| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optimum heating period constant by driving the specific heat-resistor of a plurality of heat resistors through the application of a constant energy at a predetermined period and taking a specific formula while allowing a thermal head provided with a plurality of heat-resistors and a recording medium to move relatively. SOLUTION: A recording medium with printing dots printed on a plurality of printing lines is transported, thereby reading the density of the same density dot printing from the recording medium. When the density difference in the printing line N in the reading data is made D (N), the non-application time of printing pulses in each printing lines is (t)off, the convergent value in the change of the density difference is Dcnv, and the heating period constant is τ, the heat period constant τ is calculated by the application of formula. Concretely, the measurement of recording density of the printed dots is done in a manner facing in the direction opposite to arrow A in turn from the dots 11a at the first printed position. The density measurement results by a reflection density meter 8 are sent to an analysis device 9 corresponding to respective measured line numbers. |
