Abstract: An apparatus for developing a latent image recorded on an imaging surface with a custom color toner, including a developer housing for developing a portion of the latent image with the toner of custom color. The developer housing includes a donor member for transporting toner of the custom color to a development zone to develop the latent image. A replaceable reservoir unit is provided for mixing and supplying the custom color toner to the donor member. An array of toner dispensers is provided for supplying various primary color toners, as required, to achieve the custom color, and additional reservoirs having various colored toners therein to allow for faster convergence to a given point in the color space.

Abstract: An apparatus for developing a latent image recorded on an imaging surface with a custom color toner, including a developer housing for developing a portion of said latent image with the toner of custom color. The developer housing includes a donor member for transporting toner of the custom color to a development zone to develop the latent image. A replaceable reservoir unit is provided for mixing and supplying the custom color toner to the donor member. An array of toner dispensers is provided for supplying various primary color toners, as required, to achieve the custom color, and additional reservoirs having various colored toners therein to allow for faster convergence to a given point in the color space.

Abstract: An apparatus which controls the dispensing in mixing of marking particles into a developer unit used in an electrophotograhic printing machine. In particular, the present invention is directed to a developer housing that includes a variable speed mixing apparatus for improving material life and performance. The quantity of marking particles required to reproduce the document is predicted and the dispensing and mixing of marking particles controlled in response thereto.

Abstract: An apparatus for developing a latent image recorded on a surface with toner. The apparatus includes a housing having a supply of toner therein; a donor member arranged in the housing to transport toner to a development zone adjacent the surface; a detaching toner device for detaching toner from the donor member and producing a toner cloud in the development zone; and an air handling system, associated with the housing, for collecting stray toner particles emitted from the housing, the air handling system including a separator for separating toner by size.

Abstract: A magnetic brush developer roll structure comprising a stationary magnet assembly including a magnet assembly shaft supporting magnet material. Bearings carried by the shaft, in turn, support a rotatable shell or tube forming the outer member of the roll structure. The bearings together with the shell or tube delineate an essentially sealed cavity in which one or more electrical contact brushes are disposed. The brush rubs against an inner wall of the shell or tube and provides an electrical path thereto. Using a plurality of brushes results in improved reliability.

Abstract: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps for conditioning a charge retentive surface pursuant to forming the second of the two images, a voltage sensitive corona generating device having a high characteristic slope described in a graph of the current delivered to a charge receiving surface (I) vs. grid minus charge receiving surface voltage (V) is used to both reduce the residual toner voltage across the previously toned image, and to charge the toned and untoned areas of the charge retentive surface to a substantially uniform level so that developability conditions for the subsequent image are improved.

Abstract: An apparatus for supporting wires in a wire module for use in a scavengeless development system using wire maintaining members that longitudinally support the wires. The tops of the wire maintaining members have grooves that positively position the wires and set a desired wire to wire spacing. The wire maintaining members are integral with the wire module and are part of a wire tensioning system. The wire maintaining members are part of an assembly that allow the wires to be pretensioned to the operable development tension prior to the wire module being mounted to the developer housing. The wire maintaining members also have a unique mounting system which allows the wire module to be rotatably mounted to the developer housing.

Abstract: A multicolor electrophotographic printing machine employing a plurality of developer units. Each of the developer units is actuated to develop a selected latent image with the appropriately colored toner particles. The other developer units are de-energized. In the development mode, the electrode wires and the donor roll are electrically biased to suitable voltages. In the non-development mode, the electrode wires have only a DC voltage applied thereon with the AC voltage being turned off. Substantially, simultaneously therewith, the electrical bias on the donor roll is adjusted to prevent further development. In this way, the developer unit does not develop a latent image in the non-operable mode and does not attract toner particles thereto from the latent image.

Abstract: An apparatus in which a donor roll advances toner to an electrostatic latent image recorded on a photoconductive member. A plurality of electrode wires are positioned in the space between the donor roll and the photoconductive member. The electrode wires extend in a transverse direction relative to the longitudinal axis of the donor roll. The electrode wires are electrically biased to detach the toner from the donor roll so as to form a toner cloud in the space between the electrode wires and photoconductive members. Detached toner from the toner cloud develops the latent image. Electrode wires contact a portion of the surface of the donor roll. As the donor roll rotates, friction between the electrode wires and donor roll causes trapped debris to move away from the toner powder cloud region so as to minimize contamination produced streaks on the developed image.

Abstract: A corona generating device of the type in which a control grid adjacent a corona generating electrode regulates the charge deposited onto an imaging surface. The control grid defines elongated apertures located in alignment with the electrode, extending along a portion thereof wherein the control grid is adapted to selectively control the charge deposited on the imaging surface area for preventing development of the edge regions thereof.

Abstract: A developer unit for an electrophotographic printer includes a housing defining a chamber for retaining developer material. An auger is rotatable within the chamber for the conveying of developer material within the chamber. The auger and a second rotatable member are adapted to receive rotational drive from a single source of rotational motion. A clutch is responsive to a torque above a predetermined level associated with the auger. A selectably openable outlet port is adapted to permit escape of developer material from the chamber. A linkage is operatively disposed between the clutch and the openable outlet port. A torque above a predetermined level associated with the auger causes the clutch to move the linkage, causing the mechanical linkage to open the outlet port.

Abstract: In a development system for conveying toner to a latent image on a surface in an electrophotographic printing apparatus, including a donor structure spaced from the charge retentive surface for conveying toner to a development zone adjacent the surface and an electrode structure disposed between the donor structure and the surface, contaminants are removed from the development zone by a flow of air away from the development zone.

Abstract: In a multi-color imaging apparatus, the voltage differential between developed and undeveloped areas of a charge retentive surface is reduced for precluding edge effect development. The developed areas correspond to charged areas on the photoreceptor while the undeveloped areas represent discharged or background areas on the photoreceptor. Development of the charged areas is followed by an erase step for reducing the voltage differential between the developed areas and the non-developed background areas prior to the next development step.

Abstract: An apparatus which develops an electrostatic latent image recorded on a photoconductive member with toner particles. A donor member is spaced from the photoconductive member and transports toner particles to a development zone adjacent the photoconductive member. Electrode wires are positioned in the development zone between the photoconductive member and the donor member. The electrode wires are electrically biased to detach toner particles from the donor member to form a cloud of toner particles in the development zone. Toner particles detached from the toner particle cloud develop the latent image. The electrode wires are adjustably supported in tension adjacent the donor member.

Abstract: In an electrostatograhic imaging device of the type forming a multilevel electrostatic latent image on a surface of the imaging member, and developing the multilevel electrostatic latent image with at least two types of toner, and a brush cleaner for removal of toner and debris remaining after transfer of the image to another surface, the brush is maintained in a condition loaded with a first toner type providing abrasive characteristics at the fibers of the brush, for abrading the photoreceptor for removal of toner of said second type.

Abstract: A bead pickoff device for removal of carrier beads adhering to a charge retentive surface subsequent to development of an electrostatic latent image with a developer mix including toner and carrier beads. A stationary magnet member supported within a rotating non-magnetic shell includes a permanent magnet supported in a ferromagnetic strip is provided with first and second sides disposed at an angle in the range of 70.degree. to 110.degree. with respect to each other. The first long side is supported with angled surface free end adjacent the charge retentive surface. The stationary magnet is seated on the second side, spaced from the first. The magnetic field is concentrated in the space between the magnet and the first side to provide an increased bead pickoff force at the charge retentive surface, while the field is attenuated to reduce the force of attraction on the beads as they move away from the charge retentive surface.

Abstract: An apparatus in which a latent image is developed with marking particles. In one mode of operation, the marking particles advance to the latent image. In another mode of operation, the marking particles are diverted from the latent image to prevent development thereof. A system of this type is particularly useful in color electrophotographic printing wherein successive electrostatic latent images are developed with different color marking particles.