ELECTROPHOTOGRAPHIC PRINTER AND METHOD OF ELECTROPHOTOGRAPHIC PRINTING

摘要

The apparent resolution of electrophotographic printer is enhanced accomplished by writing a gray or half-tone halo along the periphery of images written on the photoconductor. A laser directs a light beam onto the photoconductor to write white pels by discharge. The intensity of the light beam is lessened to write gray pels and the light beam is interrupted to write black pels of the image in undischarged areas. The pels are written sequentially in columns. When the image with its half-tone halo is developed, transferred and fixed by steps in the electrophotographic process, the printed image has a substantially smooth contour. In effect, the gray halo placed around the image merges with the black interior of the image when the image is developed, transferred and fixed. To prevent the image from appearing to be too thick after its contour has been smoothed by the use of the half-tone halo, the number of black picture elements used to write the image on the photoconductor are reduced. Also, the width of image segments making up the image may be adjusted by changing the level of gray used to write the half-tone halo.