Abstract: A printing apparatus is described comprising a photoconductor for receiving an electrostatic charge pattern corresponding to an image, and one or more developers for applying a colorant to the photoconductor representative of the image. The apparatus further comprises a transfer member for transferring the image from the photoconductor onto a substrate, wherein the transfer member has a substantially grounded potential.

Abstract: Certain examples of apparatus for applying fluid in a printing system are described. The apparatus comprise a first chamber having a first aperture extending along a first axis, and a second chamber having a second aperture extending along a second axis, wherein the first axis is substantially parallel to the second axis. The second chamber is movable with respect to the first chamber. Also, methods for supplying a fluid, and printing systems are described.

Abstract: In an example implementation, a method of rosette-free printing includes, in a printing device whose color plane misregistration is less than 15 percent of a screen ruling of a halftone screen, printing multiple color planes of a multicolor image using the halftone screen.

Abstract: In an example implementation, a method of cleaning a silicon photoconductor includes contacting the silicon photoconductor with a base-peroxide solution, rinsing the silicon photoconductor with a liquid, and heating the silicon photoconductor to evaporate the liquid.

Abstract: Printers comprising a plurality of imaging units are described. In an example, each imaging unit selectively deposits at least one printing substance and an intermediate transfer member cooperates with the imaging units such that, in use of the printer, a printable image may be formed thereon, the printable image comprising printing substance from at least two imaging units.

Abstract: A method is presented for automatically controlling the spacing between printer drums. The printer includes at least two print drums (920.1, 920.2) whose parallel rotation leads to image transfer, either between the drums or onto a printed surface. First the pressure a signal indicative of the pressure between the two print drums is obtained by a measurement unit (930), and then the gap between the drums is automatically adjusted in accordance with the indicator signal by a gap adjuster (940).

Abstract: Electrophotographic print system, comprising a photosensitive medium, and a laser array being provided with a plurality of laser diodes arranged to emit light onto the photosensitive medium for varying an electrical potential on a surface of the photosensitive medium, and a plurality of heat dissipation diodes, each heat dissipation diode being arranged in proximity to a corresponding laser diode, wherein each laser diode and the corresponding heat dissipation diode are coupled to a common drive circuit and are arranged in opposite current flow directions with respect to each other, so that in use the current flows either through the laser diode or through the heat dissipation diode depending on the current flow direction in the drive circuit.

Abstract: Electrophotographic print system, comprising a photosensitive medium, and a laser array being provided with a plurality of laser diodes arranged to emit light onto the photosensitive medium for varying an electrical potential on a surface of the photosensitive medium, and a plurality of heat dissipation diodes, each heat dissipation diode being arranged in proximity to a corresponding laser diode, wherein each laser diode and the corresponding heat dissipation diode are coupled to a common drive circuit and are arranged in opposite current flow directions with respect to each other, so that in use the current flows either through the laser diode or through the heat dissipation diode depending on the current flow direction in the drive circuit.

Abstract: A method is presented for automatically controlling the spacing between printer drums. The printer includes at least two print drums (920.1, 920.2) whose parallel rotation leads to image transfer, either between the drums or onto a printed surface. First the pressure a signal indicative of the pressure between the two print drums is obtained by a measurement unit (930), and then the gap between the drums is automatically adjusted in accordance with the indicator signal by a gap adjuster (940).

Abstract: A method of charging an imaging member having an outer surface with an imaging region and a seam region. A charge device is provided adjacent the imaging member. An electrical charge is provided to the imaging region of the imaging member using a voltage on the charge device. An other electrical charge is provided to the seam region of the imaging member using an other voltage on the charge device.

Abstract: A development unit for a printing device is described. An equalizing element is provided to minimize residual charges which cause ghosting. The equalizing element can, for example, be a roller or a blade positioned downstream of a cleaning nip between the cleaning roller and the development roller and charged to an electric potential which is substantially the same as an electric potential of the development roller. The equalizing element can alternatively, or in addition to being charged to perform equalization, operate to aid in charge residual charge dissipation on the development roller by blocking developer from reaching the development roller downstream of the cleaning roller.

Abstract: A method for determining a location of an uncharged region on a photoconductive drum in an electrophotographic device, including rotating the photoconductive drum, and charging a surface of the drum via a charge roller by application of a voltage to the charge roller. An electrical characteristic of one of the charge roller or photoconductive drum is measured, and an alteration in the electrical characteristic is used to determine a location of the uncharged region.

Abstract: A method for determining a location of an uncharged region on a photoconductive drum in an electrophotographic device, comprising rotating the photoconductive drum, and charging a surface of the drum via a charge roller by application of a voltage to the charge roller. An electrical characteristic of one of the charge roller or photoconductive drum is measured, and an alteration in the electrical characteristic is used to determine a location of the uncharged region.

Abstract: A method for reducing foam associated with an ink reservoir of a printing press is provided. The method can include printing a plurality of printed images with a nonaqueous ink delivered from an ink reservoir, periodically delivering a defoaming agent into the ink reservoir to reduce foam formation in the ink reservoir, and periodically delivering a charge control agent into the ink reservoir to charge the nonaqueous ink. Accordingly, fresh defoaming agent can be added to the ink reservoir periodically to reduce the level of foam in the reservoir and thus avoiding increasing foam levels associated with the degradation of the defoaming agent over time.

Abstract: Imaging methods, image engines, and photoconductor charging systems are described. According to one embodiment, an imaging method includes providing a charge device configured to provide an electrical charge to a surface of an imaging member which is usable for imaging, moving a surface of the charge device adjacent to the imaging member and a bias member, during the moving, first charging a discharged portion of the surface of the charge device using the bias member providing a charged portion of the surface of the charge device, during the moving, second charging a portion of the surface of the imaging member using the charged portion of the charge device, the second charging providing the discharged portion of the surface of the charge device, and repeating the first charging and the second charging during the moving.

Abstract: A development unit for a printing device is described. An equalizing element is provided to minimize residual charges which cause ghosting. The equalizing element can, for example, be a roller or a blade positioned downstream of a cleaning nip between the cleaning roller and the development roller and charged to an electric potential which is substantially the same as an electric potential of the development roller. The equalizing element can alternatively, or in addition to being charged to perform equalization, operate to aid in charge residual charge dissipation on the development roller by blocking developer from reaching the development roller downstream of the cleaning roller.

Abstract: Imaging methods, image engines, and photoconductor charging systems are described. According to one embodiment, an imaging method includes providing a charge device configured to provide an electrical charge to a surface of an imaging member which is usable for imaging, moving a surface of the charge device adjacent to the imaging member and a bias member, during the moving, first charging a discharged portion of the surface of the charge device using the bias member providing a charged portion of the surface of the charge device, during the moving, second charging a portion of the surface of the imaging member using the charged portion of the charge device, the second charging providing the discharged portion of the surface of the charge device, and repeating the first charging and the second charging during the moving.

Abstract: A coating system comprising: a rotating roller; an electrode having a surface located adjacent the roller that defines a space between the surface of the roller and the electrode surface, which space has first and second apertures located at different angular positions about the axis of the roller, wherein the electrode surface is formed with at least one drain aperture located between the first and second apertures; a voltage source that applies a voltage difference between the electrode and the roller; and a source of liquid toner comprising charged toner particles dispersed in a carrier liquid that discharges the liquid toner into the space through the first aperture, wherein a portion of the liquid toner discharged into the space coats a region of the surface of the roller that passes by the electrode, a portion exits the space through the second aperture and a portion exits through the at least one drain aperture.

Abstract: A coating system comprising: a rotating roller; an electrode having a surface located adjacent the roller that defines a space between the surface of the roller and the electrode surface, which space has first and second apertures located at different angular positions about the axis of the roller, wherein the electrode surface is formed with at least one drain aperture located between the first and second apertures; a voltage source that applies a voltage difference between the electrode and the roller; and a source of liquid toner comprising charged toner particles dispersed in a carrier liquid that discharges the liquid toner into the space through the first aperture, wherein a portion of the liquid toner discharged into the space coats a region of the surface of the roller that passes by the electrode, a portion exits the space through the second aperture and a portion exits through the at least one drain aperture.

Abstract: A system for double-sided imaging on a continuous-web substrate having first and second substrate surfaces, the system including an imaging device including a toner-image bearing surface having selectively formed thereon first and second images. The system further includes a web-feeder system which selectively brings the first and second substrate surfaces into operative engagement with the toner-image bearing surface, to transfer thereto the first and second images, respectively, in accordance with a preselected imaging sequence.