Push feed arm for post processing device

A sheet post-process apparatus, the apparatus comprising:

• a waiting tray which temporarily retains a transported sheet and releases the sheet;
• a processing tray which bundles the sheets dropped from the waiting tray to carry out predetermined processing and ejects the bundled sheets;
• and
• a storage tray which holds the bundle of sheets processed and ejected on the processing tray,
• wherein the processing tray comprises:
• a transport belt which transports the bundle of sheets;
• and
• a push feed arm mounted to be projected onto a surface on a sheet transport side of the transport belt, the push feed arm retaining a sheet distal end of the bundle of sheets so that the sheet distal end can be pushed and fed;
• wherein the transport belt forms a through hole through which the push feed arm penetrates, and
• the push feed arm comprises:
• a push feed face which pushes and feeds the sheet distal end;
• a penetrating projection portion which reaches a transport belt lower face from the push feed face through the through hole;
• and
• a hook shaped engagingly lock portion, formed integrally with the penetrating projection portion, engagingly locked on the transport belt lower face and being bent in the transport belt traveling direction, and
• wherein a face of the hook shaped engagingly lock portion on a side which comes into contact with the belt lower face is inclined in a downward direction at an angle of 10 degrees to 30 degrees while a longitudinal direction of the transport belt is defined as a reference.