PURPOSE: To embody the improvement of a whole printing speed by minimizing a stopping time of a print carriage.

CONSTITUTION: The development of print data A-R of n-th line in a print buffer 1 indicated by (b) has been finished, that of print data S-Z of n+1-th line in a print buffer 2 indicated by (c) has been finished. Printing of the print data A-I from the left and of the print buffer 1, i.e., a lower address to a print pointer indicating an intermediate address on a paper has been finished as indicated by (a). The area in which the print data A-I was developed in the print buffer 1 becomes again the area in which new data can be developed so that print data 1, 2,... of n+2-th line is developed.