Electronic typewriter with fixed carriage and moving print-head - uses stopper motor to control paper feed at end of each line

摘要

The control circuit rotates the plates to advance the paper by a line when the print head reaches the right band end-stop. The plates (3) can also be driven by a manual Up/Down key assembly (14) on the keyboard. A stepper motor (7) is linked to the plates via a reduction gearing (9). The min. step by which the platen can be rotated is less than two degrees. The automatic 'wrap-around' facility provides a print-head return and line feed at the end of each line. When the end stop switch (11) is operated, a time delay relay (12) causes the horizontal print-head motor (14) to return the head to the left hand margin, and simultaneously allows the pulse generator (13) to send a pre-set number of square-wave pulses to the stepping motor.