| 摘要 |
<p>PURPOSE:To keep an optimum printing speed by preventing the temp. of a printing head from rising to heat resistant temp. or higher, by controlling the operation start temp. of a templ. rising protecting circuit corresponding to the heat generating quantity of the printing head and starting the operation of the temp. rising protecting circuit when the temp. of the printing head exceeded the operation start temp. of the protecting circuit. CONSTITUTION:The temp. of a printing head 1 is detected by a temp. detector 4 and converted to a voltage signal by a voltage converter 5 and said voltage signal is inputted to a comparator Q1 as a comparing signal. The comparator Q1 compares the voltage signal corresponding to the internal temp. of the printing head 1 with the reference voltage corresponding to heat generating quantity to control the operation start temp. of a temp. rising protecting circuit 6. When the temp. of the printing head 1 rises to exceed the operation start temp. of the protecting circuit 6, the temp. rising protecting circuit 6 is operated to stop printing and, by this method, the rising in the temp. of the printing head 1 is prevented and, when the temp. thereof falls to reach a lower limit value, printing is again started.</p> |
