Patent ID: 8892932

Claim:
An image forming apparatus comprising: a first control unit driven by a first clock oscillator; and a second control unit driven by a second clock oscillator, said first control unit comprising a signal transmitting unit that generates, using a first timer driven by the first clock oscillator, a pulse signal in accordance with a predetermined clock rate, and that transmits the generated pulse signal to said second control unit, and a start notification unit that notifies said second control unit of a start of a clock correction process for calculating the correction coefficient, said second control unit comprising: a signal receiving unit that receives the pulse signal transmitted by said signal transmitting unit; a measurement unit that measures, using a second timer driven by the second clock oscillator, a pulse width of the pulse signal received by said signal receiving unit; a calculation unit that calculates a correction coefficient using a reference pulse width corresponding to the predetermined clock rate and the measurement pulse width; an execution unit that executes image formation using the calculated correction coefficient; and a start response unit that transmits information indicating whether the clock correction process can be started to said first control unit in response to receiving the start notification, wherein said signal transmitting unit transmits the generated pulse signal to said second control unit in response to receiving the information transmitted from said second control unit, the information indicating that the clock correction process can be started.