As a user turns on the power, patch processing (Step S104) is executed and image forming conditions are accordingly adjusted. However, when a setting entry for prohibiting the patch processing has been made at the time of power-on (Step S101, Step S103), after setting the image forming conditions to predetermined default conditions without performing the patch processing (Step S108), execution of an image forming operation is permitted (Step S107). The setting entry in this context is pressing of a particular switch by the user at the time of power-on.