Sheet processing apparatus, sheet processing method, and image forming apparatus

• US 20100019442A1
• Filed: 06/25/2009
• Published: 01/28/2010
• Est. Priority Date: 07/23/2008
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Yoshida, Hiroki
• Granted Patent: US 7,918,450 B2
• Time in Patent Office: Days
• US Class Current: 271/220
• CPC Class Codes: B65H 2220/01 indicating an entity as a function of which control, adjustment or change is performed, i.e. input
• CPC Class Codes: B65H 2220/02 indicating an entity which is controlled, adjusted or changed by a control process, i.e. output
• CPC Class Codes: B65H 2301/4213 of a limited number of articles, e.g. buffering, forming bundles
• CPC Class Codes: B65H 2301/42265 by moving the surface supporting the pile of articles on edge, e.g. conveyor or carriage
• CPC Class Codes: B65H 2301/42266 by acting on edge of the pile for moving it along a surface, e.g. pushing
• CPC Class Codes: B65H 2511/514 Particular portion of element
• CPC Class Codes: B65H 2513/10 Speed
• CPC Class Codes: B65H 2513/20 Acceleration or deceleration
• CPC Class Codes: B65H 2513/50 Timing
• CPC Class Codes: B65H 2557/242 involving a particular data profile or curve
• CPC Class Codes: B65H 2701/1311 leading edge
• CPC Class Codes: B65H 2701/1313 trailing edge
• CPC Class Codes: B65H 2801/27 Devices located downstream of office-type machines
• CPC Class Codes: B65H 29/14 and introducing into a pile
• CPC Class Codes: B65H 31/3072 by moving a surface supporting the pile of articles on edge, e.g. by using belts or carriages
• CPC Class Codes: B65H 31/3081 by acting on edge of the pile for moving it along a surface, e.g. by pushing
• CPC Class Codes: B65H 37/04 for securing together articles or webs, e.g. by adhesive, stitching or stapling adhering replacement to expiring web during change of web roll B65H19/18

Abstract

When a sheet is conveyed to a position where a conveying speed can be changed from a first conveying speed to a second conveying speed while a discharging unit is discharging a preceding stack of sheets, a conveyance control unit calculates a third conveying speed for conveying the sheet based on a first conveyance time to be taken until a leading end of the stack of sheets reaches a second tray unit from a first tray unit and a second conveyance time to be taken until a current discharging operation is completed from a start of the current discharging operation, and changes the conveying speed from the first conveying speed to the third conveying speed.

Claims

1. A sheet processing apparatus comprising:

a conveying unit that conveys a sheet from an upper-level apparatus;

a conveyance control unit that changes a conveying speed of the sheet from a first conveying speed to a second conveying speed to extend an interval between a current sheet and a next sheet from the upper-level device increases;

a first tray unit that stacks therein the sheet conveyed by the conveying unit;

an aligning unit that aligns sheets stacked in the first tray unit;

a second tray unit that stacks therein a stack of sheets discharged from the first tray unit;

a discharging unit that discharges the stack of sheets from the first tray unit to the second tray unit; and

a holding unit that holds a trailing end of the stack of sheets stacked in the second tray unit, wherein

when a sheet is conveyed to an acceleration position where the conveying speed can be changed from the first conveying speed to the second conveying speed while the discharging unit is discharging a preceding stack of sheets, the conveyance control unit calculates a third conveying speed for conveying the sheet based on a first conveyance time to be taken until a leading end of the stack of sheets reaches the second tray unit and a second conveyance time to be taken until a current discharging operation of the stack of sheets is completed from a start of the current discharging operation, and changes the conveying speed from the first conveying speed to the third conveying speed.

2. The sheet processing apparatus according to claim 1, wherein the second conveyance time is from when the sheet reaches the acceleration position to when the holding unit holds a trailing end of the preceding stack of sheets stacked in the second tray unit.

3. The sheet processing apparatus according to claim 1, wherein the first conveying speed is equal to or slower than the third conveying speed and the third conveying speed is slower than the second conveying speed.

4. The sheet processing apparatus according to claim 1, wherein

the aligning unit includes

a trailing-end aligning unit for aligning the sheet stacked in the first tray unit in a sheet conveying direction, and

a pair of alignment plates for aligning the sheet in a sheet width direction, and

the aligning unit moves the sheet stacked in the first tray unit in a direction opposite to the sheet conveying direction such that a trailing end of the sheet abuts the trailing-end aligning unit to align the sheet in the sheet conveying direction, and aligns the sheet in the sheet width direction using the alignment plates.

5. The sheet processing apparatus according to claim 1, wherein after changing the conveying speed from the first conveying speed to either one of the second conveying speed and the third conveying speed, the conveyance control unit changes the conveying speed from either one of the second conveying speed and the third conveying speed to a fourth conveying speed before the sheet is conveyed to the first tray unit.

6. The sheet processing apparatus according to claim 1, wherein the conveyance control unit changes the conveying speed from the first conveying speed to the second conveying speed to assure a processing time for performing an alignment operation by the aligning unit, and changes the conveying speed from the first conveying speed to the third conveying speed to assure the processing time for the alignment operation and a processing time for discharging the stack of sheets by the discharging unit.

7. A sheet processing method comprising:

conveying a sheet from an upper-level apparatus to a first tray unit;

controlling including changing a conveying speed of the sheet from a first conveying speed to a second conveying speed to extend an interval between a current sheet and a next sheet from the upper-level device increases;

aligning sheets stacked in the first tray unit;

discharging a stack of sheets from the first tray unit to a second tray unit; and

holding a trailing end of the stack of sheets stacked in the second tray unit, wherein

when a sheet is conveyed to an acceleration position where the conveying speed can be changed from the first conveying speed to the second conveying speed while a preceding stack of sheets is discharged at the discharging, the controlling includes calculating a third conveying speed for conveying the sheet based on a first conveyance time to be taken until a leading end of the stack of sheets reaches the second tray unit and a second conveyance time to be taken until a current discharging operation of the stack of sheets is completed from a start of the current discharging operation and changing the conveying speed from the first conveying speed to the third conveying speed.

8. The sheet processing method according to claim 7, wherein the second conveyance time is from when the sheet reaches the acceleration position to when a trailing end of the preceding stack of sheets stacked in the second tray unit is held at the holding.

9. The sheet processing method according to claim 7, wherein the first conveying speed is equal to or slower than the third conveying speed and the third conveying speed is slower than the second conveying speed.

10. The sheet processing method according to claim 7, wherein the aligning includes

moving the sheet stacked in the first tray unit in a direction opposite to a sheet conveying direction such that a trailing end of the sheet abuts a trailing-end aligning unit to align the sheet in the sheet conveying direction, and

aligning the sheet in the sheet width direction using a pair of alignment plates.

11. The sheet processing method according to claim 7, wherein after the conveying speed is changed from the first conveying speed to either one of the second conveying speed and the third conveying speed, the controlling further includes changing the conveying speed from either one of the second conveying speed and the third conveying speed to a fourth conveying speed before the sheet is conveyed to the first tray unit.

12. The sheet processing method according to claim 7, wherein the controlling includes changing the conveying speed from the first conveying speed to the second conveying speed to assure a processing time for performing an alignment operation at the aligning, and changing the conveying speed from the first conveying speed to the third conveying speed to assure the processing time for the alignment operation and a processing time for discharging the stack of sheets at the discharging.

13. An image forming apparatus comprising a sheet processing device including

a conveying unit that conveys a sheet from an upper-level apparatus;

a conveyance control unit that changes a conveying speed of the sheet from a first conveying speed to a second conveying speed to extend an interval between a current sheet and a next sheet from the upper-level device increases;

a first tray unit that stacks therein the sheet conveyed by the conveying unit;

an aligning unit that aligns sheets stacked in the first tray unit;

a second tray unit that stacks therein a stack of sheets discharged from the first tray unit;

a discharging unit that discharges the stack of sheets from the first tray unit to the second tray unit; and

a holding unit that holds a trailing end of the stack of sheets stacked in the second tray unit, wherein

when a sheet is conveyed to an acceleration position where the conveying speed can be changed from the first conveying speed to the second conveying speed while the discharging unit is discharging a preceding stack of sheets, the conveyance control unit calculates a third conveying speed for conveying the sheet based on a first conveyance time to be taken until a leading end of the stack of sheets reaches the second tray unit and a second conveyance time to be taken until a current discharging operation of the stack of sheets is completed from a start of the current discharging operation, and changes the conveying speed from the first conveying speed to the third conveying speed.

14. The image forming apparatus according to claim 13, wherein the second conveyance time is from when the sheet reaches the acceleration position to when the holding unit holds a trailing end of the preceding stack of sheets stacked in the second tray unit.

15. The image forming apparatus according to claim 13, wherein the first conveying speed is equal to or slower than the third conveying speed and the third conveying speed is slower than the second conveying speed.

16. The image forming apparatus according to claim 13, wherein

the aligning unit includes

a trailing-end aligning unit for aligning the sheet stacked in the first tray unit in a sheet conveying direction, and

a pair of alignment plates for aligning the sheet in a sheet width direction, and

the aligning unit moves the sheet stacked in the first tray unit in a direction opposite to the sheet conveying direction such that a trailing end of the sheet abuts the trailing-end aligning unit to align the sheet in the sheet conveying direction, and aligns the sheet in the sheet width direction using the alignment plates.

17. The image forming apparatus according to claim 13, wherein after changing the conveying speed from the first conveying speed to either one of the second conveying speed and the third conveying speed, the conveyance control unit changes the conveying speed from either one of the second conveying speed and the third conveying speed to a fourth conveying speed before the sheet is conveyed to the first tray unit.

18. The image forming apparatus according to claim 13, wherein the conveyance control unit changes the conveying speed from the first conveying speed to the second conveying speed to assure a processing time for performing an alignment operation by the aligning unit, and changes the conveying speed from the first conveying speed to the third conveying speed to assure the processing time for the alignment operation and a processing time for discharging the stack of sheets by the discharging unit.