DEVICE FOR THE PRODUCTION OF CHARGE PATTERNS ON A PHOTOCONDUCTIVE IMAGE CARRIER

摘要

In printers operating in accordance with the electrophotographic principle, it is necessary to produce on an image receiving material, e.g. a photoconductive drum, charge patterns of the characters to be printed. This takes place by means of a writing head (56), which emits light in accordance with the characters to be printed and thus discharges regions of the surface of the image carrier (52). These charge patterns are subsequently developed by means of toner, and the toner patterns created thereby are fixed directly on the image carrier or after reprinting onto an image receiving material. A writing head constructed in a particularly simple manner consists of at least one comb of light-emitting diodes (LED) situated alongside one another. The comb is disposed in the direction of the lines of charge patterns to be created on the image carrier (52) and has a width which corresponds to the writing width on the image carrier. In this case, the light-emitting surfaces of the diodes are disposed at the front of the writing head, so that the light rays emanating from the diodes are passed directly to the image carrier (52) without interposition of optical means influencing or guiding the light beams.