Bounce control system for moving coil printing element

摘要

In a drive circuit for an electromagnetic printing element of an impact printer, a drive pulse drives the printing element from a backstop toward a record medium to print indicia. A voltage comparator senses the change in the induced voltage in the printing element when it impacts on the backstop for triggering a single shot circuit to apply to the printing element a damping pulse of a polarity such as to oppose its rebound from the backstop. A latch circuit is responsive to the damping pulse to disable the single shot circuit until the end of the next drive pulse. The drive and damping pulses are applied to the printing element through a bidirectional current source.