Patent ID: 8204391

Claim:
An image forming apparatus comprising: an image forming unit that forms an image on a sheet; a first sheet discharging path that reverses a traveling direction of the sheet passed through the image forming unit so as to discharge the sheet; a cover, which is openable and closable with respect to the image forming unit, and which forms a part of the first sheet discharging path when the cover is in a closed state; a second sheet discharging path, which is formed when the cover is in an open state, which is branched from the first sheet discharging path, and which discharges the sheet passed through the image forming unit without reversing the traveling direction of the sheet; a sensor, which is positioned downstream in a conveying direction of the sheet from the image forming unit, and which detects a passage of the sheet; and a determination unit that determines a jam based on a detection result of the sensor, the determination unit changing a determination criterion of the jam in accordance with the open or closed state of the cover, wherein the determination unit relaxes the determination criterion of the jam when the cover is in the open state as compared with the determination criterion when the cover is in the closed state, and wherein the determination criterion of the jam when the cover is in the open state is that a jam is not determined when the sensor has continuously detected the sheet for a predetermined time period which is shorter than a longer predetermined time period of the determination criterion of the jam when the cover is in the closed state.