JPS5772877A - Thermal recording apparatus - Google Patents

Abstract

PURPOSE:To enable to obtain an image with good quality against a heat sensitive paper having optional sensitivity by a method wherein plural black images having different color densities are recorded and said densites are detected to be compared to an ideal density and one density near to the ideal density is selected. CONSTITUTION:Prior to recording, a color density generator circuit 1 successively applies data for setting a current passing time of a thermal head 9 to, for example, 1.2ms, 2.1ms, 3.0ms to a recording density adjusting circuit 4. Thereby, a signal Td having a width of the current passing time is developed to an output wire 4a of the circuit 4. During a time when three kinds of signals Td are developed at a constant interval, when all black data is issued from a control circuit 3, the thermal head 9 is driven to obtain black images d1, d2, d3 with different color densities. A light reflection amount from a light source of said black images is detected by a photoelectric detector 2 and, by selecting a drive time wherein the light reflection amount comes to an ideal light reflectin amount, an optimum density can be selected.