Patent ID: 7962680

Claim:
An image forming apparatus comprising: an operating unit that receives an operation input from a user; a controller that includes a first control unit for controlling the image forming apparatus; a transmission line that connects the operating unit to the controller as a channel for a data transfer between the operating unit and the controller with a differential data transfer method; and a power supplying unit that supplies an electric power to the image forming apparatus, wherein the operating unit includes a first data-transfer unit that transmits data to the controller and receives data from the controller via the transmission line, the controller includes a second data-transfer unit that transmits data to the operating unit and receives data from the operating unit via the transmission line, the controller further includes a second control unit for controlling an operation mode of the image forming apparatus, the operation mode including a normal mode in which the electric power is supplied to all units of the image forming apparatus and a power-saving mode in which the electric power is supplied to a part of units of the image forming apparatus, and regardless of the operation mode, the power supplying unit continuously supplies the electric power to the first data-transfer unit and the second data-transfer unit.