Sheet processor that adjusts a punching operation position based on a detected sheet edge and associated image forming apparatus

A sheet processor, comprising:

• means defining a sheet transportation path for transporting sheets in a sheet transportation direction;
• punching means provided in said sheet transportation path, said punching means comprising a punch slide having a punch mechanism thereon, said punch mechanism rotatable to perform a punching operation on the sheets;
• moving means for moving said punch slide between a sheet punching operation position and a punch slide home position, said movement in a direction transverse to the sheet transportation direction;
• detecting means for detecting completion of the punching operation before said punch mechanism rotates back to a punching operation home position;
• and
• movement controlling means for starting movement of said punch slide by said moving means when said detecting means detects completion of the punching operation.

A sheet processor, comprising:

• means defining a sheet transportation path for transporting sheets in a sheet transportation direction;
• punching means provided in said sheet transportation path for performing a punching operation on the sheets, said punching means comprising a punch slide having a punch mechanism thereon;
• moving means for moving said punch slide between a sheet punching operation position and a punch slide home position, said movement in a direction transverse to the sheet transportation direction;
• edge detecting means for detecting an edge, in the sheet transportation direction, of each of the sheets;
• and
• completion detecting means for detecting completion of the punching operation;
• wherein when the edge of each of the sheets is detected by said edge detecting means, said moving means causes said punch slide to move to the sheet punching operation position;
• and
• wherein when said completion detecting means detects the completion of the punching operation, said moving means causes said punch slide to move to the punch slide home position.

A sheet processor, comprising:

• means defining a sheet transportation path for transporting sheets in a sheet transportation direction;
• punching means provided in the sheet transportation path, said punching means comprising a punch slide having a punch mechanism thereon, said punch mechanism rotatable to perform a punching operation on the sheets;
• moving means for said punch slide between a sheet punching operation position and a punch slide home position, said movement in a direction transverse to the sheet transporting direction;
• edge detecting means for detecting an edge, in the sheet transportation direction, of each of the sheets;
• completion detecting means for detecting completion of the punching operation performed on each of the sheets before said punch mechanism rotates back to a punching operation home position;
• and
• movement controlling means which causes said moving means to move said punch slide to the sheet punching operation position when the edge of each of the sheets is detected by said edge detecting means, said movement controlling means causing said moving means to move said punch slide to the punch slide home position when said completion detecting means detects completion of a punching operation performed on each of the sheets.