MISPRINTING PREVENTION SYSTEM OF SERIAL PRINTER BY STEPPING PULSE CHECKING

摘要

PURPOSE:To prevent misprinting due to the interference of noise with the stepping pulse train by allowing the passage of the stepping pulse with the gate so arranged to open confined to the allowable time when the generation of the pacing pulse is expected. CONSTITUTION:A new target position is set for the target position register 3 by a printing information, and the difference thereof from the present position counter 1 is computed with a computation circuit 4 to determine the selection pitch value. Then, the selection pitch value thus obtained and the computation starting signal are inputted into the control circuit 18 to read the table out of the memory information table 23 according to the selection pitch value so that the time at which the generation of the first stepping pulse RCP is estimated is outputted from the pulse cycle computation circuit 20 to set the flip flop 21. Then, with the output of the flip flop 21, the gate 22 is opened, while upon the arrival of the stepping pulse RCP, it is turned to a pacing pulse PCP to reset the flip flop 21 causing the gate 22 to be closed. Thus, further undesired pulses are checked while the counter 1 and the stepping pulse counter 19 are advanced.