To economically use an ink ribbon without causing shade irregularities.
The dot impact printer is provided with a plurality of marks 22 to detect the position of the ink ribbon 12 and detects the marks 22 by a sensor 24 and makes areas between the marks 22 records. When printing is performed, the printer counts a print of a digit corresponding to each printed digit (equivalent to one letter of a line) in each of the records of the ribbon 12 by a counter 26, sets whether or not each digit is printable in a printable register 28 on the basis of information of the frequency of printing to each position of the ink ribbon 12. The printer sets whether or not subsequent printing data for each digit exists in a subsequent data register 30, and sets whether or not each digit is printed in a printed register 32. A printing filter logic portion 34 controls a print head 10 so as to perform printing on the basis of the values of the printable register 28, the subsequent printing data register 30 and the printed register 30.
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda