Sheet folding apparatus and image forming system having the same

A sheet folding apparatus comprising:

• a conveying roller that conveys a sheet in a predetermined conveying direction;
• a folding roller pair that is disposed downstream relative to the conveying roller in the conveying direction and rotates while nipping a predetermined position of the sheet to form a fold at the predetermined position;
• a conveying path for conveying the sheet in the conveying direction from the conveying roller to the folding roller pair;
• an abutting member that moves downstream in the conveying direction and abuts against the predetermined position of the sheet to bend the sheet downstream such that the predetermined position moves to a position nipped by the folding roller pair;
• and
• a loop space where the sheet is bent between the conveying roller and the folding roller pair in a direction crossing the conveying direction,
• the folding roller pair stopping its rotation while nipping a front end of the sheet fed from the conveying roller to form a loop of the sheet hanging down in the loop space,
• the abutting member moving so as to abut against the loop in the loop space from the upstream side in the conveying direction to move the predetermined position of the sheet to the position nipped by the folding roller pair,
• the sheet folding apparatus further comprising:
• a receiving port for receiving the sheet having a fold formed by the folding roller pair and fed in the conveying direction;
• a support member that is disposed downstream relative to the receiving port in the conveying direction and is configured movable in a predetermined direction;
• a first pressing member that is supported by the support member;
• a second pressing member that is disposed so as to face the first pressing member across the sheet conveying path and presses the fold in cooperation with the first pressing member;
• and
• a moving mechanism that moves the support member relative to the second pressing member to move the first pressing member relative to the second pressing member between a pressing position at which the fold of the sheet is pressed between the first and second pressing members and a retreating position obtained by moving the first pressing member from the pressing position in a direction separating from the second pressing member,
• the moving mechanism being disposed downward of the loop space in the sheet conveying direction so as to overlap the loop space in the sheet conveying direction.