PURPOSE: To simplify the hard copy of a window screen.

CONSTITUTION: A server part 1 is provided to control the input/output of various peripheral devices which are connected to a work station, together with a quick switch which starts a hard copy processor placed near a CRT screen, and a window control part 4 which controls the arrangement and the numbers of plural windows. Furthermore a hard copy control part 5 is added to receive a hard copy processing request from the quick switch, to acquire the number of the window that is shown on the highest surface to the part 4, and to fetch the screen image of the corresponding window from the part 1, together with a printer control part 6 which is started by the part 5 and sends the screen image to printer. In such a constitution of a hard copy device for CRT screen, other systems set in a work station never have their malfunctions.