Abstract: Current density to copy substrates of varying widths if monitored and controlled in the electrostatic transfer unit of an electrostatic reproduction device. Current density through a copy substrate is appropriately adjusted to compensate for the presence of end leakage current effect to a receptor. Voltage supplied to a current generation unit in an electrostatic transfer unit is controlled independent of the characteristic properties of the copy substrate. Image reproduction quality is maintained in an electrostatic reproduction device even as the width of the copy substrate changes and in the presence of end leakage current effect.

Abstract: In a high speed color printer wherein color images are produced by superposing a developed image atop another developed image, the improvement including a charging system for charging a surface, including: at least two coronodes; a housing with the at least two coronodes spaced from each other; a grid interposed between the surface and the at least two coronodes; a shield, interposed between the housing and the at least two coronodes; a first power supply for biasing the grid and shield; a second power supply for energizing each of the at least two coronodes; and a phase controller connected to the second power supply and adapted to control energizing of the at least two coronodes such that each of the at least two coronodes is charged at a phase difference.

Abstract: In a high speed color printer wherein color images are produce by superposing a developed image atop another developed image, the improvement comprising a charging system for charging a surface, including: at least two coronodes; a housing with at least two coronodes spaced from each other; a grid interposed between the surface and said at least two coronodes; a shield, interposed between the housing and said at least two coronodes; a first power supply for biasing the grid and shield; a second power supply for energizing each of said at least two coronodes; and a phase control connected to the power supply and adapted to control energizing of said at least two coronodes such that each of said at least two coronodes is charged at a phase difference.

Abstract: A transfer charging device is arranged with dual transfer-assist blades consisting of a pressure blade and a halo blade. The pressure blade is arranged for contacting and thereby urging a substrate against an image-bearing photoreceptor. The pressure blade is formed of a relatively conductive material. The halo blade is formed of a dielectric material. The halo blade is positioned between the transfer charging device and the pressure blade to shield the pressure blade from being charged-up by the transfer charging device.

Abstract: A pretransfer sheet feeding device for an electrophotographic printing machine that minimizes impact with and delivers a sheet to a photoreceptor at a desired tangential position. The sheet feeding device includes a selectively engageable drive nip and a biased baffle member which forms a buckle chamber. There is further a plurality of rollers located so as to provide substantially frictionless directional guidance to the sheet while also inducing a predetermined bend to the sheet so as to deliver the sheet to the photoreceptor. The pretransfer rollers are also moveable so that the angle of approach of a sheet can be adjusted based on sheet weight or other characteristics. Once the sheet is tacked to the photoreceptor in the transfer zone, the disengageable drive nip is released and the sheet is controlled by the photoreceptor so that speed mismatch is not a problem.

Abstract: An electrostatographic printing machine and apparatus that utilizes a foam roll aquatron with a hydrophilic web between it and the photoreceptor. The porous web captures and removes toner particles which ordinarily would be trapped in the foam roll nip and cause image quality defects, such as streaking.

Abstract: A Liquid Immersion Development, LID, reproduction machine having a moving liquid toner image carrying surface, includes an excess carrier liquid removing apparatus. The excess carrier liquid removing apparatus includes a housing defining a chamber, and an opening through the housing into the chamber for mounting against the liquid toner image carrying surface. The excess carrier liquid removing apparatus also includes a roller mounted rotatably to the housing and within the chamber for forming an image processing nip gap, that has an image entrance side and an image exit side, with the liquid toner image carrying surface.

Abstract: An electrophotographic printing machine in which an electrostatic latent image recorded on a photoconductive member is developed with a liquid developer material. The liquid developer material is advanced by a substantially smooth donor roll from a supply to the latent image at a development zone. The liquid developer material on the donor roll is maintained at a thickness ranging from about 3 microns to about 10 microns.

Abstract: A system for decurling a sheet which is being advanced in a predetermined path within a printing machine includes a mechanism for generating a flow of room ambient air. The decurling system further includes a mechanism for directing the flow of room ambient air onto the sheet. Moreover, the decurling system includes a decurler adapted to apply mechanical force to the sheet after the flow of room ambient air has been directed onto the sheet by the directing mechanism. Finally, a mechanism is included for rotating the sheet to advance the sheet to the decurler in a direction substantially perpendicular to the direction of the predetermined path.

Abstract: A corotron assembly comprising a coronode for generating an electrostatic field and including an electrically nonconductive protective guard having a U-shaped base member forming a channel for receiving the coronode wherein a plurality of finger elements are provided, extending from the sidewalls such that the coronode is recessed between the finger elements. Each finger element is further provided with a spherical radii tip for reducing the attenuating effects of the finger elements on the electrostatic field generated by the coronode.

Abstract: An apparatus which transfers successive different color toner images from a photoconductive belt to a sheet. The toner images are in superimposed registration with one another. Transfer efficiency of successive toner images is improved by neutralizing the charge on the toner image prior to the transfer of the next successive toner image to the sheet. This is accomplished by passing the sheet with the toner image transferred thereto between upper and lower neutralization corona generators. The upper neutralization corona generator applies a charge on the toner image having an opposite polarity to the normal polarity of the toner image. The lower neutralization corona generator applies a charge on the backside of the sheet having the same polarity as the normal polarity of the toner image.

Abstract: An apparatus in which a latent image recorded on a member is developed with a developer material comprising at least carrier granules and toner particles. Toner particles are dispensed into the developer housing and mixed with unused developer material. The toner particles and developer material are advanced along an extended path so that the toner particles are gently mixed and triboelectrically charged to substantially the nominal level prior to contacting the latent image. A system of this type is particularly useful for toner particles requiring extensive gentle mixing to achieve the desired triboelectric charge.

Abstract: A coating applicator system comprising a stationary coater blade, reciprocating valve and applicator plates and, interposed between the valve and applicator plates, a stationary metering plate which includes a metering cavity. In operation, a quantity of photoelectrophoretic imaging suspension is supplied to the metering cavity in the metering plate when the valve and applicator plates are cammed in. When the reciprocating plates are cammed out, a metered amount of the suspension is deposited on the coater blade and when the plates are cammed in the imaging suspension is caused to move into a coating gap to supply a uniform quantity of suspension to a surface to be coated.