Eastman-kodak Company

Heidelberger Druckmaschinen Ag

Nexpress Digital LLC

Joseph E Guth

Eric C Stelter

Kenneth P Friedrich

Matthias Hermann Regelsberger

Edward Michael Eck

W Charles Kasiske

James Raymond Flick

Michael Frauens

Ulrich Mutze

Laverne N Lincoln, Jr

Yee S Ng

Peter S Alexandrovich

William B Vreeland

James Douglas Shifley

Patrick M Lambert

George R Walgrove, Iii

Joseph Y Kaukeinen

Thomas A Jadwin

Paul Essic Thompson

Wunan Chang

Paul S Gloyer

A developer station and method for an electrographic printer is provided that reduces developer agitation. The developer station includes a sump of magnetic developer, and a magnetic brush roller mounted above sump and having a rotatable magnetic core surrounded by a substantially cylindrical toning shell rotatably mounted with respect to the core. The toning shell defines a nip at its closest point to the photoconductor element. A tangent line tangent to the cylindrical toning shell at the nip is oriented substantially vertically, and the magnetic developer is applied to the toning shell at an angular distance of no more than about 120&#xb0; from the nip. The toning shell may be eccentrically mounted with respect to the magnetic core and is substantially closest to the rotatable magnetic core within about +30&#xb0; and &#x2212;30&#xb0; from the nip. Such a configuration advantageously reduces the residence time of the developer on the toning shell.

Developer station for an electrographic printer having reduced developer agitation

An electrostatic printing method in which the toning shell and the magnetic core each rotate in a co-current direction with the imaging member such that the portion of the toning shell adjacent to the image development area moves in a process direction, and the magnetic core rotates in the same direction as the toning shell such that a the average developer bulk velocity (ADBV) of the developer on the toning shell is in the same direction and proportional to the photoconductor velocity.

Electrographic image developing apparatus and method for developing including compensation for slippage

An apparatus and method for distributed mixing and transport of toner and powders in an electrostatographic printer containing at least powder and magnetic carrier. The apparatus includes a powder conveying apparatus for transporting powder in a developer station including a development station housing having two or more auger assemblies, each auger assembly including two or more screw augers supported in a channel profile. The two or more screw augers having multiple intermeshed screw blades and controlled by a conveyance controller. The conveyance controller is in communication with the powder the one or more augers, such that each auger preferentially mixes and transports in a first or second direction as the powder conveying device conveys the powder in the developer sump of a print engine.

Dual channel apparatus for transporting powder in an electrostatographic printer

A printer or other powder deposition device may include multiple toning stations, and the toning stations may be positioned in various configurations within the device. The various configurations may position the toning stations so as to increase the toning width of the device, thereby allowing the device to print larger process widths. The device may also perform processing control for the multiple toning stations.

Method and system for wide format toning

A developer station and related method for distributed replenishment of toner as well as powder coatings and related materials. The developer station is divided into a first space adjacent or within a second space, the first space located adjacent a toner supply and the second space including a developer sump. The first space includes a toner-conveying device located in the first space, the toner-conveying device having a tapered body with a first end and a second end. A conveyance housing is located adjacent to and disposed such that the toner conveying device conveys the toner toward the developer sump as it travels from the first end of the toner conveying device to the second end of the toner conveying device, the housing having slots or openings so that the toner is deposited in the developer sump along the length of the conveying device.

Electrographic distributed replenishment apparatus and method

A printing machine, comprising an intermediate medium; an ink jet printhead, for dispensing phase-change ink droplets at selected locations of a surface of the intermediate medium, the selected locations corresponding to an image to be printed; a receiver source, for providing a receiver; and a transfer station, for electrostatically transferring the dispensed phase-change ink droplets to the receiver.

Phase-change ink jet printing with electrostatic transfer

Apparatus and methods for applying powder coatings to a substrate either directly or by intermediate transfer using a magnetic brush developer.

Powder coating apparatus and method of powder coating using an electromagnetic brush

A developer mixing apparatus, comprising: a housing including a chamber that holds developer; a first ribbon blender disposed within the chamber and elongate along a first longitudinal axis; and, a second ribbon blender disposed within the chamber and elongate along a second longitudinal axis, wherein the first and second ribbon blenders move developer in different directions.

Developer mixing apparatus having four ribbon blenders

An electrographic machine has a transfer station where a toner image is transferred to a receiver sheet. That sheet travels at a high speed of more than 15 inches per second and up to as high as 35 inches per second. A transfer roller has a metal core and an elastomeric sleeve with a resistivity selected to optimize transfer of toner at high speeds. The resistivity of the sleeve is selected to be high enough to support transfer of the toner but not so high as to cause the surface voltage to exceed the breakdown voltage of the dielectric material that includes the elastomeric sleeve, the receiver sheet, the toner and the photoconductor.

Transfer roller with resistivity range

Apparatus and methods for electrographic image development, wherein the image development process is optimized by subjecting the developer to magnetic field maxima, thereby imparting to the developer a velocity component in a direction perpendicular to the process direction, ensuring that the toner particles thus accelerated have sufficient kinetic energy to overcome the binding energy binding the toner particles to the carrier particles in the developer, and to be deposited on a receiver bearing an electrostatic latent image. The optimized image is developed to completion, where development to completion is characterized by a proportionality between the cube of the toner charge to mass ratio and a quantity consisting of the magnitude of the voltage of the toning shell minus the magnitude of the voltage of the toned image.

Electrographic image developing apparatus and process

Compositions and methods for electrographic image development, wherein the image development process employs a two-component developer that includes toner particles having a radius Rand magnetic carrier particles having a radius R, wherein Ris preferably less than about 5Rand is more preferably less than or equal to about 3R.

Electrostatic image developing processes and compositions

A mechanism and process for detecting mottle or banding in a developed electrophotographic image. Within an electrophotographic reproduction apparatus, a photoconductor is used for receiving and developing a latent image. The photoconductor traverses a path that passes a charging station, an exposure station, a toning station, and a transfer station. Either a densitometerfor measuring the density of the developed image on the photoconductor, or an electrometerorfor detecting the voltage of the image on the photoconductor, detects mottle or banding on the developed image. The densitometeror electrometerorhas an aperture small enough to detect mottle or banding with wavelengths perceptible by human eyes. A logic and control unitaverages the image density or voltage measurements, calculates the variations of the measurements about the average and the periodicities of the measurements, and if the variations or periodicities indicate mottle or banding is present, changes the operation of one or more stations to reduce mottle or banding.

Reduction of banding and mottle in electrophotographic systems

A method and apparatus for replenishing toner based on the electric current used over time by the exposure subsystem. Toner take-out for each image is estimated by measuring the current used by the exposure system, subtracting the quiescent current, integrating over a page or frame, and multiplying by a predetermined value that indicates the amount of toner required by the image, based on the average current used for the exposure and other process parameters. These calculations are done either in hardware or in software. The replenishment system is used to add the correct amount of toner to the developer station to maintain the toner concentration at an approximately constant aim value.

Toner replenishment based on writer current

The invention relates generally to processes for electrostatic image development, and setpoints that provide uniform image development. In particular, an apparatus and process having a magnetic brush that implements a rotating magnetic core within a shell is disclosed. The process implements one or more of the following optimum setpoints: a range of shell surface speeds that provide uniform toning density, a range of shell surface speeds that prevent toner plate-out, a skive spacing that minimizes sensitivity to variation, a magnetic core speed that minimizes sensitivity to variation, and an imaging member spacing that minimizes sensitivity to variation.

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Holley, NY, United States of America

Joseph E Guth