Sheet processing device, sheet laminator, image forming apparatus, and image forming system

1. A sheet processing device configured to separate a non-bonding portion of a two-ply sheet in which two sheets are overlapped and bonded together at one end as a bonding portion of the two-ply sheet, the sheet processing device comprising:

a first sheet feeder configured to feed the two-ply sheet;

a second sheet feeder configured to feed an inner sheet to be inserted between the two sheets of the two-ply sheet in a state in which the non-bonding portion of the two-ply sheet is separated; and

circuitry configured to:

cause the first sheet feeder to feed the two-ply sheet;

perform a sheet separating operation on the two-ply sheet to separate the non-bonding portion of the two-ply sheet; and

cause the second sheet feeder to start feeding the inner sheet before completion of the sheet separating operation on the two-ply sheet.

2. The sheet processing device according to claim 1 ,

wherein the circuitry is configured to:

cause the first sheet feeder to start feeding the two-ply sheet from the first sheet feeder; and

cause the second sheet feeder to start feeding the inner sheet from the second sheet feeder after a set time that is previously set for each size of the two-ply sheet in a sheet conveyance direction of the two-ply sheet has elapsed from when the first sheet feeder started feeding the two-ply sheet.

3. The sheet processing device according to claim 1 , further comprising a sheet detector configured to detect presence of the two-ply sheet at a predetermined position,

wherein the circuitry is configured to cause the second sheet feeder to start feeding the inner sheet from the second sheet feeder, based on a detection result of the sheet detector.

4. The sheet processing device according to claim 1 , further comprising a sheet separation detector configured to detect a state in which the non-bonding portion of the two-ply sheet is successfully separated,

wherein the circuitry is configured to cause the second sheet feeder to start feeding the inner sheet from the second sheet feeder, based on a detection result of the sheet separation detector.

5. The sheet processing device according to claim 1 , further comprising:

a winding roller configured to rotate in a predetermined rotational direction to wind the two-ply sheet;

a conveyance roller pair configured to convey the two-ply sheet toward the winding roller in a sheet conveyance passage between the conveyance roller pair and the winding roller;

a separator configured to be inserted into a gap formed at the non-bonding portion between the two sheets of the two-ply sheet at a position between the winding roller and the conveyance roller pair, in a state in which the two-ply sheet is wound from a leading end of the two-ply sheet by the winding roller and an upstream side of the two-ply sheet upstream from the leading end of the two-ply sheet in a sheet conveyance direction of the two-ply sheet is nipped by the conveyance roller pair; and

a switcher configured to guide the two sheets separated by the separator, to two branched sheet conveyance passages branching off the two sheets in different directions.

6. The sheet processing device according to claim 5 ,

wherein the circuitry is configured to:

cause the conveyance roller pair to convey the two-ply sheet in a reverse direction opposite the sheet conveyance direction to release winding of the leading end of the two-ply sheet on the winding roller after the separator is inserted into the gap;

cause the conveyance roller pair to convey the two-ply sheet in the sheet conveyance direction;

cause the switcher to guide the two sheets separated by the separator, to the two branched sheet conveyance passages separately; and

cause the conveyance roller pair to convey the inner sheet fed by the second sheet feeder, in the reverse direction of the sheet conveyance passage, to insert the inner sheet between the two sheets separated from the two-ply sheet.

7. The sheet processing device according to claim 6 , further comprising:

a gripper configured to grip the leading end of the two-ply sheet as a gripped portion, between a receiving portion of the winding roller and the gripper; and

a moving mechanism configured to move the gripper between a gripping position at which the gripper grips the two-ply sheet and a releasing position at which the gripper is released from the gripping position.

8. The sheet processing device according to claim 1 ,

wherein the two-ply sheet is conveyed through a sheet conveyance passage, from the first sheet feeder to an insertion position at which the inner sheet is inserted into the two-ply sheet,

wherein the inner sheet is conveyed through another sheet conveyance passage, from the second sheet feeder to the insertion position, and

wherein a length of the sheet conveyance passage is shorter than a length of said another sheet conveyance passage.

9. The sheet processing device according to claim 8 ,

wherein the sheet conveyance passage, through which the two-ply sheet is conveyed, meets said another sheet conveyance passage, through which the inner sheet is conveyed, at a meeting point,

wherein the sheet conveyance passage through which the two-ply sheet is conveyed is a straight sheet conveyance passage in which the two-ply sheet is not reversed upside down, and

wherein said another sheet conveyance passage through which the inner sheet is conveyed, from the second sheet feeder to the meeting point, is a reverse conveyance passage in which the inner sheet is reversed upside down.

10. The sheet processing device according to claim 8 ,

wherein the sheet conveyance passage through which the two-ply sheet is conveyed is a reverse conveyance passage in which the two-ply sheet is reversed upside down,

wherein said another sheet conveyance passage through which the inner sheet is conveyed is another reverse conveyance passage in which the inner sheet is reversed upside down, and

wherein the first sheet feeder is closer than the second sheet feeder, with respect to a meeting point at which the sheet conveyance passage through which the two-ply sheet is conveyed meets said another sheet conveyance passage through which the inner sheet is conveyed.

11. A sheet laminator comprising:

the sheet processing device according to claim 1 ; and

a sheet lamination device configured to perform a sheet laminating operation on the two-ply sheet in which an inner sheet is inserted between the two sheets separated by the sheet processing device.

12. An image forming apparatus comprising:

an image forming device configured to form an image on a sheet; and

the sheet laminator according to claim 11 .

13. The image forming apparatus according to claim 12 ,

wherein the first sheet feeder is provided in the sheet laminator, and

wherein the second sheet feeder is provided in the image forming device.

14. An image forming system comprising:

an image forming apparatus configured to form an image on a sheet; and

the sheet laminator according to claim 11 , detachably attached to the image forming apparatus.

15. The image forming system according to claim 14 ,

wherein the first sheet feeder is provided in the sheet laminator, and

wherein the second sheet feeder is provided in the image forming apparatus.

16. An image forming apparatus comprising:

an image forming device configured to form an image on a sheet; and

the sheet processing device according to claim 1 .

17. The image forming apparatus according to claim 16 ,

wherein the first sheet feeder is provided in the sheet processing device, and

wherein the second sheet feeder is provided in the image forming device.

18. An image forming system comprising:

an image forming apparatus configured to form an image on a sheet; and

the sheet processing device according to claim 1 , detachably attached to the image forming apparatus.

19. The image forming system according to claim 18 ,

wherein the first sheet feeder is provided in the sheet processing device, and

wherein the second sheet feeder is provided in the image forming apparatus.