Compact high-speed printer with single step-motor - has control circuit generating drive pulses of differing frequencies for varying motor functions

摘要

The printer, with a printing head mounted on a carriage which moves across the recording medium, permits incorporation in a portable desk calculator. A single step-motor (1) is controlled by sequences of step pulses with differing frequencies generated by a control circuit. One sequence drives the motor in one direction, so that the print head moves on its carriage during the print operation. A second sequence of step pulses drives the motor at greater speed in the opposite direction for return of the carriage beyond its initial start of printing position. At this point the print head is out of contact with the recording medium, which is advanced one line by a single direction transport arrangement (6,7,30,34). The step-motor is then switched back from reverse rotation to normal. Pref. the single direction transport arrangemet has a disk with a lug (7) in contact with the shaft (3) of the step-motor through a gear drive (6) and coupled with the carriage through a wire cable.