COPIER/PRINTER WITH TWO DEVELOPMENT SYSTEMS OF OPPOSITE POLARITY
Original Publication Date: 1987-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
A copiedprinter is proposed, with each function operating separately. A tri-level development system is proposed for the machine. The two xerographic development systems would be used in independently; positive for copying, reversal for printing. The CopierPrinter would produce copies using the conventional light-lens approach which uses a normal xerographic reproduction process. The Printer function would use an LED array bar and lens to expose the photoconductor. Using a conventional xerographic development system requires writing white; that is, the LEDs are energized to discharge the photoreceptor wherever the output document is to be toner-free. Writing black, energizing the LED for the corresponding toned parts of a document, requires reversal xerography. The advantages to write black are that the LEDs are used at a much lower duty cycle which results in extending the LED print bar life; estimated to be about five times. Also, the LED power supply requirements are reduced. Using a Tri-Level development system as shown in the Figures, would yield these benefits. In copier operation, the development would occur using the positive or conventional xerography. But for the printer operation, reversal xerography would be employed.