Abstract: A multicolor imaging apparatus utilizes a recording medium adapted to having a plurality of latent electrostatographic images defined by image charge potential areas and background charge potential areas. The recording medium moves in a process direction such that an image is recorded on the recording medium and then developed at a plurality of development stations. At least one of the development stations includes not less than two development housings, with each such housing including at least one donor roll, which is electrically biased.

Abstract: An apparatus for developing a latent image recorded on an imaging surface, including a housing defining a reservoir storing a supply of developer material including toner. A mag roll loads a toner layer onto a region of said outer surface of said donor member. A donor member, spaced from the imaging surface, moves toner on an outer surface of said donor member to a development zone opposed from the imaging surface. A shield, adjacent to said donor member and said development zone, said shield being electrical biased to generate a toner cloud between said shield and said donor member which said toner cloud releases to the development zone to develop the latent image, in response to the movement of toner on the outer surface of said donor member.

Abstract: A high slope charging device including a DC portion followed by an AC portion. The high slope device includes an insulative shell housing, an electrode and a corona wire. The electrode is coupled to direct current power source which supplies a constant potential to the electrode thereby generating a corona at the electrode. An alternating current power source supplies an alternating voltage to the corona wire. The high slope device beneficially is designed such that both the electrode and the corona wire charge a charge retentive surface to the same potential.

Abstract: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps for recharging a charge retentive surface to a predetermined potential pursuant to forming the second of the two images, a first corona generating device recharges the charge retentive surface to a higher absolute potential than a predetermined potential, and then a second corona generating device recharges the charge retentive surface to the predetermined potential. An electrical charge associated with the first image is substantially neutralized after being recharged by the first and second corona generating device.

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: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps, a corona generating device is used to recharge the developed image areas and untoned areas of a charge retentive surface to a lower electrical potential than that associated with the developed image areas before recharge, so that the residual voltage associated with the developed image is substantially reduced and a minimal level of negative charge is driven through the toner layer(s). An electrical charge associated with any previously developed images is substantially neutralized prior to development of any subsequent images thereon.

Abstract: Corona generating devices, and printing machines which use such devices, which include a shell, a plurality of corona wires within the shell, and a power source which outputs first and second alternating voltages which are out-of-phase with each other. The plurality of corona wires are interconnected so as to form two groups of wires. The wires in the first group are operatively connected to the first alternating voltage and the wires in the second group are operatively connected to the second alternating voltage. The corona wires are located within the shell such that wires of the first group are adjacent wires of the second group, and such that wires of the second group are adjacent wires of the first group. The corona generating device beneficially includes a metallic screen which acts as a grid and which controls the corona flow from the corona generating device.

Abstract: A bias transfer member including a peripheral surface having low surface energy is disclosed. The low surface energy provides improved cleanability for enhancing the electrostatographic process and increasing the life of the bias transfer member. A low surface energy layer is provided by plasma fluorination to chemically modify the makeup of the surface material or by coating to form a low surface energy layer on the bias transfer member.

Abstract: An ink jet printhead is disclosed which includes at least one nozzle-defining channel having non-wetting walls and a step structure therein. The step structure is arranged within the channel so that the inlet to the channel has a cross-section which is larger in area than a cross-section of the nozzle outlet. The non-wetting walls of the channel prevent ink from being driven towards the outlet nozzle by capillary action as would normally occur with wetting channel walls. By controlling a positive pressure applied to an ink supply, the meniscus of the ink within the channel can be controlled to be located adjacent the step structure of the channel and spaced away from the nozzle outlet. When an actuator, such as, for example, a resistive heating element, is actuated, a droplet of ink will be expelled from the outlet nozzle of the channel.

Abstract: A device to cap a thermal ink jet printhead, without the need of moving the printhead or the paper transport is described. The capping device has a resilient gasket which contains magnetic material and is attached to the printhead by a relatively thin flexible boot or sleeve. A steel bar is disposed in sliding contact beneath a paper transport belt. The belt is adjacently spaced parallel to the printhead. The paper transport belt is flat and smooth and has a hole-free surface. During operation of the printer, an electromagnet disposed on the printhead is energized and attracts the magnetic gasket, resulting in the attraction of the gasket above the printhead nozzles to enable printing. When the printhead is not in operation, the electromagnet is de-energized, allowing the steel bar to attract the magnetic gasket and seal the gasket to the belt, capping the printhead. The capping device eliminates the need for movement of the printhead or moving the paper transport.