| 摘要 |
PURPOSE:To make it possible to record characters of small numbers of strokes with good picture quality by causing a specific current to flow through elements unselected at the time of recording thereby to cause the elements to generate heat at a temperature below a coloring temperature, in a thermal recorder using a thermal head having a plurality of heat generating resistance elements. CONSTITUTION:A driving circuit for the thermal head comprises resistance elements R11, R22..., diodes D11, D22..., and grounded emitter NPN transistors Q21, Q22.... Diodes DS1-DSn and a Zener diode DZ are placed in the driving circuit, and a specific current is caused to flow through heat generating resistance elements not selected to cause them to generate heat at a temperature below the coloring temperature. By this procedure, by only adding some circuits such as diodes to the recorder, a width of the impressed pulse becomes short and degradation of a picture quality can be prevented and high speed recording can be performed in carrying out recording of characters having a small number of strokes. |
