Image forming apparatus that uses a common motor for driving a plurality of gear mechanisms

An image forming apparatus comprising:

• a driving source configured to rotate in a first direction and a second direction reverse to the first direction;
• an image forming unit configured to transfer a developer image onto a recording sheet;
• an apparatus main body having an insertion opening formed on a front surface thereof and for inserting the recording sheet, a discharge opening for discharging the recording sheet on which the developer image is transferred by the image forming unit, and a discharge tray which receives the recording sheet discharged from the discharge opening;
• a supply roller provided between the insertion opening and the image forming unit on a conveying path and configured to supply the recording sheet inserted in the insertion opening while rotating in a forward conveyance direction;
• a sensor provided on a feeding path of the recording sheet between the insertion opening and the supply roller in the apparatus main body, the sensor being configured to detect whether a recording sheet is inserted into the insertion opening of the apparatus main body;
• a fixing device configured to heat-fix the developer image transferred onto the recording sheet;
• a fixing driving gear mechanism configured to transmit a driving force of the driving source to the fixing device, the fixing driving gear mechanism including a fixing driving interruption mechanism configured to interrupt a transmission of the driving force of the driving source when the driving source rotates in the second direction;
• a supply driving gear mechanism configured to transmit the driving force of the driving source to the supply roller, the supply driving gear mechanism including a supply driving switching mechanism configured to cause a rotating direction of the supply roller when the driving source rotates in the first direction to be the forward conveyance direction which is the same as the rotating direction of the supply roller when the driving source rotates in the second direction;
• and
• a control device,
• wherein the control device is configured to:
• determine a temperature of the fixing device;
• control the driving source to rotate in the first direction such that the supply roller rotates in the forward conveyance direction and the driving force of the driving source is transmitted to the fixing device when the temperature of the fixing device exceeds a predetermined temperature and a recording sheet is detected by the sensor;
• and
• control the driving source to rotate in the second direction such that the supply roller rotates in the forward conveyance direction and the transmission of the driving force of the driving source to the fixing device is interrupted by the fixing driving interruption mechanism when the temperature of the fixing device is the predetermined temperature or lower and a recording sheet is detected by the sensor.