CIRCUIT INFERIORITY TESTING METHOD OF PRINTING HEAD IN THERMAL PRINTER AND APPARATUS THEREFOR

摘要

PURPOSE:To enable a printing to be carried out except a case of the printing can not be carried out by making possible the printing to be carried out when a detected inferior heat generation circuit is not involved in a printing area. CONSTITUTION:An inferiority detecting circuit 42 consist of a resistance (r) connected between a power source V and a common terminal 44 of a printing head 41 and a detector 45 which supplies an output signal obtained by a detec tion of a voltage drop due to this resistance (r) and an amplification thereof to an I/O port 33. The monitoring of an output of the detector 45 and the judg ment whether a heat generation circuit S1 in a first row consisted of a heat generation resistance body R1, transistor Tr 1 and an AND gate circuit G1 is inferior or not are carried out by a CPU30. In the case that the inferior heat generation circuit is existent, as a result of a test, the judgment whether the inferior heat generation circuit is in a printing area P or not is carried out, and the printing is carried out under the judgment that a normal printing is possible when the former is not in the printing area P.