A thermal ink jet printer has two columns of nozzles in its nozzle plate parallel to the direction of motion of each sheet of media. When the sheet of media is thin such as bond paper having a thickness of 0.1 mm, for example, all of the nozzles are available for printing. When the sheet of media is thick such as an envelope having a thickness of 0.5 mm, for example, one-fourth of the nozzles are available for printing, and these are the nozzles first passed by the sheet of media during its advancement. Each sheet of media has the same feed rate although it takes four times as long for the thick sheet of media to be printed.