and is controlled to descend based on detection information of a paper surface detecting means (not shown) for detecting the upper surface of the discharged paper bundle. A large amount of paper can be discharged while keeping the paper height almost constant. The driven roller 38 is
One end portion is rotatably supported on the free end side of a transport guide plate 42 which is rotatably provided in the up-down direction with one end pivotally supported, and comes into contact with the discharge roller 36 by its own weight. For this reason, even if the thickness of the conveyed sheet bundle changes, the same conveying force can be obtained.

A switching claw 44 as backflow prevention means for preventing backflow of the paper P is pivotally supported at the base end near the downstream side of the conveyance roller pair 16 in the sheet conveyance direction (a predetermined position in the conveyance path 10). It is provided freely. The switching claw 44 is urged in the direction of the arrow by a spring (not shown), and
Is always returned to the N position. The spring force of the spring is set so that the switching claw 44 is rotated by the moving force (conveying force) of the sheet P. A branch path 46 for holding the sheet P on standby is formed near the switching claw 44 downstream of the sheet conveyance direction. The branch path 46 is provided for the conveying roller 2.
2 is formed as a short gap between the guide roller 48 and the guide plate 48 having a shape along the outer peripheral surface of the transport roller 22, and is configured to accommodate the paper P in a hanging state. Guide plate 4
On the downstream side of the roller 8, a driven roller 50 for holding the sheet P in a hanging state is pressed against the transport roller 22.

As shown in FIG. 2, the pair of entrance rollers 8 and the pair of transport rollers 16 located upstream of a predetermined position (position of the switching claw 44) of the sheet transport means 12 are driven by the transport motor 52 and are located downstream. The transport roller pairs 18 and 20 located are driven by a paper discharge motor 54. The control means 30 controls these motors based on the detection signal of the paper sensor S2.

Next, a control operation for copying two or more copies will be described with reference to FIGS. 3 and 4 (flow chart). When the number of copies (the number of image forming copies) is two or more, the image forming apparatus 2 sets the copy interval between the last sheet of the set and the first sheet of the next set in other cases (for example, the copy interval between the last sheet and the first sheet of the same set). Copying is continued at the same interval as in the case of the second sheet, and sent to the post-processing device 6. FIG.
As shown in (a), the entrance roller pair 8 and the conveyance roller pair 1
The first sheet P1 of the second copy is transferred to the transport path 10 while the rollers 6, 18, 20 and the transport roller 22 rotate in the counterclockwise direction.
Is transported toward the post-processing tray. In this case, the sheet P1 that has passed through the pair of transport rollers 16 abuts on the switching claw 44, but the switching claw 44 is rotationally displaced by the moving force of the sheet P1 as shown by a two-dot chain line, thereby allowing the sheet P1 to pass. The sheet P1 that has passed through the switching claw 44 is conveyed toward the post-processing tray by the conveying roller pairs 18 and 20. At this time, as shown in FIG. 4, the control unit 30 checks whether the paper sensor S2 is ON (passing the leading edge of the paper P1) (ST1), and when it is ON, turns off the paper sensor S2 (the trailing edge of the paper P1). Passing)
Is checked (ST2).

If the post-processing unit 14 is not in a state of receiving the sheet after the trailing edge of the sheet P1 has been confirmed,
That is, when the processing of the preceding copy is not completed, the control means 30 controls the paper discharge motor 54 to rotate in the reverse direction (ST3). When the discharge motor 54 rotates in the reverse direction,
As shown in FIG. 3B, the transport roller 22 and the transport roller pairs 18 and 20 rotate clockwise, whereby the sheet P1 flows backward. Since the switching claw 44 has returned to the position where the transport path 10 is closed, the rear end of the sheet P1 is deflected by the switching claw 44 and guided to the branch path 46. At this time, as shown in FIG. 4, the control means 30 checks whether the paper sensor S2 is on (passing the rear end of the paper P1) (ST4), and if it is on, if it is on, it is off. Check (pass the leading edge of the sheet P1) (ST5). When the leading end of the sheet P1 has passed the sheet sensor S2, the control means 30 stops the sheet discharging motor 54 (ST6).

When the paper discharge motor 54 stops, FIG.
As shown in the figure, the paper P1
0, and is made to stand by at the branch road 46 in a state where the substantially lower half is hung down. In this embodiment, the branch path 46 is formed substantially only by the transport roller 22 and the guide plate 48, and the portion that cannot be accommodated here is made to hang down by utilizing the space in the apparatus. It is possible to make the size constant regardless of the size of the sheet P1. As shown in FIG. 3C, the second sheet P2 is transported by the entrance roller pair 8 and the transport roller pair 16 in a state where the sheet P1 is on standby. Similarly to the first sheet, the leading end of the sheet P2 comes into contact with the switching claw 44, but the switching claw 44 is rotationally displaced by the moving force of the sheet P2 as shown by the solid line, and the sheet P2 is moved.
Is allowed to pass. At this time, as shown in FIG. 4, the control means 30 checks whether the paper sensor S2 is on (the leading edge of the paper P2 has passed) (ST7), and if it is on, rotates the paper discharge motor 54 forward (ST8).

When the paper discharge motor 54 rotates forward, FIG.
As shown in FIG.
0 rotates counterclockwise, and the sheet P1 waiting and the sheet P2 conveyed later are superimposed and conveyed. The detection of the leading edge of the sheet P1 when the sheet P1 is caused to flow backward and waits, and the normal detection of the leading edge of the sheet P2 conveyed later are detections in opposite directions. The projection is shifted by a dimension m in the direction. Thereafter, as shown in FIG.
A value of 0 checks the ON state of the sheet sensor S2 (passing of the rear end of the superposed sheets, more specifically, passing of the rear end of the sheet P1) (ST9). When the post-processing unit 14 is in a state of receiving a sheet while the passage of the trailing edge of the superposed sheets is confirmed, the control unit 30 maintains the normal rotation of the sheet discharge motor 54, and thereby the sheet P1 and the sheet P1 P2 is discharged in a state of being superposed on the post-processing tray of the post-processing unit 14 (ST10). Then, the subsequent sheets P3, P4,
P5 are sequentially discharged and stacked.

If the post-processing unit 14 is not in a state of receiving the sheet while the trailing edge of the superposed sheets is confirmed, the sheets P1 and P
2 is superposed in the state of being overlapped, and is caused to stand by in a branch path 46. This operation is repeated until the post-processing unit 14 is in a state of receiving sheets. Discharge to tray.

According to the above-described control method, as shown in FIG. 5, when the sheets are stacked on the post-processing tray 56 (virtual display), the paper is shifted such that the leading end in the transport direction projects in the transport direction. As a result, the lower sheet is less likely to fall under its own weight due to the upper sheet, so that the lower sheet can be smoothly dropped and misalignment in the transport direction can be prevented. The shift amount of the leading edge of the sheet may be intentionally increased by time management.

The branch path 46 may be sized to completely accommodate the entire sheet. Even in this case, the number of the branch paths 46 may be one irrespective of the number of sheets to be kept on standby, so that the configuration is simplified and the cost is reduced as compared with the related art that requires a number of bypass conveyance paths according to the number of sheets to be on standby. Can be achieved. Further, the backflow preventing means is not limited to the switching claw 44 biased by the spring, but may be a structure in which the switching claw is fixed and the sheet is passed by its material elastic deformation. Further, in the above-described embodiment, the sheet standby operation and the like are performed by the sheet sensor S.
Although the control is performed based on the detection information of No. 2, the sheet may be detected by a sensor on the upstream side in the sheet conveyance direction, and the control timing may be determined by a pulse count of a motor, a timer, or the like. Further, the control unit of the image forming apparatus 2 may be configured to also serve as the control unit 30.

[0024]

According to the first aspect of the present invention, the sheet is made to flow backward, wait in the branch path, and is discharged to the post-processing tray in a state of being overlapped with the sheet conveyed later. It is possible to avoid a decrease in productivity in image formation without increasing the complexity, size, and cost.

According to the second aspect of the present invention, the upper sheets when stacked on the post-processing tray are stacked in such a manner that their leading ends in the conveying direction are shifted so as to protrude in the conveying direction. Therefore, it is possible to suppress the poor alignment in the transport direction due to the weight drop.

According to the third aspect of the present invention, only the downstream side of the predetermined position in the sheet conveying means is controlled so as to reverse the sheet. It is possible to cope with high-speed formation.

According to the fourth aspect of the present invention, the branch road is
Since the configuration is such that only one end of the sheet is sandwiched and hung down, simplification of the configuration and cost reduction can be further improved.

According to the fifth aspect of the present invention, since the backflow preventing means for permitting the passage of the sheet by the displacement due to the elastic force is provided, the backflow prevention of the sheet can be realized with a simple structure.

According to the sixth aspect of the invention, the control is performed based on the detection information of the sheet detecting means provided downstream of the predetermined position, so that the sheet conveyance state can be accurately grasped. Control can be simplified and high accuracy can be achieved.

[Brief description of the drawings]

FIG. 1 is an overall schematic front view of a post-processing apparatus as a sheet processing apparatus according to an embodiment of the present invention.

FIG. 2 is a control block diagram.

3A and 3B are diagrams illustrating a standby control operation of a sheet, and FIG.
FIG. 3B is a diagram illustrating a state in which the first sheet P1 has been conveyed until immediately before being discharged to a post-processing tray, FIG. 2B is a diagram illustrating a state in which the conveyed sheet P1 is caused to flow backward and waits in a branch path, and FIG. FIG. 9D is a diagram illustrating a state in which the sheet P2 has been conveyed, and FIG. 9D is a diagram illustrating a state in which the sheet P1 and the sheet P2 are conveyed in a superimposed state until immediately before being discharged to a post-processing tray.

FIG. 4 is a flowchart illustrating a sheet standby control operation.

FIG. 5 is a schematic side view showing a state in which a plurality of sheets are discharged to a post-processing tray in a superposed state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Conveyance path 12 Sheet conveyance means 44 Switching claw as backflow prevention means 46 Branch path 52 Conveyance motor as an upstream drive source 54 Discharge motor as a downstream drive source S2 Paper sensor as sheet detection means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukitaka Nakazato 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Junichi Iida 1-3-6 Nakamagome, Ota-ku, Tokyo・ In Ricoh Co., Ltd. (72) Inventor Akito Ando 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 3F053 EA02 EA04 EB04 EC02 EC06 GB02 GB11 LA02 LA05 LB03 3F054 AA01 AB01 AC02 AC05 BA04 BB07 BF03 BJ04 BJ11 CA07 DA01 DA12 3F108 GA02 GA04 HA02 HA32

Claims (6)

[Claims] A post-processing tray provided inside the apparatus;
It has a conveyance path that guides the sheet toward this post-processing tray, and a sheet conveyance unit that conveys the sheet, stacks the sheets on the post-processing tray, and performs a binding process or the like on the discharge tray. In the sheet processing apparatus for discharging, the sheet is formed so as not to be able to flow backward at a predetermined position of the conveyance path, and a branch path is formed downstream of the predetermined position, and the sheet conveyance means has passed the predetermined position. The post-processing tray is capable of causing a sheet to flow backward and to be made to stand by in the branch path, and one or more sheets that have been made to stand by in the branch path and a sheet to be conveyed next are superimposed. A sheet processing apparatus characterized in that it can be transported toward 2. The sheet processing apparatus according to claim 1, wherein the upper sheets stacked on the post-processing tray are superimposed such that the leading ends in the transport direction project in the transport direction. A sheet processing apparatus, characterized in that: 3. The sheet processing apparatus according to claim 1, wherein the upstream and downstream drive sources of the predetermined position in the sheet conveying means are different, and only the downstream side is controlled so as to reverse the sheet. A sheet processing apparatus, characterized in that: 4. The sheet processing apparatus according to claim 1, wherein the branch path is configured to accommodate the sheet in a hanging state with only one end of the sheet held therebetween. . 5. The sheet processing apparatus according to claim 1, further comprising a backflow preventing means at a predetermined position for preventing backflow of the sheet, wherein the backflow preventing means displaces the sheet by an elastic force. A sheet processing apparatus provided so as to allow the sheet processing. 6. The sheet processing apparatus according to claim 1, further comprising a sheet detecting means provided downstream of the predetermined position, wherein a standby operation to the branch path is performed based on detection information of the sheet detecting means. A sheet processing apparatus for controlling a conveying operation in a state where the sheet is overlapped.