PURPOSE: To guarantee the quality of printing, by finding out the print miss correctly, through the checking of the comparison check circuit between the letters read in with optical reader and the print letter data at the print control section.

CONSTITUTION: The print control section 2 indicates the print letter data to the print section 1, and the letters printed with the print section are read in with the optical reader 4. Further, the letters read in with the optical reader 4 and the print letter data of the print control section 2 are compared with the comparison check circuit 5. By controlling the print control section 2 with the result of comparison printed at the comparison check section 5, the result of print printed with the print section 1 is checked and the print miss can correctly be found out, allowing to guarantee the quality of printing.