Xerox Corporation

Zerox Corporation

John J Kopko

Dan A Hays

Joseph A Seyfried

Clive R Daunton

Ravi Sampath

Stephen T Dunn

An apparatus for charging a photoconductive surface to a substantially uniform potential in a printing machine having a cleaning station for cleaning the surface and an exposure station for exposing the surface to a light source includes a first mechanism for charging the surface to a substantially uniform potential of a first polarity after the surface is cleaned at the cleaning station. The apparatus further includes a second mechanism for charging the surface to a substantially uniform potential of a second polarity opposite to the first polarity after the surface is charged to the substantially uniform potential of the first polarity by the first charging mechanism and before the surface is exposed to the light source at the exposure station. Similarly, a method of charging a photoconductive surface to a substantially uniform potential in a printing machine having a cleaning station for cleaning the surface and an exposure station for exposing the surface to a light source, includes the steps of (1) charging the surface to a substantially uniform potential of a first polarity after the surface is cleaned at the cleaning station; and (2) charging the surface to a substantially uniform potential of a second polarity opposite to the first polarity after the first polarity charging step and before the surface is exposed to the light source at the exposure station.

Method and apparatus for charging a photoconductive surface to a uniform

Apparatus for cleaning residual toner from a charge retentive surface is provided with a rotating abrading brush, located upstream of a primary cleaner relative to a feeding direction of the charge retentive surface. The abrading brush contacts and abrades the charge retentive surface. The abrasion of the charge retentive surface reduces the friction between the charge retentive surface and a primary cleaner (which is preferably a cleaning blade biased against the charge retentive surface) and prevents the formation of comets (adhered toner particles) on the charge retentive surface.

Cleaning device including abrading cleaning brush for comet control

An apparatus in which a latent image is developed with magnetic developer material. A rotating applicator roll transports the developer material. A magnet is mounted rotatably interiorly of the applicator roll and generates a magnetic flux field which attracts the developer material to a portion of the surface of the applicator roll. The magnet rotates under the influence of the magnetic flux field force applied thereon. When the apparatus is developing the latent image, the magnet is prevented from rotating in a first position wherein the magnetic flux field attracts the developer material to the portion of the applicator roll adjacent the latent image. Conversely, when the apparatus is not developing the latent image, the magnet is prevented from rotating in a second position wherein the magnetic flux field attracts the developer material to the portion of the applicator roll spaced from the latent image. An apparatus of this type is particularly useful in color electrophotographic printing wherein successive electrostatic latent images are developed with different color developer materials. In a color printing machine, one color developer material is being developed on the latent image with the other color developer materials being spaced from the latent image to prevent intermingling of colors.

Developer unit having an indexable magnet

This invention is directed to an improved process for causing the development of electrostatic latent images on an imaging member comprising providing a development zone situated between a tensioned deflected flexible imaging member and a transporting member, adding conductive developer particles to the development zone comprised of toner particles and conductive magnetic carrier particles, causing the flexible imaging member to move at a speed of from about 5 cm/sec to about 80 cm/sec, causing the transporting member to move at a speed of from about 6 cm/sec to about 160 cm/sec, said flexible member and said transporting member moving at different speeds, maintaining a distance between the tensioned deflected flexible imaging member and the transporting member of from about 0.05 millimeters to about 1.5 millimeters, introducing a high electric field in the development zone, wherein the developer particles contained in the development zone are agitated, thereby providing contact between the conductive carrier particles, causing charge to rapidly flow in the direction of the deflected imaging member, said process being accomplished in the presence of a low magnetic field of less than 150 gauss, and a method of imaging utilizing such a process.

Development process utilizing conductive materials

An apparatus in which a developer roller transports developer material into contact with a photoconductive surface having either a continuous tone or a half-tone latent image recorded thereon. The speed of the developer roller is controlled so that it rotates at a higher speed when developing the continuous tone latent image than when developing the half-tone latent image. In this way, development is optimized for the continuous tone and half-tone latent images so as to produce high quality copies.

Multispeed development system

An apparatus which develops a latent image recorded on a flexible member. Developer material is transported into contact with the flexible member in the development zone so as to develop the latent image. The flexible member is maintained at a pre-selected tension. As the developer material contacts the flexible member in the development zone, the flexible member deforms so as to conform, at least partially, to the developer material.

Self-spaced development system

An apparatus which develops a latent image recorded on a flexible member. Developer material is transported into contact with the flexible member in at least two development zones. The first development zone optimizes line development and the second development zone optimizes solid area development. At least in the second development zone, the flexible member is maintained at a preselected tension so that the developer material being transported into contact is compressed and deflects the flexible member thereabout.

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Macedon, NY, United States of America

John J Kopko