Sheet stack ejecting apparatus, image forming apparatus, and sheet stack processing apparatus

An image forming apparatus comprising:

• an image forming section for forming an image on a sheet of paper;
• a processing tray for storing sheets of paper on which images have been formed by the image forming section and making a sheet stack;
• and
• a sheet stack ejecting apparatus for carrying and ejecting a sheet stack taken out from the processing tray, the sheet stack ejecting apparatus holding a sheet stack with two rotating members to carry the sheet stack,
• wherein the sheet stack ejecting apparatus comprises:
• an ejecting device for carrying and ejecting a sheet stack, the ejecting device holding a sheet stack with two rotating members to carry the sheet stack, wherein the sheet stack continues moving until completely ejected;
• an open-close mechanism for switching states of the two rotating members by shifting at least one of the two rotating members to adjust pressing force, the open-close mechanism switching between a contact and pressing state and a contact-and-pressing free state;
• and
• a controller for controlling the open-close mechanism that controls the two rotating members to be in the contact and pressing state by the open-close mechanism when a sheet stack is ejected, and controls the two rotating members to be in the contact-and-pressing free state before a back end of the sheet stack escapes from nips of the two rotating members and to remain in the contact-and-pressing free state until the sheet stack is completely ejected.

A sheet stack processing apparatus comprising:

• a processing tray for storing plural sheets of paper in order and making a sheet stack;
• an ejecting device for carrying and ejecting a sheet stack piled on the processing tray, the ejecting device holding a sheet stack with two rotating members to carry the sheet stack, wherein the sheet stack continues moving until completely ejected;
• a stack processing device for conducting stack processing to a sheet stack piled on the processing tray before the sheet stack is ejected by the ejecting device;
• an open-close mechanism for switching states of the two rotating members by shifting at least one of the two rotating members to adjust pressing force, the open-close mechanism switching between a contact and pressing state and a contact-and-pressing free state;
• and
• a controller for controlling the open-close mechanism that controls the two rotating members to be in the contact and pressing state by the open-close mechanism when a sheet stack is ejected, and controls the two rotating members to be in the contact-and-pressing free state before a back end of the sheet stack escapes from nips of the two rotating members and to remain in the contact-and-pressing free state until the sheet stack is completely ejected.