| 摘要 |
<p>PURPOSE:To prevent heating elements from being broken, by a method wherein recording is conducted by passing electric currents through a plurality of heating elements in a plurality of blocks on a matrix base, and when the electric current passed through a block reaches or exceeds a specified value, the block-selecting means and a bit-selecting means are turned OFF. CONSTITUTION:In normal operation, printing is conducted by operating a group of heating elements 2 on a matrix base by using block signals A-D, which are maintained to be ''H'' for a predetermined period of time when being designated by a block-selecting circuit 6, and the designation of bits by a bit-selecting circuit 8 which is inputted with sequential recording signals through a terminal 20. When the signal A, for example, is maintained to be ''H'' for not less than a predetermined period of time due to some cause, a switching element 10 also continues to be OFF, and a capacitor 14 continues to be charged, and when the voltage E of the capacitor 14 exceeds a set point 15, a comparator 16 outputs an ''H'' signal to maintain the selecting circuits 6, 8 in OFF states. Accordingly, the heating elements can be securely prevented from being broken.</p> |
