Patent ID: 8598830

Claim:
An image forming apparatus, comprising: an engine unit used for performing an image forming job; an engine control unit which controls the operation of the engine unit; a brushless direct current (BLDC) motor which drives the engine unit; a sensor unit which senses the driving information of the BLDC motor; a communication interface unit which receives a digital control command with respect to the BLDC motor from the engine control unit; a driving signal unit which generates a driving signal to control the BLDC motor; and a digital control unit which controls the operation of the driving signal unit in a digital phase locked loop (PLL) manner, based on the received digital control command, the detected driving information and a digital gain value as a control factor with respect to the BLDC motor, wherein the digital control unit includes an error detecting unit which computes a digital error value by comparing the received digital control command with the detected driving information, and the error detecting unit comprises a frequency error detecting unit which computes a frequency error value by comparing a velocity command value with respect to the BLDC motor with velocity information of the BLDC motor, and a phase error detecting unit which computes a phase error value by comparing a velocity command value with respect to the BLDC motor with velocity information of the BLDC motor.