| 摘要 |
<p>PURPOSE:To obtain a thermal head driving device of a simple structure capable of printing data with uniform density by allowing generation of a strobe pulse which become high level until the integral value of energy supplied to a heat generating element from a power supply for each heat generation reaches a specified value and allowing a switching element to be turned ON during a period when the strobe pulse is at high level with regard to a heat generating element to which print data is entered. CONSTITUTION:An energy calculation circuit 10 which calculates the integral value of energy of an output rectified by an AC rectified power supply and generates a pulse becoming 0 once each time a specified value is reached while the integral value is at high level until it arrives at the specified value, and a pulse distribution circuit 11 which distributes the pulse to a group of heat generating elements are provided. The energy calculation circuit 10 consists of a squaring circuit 10a which squares an output voltage (signal A) from the AC rectified power supply 7, an integrating circuit 10b which integrates the squared value (signal B) and a comparison circuit 10c which outputs a high level signal D until the integrated value (signal C) reaches a specified value and at the same time, resets the value of the integration circuit 10b.</p> |
