CONTROLLER OF A LABEL PRINTER

A controller of a label printer employs an electronic photographic system which makes printing successively on a continuous printing paper on which a multiplicity of label papers are affixed. There are provided a position sensor using a photoelectric transducer element which is disposed to face the continuous printing paper and detect a difference in the transmissivity of light of the continuous printing paper and a label position detector for processing a detection signal of the position sensor to derive a timing control signal corresponding to a position of the label paper. The timing control signal of the label position detector is used to control operation timings for each of the portions for the continuous printing paper. The label position detector includes an amplifier for amplifying the detection signal of the position sensor and a comparator for comparing the detection signal with a reference signal, and particularly includes a variable setting function for a gain of the amplifier and a magnitude of the reference signal to automatically set so that a relative detection output for the label paper is increased.