A CPU 150 in a personal computer PC acquires printing conditions stored in a RAM 151 set by a printer driver for controlling a printing operation in a color printer 20. The CPU 150 searches for set printing conditions, determines whether automatic image quality adjustment has been turned ON by the printer driver, and if it is determined that it has, the CPU 150 determines whether automatic image quality adjustment by an image processing application being executed is required. If it is determined that automatic image quality adjustment by the application is required, the CPU 150 sends an instruction to the printer driver to turn OFF the automatic image quality adjustment which is ON.