Sheet post-processing apparatus and image forming system

Patent metadata

Field	Value
Publication number	US-2016355364-A1
Application number	US-201615170310-A
Country	US
Kind code	A1
Filing date	Jun 1, 2016
Priority date	Jun 3, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A sheet post-processing apparatus includes: a sheet stack tray; a rear-end-position regulating member, against which a rear end of the sheet on the tray is butted to align a position of the sheet in a sheet conveying direction to the stack tray, the rear end of the sheet being a rear end in the conveying direction; and a roller member that comes in contact with an upper surface of the sheet conveyed to an upper side of the tray, before the sheet is stacked on a stacking surface on the tray, and conveys the sheet stacked on the stacking surface toward the rear-end-position regulating member, wherein a rotation speed before stacking is set to be smaller than a rotation speed after stacking, and the rotation speed of before stacking is greater than zero.

First claim

What is claimed is:

1 . A sheet post-processing apparatus comprising:
a stack tray for stacking a sheet; a rear-end-position regulating member, against which a rear end of the sheet stacked on the stack tray is butted to align a position of the sheet in a conveying direction in which the sheet is conveyed toward the stack tray, the rear end of the sheet being a rear end in the conveying direction; and a roller member that comes in contact with an upper surface of the sheet conveyed to an upper side of the stack tray, before the sheet is stacked on a stacking surface on the stack tray, and conveys the sheet stacked on the stacking surface toward the rear-end-position regulating member, wherein a rotation speed before stacking, which is a rotation speed of the roller member when the roller member is in contact with the sheet while the rear end of the sheet in the conveying direction is not landed on the stacking surface, is set to be smaller than a rotation speed after stacking, which is a rotation speed of the roller member when the roller member conveys the sheet to the rear-end-position regulating member while the sheet is stacked on the stacking surface, and the rotation speed of before stacking is greater than zero.

2 . The sheet post-processing apparatus according to claim 1 , wherein
the roller member comes in contact with the sheet while the roller member is in a non-rotating state, and is set to the rotation speed before stacking a predetermined time t 1 before the roller member comes in contact with the stacking surface via the sheet.

3 . The sheet post-processing apparatus according to claim 2 , wherein
the rotation speed of the roller member is changed to the rotation speed after stacking after a predetermined time t 2 since the contact of the roller member with the stacking surface via the sheet.

4 . The sheet post-processing apparatus according to claim 3 , wherein
the rotation speed of the roller member is changed to a rotation speed that is higher than the rotation speed before stacking and lower than the rotation speed after stacking for a predetermined time t 3 before the end of the predetermined time t 2 .

5 . The sheet post-processing apparatus according to claim 2 , wherein
the predetermined time t 1 is changed for each number of stacked sheets.

6 . The sheet post-processing apparatus according to claim 3 , wherein
one of the predetermined times t 1 and t 2 is changed for each number of stacked sheets.

7 . The sheet post-processing apparatus according to claim 4 , wherein
one of the predetermined times t 1 , t 2 , and t 3 is changed for each number of stacked sheets.

8 . The sheet post-processing apparatus according to claim 2 , wherein
the predetermined time t 1 is changed depending on a sheet type.

9 . The sheet post-processing apparatus according to claim 3 , wherein
one of the predetermined times t 1 and t 2 is changed depending on a sheet type.

10 . The sheet post-processing apparatus according to claim 4 , wherein
one of the predetermined times t 1 , t 2 , and t 3 is changed depending on a sheet type.

11 . The sheet post-processing apparatus according to claim 2 , further comprising:
a stack height detecting unit that detects a height of a stack of sheets on the stack tray, and changes the predetermined time t 1 based on detection information obtained from the stack height detecting unit.

12 . The sheet post-processing apparatus according to claim 3 , further comprising:
a stack height detecting unit that detects a height of a stack of sheets on the stack tray, and changes one of the predetermined times t 1 and t 2 based on detection information obtained from the stack height detecting unit.

13 . The sheet post-processing apparatus according to claim 4 , further comprising:
a stack height detecting unit that detects a height of a stack of sheets on the stack tray, and changes one of the predetermined times t 1 , t 2 , and t 3 based on detection information obtained from the stack height detecting unit.

14 . The sheet post-processing apparatus according to claim 1 , wherein
at least one of the rotation speed before stacking and the rotation speed after stacking is changed depending on a sheet type.

15 . The sheet post-processing apparatus according to claim 1 , further comprising:
a butting member that is capable of coming in contact with and away from the stacking surface, rotates to convey a sheet conveyed toward the rear-end-position regulating member by the roller member, and causes the sheet to butt against the rear-end-position regulating member; a deflection detecting unit that detects deflection of a sheet caused by conveyance by the roller member while rotation of the butting member is stopped; and a sheet detecting unit that is arranged between the roller member and the butting member and that detects the sheet, wherein a time from when the sheet detecting unit detects a sheet to when the deflection detecting unit detects predetermined deflection is measured, and the rotation speed after stacking is changed in accordance with the measured time.

16 . The sheet post-processing apparatus according to claim 15 , wherein
a time from when the sheet detecting unit detects a sheet to when the deflection detecting unit detects predetermined deflection is measured for second and subsequent sheets, and the rotation speed after stacking is changed in accordance with the measured time for each of the sheets.

17 . The sheet post-processing apparatus according to claim 15 , further comprising:
a paper ejection tray for stacking a sheet discharged from the stack tray; and a returning member that rotates to return a sheet discharged on the paper ejection tray to an upstream side in a discharging direction, wherein a rotation speed of the returning member is changed in accordance with the measured time.

18 . An image forming system comprising: an image forming apparatus that forms an image on a sheet based on image information; and a sheet post-processing apparatus, wherein
the sheet post-processing apparatus comprises;
a stack tray for stacking the sheet;
a rear-end-position regulating member, against which a rear end of the sheet stacked on the stack tray is butted to align a position of the sheet in a conveying direction in which the sheet is conveyed toward the stack tray, the rear end of the sheet being a rear end in the conveying direction; and
a roller member that comes in contact with an upper surface of the sheet conveyed to an upper side of the stack tray, before the sheet is stacked on a stacking surface on the stack tray, and conveys the sheet stacked on the stacking surface toward the rear-end-position regulating member, wherein
a rotation speed before stacking, which is a rotation speed of the roller member when the roller member is in contact with the sheet while the rear end of the sheet in the conveying direction is not landed on the stacking surface, is set to be smaller than a rotation speed after stacking, which is a rotation speed of the roller member when the roller member conveys the sheet to the rear-end-position regulating member while the sheet is stacked on the stacking surface, and
the rotation speed of before stacking is greater than zero.

Assignees

• Shibata Hidefumi
• Kimata Masanobu
• Kawasaki Masaaki
• Morisaki Ryohei
• Murakami Norihiko
• Nishide Maki
• Ricoh Co Ltd

Inventors

• Shibata Hidefumi
• Kimata Masanobu
• Kawasaki Masaaki
• Morisaki Ryohei
• Murakami Norihiko
• Nishide Maki

Classifications

• B65H2405/11151

  with surface inclined upwardly in transport direction · CPC title

• B65H2513/11

  angular · CPC title

• B65H2404/723

  formed of forwarding means · CPC title

• B65H2404/1521

  rotating, pivoting or oscillating around an axis, e.g. parallel to the roller axis · CPC title

• G03G15/6582

  Special processing for irreversibly adding or changing the sheet copy material characteristics or its appearance, e.g. stamping, annotation printing, punching · CPC title