Abstract: 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.

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

Abstract: A mechanism and process for detecting mottle or banding in a developed electrophotographic image. Within an electrophotographic reproduction apparatus 10, a photoconductor is used for receiving and developing a latent image. The photoconductor traverses a path that passes a charging station 28, an exposure station 34, a toning station 38, and a transfer station 46. Either a densitometer 76 for measuring the density of the developed image on the photoconductor, or an electrometer 50a or 50b for detecting the voltage of the image on the photoconductor, detects mottle or banding on the developed image. The densitometer 76 or electrometer 50a or 50b has an aperture small enough to detect mottle or banding with wavelengths perceptible by human eyes.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: 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.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: An electrographic machine 10 has a transfer station where a toner image is transferred to a receiver sheet 8. That sheet travels at a high speed of more than 15 inches per second and up to as high as 40 inches per second. A transfer roller has a metal core 212 and an elastomeric sleeve 214 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 photoreceptor.

Abstract: Apparatus and methods for electrographic image development, wherein the image development process is optimized by setting the average developer bulk flow velocity with reference to the imaging member velocity, for example, where the average developer bulk velocity is about the same as the imaging member velocity, or within preferred ranges, such as between about 40% to about 130% of the imaging member velocity.

Abstract: Methods for development of an electrostatic image are disclosed that utilize developer compositions with hard magnetic carrier compositions which can provide improved development efficiencies and reduced amounts of image carrier pick-up. The methods utilize hard magnetic carrier particles that are modified to have specific levels of resistivity, such as, for example, of from about 1×105 ohm-cm to about 1×1010 ohm-cm, and a carrier charge-to-mass of greater than about 1.0 &mgr;C/g, which carriers can provide greater development speeds without unacceptable levels of image carrier pick-up. In embodiments, the hard magnetic materials are doped, i.e., bulk substituted, with multi-valent metals to adjust resistivity, while in other embodiments, the hard magnetic materials are coated with at least one multi-valent metal oxide.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: 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.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

Abstract: Disclosed are methods and apparatus for electrographic development which utilize a rotating magnetic core, a toner shell disposed around the rotating magnetic core, and developer compositions disposed on the toner shell which include a hard magnetic material, such as a strontium ferrite. The shell in embodiments has an outer surface with a surface roughness Ra of less than 32 microinches. The methods and apparatus do not require special manufacturing steps to place surface roughness or irregularities on the shell, and, thus, can provide the same or better image quality with relatively less complex manufacturing steps and at reduced cost.

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

Abstract: A copier or a printer 10 includes a controller 16/30 with a rendering algorithm that groups sets of adjacent pixels into sets of adjacent cells where each cell corresponds to a halftone dot of an image. The algorithm operates in conjunction with a gray scale printhead 22. In sending data to the printhead, the controller 16 parses a scanned image and set the exposure for each pixel in accordance with a growth and density program. The algorithm selectively grows halftone dots from zero size to a desired size equal to or less than a maximum size. It repeats this step for the rest of the pixels until the cell is at its desired size and at an initial density. If a higher density is desired, the algorithm selectively adjusts the fully grown cells by sequentially increasing the level of exposure of each pixel in the cell. The image is developed with developer including a hard magnetic carrier and toner.

Abstract: A system and method for increasing the rate at which the printing of images and documents can take place, is provided. The document or image to be reproduced is positioned at an image capture location. To capture the image, the desired image is illuminated by lamps and ultimately transferred onto paper. The illumination device is driven by multiple energy sources that can be synchronized to charge and fire in an alternating manner to drive the illumination device at the desired rate.

Abstract: 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 hard carriers and 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.