| 摘要 |
A thermal printing system having a plurality of thermal elements aligned on a straight line in the direction perpendicular to the moving direction of a thermal paper for printing characters on a dot matrix principle has been found. Each thermal element is selectively energized by a power pulse according to the desired pattern to be printed, and the pulse width of said power pulse which is applied to a thermal element is controlled according to the moving speed of a thermal paper and/or the status (black/white) of the previously printed several dots so that the desired concentration or color density is obtained. A digital memory which stores the status of the previously printed dots or the duration between the time that the last black dot is printed and the present time is provided, and according to that digital memory, the trigger pulse for initiating the power pulse for each thermal element is defined. Thus, a thermal paper is always heated to a proper temperature to provide the desired printed concentration in spite of the change of the moving speed of a thermal paper and/or the status of the previously printed dots. Then, the high speed printing and/or the variable speed printing is obtained.
|
