Patent ID: 8289552

Claim:
An image forming apparatus comprising: a controller that issues a print instruction; and an engine that performs a printing in response to the print instruction from the controller, wherein the controller includes a determining unit that calculates an estimated time until drawing data for each page to be used in the printing is transmitted to the engine, and transmits the drawing data for each page, an instruction to print the drawing data for each page, and the estimated time to the engine, and the engine includes an activating/terminating unit that activates or terminates each unit of the engine, a confirming unit that judges whether the print instruction for each page is received, and when the print instruction for each page is not received, inquires the controller of whether there is drawing data of a next page, and when it is confirmed that there is the drawing data of the next page, acquires the estimated time to judge whether the estimated time is longer than an activation/termination time that is a sum of a time required for activating each unit of the engine and a time required for terminating each unit of the engine, and an activation/termination controlling unit that controls the activating/terminating unit to activate or terminate each unit of the engine when it is judged that the estimated time is longer than the activation/termination time.