Trimming device, post-processing device, and image forming apparatus with post-processing device

1. A trimming device comprising:

a moving unit including

a roller that transports a booklet which includes one or more sheets and which is folded in half at a center portion of the booklet, with a folded portion of the booklet at a front,

a skew correction gate that corrects a posture of the booklet in response to a leading end of the booklet transported by the roller abutting against the skew correction gate, the skew correction gate being capable of advancing to an abutting position on a path of the booklet and retracting from the path, and

an upper guide that extends at least between the roller and the skew correction gate, the upper guide guides an upper surface of the booklet, the moving unit being movable in a transport direction between (i) a predetermined upstream position and (ii) a downstream position downstream of the upstream position in the transport direction;

a lower guide that guides a lower surface of the booklet transported by the roller; and

a cutter that cuts a downstream fore edge portion of the booklet in the transport direction, the cutter being capable of advancing to the path of the booklet and retracting from the path of the booklet, wherein

the upper guide is configured such that a gap between the upper guide and the lower guide widens in accordance with a thickness of the booklet to allow the booklet to pass through the gap,

the roller is capable of adjusting a speed at which the booklet is transported toward the skew correction gate in at least two steps, and

when a number of sheets constituting the booklet is small, the roller reduces the speed.

2. The trimming device according to claim 1 , wherein

the roller is capable of adjusting a pushing amount by which the roller pushes the booklet toward the skew correction gate after timing at which the folded portion of the booklet comes into contact with the skew correction gate, in at least two steps, and

when the number of sheets constituting the booklet is small, the roller reduces the pushing amount.

3. The trimming device according to claim 2 , wherein

the roller includes

a lower roller that comes into contact with the lower surface of the booklet, and

an upper roller that comes into contact with the upper surface of the booklet, the upper roller being capable of moving up and down, and

an upstream portion of the upper guide at the upstream position is supported by the upper roller and moves up and down as the upper roller moves up and down.

4. The trimming device according to claim 3 , wherein

the upper roller includes

a rotation shaft, and

a bearing including an elongating slot into which the rotation shaft is inserted, and

the upstream portion is supported by the bearing.

5. The trimming device according to claim 2 , wherein

the upper guide or the lower guide includes a boss that defines a minimum interval between the lower guide and the upper guide.

6. The trimming device according to claim 1 , wherein

the roller includes

a lower roller that comes into contact with the lower surface of the booklet, and

an upper roller that comes into contact with the upper surface of the booklet, the upper roller being capable of moving up and down, and

an upstream portion of the upper guide at the upstream position is supported by the upper roller and moves up and down as the upper roller moves up and down.

7. The trimming device according to claim 6 , wherein

the upper roller includes

a rotation shaft, and

a bearing including an elongating slot into which the rotation shaft is inserted, and

the upstream portion is supported by the bearing.

8. The trimming device according to claim 6 , wherein

the upper guide or the lower guide includes a boss that defines a minimum interval between the lower guide and the upper guide.

9. The trimming device according to claim 1 , wherein

the upper guide or the lower guide includes a boss that defines a minimum interval between the lower guide and the upper guide.

10. The trimming device according to claim 9 , wherein

the skew correction gate moves upward to retract from the path, and

in moving upward, the skew correction gate hooks the upper guide to lift a downstream portion of the upper guide.

11. The trimming device according to claim 1 , wherein

the skew correction gate includes a pair of abutting portions at two positions separated from each other in a width direction intersecting the transport direction of the booklet, two parts of the folded portion of the booklet which are separated from each other in the width direction abutting against the abutting portions.

12. The trimming device according to claim 11 , wherein

the roller includes two sets of transport rollers, each set being at a respective one of the two positions separated from each other in the width direction which intersects the transport direction of the booklet, the two sets of transport rollers sandwiching the booklet from above and below.

13. The trimming device according to claim 12 , wherein

when viewed from the transport direction of the booklet, each of the abutting portions and a respective one of the transport rollers at least partially overlap each other.

14. The trimming device according to claim 12 , wherein

the roller includes torque limiters that act on the two sets of transport rollers independently.

15. A post-processing device comprising:

a booklet manufacturing device that

receives sequentially transported sheets,

manufactures a booklet which includes one or more sheets and which is folded in half in a center portion of the booklet, and

feeds the booklet with a folded portion of the booklet at a front; and

the trimming device according to claim 1 that

receives the booklet fed from the booklet manufacturing device and

trims the downstream fore edge portion of the booklet in the transport direction.

16. An image forming apparatus with a post-processing device, comprising:

the post-processing device according to claim 15 ; and

an image forming device that forms images on the sheets and transports the sheets on which the images are formed toward the post-processing device.

17. A trimming device comprising:

a moving unit including

a roller that transports a booklet which includes one or more sheets and which is folded in half at a center portion of the booklet, with a folded portion of the booklet at a front,

a skew correction gate that corrects a posture of the booklet in response to a leading end of the booklet transported by the roller abutting against the skew correction gate, the skew correction gate being capable of advancing to an abutting position on a path of the booklet and retracting from the path, and

an upper guide that extends at least between the roller and the skew correction gate, the upper guide guides an upper surface of the booklet, the moving unit being movable in a transport direction between (i) a predetermined upstream position and (ii) a downstream position downstream of the upstream position in the transport direction;

a lower guide that guides a lower surface of the booklet transported by the roller; and

a cutter that cuts a downstream fore edge portion of the booklet in the transport direction, the cutter being capable of advancing to the path of the booklet and retracting from the path of the booklet, wherein

the upper guide is configured such that a gap between the upper guide and the lower guide widens in accordance with a thickness of the booklet to allow the booklet to pass through the gap,

the roller includes

a lower roller that comes into contact with the lower surface of the booklet, and

an upper roller that comes into contact with the upper surface of the booklet, the upper roller being capable of moving up and down, and

an upstream portion of the upper guide at the upstream position is supported by the upper roller and moves up and down as the upper roller moves up and down, and

the upper roller includes

a rotation shaft, and

a bearing including an elongating slot into which the rotation shaft is inserted, and

the upstream portion is supported by the bearing.

18. A trimming device comprising:

a moving unit including

a roller that transports a booklet which includes one or more sheets and which is folded in half at a center portion of the booklet, with a folded portion of the booklet at a front,

a skew correction gate that corrects a posture of the booklet in response to a leading end of the booklet transported by the roller abutting against the skew correction gate, the skew correction gate being capable of advancing to an abutting position on a path of the booklet and retracting from the path, and

an upper guide that extends at least between the roller and the skew correction gate, the upper guide guides an upper surface of the booklet, the moving unit being movable in a transport direction between (i) a predetermined upstream position and (ii) a downstream position downstream of the upstream position in the transport direction;

a lower guide that guides a lower surface of the booklet transported by the roller; and

a cutter that cuts a downstream fore edge portion of the booklet in the transport direction, the cutter being capable of advancing to the path of the booklet and retracting from the path of the booklet, wherein

the upper guide is configured such that a gap between the upper guide and the lower guide widens in accordance with a thickness of the booklet to allow the booklet to pass through the gap,

the upper guide or the lower guide includes a boss that defines a minimum interval between the lower guide and the upper guide,

the skew correction gate moves upward to retract from the path, and

in moving upward, the skew correction gate hooks the upper guide to lift a downstream portion of the upper guide.