Sheet processing unit that switches transport destination of sheet

A sheet processing unit comprising:

• a postprocessing apparatus that performs postprocessing on a printed sheet;
• a sorting device removably attached to the postprocessing apparatus, and configured to sort the printed sheet to a predetermined tray,
• wherein the postprocessing apparatus includes:
• a postprocessing device that performs postprocessing on the sheet;
• and
• a processing destination switch guide that switches a destination of the sheet to be processed, between the postprocessing device and the sorting device,
• the sorting device includes:
• a sorting destination switch guide that switches the tray to which the sheet is to be sorted;
• and
• a guide drive device that drives the sorting destination switch guide, and
• the guide drive device also drives the processing destination switch guide,
• wherein the processing destination switch guide changes a posture so as to selectively switch the destination of the sheet to be processed, between the postprocessing device and the sorting device,
• the sorting destination switch guide changes a posture so as to selectively switch the destination of the sheet among a plurality of the sorting destinations, and
• the guide drive device exerts a switching force for switching the posture, to each of the processing destination switch guide and the sorting destination switch guide,
• wherein the processing destination switch guide receives a mechanical force that sets the destination of the sheet to the sorting device, and switches the destination of the sheet to the postprocessing device, by further receiving the switching force,
• wherein the sorting destination switch guide receives a mechanical force that causes the sorting destination switch guide to assume the posture for not sorting the sheet to the tray, and assumes the posture for sorting the sheet to the tray, by further receiving the switching force,
• wherein the guide drive device includes:
• a moving element stretched around a driving body;
• and
• an acting member attached to the moving element, and
• the acting member changes the posture of each of the sorting destination switch guide and the processing destination switch guide, by exerting thereto the switching force,
• wherein the moving element includes a cord-shaped body,
• the sheet processing unit further comprises a cover attached to the postprocessing apparatus in place of the sorting device, when the sorting device is removed from the postprocessing apparatus,
• wherein a part of the cover attached to the postprocessing apparatus switches the posture of the processing destination switch guide, by exerting thereto the switching force.