Image forming apparatus

An image forming apparatus forming images using image data stored in a storage unit, the apparatus comprising:

• a display unit displaying images;
• a reading unit reading the image data from the storage unit;
• an image forming mechanism forming images by the mechanical operation of the mechanism;
• a power supply unit supplying power to the display unit, the reading unit, and the image forming mechanism;
• a main controller controlling:
• the reading unit and the display unit to read the image data from the storage unit and to display the data on a viewing screen when an image display instruction is provided,
• the display unit to display the image being displayed on a formation screen when an instruction for switching the screen from the viewing screen to a formation screen is provided, and
• the image forming mechanism to form the image instructed to be formed when an image forming instruction is provided during the display of the formation screen;
• and
• a power supply controller controlling the power supply unit to:
• start the power supply to the reading unit when the image display instruction is received,
• start the power supply to the display unit when the instruction for switching the screen is received,
• start the power supply to the image forming mechanism when the image forming instruction is received, and
• stop the power supply to the image forming mechanism after the image forming instruction is executed, and
• the image forming mechanism at a predetermined timing when an operation regarding the preparation for image formation is performed before the forming instruction is provided, wherein the forming instruction is provided via the display unit displaying the formation screen.