Imaging system with electrophotographic patterning of an image definition material and methods therefor
View Patent ↗A system comprises an electrophotographic subsystem, a transfer subsystem, an imaging member, and an inking subsystem. The electrophotographic subsystem comprises a photoreceptor, a charging subsystem, an exposure subsystem, and a development subsystem. In operation, the photoreceptor is charged areawise. An exposure pattern is formed by the exposure subsystem on the surface of the charged photoreceptor to thereby write a latent charge image onto the photoreceptor surface. The image is developed with an image defining material, such as a dampening fluid. The image defining material forms a negative pattern of the image to be printed. This negative image is then transferred to the reimageable surface. The negative image is then developed with ink. The inked image may be transferred to a substrate.
1. A variable data lithography system, comprising:
a photoreceptor;
a charging subsystem for applying a first electrostatic charge to said photoreceptor;
an exposure subsystem disposed for selective exposure of said photoreceptor to thereby form an exposure pattern from regions that are exposed and unexposed by said exposure subsystem on a surface of said photoreceptor, said exposure enabling altering the electrostatic charge on said photoreceptor to thereby define regions of said photoreceptor having a first electrostatic charge state and a second electrostatic charge state;
an image defining material subsystem disposed proximate said photoreceptor for selectively applying an image defining material substantially over regions of said photoreceptor having said first electrostatic charge state and not over regions having said second electrostatic charge state to thereby form an image defining material image on a surface of said photoreceptor corresponding to said exposure pattern;
an imaging member having a reimageable surface formed thereover, disposed proximate said photoreceptor such that said image defining material selectively applied over said photoreceptor is transferred to said reimageable surface, forming regions of image defining material separated by regions of no image defining material on said reimageable surface, and thereby transferring said image defining material image from said photoreceptor to said reimageable surface;
an inking subsystem, disposed prior to said photoreceptor in a direction of rotation of said imaging member, for applying an ink layer substantially uniformly over said reimageable surface;
said photoreceptor disposed relative to said imaging member such that said image defining material image may be transferred from said photoreceptor to said reimageable surface over said imaging member, and further such that image defining material comprising said image defining material image at least in part mix with ink in said ink layer;
a cleaning subsystem disposed proximate said imaging member such that said image defining material may be removed from over said imaging member, said cleaning subsystem further configured such that said image defining material removes with it at least a portion of said ink with which said image defining material has mixed, and leaving on said reimageable surface at least a portion of said ink which has not mixed with said image defining material, to thereby form an inked image over said reimageable surface; and
an image transfer subsystem for transferring the ink forming said inked image to a substrate to thereby transfer said inked image from said reimageable surface to said substrate.
2. The variable data lithography system of claim 1 , wherein said image defining material comprises a particulate material, said particulate material capable of retaining an electrostatic charge and of intermixing into said ink upon transfer from said photoreceptor to said imaging member, and said cleaning subsystem is configured to remove said particulate material together with a portion of said ink by way of said electrostatic charge.
3. The variable data lithography system of claim 1 , wherein said image defining material comprises a particulate material, said particulate material capable of being magnetized and of intermixing into said ink upon transfer from said photoreceptor to said imaging member, and said cleaning subsystem is configured to remove said particulate material together with a portion of said ink by way of magnetic attraction of said particulate material.