Sheet medium adjustment apparatus and image formation system capable of sorting sheet media

A method of operating a sheet medium adjustment apparatus, the method comprising:

• ejecting a conveyed sheet of a printable medium;
• stacking the ejected sheet into a stack on a tray;
• shifting a stack that includes the stacked sheet in a movement direction perpendicular to a sheet-ejecting direction;
• aligning, via an aligning member, ends of the sheets in the stack that are parallel to the sheet-ejecting direction;
• evacuating the aligning member by an amount representing an evacuation displacement in the movement direction at a timing of aligning the sheet;
• and
• determining the evacuation displacement adaptively according to at least one of an attribute of a given sheet in the stack, an attribute of the stack as a whole and an attribute of the tray, wherein the evacuating displacement is determined as a percentage of a maximum evacuating displacement, wherein
• the attribute of the given sheet is whether the given sheet is folded or unfolded, and
• when the number of sheets in the stack is fewer than 3, the evacuation displacement is set to a first percentage (P1) of the maximum evacuation displacement,
• when the number of sheets in the stack is between 3 and 4, the evacuation displacement is set to a second percentage (P2) of the maximum evacuation displacement, where P2>P1, and
• when the number of sheets in the stack exceeds 4, the evacuation displacement is set to the maximum evacuation displacement.

A method of operating a sheet medium adjustment apparatus, the method comprising:

• ejecting a conveyed sheet of a printable medium;
• stacking the ejected sheet into a stack on a tray;
• shifting a stack that includes the stacked sheet in a movement direction perpendicular to a sheet-ejecting direction;
• aligning, via an aligning member, ends of the sheets in the stack that are parallel to the sheet-ejecting direction;
• evacuating the aligning member by an amount representing an evacuation displacement in the movement direction at a timing of aligning the sheet;
• and
• determining the evacuation displacement adaptively according to at least one of an attribute of a given sheet in the stack, an attribute of the stack as a whole and an attribute of the tray, wherein the evacuating displacement is determined as a percentage of a maximum evacuating displacement, wherein
• the attribute of the tray is a falling distance thereof, and
• when the number of sheets in the stack is fewer than 3, the evacuation displacement is set to a first percentage (P1) of the maximum evacuation displacement,
• when the number of sheets in the stack is between 3 and 4, the evacuation displacement is set to a second percentage (P2) of the maximum evacuation displacement, where P2>P1, and
• when the number of sheets in the stack exceeds 4, the evacuation displacement is set to a third percentage (P3) of the maximum evacuation displacement, where P3>P2.