Jam detection of image forming apparatus based on sizes of motor currents measured in multiple intervals

An image forming apparatus, comprising:

• a print engine to be used to perform an image forming job;
• a motor to start the print engine;
• a driving circuit to supply a power to the motor and to include a sensor to sense a size of current of the power supplied to the motor during an operation to perform the image forming job;
• and
• a processor to detect an occurrence of jam based on a size of current sensed by the sensor in a first time interval, among first time intervals, while the motor is driven to perform the operation, and a size of current sensed by the sensor in a second time interval, among second time intervals, after a determined time from the first time interval.