PURPOSE: To obtain a printer where it is unnecessary to change receiving information even if format is changed, by generating space data by the printer itself according to designation of a format designation part when the print head is outside the print area of the form format.

CONSTITUTION: The left end and the right end of the print area of print head 1 are P1 and P4 when form format selector switch 2 is switched to the A side, and they are P2 and P3 when switch 2 is switched to the B side, and position information of both ends are supplied to position comparison part 11 as print area signal f from format designation part 3 due to designation of switch 2. The position of print head 1 is given to comparison part 11 from head position detection part 9 as signal e and is compared with the area of signal f. Then, data from the center is given to output buffer 6 through receiving control part 8, conversion part 7 and switch 12 and is printed if the position of print head 1 is inside the area, and switch 12 is switched to perform space operation by the output of a space data generation part if the position of print head 1 is outside the area.