Patent ID: 8038146

Claim:
A post-processing device for use with a sheet processing apparatus configured to perform predetermined processing on a sheet, the post-processing device being configured to perform post-processing on the sheet having been subjected to the predetermined processing at a sheet processing section of the sheet processing apparatus, the post-processing device comprising: an introductory feed path configured to allow the sheet having been subjected to the predetermined processing at the sheet processing section to be introduced therein; a processing tray disposed below the introductory feed path and configured to place thereon the sheet having passed through the introductory feed path; a post-processing section configured to perform post-processing on the sheet placed on the processing tray; a catch tray disposed below the processing tray and configured to receive the sheet delivered from the processing tray after the post-processing by the post-processing section; a sheet delivery section having an upper rotary member and a lower rotary member which are disposed at an end of the processing tray lying on a catch tray side so as to be movable toward and away from each other, the sheet delivery section being configured to draw a sheet into the processing tray by the upper rotary member and the lower rotary member pressing against each other and rotating in a state where the members hold the sheet directed to the catch tray; and a control section configured to control at least operation of the sheet delivery section, wherein the control section shifts the upper rotary member and the lower rotary member from in a separate state to in a press-contact state at latest by the time a leading edge of a first sheet of a group of sheets to be post-processed at a time is brought into contact with the catch tray, and shifts the upper rotary member and the lower rotary member from in a separate state to in a press-contact state after a trailing edge of a succeeding sheet reaches a space between the upper rotary member and the lower rotary member.