Patent ID: 8235387

Claim:
An image forming apparatus including an image forming section, comprising: a plurality of trays loaded with a first sheet, the first sheet referring to a sheet output from the image forming section; a plurality of full-stack detectors each being provided at one of the plurality of trays, each full-stack detector detecting that a corresponding tray is full of first sheets; a first storage section that stores the number of second sheets by sheet type, the second sheets referring to sheets printed by the image forming apparatus in the past; a second storage section that stores usage priorities of the trays by sheet type based on contents stored in the first storage section and a sheet stack capacity of each tray; and a controller that decides a first tray for outputting a third sheet based on the priorities stored in the second storage section, the third sheet referring to a sheet that is output from the image forming section this time, wherein when the full-stack detector corresponding to the first tray detects that the first tray is full of first sheets, the controller decides a third sheet to be output to a second tray having a priority lower by one than the priority of the first tray.