A printing apparatus having a print unit and a print controller with a first density correcting component performing a density correction to image data transmitted to the unit is provided. The correction accords with a printing capacity of the unit. The apparatus comprises a component notifying a separate apparatus of an order to make a second density correcting component perform a density correction an amount of which is the same as that of the density correction by the first correcting component. The separate apparatus is provided with a transmitter and the second correcting component, the transmitter being capable of transmitting image data to the unit bypassing the first correcting component provided in the controller, and the second correcting component being capable of performing a density correction to the image data. The correction accords with the printing capacity of the unit.