Patent ID: 8666297

Claim:
An image forming apparatus comprising: an image forming unit configured to form an image on a sheet in a printing operation; a transport unit configured to transport the sheet via a transport path; a sheet stacking unit configured to stack the sheet transported by the transport unit; a sheet detecting unit disposed in the transport path and configured to detect the presence or absence of the sheet in the transport path; a counting unit-configured to count a number of times that the sheet is detected by the sheet detecting unit in order to determine whether the sheet has been stacked on the sheet stacking unit; and a control unit configured to control the printing operation performed by the image forming unit and the transport unit in accordance with a first print request from a print instructing unit for a print job and based on a count value obtained by adding a value to the count value each time that a sheet is determined to have been stacked on the sheet stack, the value added to the count value being a setting value that is set in advance and is set to a different value depending on a type or characteristic of the sheet, wherein the control unit clears the count value in response to an absence of a next print request from the print instructing unit within a predetermined time after the printing operation associated with the first print job request is completed.