Howard M. Stark

Single-pass highlight color electrophotography

Single-pass highlight color printers (black plus one color) are advantaged over multi-pass systems in that image throughput is not sacrificed in obtaining the additional color. Furthermore, single exposure systems are advantageous since perfect registration is inherently assured. In this paper we will review several approaches to single-pass highlight color systems and then focus on the recently announced Xerox highlight color printer.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Development of trilevel xerographic images

One exposure, trilevel xerography provides a novel means to produce, single pass, highlight color prints. In this scheme, a ROS creates an imagewise three level, unipolar latent image in which the color information is encoded in the discharge level. The highest charge regions represent one color, and the lowest charge regions a second color. An intermediate charge level, approximately midway between the high and low charge, serves as the background reference and is not printed. The components of the composite two color latent image are developed sequentially using charged area and discharged area development and bipolar developers. Electrostatic transfer is enabled by converting the developed bipolar image to a unipolar image using a pretransfer charging step. Because of the nature of the latent image, a trilevel development system must satisfy demands substantially beyond those required in conventional xerography. This paper will discuss these requirements.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Some Theoretical Aspects of High Resolution Xerographic Development

The distribution of toner on the surface of a xerographic plate for an arbitrary one-dimensional periodic charge pattern is considered. Development is taken to be complete, by which it is meant that the electrostatic fields vanish outside the toner already deposited on the surface. The toner is assumed to be a continuous nonconducting medium with a uniform charge density per unit volume. Simultaneous algebraic transcendental equations are formulated for the field-free surface bounding the toner. Examples are given for certain important cases, and the effects of relevant parameters of the system are discussed.