Oki Electric Industry Co., Ltd.

Toshikazu Itoh

Tadao Shimizu

Satoru Tsuchiya

Toshiroh Suemune

Method of compressing and expanding dot-matrix character

When a first timer, after started, counts a prescribed time interval, and becomes time-out, it is judged whether or not the total of a heat release value exceeds a first prescribed one, and if it does not exceed that value, then the first timer is restarted. If it exceeds, then a second timer is started, and a prescribed pause time is taken, before a heating element is driven, in a time interval when the second timer is counting. When the second timer becomes time-out, it is judged whether or not the total of the heat release value exceeds a second prescribed amount, and if it does exceed that value, the first timer is started. If it exceeds that value, then the second timer is restarted. In such a manner, in the operation of the second timer the prescribed pause time is taken before driving the heating element to make longer a driving period of the heating element than that during the operation of the first timer. Furthermore, the number of times of the operation of the second timer is controlled responsively to the heat release value.

Method of and apparatus for preventing overheating of heating element

A print head driving system for driving a print head having a plurality of print wire controlling magnetic circuits and a plurality of print wires respectively operatively associated with the print wire controlling magnetic circuits regulates the flight starting timing of the print wires through the regulation of respective timings for supplying driving currents to the print wire controlling magnetic circuits to be used for a preceding printing cycle and the print wire controlling magnetic circuits to be used for a succeeding printing cycle, according to control data calculated on the basis of the number of the print wires which were used for the preceding printing cycle and the number of the print wires to be used for the succeeding printing cycle so that dots are printed at expected positions to thereby provide a clear print.

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Tokyo, Japan

Toshikazu Itoh