Image forming apparatus

An image forming apparatus comprising:

• a conveyance roller configured to convey a sheet;
• a photosensitive drum configured to bear a toner image to be transferred to the sheet;
• a fuser configured to fix the transferred toner image to the sheet;
• a sheet discharge tray;
• a sensor located upstream of the conveyance roller in a sheet conveyance direction, the sensor being configured to detect the sheet;
• a switch configured to switch driving and stopping of the photosensitive drum;
• and
• a controller configured to perform a first mode process as a warm-up process of driving the conveyance roller and the fuser, the first mode process including:
• driving the photosensitive drum for a particular time;
• in response to detecting the sheet within the particular time by the sensor, controlling the switch to continue driving the photosensitive drum after the particular time elapses and to discharge the detected sheet to the sheet discharge tray;
• and
• in response to not detecting the sheet within the particular time by the sensor, controlling the switch to stop driving the photosensitive drum at a time point when the particular time elapses, and driving the conveyance roller and the fuser to complete the warm-up process in a state where the photosensitive drum is stopped.