Label printing apparatus for laser printing a heat-sensitive color developing ink layer of the label

The label printing apparatus has a structure including: a label feed means for successively feeding plural labels, each having an information printing area including a heat-sensitive color developing ink layer, to predetermined printing positions; a laser printing device which is provided with a sensor and a light source, said sensor serving to discriminate between presence and absence of the label in the predetermined printing position and to output a label detection signal, said light source serving to release a laser beam, and which receives the label detection signal directly from the sensor, prints information on the label by means of the laser beam when the presence of the label on the predetermined printing position is confirmed by the label detection signal, and outputs a shot signal; and a controller to discriminate whether the output interval between the shot signals is within a given period of time or not and to output an error signal when the output interval between the shot signals is not within the given period of time. Owing to the above-mentioned structure, the label printing apparatus of the present invention can be easily controlled, is free from any useless motion and is able to reduce occurrence of a defective.