Image forming apparatus and control method of image forming apparatus having a normal mode and a power saving mode

An image forming apparatus having a normal mode and a power saving mode for reducing power consumption to be smaller than that in the normal mode, in which the normal mode is changed to the power saving mode when a predetermined condition for proceeding to the power saving mode is satisfied in the normal mode, and the normal mode is restored when a predetermined restoration condition is satisfied in the power saving mode, the apparatus comprising:

• a printing portion constituting a system so as to perform printing;
• a communication portion connected to a network so as to perform a communication process;
• a system controller configured to perform control concerning operation of the image forming apparatus, and a process concerning communication for performing network communication by the communication portion, and to perform the process concerning communication even during the power saving mode;
• and
• a power supply controller configured to supply power to the printing portion, the system controller, and the communication portion in the normal mode, while in the power saving mode, to continue power supply to the communication portion, to stop power supply to the printing portion, and to repeat a supply time during which power is supplied to the system controller and a stop time during which power supply to the system controller is stopped, and configured to adjust a length of the stop time during the power saving mode so that average power consumption of the image forming apparatus in the power saving mode does not exceed a predetermined permissible maximum power, so as to temporarily restore the system controller during the power saving mode.