Tracking Carrier Position for Printing in Bidirectional Printers
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
A method is disclosed that eliminates position error due to a two-phase position sensing system when used bidirectionally while maintaining the ability to sense displacements caused by external forces by using the same phase transition in either movement direction. In a microprocessor-controlled DC servo motor system, the position is tracked using some sensing mechanism on the motor shaft to detect movement. In bidirectional applications, direction can be sensed by using a two-phase signal to encode the direction. The two encoder signals, which are 90 degrees out-of-phase, can be fed into an electronic circuit to provide an encoder interrupt signal and a direction signal or can be read by the processor directly to determine movement direction and to track position via a counter in software.