Sheet processing apparatus having reversing swing arm shaft pregripper

A sheet processing apparatus comprising:

• a sheet supply device which supplies sheets one by one;
• a first cylinder which comprises at least one gripper device that grips a first edge of the sheet supplied from said sheet supply device, and grips and conveys the sheet by said gripper device;
• a processing device which processes the sheet conveyed by said first cylinder;
• a sheet discharge device which discharges the sheet processed by said processing device;
• and
• conveyance devices which include a plurality of gripper devices including at least one reversing gripper device that grips and holds the a second edge of the sheet, convey the sheet that has undergone a single-sided process and is received from said first cylinder while sequentially transferring the sheet by a gripping change by said plurality of gripper devices, reverse the sheet in the process of conveyance, and supply the sheet onto said first cylinder,
• said conveyance devices comprising
• a second cylinder which grips and conveys a first edge of the sheet by one gripper device of said plurality of gripper devices, and
• a reversing swing arm shaft pregripper which is supported to be swingable between said first cylinder and said second cylinder, receives by said reversing gripper device the second edge of the sheet conveyed by said second cylinder, rotates in a first direction directed from said second cylinder to said first cylinder, transfers the received second edge of the sheet to said gripper device of said first cylinder by a gripping change, and rotates in a second direction opposite to the first direction.