Sheet puncher, sheet finisher equipped with the sheet puncher and image forming apparatus using the sheet finisher

A sheet finisher comprising:

• a sheet puncher comprising:
• (a) a reversal conveying section having a displaceable stopping member for stopping a sheet at a predetermined position representing a bottom position, the stopping member being movable to an intermediate position or a top position, and a punching device for punching the sheet;
• and
• (b) a conveying-in and conveying out section having a conveying-in device and a conveying-out device for conveying-in the sheet from a main conveying path into the reversal conveying section, and conveying-out the sheet from the reversal conveying section to the main conveying path,
• wherein the conveying-in device (1) conveys a first sheet into the reversal conveying section and the stopping member stops the first sheet at the predetermined position, the stopping member (2) moves to the intermediate position to move up the first sheet, then the punching device (3) punches the first sheet, the conveying-in device (4) conveys a second sheet following the first sheet into the reversal conveying section, the stopping member (5) moves to the top position at which the conveying-out device (6) conveys the first sheet from the reversal conveying section while the conveying-in device continues to convey the second sheet, further the stopping member (7) moves down to the predetermined position while the conveying-out device continues to convey the first sheet and the conveying-in device further continues to convey the second sheet, and thereafter the operations of (1) to (7) are performed on a third sheet onward following the second sheet.

An image forming apparatus comprising:

• a sheet puncher comprising:
• (a) a reversal conveying section having a displaceable stopping member for stopping a sheet at a predetermined position representing a bottom position, the stopping member being movable to an intermediate position or a top position, and a punching device for punching the sheet;
• and
• (b) a conveying-in and conveying out section having a conveying-in device and a conveying-out device for conveying-in the sheet from a main conveying path into the reversal conveying section, and conveying-out the sheet from the reversal conveying section to the main conveying path,
• wherein the conveying-in device (1) conveys a first sheet into the reversal conveying section and the stopping member stops the first sheet at the predetermined position, the stopping member (2) moves to the intermediate position to move up the first sheet, then the punching device (3) punches the first sheet, the conveying-in device (4) conveys a second sheet following the first sheet into the reversal conveying section, the stopping member (5) moves to the top position at which the conveying-out device (6) conveys the first sheet from the reversal conveying section while the conveying-in device continues to convey the second sheet, further the stopping member (7) moves down to the predetermined position while the conveying-out device continues to convey the first sheet and the conveying-in device further continues to convey the second sheet, and thereafter the operations of (1) to (7) are performed on a third sheet onward following the second sheet.