Sheet receiving apparatus for sorting and stacking sheets on a tray with friction-free horizontal reciprocation

A sheet post-processing device, comprising:

• ejection means, provided vertically movable, onto which a sheet on which an image is already formed is ejected after undergoing post processing;
• sorting means for sorting the sheet on the ejection means by reciprocating the ejection means horizontally and at a right angle to an ejection direction of the sheet;
• sheet edge stopper columns, provided to be horizontally freely rotatable, for aligning a trailing edge of the sheet eiected onto the ejection means disposed diagonally upward with respect to the ejection direction;
• and
• linking means for rotating the sheet edge stopper columns in accordance with a horizontal movement of the ejection means so as to horizontally move the sheets already aligned, and, when the ejection means is moved vertically, lifting and lowering the ejection means in a manner causing little friction between the linking means and the sheet edge stopper columns without rotating the sheet edge stopper columns,
• wherein the sheet edge stopper columns are pinion gears, and the linking means is integrally provided with the ejection means and is a gear which is in mesh with the pinion gears.

A sheet post-processing device for conducting post processing on a sheet ejected from an image forming apparatus and then ejecting the sheet onto an ejection tray, and meanwhile for sorting the sheet with sorting means reciprocating the ejection tray horizontally and at a right angle to an ejection direction of the sheet when the sheet is ejected onto the ejection tray, aligning a trailing edge of the sheet ejected onto the ejection tray disposed diagonally upward with respect to the ejection direction with a plurality of sheet edge stopper columns erected to be freely rotatable, and lifting and lowering the ejection tray with a lifting and lowering means along the sheet edge stopper columns,

• the sheet post-processing device comprising linking means for rotating the sheet edge stopper columns in accordance with a horizontal movement of the ejection tray and for lifting and lowering the ejection tray in a manner causing little friction between the linking means and the sheet edge stopper columns when the ejection tray is moved vertically, and as to the horizontal movement and the vertical movement of the ejection tray, the linking means transmits a driving force to the sheet edge stopper columns only when the ejection tray is moved horizontally,
• wherein the linking means includes freely rotatable friction rollers provided integrally to the ejection tray,
• the friction rollers being disposed at a right angle to the sheet edge stopper columns and rotating the sheet edge stopper columns by contact friction when the ejection tray is moved horizontally.