Patent ID: 8159696

Claim:
An image forming apparatus comprising: an engine mechanism to perform a printing operation with respect to print data, the engine mechanism including a paper feeding unit to pick up paper from a paper feeding cassette sheet by sheet in accordance with a paper feed control signal, a laser scanning unit to form an electrostatic latent image on a photosensitive drum by emitting a laser beam in accordance with image data, a developing unit to develop an electrostatic latent image by feeding a developer on the photosensitive drum, a transfer unit to transfer the developed image onto a fed sheet and a fusing unit to fuse the transferred image onto the paper with heat and pressure; a video unit including a first memory and a microprocessor to execute software instructions to generate image data based on the print data and to store the image data in the first memory; an engine control unit embodied as an application specific integrated circuit (ASIC) chip configured to receive operation state information relating to operational states of the engine mechanism, the engine control unit including a second memory to store the operation state information received from the engine mechanism; and a bi-directional parallel bus provided between the engine control unit and the microprocessor of the video unit, wherein the microprocessor of the video unit generates and transmits instruction commands to the ASIC chip of the engine control unit, the engine control unit drives the engine mechanism, including the paper feeding unit, the laser scanning unit, the developing unit, the transfer unit and the fusing unit, according to the image data and the instruction commands generated and transmitted by the microprocessor of the video unit, the video unit and the engine control unit are arranged on a single printed circuit board (PCB), and the ASIC chip of the engine control unit does not employ an internal processor.