Print head motor control system using analog and digital feedback

Claim 1

Print head velocity control means for maintaining a constant velocity of a print head as it moves across a record medium, said print head being bidirectionally movable across said record medium and being movable at either a high speed or a low speed on different passes across said record medium, said record medium having a print area and margin areas on either side of said print area, comprising: motor means having a rotatable shaft, said shaft rotating at a velocity related to the magnitude of a control signal applied to said motor means, said shaft means being coupled to said print head such that said print head moves as said shaft rotates; emitter means coupled to said shaft for providing pulses representing increments of movement of said shaft; processor means for providing a reference voltage, said processor means responding to said emitter means pulses to vary said reference voltage as the time between emitter pulses varies; frequency-to-voltage converter means repsonsive to said emitter means pulses for providing a voltage related to the velocity of rotation of said shaft; means for generating said control signal in response to the difference between said reference voltage and said voltage from said frequency-to-voltage converter means, means for stopping said print head after it leaves said print area, and means responsive to the print head moving at said slow speed for delaying said stopping of said print head when said print head has made a pass across said record medium at said low speed.