Sheet punching device and image forming apparatus

A sheet punching device, comprising:

• a die which has a die hole and is configured to be driven to rotate;
• a punch configured to punch a hole in a sheet;
• a punch holding portion configured to hold the punch, the punch holding portion being configured to rotate in a first direction around a rotation axis of the die in synchronization with the die from a predetermined area, and then to return in a second direction different from the first direction to the predetermined area, the punch holding portion having:
• a first portion having a length extending in a direction parallel to the rotation axis, wherein the first portion has a first end and a second end, and the punch is held by the first portion adjacent to the second end, and
• a second portion extending from the first end of the first portion and surrounding the the rotation axis;
• and
• a punch moving portion configured to move the punch in and out of the die hole, the punch moving portion being configured to move the punch into, and then out of, the die hole while the punch holding portion rotates in the first direction around the rotation axis in synchronization with the die from the predetermined area and causes the punch to rotate around the rotation axis in the first direction,
• wherein the punch holding portion holds the punch such that the punch does not make a revolution around the rotation axis as the punch holding portion is rotated from the predetermined area to punch a hole in a sheet by the punch and then returned to the predetermined area.