Folding device, post-processing device and image forming apparatus

A folding device comprising:

• a conveying path that can convey a sheet member in a predetermined conveying direction;
• a placement portion that constitutes a part of the conveying path and has a placement face on which the sheet member can be placed;
• a through portion that is formed on the placement portion and formed to be through from the placement face side to an opposite face on an opposite side of the placement face;
• a first folding member that is arranged on the opposite face side in the placement portion, to be movable between an initial position where a tip end part thereof is positioned at a predetermined position on the opposite face side and a protruded position where the tip end part penetrates the through portion and is positioned at a predetermined position on the placement face side, the first folding member folding and moving the sheet member by moving from the initial position to the protruded position in a state in which the sheet member is placed thereon;
• a second folding member that is arranged on the placement face side of the placement portion, and pinches and receives the sheet member thus folded as well as the first folding member in a state in which the first folding member is positioned at the protruded position;
• a driving mechanism having a rotational driving unit that can output a rotational driving force and a rotating member that is rotated by the rotational driving force from the rotational driving unit, the driving mechanism making the first folding member reciprocate between the initial position and the protruded position;
• a rotational position detecting mechanism that detects a rotational position of the rotating member and outputs rotational position information;
• a rotational load monitoring unit that detects a rotational load generated in the rotational driving unit and determines whether the rotational load is at least a predetermined load;
• a rotational drive control unit that receives the rotational position information from the rotational position detecting mechanism,
• wherein:
• the driving mechanism includes a converting unit that converts a rotational motion of the rotating member into a reciprocating motion;
• the rotational driving unit can reverse a direction of rotational drive;
• the rotating member is directly or indirectly connected to the rotational driving unit;
• and
• the rotational drive control unit, when the rotational load monitoring unit determines that the rotational load is at least the predetermined load, determines whether the first folding member is in a state of moving from the initial position to the protruded position or the first folding member is in a state of moving from the protruded position to the initial position based on the rotational position information, and, in a case in which the first folding member is determined to be in the state of moving from the initial position to the protruded position, controls the rotational driving unit to reverse the direction of rotational drive, and in a case in which the first folding member is determined to be in the state of moving from the protruded position to the initial position, controls the rotational driving unit to maintain the direction of rotational drive.