Print system and dielectric imaging member
AssigneeDelphax Systems
InventorIgor Kubelik
Life of this patent
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Abstract
A dielectric imaging member of a printer receives a latent charge image that is preferably projected as a plurality of charge dots from a multi-electrode printhead. The member has charging characteristics that diminish the normal electric field component at the edge of charge dots deposited on its surface. The dielectric constant of a surface layer of the imaging member decreases with depth, either continuously, or in a stepwise manner. Various printing aberrations, such as voids in grey-scale images, fringing rings about dots, dot spreading and filling between dots are corrected, so that compensating image coding of printhead actuation sequences is not required to deposit a faithful electrostatic latent image.
Claims13
A dielectric imaging member for receiving a latent charge image for development to form a recording, such dielectric imaging member being movable to receive the latent charge image on a surface thereof and wherein the surface comprises an outer surface region and a subsurface region having dielectric constants .epsilon..sub.0 and .epsilon..sub.1, respectively, such that .epsilon..sub.0 is greater than .epsilon..sub.1.
An electrographic printer comprising
- printhead means for projecting charge carriers to form an imagewise charge pattern
- a latent dielectric imaging member for receiving the imagewise charge pattern as a latent charge image, said latent imaging member having an image-receiving surface construction characterized by a dielectric constant that decreases with increasing depth
- means for developing the latent charge image to form a developed image, and
- means for fixing the developed image as a print.
A method of controlling charge spreading of a latent charge image deposited on an dielectric imaging surface, such method comprising the steps of providing as said imaging surface a chargeable surface having a dielectric constant decreasing with depth, and depositing the latent charge image on said chargeable surface.
A method of accurately controlling a level of charge in a latent charge image deposited on a chargeable dielectric surface, such method comprising the step of providing a chargeable surface having a dielectric constant, that decreases with depth thereby reducing a fringing field around regions of deposited charge, wherein equipotentials in an air gap above the surface approach normal incidence at an edge of a deposited charge dot.
Dependencies are inferred from the claim text.