| 摘要 |
PURPOSE:To protect a line head sufficiently at the time of performing a multiple gradation picture recording by equipping a counting means for counting the number of strobing signals for every one line of picture records and a protection means for comparing the counted value with a reference value to detect driving abnormalities in a heating part to protect the line head. CONSTITUTION:When abnormality occurs, e.g. no strobe pulse comes out from a strobe pulse generator 27, a counter 30 outputs no counted-over signal CO because a counted values does not reach the counter and the inverted output signal of a flip-flop 31 does not lower to a low level because the flip-flop cannot be set. Therefore, the non-inverted output signal of a flip-flop 32 reaches a high level and is sent as an error signal to an OR circuit 28 so that the strobe pulse from the strobe pulse generator 27 is hindered by the OR circuit 28. That is, the output of the OR circuit 28 reaches a high level and the heating paper of a thermal head 29 is protected without application of excessive power to that part. |
