Patent ID: 8615675

Claim:
An image forming apparatus comprising: an upper layer control unit that controls a function for forming an image on a printing material; a first lower layer control unit and a second lower layer control unit that are controlled by said upper layer control unit and that control loads for implementing the function; and a sensor that outputs a detecting result to said first lower layer control unit and said second lower layer control unit, wherein said first lower layer control unit and said second lower layer control unit each include: a clock oscillator; a measurement unit that measures a time period of an interval determined by the detecting result by using said clock oscillator; and a notifying unit that notifies said upper layer control unit of the measured time period, wherein said first lower layer control unit further includes a correction unit that acquires a correction coefficient from said upper layer control unit, and corrects, based on the correction coefficient, a clock count value, and wherein said upper layer control unit includes a determining unit that (1) determines the correction coefficient for said first lower layer control unit to correct an error between said clock oscillators in said first lower layer control unit and said second lower layer control unit based on the measured time periods of said first lower layer control unit and said second lower layer control unit, and (2) transmits the determined correction coefficient to said first lower layer control unit.