Xerox Corporation

Howard M Stark

Delmer G Parker

Jerome E May

William M Allen

William Streifer

P Keith Watson

Robert N Goren

An apparatus for developing a latent image recorded on an imaging surface, comprising a housing defining a chamber storing a supply of developer material comprising toner a porous toner donor member spaced from the surface and being adapted to transport toner to a region opposed from the imaging surface; and means for conveying said developer material in the chamber of said housing onto said donor member.

Fluidized toner development using a rigid porous donor roll

Tri-Level Highlight color imaging apparatus utilizing two-component developer materials in each of a plurality of developer housings. The triboelectric properties of the toners and carriers forming the two-component developers are such that inter-mixing of the components of each developer with the components in another developer housing is minimized.

Preferred toner/carrier properties

In a tri-level imaging apparatus, a development control arrangement wherein the white discharge level is stabilized at a predetermined voltage and the bias voltages for the developer housings for charged area and discharged area development are independently adjustable for maintaining image background levels within acceptable limits. The white discharge level can be shifted to preferentially enhance the copy quality of one or the other of the charged area or discharged area images.

Adaptive bias control for tri-level xerography

Stabilization of the white or background discharge voltage level of tri-level images is accomplished by monitoring photoreceptor white discharge level in the inter-document area of the photoreceptor using an electrostatic voltmeter. The information obtained thereby is utilized to control the output of a raster output scanner so as to maintain the white discharge level at a predetermined level.

White level stabilization for tri-level imaging

Tri-Level Highlight color imaging apparatus and cleaner apparatus therefor. Improved cleaning of a charge retentive surface is accomplished through matching the triboelectric properties of the positive and negative toners and their associated carriers as well as the carrier used in the magnetic brush cleaner apparatus. The carrier in the cleaner upon interaction with the two toners causes them to charge to the same polarity. The carrier used in the cleaner is identical to the one use in the positive developer. The carrier of the negative developer was chosen so that the toner mixed therewith charged negatively in the developer housing.

Highlight color imaging apparatus

Apparatus for minimizing the contamination of one dry toner or developer by another dry toner or developer used for rendering visible latent electrostatic images formed on a charge retentive surface such as a photoconductive imaging member. The apparatus causes the otherwise contaminating dry toner or developer to be attracted to the charge retentive surface in its inter-document and outboard areas. The dry toner or developer so attracted is subsequently removed from the imaging member at the cleaning station.

Highlight color printer

The method and apparatus for rendering latent electrostatic images visible using multiple colors of dry toner or developer and more particularly to printing toner images in black and at least two highlighting colors in a single pass of the imaging surface through the processing areas of the printing apparatus. Two of the toners are attracted to only one charge level on a charge retentive surface to thereby providing black and one highlight color while two toners are attracted to another charge level to form the second highlight color.

Apparatus for printing black and plural highlight color images in a

Half-tone imaging is achieved in a flying spot scanning system wherein a highly collimated light beam is modulated with imaging information, reflected from a multifaceted rotating polygon and directed to a scanned medium through a light attenuating member. The latter member is supported proximate the imaging focal plane and orthogonal to the collimated, reflected light beam. The light attenuating member has an optical light transmission characteristic that varies in a continuous and cyclic pattern with a cycle period at least about ten times the maximum lateral extent of the collimated light beam, thereby serving to alter the system imaging from contrasting black and white patterns to half tones and gray colorations.

Half-tone imaging with flying spot scanner system

An electrophotographic printing machine in which an arcuate screen member has a curvature substantially equal to the curvature of an arcuate photoconductive member employed therein. The centers of curvature of the screen member and photoconductive member are located in substantial coincidence with one another.

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Webster, NY, United States of America

Howard M Stark