Sheet finishing apparatus

A sheet finishing apparatus comprising:

• a gate for taking in sheets of paper ejected from an image forming apparatus through a taking-in port and switching to either of a first conveying path for post processing or a second conveying path for non-post processing to convey said sheets of paper,
• a first tray which is attached to an upper part of said sheet finishing apparatus by a link mechanism and can rotate between a first height position where said sheets of paper conveyed via said second conveying path can be stored and a second height position away from said upper part,
• a sheet guidance member which supports one of a pair of pinch rollers for clamping and conveying said sheets of paper passing said first conveying path and can rotate between a first position where said one pinch roller makes contact with another pinch roller and a second position where said one pinch roller is released from said another pinch roller,
• a connection member for connecting said link mechanism and said sheet guidance member so as to set said sheet guidance member at said first position when said first tray is at said first height position and set said sheet guidance member at said second position when said tray is at said second height position,
• a second tray for loading said sheets of paper conveyed by said pair of pinch rollers at a pre-stage of post processing,
• an assist arm which is attached rotatably to said sheet guidance member and when said sheet guidance member is at said first position, is projected in a first direction for pressing said sheets of paper in said tray and when said sheet guidance member is at said second position, is rotated in a second direction opposite to said first direction, and
• a processing mechanism for post-processing said sheets of paper loaded on said second tray.