| 摘要 |
PROBLEM TO BE SOLVED: To simplify a paper color development confirming circuit, and commonly use other circuits in a thermal printer and parts such as a sensor. SOLUTION: This circuit comprises a sensor 1 having a light emitting diode 11 and a light receiving transistor 12 for receiving a transmitted light via a paper 5, a sensor sensitivity adjusting circuit 2 provided with sensitivity adjusting resistors for turning off the light receiving transistor 12 with respect to a transmitted light amount of a color to be confirmed, and turning on the same with respect to another color with a larger transmitted light amount by the same number as colors to be confirmed, a comparator 3 for outputting a comparison result of a voltage level according to the on or off state of light receiving transistor 12, and a reference voltage, and a controller 4 for storing a combination of a detection level of each sensitivity adjusting resistor, and a color corresponding thereto preliminarily as judgment information, successively selecting the sensitivity adjusting resistors, receiving the output from the comparator 3 based on the on or off state of the light receiving transistor 12 each time so as to judge the color with reference to the judgment information.
|
