Apparatus and method for jet drop copying with an array of jets and photodetectors

摘要

A jet drop copying apparatus has a print head which directs a row of jets toward a print sheet mounted on a rotating drum. The row of jets extend substantially across the full width of the print sheet and are operated under control of a printing controller to print a series of tracks extending circumferentially along the sheet. The jets are shifted laterally in synchronism with the drum rotation such that each jet is moved a distance equal to the width of one printing track during one rotation of the drum. The shifting continues until a solid print has been obtained. An illumination device is provided for illuminating a narrow strip extending across a document to be copied and projecting an image of the illuminated strip upon a row of photodetectors. Longitudinal image scanning proceeds in synchronism with the rotation of the printing drum, and there is a lateral shifting of the image in synchronism with the shifting of the jet printing tracks.