| 摘要 |
PURPOSE:To ensure uniform printing quality, by a system wherein the density of a printed predetermined symbol is detected by a photosensor, and when the detected density is lower than a preset value, it is displayed on a display part. CONSTITUTION:A printer 1 in which a printing head 2 is reciprocated under the control of a driving part 12 in the direction of arrow A relative to a printing medium 3 moved in the direction of arrow F to thereby perform predetermined printing 10, is provided with the photosensor 6 for detecting the predetermined symbols 4 printed, and a detecting part 7 supplied with an output signal S1 of the sensor 6 and a predetermined signal level V to output a display signal to the display part 8. The symbol 4 is printed at a position P2 between a home position P1 of the printing head 2 and the first digit place P3, one time for each several printing lines under the function of a line feed counter 11. |
