阅读说明：本技术 片材堆叠装置和后处理装置 (Sheet stacking apparatus and post-processing apparatus ) 是由 岸本正尚 于 2020-02-12 设计创作，主要内容包括：本发明提供一种片材堆叠装置。片材堆叠装置具有输送部和止挡件。输送部具有：托盘部,其堆叠片材合集；和输送部件,其沿规定的输送方向输送托盘部上的片材合集。止挡件被配置于托盘部的输送方向上的下游侧,并防止片材合集从托盘部落下。止挡件具有主体板和至少一个防滑部件。主体板相对于托盘部朝下游侧向上倾斜,并包括：接触面,其与片材合集接触；和弯曲面,其以从接触面退避的方式从接触面的下游侧的顶端缘向下方弯曲。防滑部件从接触面的下游侧的端部跨弯曲面而设置,其相对于片材合集的摩擦系数大于接触面相对于片材合集的摩擦系数。根据本发明,即使在连续输送片材合集(小册子)的情况下,也能够不使片材合集落下而堆叠。(The invention provides a sheet stacking apparatus. The sheet stacking apparatus has a conveying portion and a stopper. The conveying part is provided with: a tray section that stacks a collection of sheets; and a conveying member that conveys the sheet assembly on the tray portion in a predetermined conveying direction. The stopper is disposed on a downstream side in the conveying direction of the tray portion, and prevents the sheet set from falling from the tray portion. The stopper has a body plate and at least one slip resistant component. The main body plate is inclined upward toward the downstream side with respect to the tray portion, and includes: a contact surface in contact with the collection of sheets; and a curved surface that curves downward from a distal edge on a downstream side of the contact surface so as to recede from the contact surface. The anti-slip member is provided across the curved surface from the end portion on the downstream side of the contact surface, and the friction coefficient thereof with respect to the collection of sheets is larger than the friction coefficient thereof with respect to the collection of sheets. According to the present invention, even in the case of continuously conveying a collection of sheets (booklet), the collection of sheets can be stacked without being dropped.)

1. A sheet stacking apparatus is characterized in that,

having a transport section and a stop, wherein,

the conveying section includes a tray section on which sheets discharged from the discharging section at a predetermined interval are collectively stacked, and a conveying member; the conveying component conveys the sheet collection on the tray part along a specified conveying direction;

the stopper is disposed on a downstream side of the tray portion in the conveying direction, and prevents the sheet set from falling from the tray portion,

the stopper has a body plate and at least one slip prevention part, wherein,

the main body plate is inclined upward toward the downstream side with respect to the tray portion, and includes a contact surface and a curved surface, wherein the contact surface is in contact with the sheet set; the curved surface is curved downward from a distal edge of the downstream side of the contact surface so as to retreat from the contact surface;

the slip prevention member is provided across the curved surface from the downstream end of the contact surface, and has a friction coefficient with respect to a collection of sheets larger than a friction coefficient with respect to the collection of sheets of the contact surface.

2. The sheet stacking apparatus according to claim 1,

the at least one anti-slip component comprises two of the anti-slip components,

the two anti-slip members are disposed at both ends of the stopper in a width direction orthogonal to the conveying direction.

3. The sheet stacking apparatus according to claim 2,

the main body plate has a plurality of ribs protruding from the contact surface along the conveying direction and formed at predetermined intervals in the width direction,

an upper surface of the slip prevention member is lower than upper surfaces of the plurality of ribs.

4. The sheet stacking apparatus according to claim 3,

the two anti-slip members are arranged outside the plurality of ribs in the width direction,

the downstream end of the plurality of ribs is disposed on the upstream side of the curved surface in the conveying direction,

the upstream-side end portions of the two antiskid members are arranged on the upstream side of the downstream-side end portions of the plurality of ribs.

5. The sheet stacking apparatus according to claim 2,

two cover portions are formed on the curved surface, the two cover portions respectively including a base portion and a tip portion, wherein the base portion stands at a right angle from the curved surface; the tip portion is bent upward at a right angle from the tip of the base portion,

the two cover portions cover the downstream-side end portions of the two antiskid members with the base portion and the tip portion.

6. The sheet stacking apparatus according to claim 1,

the friction coefficient between the slip-preventing member and the collection of sheets is larger than the friction coefficient between the collection of sheets.

7. The sheet stacking apparatus according to claim 1 or 2,

further comprising a collecting section disposed below an end portion on the downstream side of the tray section and collecting the collected sheets,

the stopper is supported so as to be rotatable between a limit position and a retracted position, the limit position being a position in which the stopper is inclined upward from the end of the tray portion on the downstream side toward the downstream side; the retreat position is a position where the tray portion is turned to a lower side and retreated from the tray portion downward,

the stack of sheets is collected by the collection unit in a state where the stopper is rotated to the retreat position.

8. The sheet stacking apparatus according to claim 1 or 2,

the conveying member includes an endless belt that circulates on the tray portion to convey the sheet collection,

the sheet set is discharged to the tray portion by the discharge portion at a predetermined interval and conveyed by the endless belt, whereby the sheet set is stacked on the tray portion at a predetermined distance in the conveying direction.

9. The sheet stacking apparatus according to claim 1 or 2,

the conveying section has a detection section disposed at an end portion on the downstream side of the tray section, and detects a state in which the tray section is fully assembled from the sheets stacked on the tray section,

stopping the conveyance by the conveyance section after the detection section detects that the collection of sheets is full.

10. An aftertreatment device, characterized in that,

having a binding portion, a fold back portion and the sheet stacking apparatus according to any one of claims 1 to 9,

the binding part binds a sheet collection;

the folding portion folds the sheets bound by the binding portion together;

the sheet stacking apparatus stacks a collection of sheets folded in half by the folded-back portion.

Technical Field

The present invention relates to a sheet stacking apparatus that conveys and stacks a collection of sheets and a post-processing apparatus having the sheet stacking apparatus.

Background

In a binding job such as a booklet (a book), a post-processing apparatus that binds a collection of sheets and folds the sheets in two is sometimes used. Such a post-processing apparatus includes a sheet stacking apparatus that conveys and stacks a collection of sheets (booklet) folded in two. The sheet stacking device has a tray portion on which a collection of sheets is stacked, a conveying belt, and a stopper member; a conveyor belt provided in the tray section and conveying the sheet collection along a conveying direction; the stopper member is provided at an end portion on a downstream side in the conveying direction of the tray portion.

The stopper member is provided so as to be movable between a position at which conveyance of the collection of sheets is prevented and a position at which conveyance of the collection of sheets is not prevented. When the number of the collected sheets is small, the stopper member is moved to a position where the conveyance of the sheets is stopped, and the sheets are collected and stacked on the tray portion. In this case, if the conveying force of the conveyor belt is too large, the collection of sheets that are prevented from being conveyed by the stopper member may collapse.

Therefore, when the stopper member moves to a position where conveyance of the sheet is stopped, a conveyance force reducing portion for reducing the conveyance force of the conveyance belt may be provided.

However, even when the stopper member is moved to a position at which the conveyance of the sheet collection is stopped, in the case of continuously conveying the sheet collection, there is a risk that the previously discharged sheet collection is pushed by the subsequently discharged sheet collection and falls off the stopper member.

Disclosure of Invention

In view of the above, the present invention provides a sheet stacking apparatus and a post-processing apparatus having the same, which can stack a collection of sheets (booklets) without dropping the collection even in the case of continuously conveying the collection of sheets.

A sheet stacking apparatus according to an aspect of the present invention includes a conveying portion and a stopper (stopper). The conveying section has a tray section on which a collection of sheets discharged from the discharging section at a predetermined interval is stacked, and a conveying member; the conveying member conveys the sheet set on the tray portion in a predetermined conveying direction. The stopper is disposed on a downstream side of the tray portion in the conveying direction, and prevents the sheet set from falling off the tray portion. The stopper has a body plate and at least one slip resistant component. The main body plate is inclined upward toward the downstream side with respect to the tray portion, and includes a contact surface and a curved surface, wherein the contact surface is in contact with the sheet set; the curved surface is curved downward from the downstream-side tip edge of the contact surface so as to recede from the contact surface. The slip prevention member is provided across the curved surface from the downstream end of the contact surface, and has a friction coefficient with respect to a collection of sheets that is greater than a friction coefficient of the contact surface with respect to a stack of sheets.

A post-processing apparatus according to an aspect of the present invention includes a binding portion that binds a collection of sheets, a folding portion, and the sheet stacking apparatus; the folding portion folds a set of sheets bound at the binding portion in two; the sheet stacking apparatus stacks a collection of sheets folded in half at the folded portion.

Drawings

Fig. 1 is a front view schematically showing an aftertreatment device according to an embodiment of the present invention.

Fig. 2 is a front view schematically showing a folding-back device of the post-processing device according to the embodiment of the present invention.

Fig. 3 is a perspective view showing a processing tray of the half-folding device in the post-processing device according to the embodiment of the present invention.

Fig. 4 is a front view schematically showing a sheet stacking apparatus in a post-processing apparatus according to an embodiment of the present invention.

Fig. 5 is a plan view showing a stopper in the post-processing apparatus according to the embodiment of the present invention.

Fig. 6 is a front view showing a downstream end of a stopper in the post-processing apparatus according to the embodiment of the present invention.

Fig. 7 is a front view showing the sheet stacking apparatus in the booklet conveyance process in the post-processing apparatus according to the embodiment of the present invention.

Fig. 8 is a front view showing the sheet stacking apparatus in the booklet conveyance process in the post-processing apparatus according to the embodiment of the present invention.

Detailed Description

Next, a post-processing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

First, the overall configuration of the post-processing apparatus 1 will be described with reference to fig. 1. Fig. 1 is a front view schematically showing the overall structure of an aftertreatment device. The front side of the sheet of fig. 1 is the front side of the post-processing apparatus. Fr, Rr, L, R in each figure represent the front, rear, left, and right sides of the post-treatment device, respectively.

In the main body 3 of the post-processing apparatus 1, a sheet receiving opening 5 is formed in an upper portion of one side surface (right side surface). The first discharge port 7, the second discharge port 9, and the third discharge port 11 are formed in this order from above on the other side surface (left side surface) of the body 3. A first discharge tray 13 is provided below the first discharge port 7, a second discharge tray 15 is provided below the second discharge port 9, and a sheet stacking device 17 (described later in detail) is provided below the third discharge port 11.

A conveyance path 21 for conveying the sheet in a conveyance direction from the inlet 5 toward the inside of the main body 3 is provided inside the main body 3. A punching device 23 for punching a sheet is provided in the conveying path 21.

The conveying path 21 branches into a first branch path 25 and a second branch path 27 at a first branch point R1 on the downstream side of the punching device 23. The first branch path 25 is formed from the first branch point R1 toward the first discharge port 7. The second branch path 27 is formed from the first branch point R1 toward the second discharge port 9. The second branch path 27 is provided with a stapler 29 for stapling a sheet bundle by a stapler (staple).

The second branch path 27 branches into a third branch path 35 at a second branch point R2 on the downstream side of the first branch point R1, and the third branch path 35 extends downward via a retreat path 33 provided along the retreat roller 31 that temporarily retreats the sheet. A half-folding device 41 for binding and folding the sheet collection in two is provided below the third branch path 35.

Next, the folding-back device 41 will be described with reference to fig. 2 and 3. Fig. 2 is a front view schematically showing the structure of the folio apparatus, and fig. 3 is a perspective view showing a processing tray of the folio apparatus.

The folding device 41 includes: a feeding path 45 extending in the vertical direction, a processing tray 47 disposed below the feeding path 45, a staple part 49 and a fold back part 51 supported by the processing tray 47, and a discharge part 53 disposed between the fold back part 51 and the third discharge port 11.

The feed path 45 is formed to extend downward from the outlet of the third branch path 35. The lower end portion 45a of the carry-in path 45 is inclined obliquely downward leftward. A feed roller pair 61 is disposed at the outlet of the lower end portion 45 a. The feed roller pair 61 has a drive roller and a driven roller, wherein the drive roller is driven to rotate by a drive source (not shown); the driven roller rotates following the driving roller. The feed roller pair 61 feeds out the sheet fed into the feed path 45 obliquely downward from the feed path 45 so as to follow the oblique direction of the lower end portion 45 a. In the following description, the direction in which the sheet is fed out by the feeding roller pair 61 is referred to as a conveying direction Y1.

The processing tray 47 has an upstream tray 63 and a downstream tray 65, wherein the upstream tray is disposed upstream in the conveying direction Y1; the downstream tray 65 is disposed downstream of the upstream tray 63 with a predetermined gap D therebetween. The upstream tray 63 and the downstream tray 65 are arranged to be inclined downward along the conveying direction Y1. As shown in fig. 3, slits 63a and 65a along the conveying direction Y1 are formed in the upstream tray 63 and the downstream tray 65 at the center in the width direction W orthogonal to the conveying direction Y1.

The upstream cursor 67 is supported by the upstream tray 63 so as to be slidable in the conveying direction Y1 and the opposite direction. Pulleys 69A, 69B are rotatably supported below the upstream end and the downstream end of the upstream tray 63 in the conveying direction Y1, respectively. An endless belt 71 is wound around the pair of pulleys 69A and 69B. The upstream cursor 67 is attached to the endless belt 71 and protrudes upward from the upstream tray 63 through the slit 63 a. The pair of pulleys 69A and 69B are rotated to move the endless belt 71, and the upstream side cursor 67 moves along the slit 63 a.

The downstream cursor 75 is supported by the downstream tray 65 so as to be slidable in the conveying direction Y1 and the opposite direction. Pulleys 77A, 77B are rotatably supported below the upstream end and the downstream end of the downstream tray 65 in the conveying direction Y1, respectively. An endless belt 79 is wound around the pair of pulleys 77A, 77B. The downstream cursor 75 is attached to the annular belt 79 and protrudes upward from the downstream tray 65 through the slit 65 a. The pair of pulleys 77A and 77B are rotated to move the endless belt 79, whereby the downstream cursor 75 moves along the slit 65 a.

The pair of width aligning members 81U and 81D are supported by the upstream tray 63 and the downstream tray 65, respectively, so as to be movable in the width direction. The conveying members 83U and 83D are rotatably supported above the upstream tray 63 and the downstream tray 65, respectively.

The binding portion 49 is a saddle-stitch stapler for stapling a center portion of the sheet, and is disposed above the upstream tray 63.

The folding portion 51 includes a pair of folding rollers 91 and a folding plate 93, and the pair of folding plates 93 can advance and retreat in the nip portion N between the pair of folding rollers 91. The pair of folding rollers 91 are arranged in the width direction above the gap D between the upstream tray 63 and the downstream tray 65. The upstream half-folding roller 91 is driven by a drive source (not shown) and rotates clockwise in fig. 2. The folding rollers 91 on the downstream side are pressed against the folding rollers 91 on the upstream side by a biasing member (not shown). The folding plate 93 is driven by a driving mechanism (not shown), and advances and retreats through the gap D in the nip portion N between the pair of folding rollers.

The discharge portion 53 has a discharge path 97 and a discharge roller 99. The discharge path 97 is formed from above the nip portion N between the pair of folding rollers of the fold back portion 51 toward the third discharge port 11. The discharge roller 99 is rotatably supported at the outlet of the discharge path 97.

Next, the sheet stacking apparatus 17 will be described with reference to fig. 4. The sheet stacking device 17 is provided so as to protrude leftward from the left side surface of the main body portion 3 below the third discharge port 11. The sheet stacking apparatus 17 has a conveying portion 101 and a stopper 103, wherein the conveying portion 101 conveys the booklet formed by the center folding apparatus 41, which is a collection of sheets discharged from the third discharge port 11, to the left. In this example, the conveying direction Y2 in which the booklet is conveyed by the conveying section 101 is the left direction along the substantially horizontal direction.

The conveying unit 101 includes an upstream conveying mechanism 107 and a downstream conveying mechanism 109 arranged along the conveying direction Y2. Each of the conveying mechanisms 107 and 109 has a tray portion 111, a driving roller 113, a driven roller 115, and two endless belts 117 as conveying members.

Two grooves are formed in the tray portion 111 at predetermined intervals in the width direction along the transport direction Y2. The driving roller 113 and the driven roller 115 are rotatably supported below the upstream and downstream ends of the tray portion 111. The two endless belts 117 are disposed in the two grooves of the tray portion 111, and are wound around the driving roller 113 and the driven roller 115. The upper traveling surface of the endless belt 117 wound around the two rollers 113 and 115 is set to be substantially the same height as the upper surface of the tray portion 111.

The drive roller 113 rotates to circulate the endless belt 117, thereby conveying the booklet in the conveying direction along the upper surface of the tray portion 111. Accordingly, the booklet discharged from the third discharge port 11 and falling onto the upstream conveying mechanism 107 is conveyed from the upstream conveying mechanism 107 to the downstream conveying mechanism 109 along the conveying direction Y2.

An actuator 119 as a detection unit is provided on the tray unit 111 of the downstream conveying mechanism 109. The actuator 119 is disposed at an end portion of the tray section 111 on the downstream side in the conveying direction Y2, and rotates between a protruding position protruding from the upper surface of the tray section 111 and a retracted position retracted downward from the upper surface of the tray section 111. The actuator 119 is pushed by the booklet conveyed along the tray portion 111, and thereby is rotated from the protruding position to the retracted position. By the rotation of the actuator 119, it is detected that the booklet has been conveyed to a prescribed position.

Next, the stopper 103 will be described with reference to fig. 5 and 6. Fig. 5 is a plan view of the stopper 103, and fig. 6 is a front view of the downstream end of the stopper 103.

The stopper 103 has a main body plate 121 and two anti-slip members 123, wherein the two anti-slip members 123 are adhered to the main body plate 121.

The main body plate 121 has a rectangular planar shape elongated in the width direction W, and includes a contact surface 121a and a curved surface 121b (left side surface), and the curved surface 121b is curved downward (in a direction retreating from the contact surface 121a) from a distal end edge on the downstream side in the conveyance direction Y2 of the contact surface 121 a. A plurality of ribs 131 along the conveying direction Y2 are formed to protrude from the contact surface 121 a. The downstream end of the rib 131 does not reach the downstream end (upper end) of the contact surface 121 a.

As shown in fig. 4, a hook (hook)133 protruding downward from a substantially center in the width direction is formed at the downstream end of the main body plate 121. Two cover portions 135 are formed on the curved surface 121b of the main body plate 121 at a predetermined interval in the width direction. As shown in fig. 6, each cover section 135 has a base portion 135a and a tip portion 135b, wherein the base portion 135a stands substantially perpendicularly from the curved surface 121 b; the tip portion 135b is bent upward from the tip of the base portion 135a at substantially right angles to the base portion 135 a.

As shown in fig. 4, the main body plate 121 is supported rotatably between a restricting position and a retracted position at the end portion on the downstream side of the tray section 111 of the downstream conveying mechanism 109. In the restricting position shown by the solid line in fig. 2, the main body panel 121 is inclined upward toward the downstream side in the conveying direction Y2 with respect to the tray portion 111 to prevent the conveyance of the booklet by the conveying portion 101 and prevent the booklet from falling off from the tray portion 111. At the restricting position, the contact surface 121a of the main body plate 121 continues smoothly from the upper surface of the tray portion 111 of the downstream side conveying mechanism 109. In the retracted position shown by the two-dot chain line in fig. 2, the main body plate 121 is retracted from the upper surface of the tray portion 111 of the downstream side conveying mechanism 109, and is turned below the conveying portion 101, so that the hook 133 enters the opening 139 formed in the main body portion 3. The main body plate 121 is held at the restricting position and the retracted position by a locking mechanism (not shown).

The anti-slip member 123 is a rectangular sheet-like member that is long in the conveyance direction Y2. The anti-slip member 123 is disposed at a predetermined interval in the width direction W on the outer side of the rib 131, and is bonded so as to cover the upper corner portion of the main body panel 121, specifically, the contact surface 121a and the curved surface 121b excluding the rib 131, and the corner 121c of the contact surface 121a and the curved surface 121 b. At this time, the upstream end 123u of the anti-slip member 123 is disposed upstream of the downstream end of the rib 131. The end face 123d on the downstream side of the anti-slip member 123 is housed in the cover 135. Specifically, the end surface and the outer surface of the downstream end 123d are covered with the base portion 135a and the tip portion 135b of the cover 135. The number of the anti-slip members 123 is not limited to two, and may be one or three or more.

The anti-slip member 123 is formed of, for example, felt (felt), and is bonded to the main body panel 121 with an adhesive or a double-sided tape. Alternatively, the sheet may be formed of an adhesive sheet. The thickness of the slip prevention member 123 is thinner than the height of the rib 131. That is, the upper surface of the non-slip member 123 is lower than the upper surface of the rib 131. In addition, the frictional force (coefficient of friction) of the slip prevention member 123 and the booklet is larger than the frictional force of the main body plate 121 (contact surface 121a) and the booklet. Also, the frictional force between the slip prevention member 123 and the booklet is larger than the frictional force between the booklets.

Next, a booklet forming operation using the half-folding device 41 having the above-described configuration will be described mainly with reference to fig. 2. In the initial state, the downstream cursor 75 slides to the receiving position on the downstream side of the conveying member 83D. The upstream cursor 67 slides to a position upstream of the feed roller pair 61. The width alignment members 81U, 81D slide to standby positions outside both side edges in the width direction of the sheet.

When the sheet is conveyed from the third branch path 35 to the feed path 45, the feed roller pair 61 rotates, and the first sheet conveyed thereto is fed out from the lower end portion 45a of the feed path 45 to the processing tray 47. The fed sheet slides on the processing tray 47 toward the downstream side cursor 75. At this time, the two conveying members 83U, 83D rotate to assist the conveyance of the sheet on the processing tray 47. The first sheet is conveyed until the tip abuts against the downstream cursor 75. Then, the downstream cursor 75 is slid in the upstream direction to bring the sheet into contact with the upstream cursor 67. Accordingly, the sheet is aligned in the conveying direction Y1 by the upstream side cursor 67 and the downstream side cursor 75.

Next, the width alignment members 81U, 81D are slid in the width direction to be brought into contact with both side edges of the sheet. Accordingly, the sheets are aligned in the width direction. After aligning the sheets, the downstream side cursor 75 is slid to the receiving position, and the width aligning members 81U, 81D are slid to the standby position.

Then, the second sheet is fed out from the feeding path 45 by the feeding roller pair 61. The fed sheet is conveyed to the downstream side cursor 75 on the first sheet by the two conveying members 83U, 83D. Then, the downstream cursor 75 is slid in the upstream direction to bring the two sheets into contact with the upstream cursor 67, and the two sheets are aligned in the conveyance direction Y1. Next, the width aligning members 81U and 81D are slid in the width direction to be in contact with both side edges of the two sheets, thereby aligning the two sheets in the width direction. The alignment in the conveying direction Y by the downstream side cursor 75 and the upstream side cursor 67 and the alignment in the width direction by the width aligning members 81U, 81D are performed for each sheet.

By feeding a predetermined number of sheets (20 sheets in one example) from the feeding path 45 in this manner, a sheet collection is formed on the processing tray 47.

The sheet set is conveyed along the processing tray 47 to the binding portion 49 by the upstream side cursor 67 and the downstream side cursor 75, and the center of the sheet set is bound by the binding portion 49. Then, the center-stapled sheet set is conveyed along the processing tray 47 to the fold-back position by the upstream side cursor 67 and the downstream side cursor 75. That is, the upstream side cursor 67 and the downstream side cursor 75 move simultaneously in the downstream direction until the center of the sheet collection in the conveying direction Y1 reaches the fold back position of the fold back portion 51 (the position of the fold back roller 91 corresponding to the nip portion N).

In the half-folding position, the folding plate 93 is driven by the driving mechanism, passes through the gap D, and enters and exits the nip portion N of the pair of folding rollers 91. Accordingly, the central portion of the sheet collection is pushed up toward the nip portion N by the folding plate 93, and the sheet collection is pushed from both sides by the upstream roller and the downstream roller and folded in two. Whereby a booklet is formed. Further, the downstream side roller is moved against the application force by an amount corresponding to the thickness of the gathered sheet after the double folding.

The folding plate 93 is retracted at a predetermined timing, the upstream roller and the downstream roller of the folding roller 91 are further rotated, and the booklet is discharged from the nip portion N to the discharge path 97 of the discharge portion 53 with the center portion folded in two as the leading end.

The booklet discharged to the discharge path 97 is discharged from the third discharge port 11 by the discharge rollers 99. The discharged booklet falls to the conveying portion 101 of the sheet stacking device 17.

The conveyance and stacking operation of the booklet by the sheet stacking device 17 will be described with reference to fig. 4, 7, and 8. Fig. 7 and 8 are front views showing the sheet stacking apparatus.

The first-part (booklet) booklet B1 discharged from the center-folding device is stacked on the tray portion 111 of the upstream-side conveying mechanism 107 of the conveying portion 101 of the sheet stacking device 17. Then, the endless belts 117 of the upstream-side conveying mechanism 107 and the downstream-side conveying mechanism 109 are driven to convey the first booklet B1 in the conveying direction Y2 on the tray portion 111 with the center portion folded in two as the leading end. The endless belt 117 of each conveying mechanism is driven for a predetermined time and then stopped. Accordingly, the first booklet B1 is conveyed by a predetermined distance.

Next, at the time when the second booklet B2 is stacked on the tray portion 111 of the upstream conveying mechanism 107, the endless belts 117 of the respective conveying mechanisms are driven and stopped after a predetermined time has elapsed. Accordingly, the booklet B2 of the second section is stacked at a position spaced apart from the booklet B1 of the first section by a prescribed distance, and is conveyed by the prescribed distance. By repeating this operation, a plurality of booklets are stacked on the tray portion 111 of each transport mechanism at predetermined intervals.

When the first booklet B1 reaches the end portion on the downstream side of the tray portion 111 of the downstream-side conveying mechanism 109, the actuator 119 is pushed by the first booklet B1 and rotates from the protruding position to the retracted position. Accordingly, the conveyance of the first booklet B1 to the predetermined position is detected.

When the first-part booklet B1 reaches the end on the downstream side of the conveying section 101, the tip (downstream side) of the booklet B1 rides up on the stopper 103. Since the transport unit 101 is also driven during this period, the booklet is completely pushed over the contact surface 121a of the main body panel 121 and held. In other words, the booklet is prevented from being conveyed by the conveying portion 101 as the booklet moves up the stopper 103. Since the booklet is guided along the rib 131 as it goes over the stopper 103, it smoothly goes over the contact surface 121 a.

Subsequently, the discharged second booklet B2 is also conveyed by the conveying unit 101 in the same manner. When the booklet B2 reaches the end on the downstream side of the transport section 101, the tip end (downstream side end) of the second booklet B2 gets over the first booklet B1 mounted on the stopper 103. Since the conveying section 101 is also driven during this time, as shown in fig. 7, the second-section booklet B2 gets over the first-section booklet B1 so that it overlaps with the first-section booklet B1.

When the booklets B are continuously conveyed in this way, the booklets B are aligned so as to gradually assume a vertical posture, and are stacked on the tray portion 111 of each conveying mechanism. After the first booklet B1 is conveyed to the predetermined position (after the conveyance of the collective sheets to the predetermined position is detected by the rotation of the actuator 119), it is determined that the tray section 111 of each of the conveying mechanisms is in the full state at the time when the booklets of the predetermined number of booklets are stacked. When it is determined as the full state in this way, the driving of the endless belts 117 of the respective conveying mechanisms is stopped. This prevents the booklet from falling from the transport unit 101. The timing of detecting the full state differs depending on the size of the sheets and the number of sheets forming the sheet set.

However, when the full state is determined from the number of booklets of the booklet as described above, the conveying unit 101 may be in the full state even if the number of booklets is smaller than the number of booklets determined to be in the full state, depending on the characteristics (thickness, hardness, etc.) of the sheets or the folded state. In this case, the first-part booklet B1 is pushed out to the downstream side from the stopper 103 by the subsequently discharged booklet. Then, the first booklet B1 goes along the rib 131 of the main body panel 121 to the contact surface 121a and finally reaches the nonslip member 123. As shown in fig. 8, since the frictional force between the slide preventing member 123 and the booklet is larger than the frictional force between the main body plate 121 (contact surface 121a) and the booklet, the first partial booklet B1 is prevented from being pushed out by the frictional force with the slide preventing member 123. I.e., does not fall from the main body plate 121. As shown by the two-dot chain line in fig. 8, even if the tip end of the booklet B1 is pushed out along the upper corner of the main body panel 121, the booklet B1 can be prevented from falling down by the anti-slip member 123 adhered to the corner 121c or the curved surface 121B of the main body panel 121.

In addition, it is also possible that the second-part booklet B2 is pushed up along the first-part booklet B1. In this case, even if the second booklet B2 is pushed out from the stopper 103, the second booklet does not fall down because the slide preventing member 123 contacts the second booklet B2.

When the number of booklets is small, the booklets are received by the stopper 103 and stacked on the conveying unit 101. However, when the number of booklets is large, the stopper 103 is rotated from the restricting position to the retracted position (see the two-dot chain line in fig. 4). A recovery tank 141 (recovery unit) is disposed below the downstream conveying mechanism 109. Accordingly, the booklet conveyed by the conveying unit 101 falls from the downstream conveying mechanism 109, and is collected in the collection box 141.

According to the sheet stacking apparatus 17 of the present invention as described above, even in a case where a previously conveyed booklet is pushed out from the main body panel 121 by a subsequently conveyed booklet, the booklet can be prevented from falling down by the slide preventing member 123. Since the nonslip member 123 is bonded to the upper corner portion of the main body panel 121, specifically, the contact surface 121a except for the rib 131, the curved surface 121b, and the corner 121c between the contact surface 121a and the curved surface 121b, the contact area between the nonslip member 123 and the booklet can be increased. Therefore, the booklets can be stably stacked on the transport unit 101. The nonslip member 123 can be formed of an inexpensive material such as felt, and can be attached by a simple operation of being stuck to the contact surface 121a and the curved surface 121b of the main body plate 121. Therefore, it is not necessary to provide a mechanism for reducing the conveying force of the conveying unit as in the conventional technique described above.

Further, since the upper surface of the slip-preventing member 123 is lower than the upper surface of the rib 131, the tip end of the booklet is not caught by the slip-preventing member 123. Further, since the upstream end 123u of the slide preventing member 123 is disposed upstream of the downstream end of the rib 131, the tip of the booklet is not caught by the slide preventing member 123. Therefore, the booklet can be smoothly guided along the ribs 131.

Further, since the downstream end portion 123d of the antiskid member 123 is covered with the base portion 135a and the tip portion 135b of the cover portion 135, the end portion 123d can be prevented from turning up.

The stopper 103 is rotatably supported at a restricting position and a retracted position. When the number of booklets is small, the stopper 103 is rotated to the restricting position, whereby the booklets can be stacked on the conveying portion 101 without using the collection box. On the other hand, when the number of booklets is large, the booklets can be directly collected from the transport unit 101 to the collection box 141 without interference by the stopper 103 by rotating the stopper 103 to the retracted position.

The post-processing apparatus 1 of the present embodiment is connected to an image forming apparatus of an electrophotographic system or an inkjet system, and can create a booklet using sheets on which images are formed by the image forming apparatus. Alternatively, a booklet may be formed by receiving sheets formed by a mechanism different from the image forming apparatus. The sheet stacking apparatus 17 of the present invention can be applied as a stacking apparatus such as a general printer.