PURPOSE: To select a paper supply tray and a paper discharge tray independently of the setting of an application program even in an engine having a paper supply/discharge tray construction of every type and to select the tray on a text-format control command.

CONSTITUTION: A CPU 2-2 as a controller is provided with a non-text-format command analysis processing part 2-2A and a text-format command analysis processing part 2-2B. When the analysis processing part 2-2A receives a text- format control command through an input buffer 2-6B, a control is transferred from the analysis processing part 2-2B to the analysis processing part 2-2A, a paper supply tray or a paper discharge tray is selected, and printing processing is conducted.