Method and apparatus for registration of sequential images in a single pass, multi-LED printbar printer

摘要

A precision belt hole sensor and associated conditioning circuitry provides precise trigger signals that enable synchronous printing in a color printer. An image bar recording system, which, in a preferred embodiment, utilizes a plurality of LED image bars, forms a plurality of latent images on a moving photoreceptor which may subsequently be developed in different colors. A pair of sensors associated with each printbar views illuminated pixels at the end of a printbar, through a pair of oppositely aligned photoreceptor holes. The signals detected by the sensor are amplified and processed to provide inputs to a comparitor circuit which generates an output signal at a time which precisely defines the passage of the trailing edge of the hole, past the sensors. The signal from the comparitor is used to accomplish skew registration of the printbar and to provide sync signals to enable precise formation of the leading edge of the associated image frame.