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US 4,542,979 AGranted
Method and apparatus for forming a multicolor proof print
AssigneeCoulter Stork Patents B.V.
InventorMilan Percic
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AssigneeCoulter Stork Patents B.V.
InventorMilan Percic
Estimating the term…
A method and apparatus for electrophotographically forming a multi-color proof print using at least two color separations. Two toner images of different color are formed in registration with each other. The photoconductive coating for each toner image is charged to an identical final charge state. Development of the charge pattern on each color separation is commenced after correspondingly identical time periods.
Method for electrophotographically forming a multi-color proof print sequentially from at least two light transmitting color separations employing at least one electrophotographic recording member having a photoconductive coating that is capable of having an electrostatic charge applied thereto and possessed of a predetermined characteristic dark decay and wherein a charge pattern from each color separation is formed on the photoconductive surface by exposure of the said surface which has been charged to a predetermined charge state, the charge pattern being developed for a predetermined period after the charge state is achieved to form a toner image using toner having a color corresponding to a selected color separation and the toner image is transferred to a receptor surface such that the subsequently formed toner image is in registry therewith;
A method of making multi-color prints from a series of color separation transparencies by electrophotographic imaging and transferring apparatus which comprises:
Apparatus for forming a multi-color proof print electrophotographically comprising a housing, a flat support with a photoconductive coating carried thereon and retained on said housing, means for charging said coating to a predetermined surface charge potential, means for exposing said charged photoconductive coating to form a latent charge image thereon, a plurality of toner holders each with different color toner supply means, means for moving selectively said toner holders individually with respect to the other respectively to interact with the photoconductive coating carrying a latent charge image thereon to form a visible toner image, a transfer medium including a receptor surface positioned proximate said toner image carrying photoconductive coating and means for effecting transfer of said toner image to said receptor surface, control means for said charging, exposure, toning and transfer means whereby the duration of charging is the same for all color images.
Apparatus for multi-color imaging by electrophotographic techniques which includes disposing an electrophotographic member having a photoconductive coating in position to be charged, charging the coating, producing from a first separation transparency a latent image on said charged coating by selectively exposing the coating to radiant energy, toning the latent image, transferring the toned image to a receptor and repeating the process for at least another of the separation transparencies and another toner but for the same receptor, which comprises:
In an apparatus for imaging by electrophotographic techniques in which there is a carriage which is reciprocated back and forth relative to the photoconductive surface of an electrophotographic member, the photoconductive surface facing generally downward and adapted to have a latent image thereon to be toned, the carriage movement being effective to tone said latent image, the invention herein which comprises:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
Structure of complete machines: using a single reusable electrographic recording member
Checking the colour or tonal value of separation negatives or positives: using electro photographic materials
Plural rotations of recording member to produce multicoloured copy: linearly moving set of developing units, one at a time adjacent the recording…
Electrography
Term ended 11 Aug 2003 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
This invention relates generally to xerography and more particularly, to a method and apparatus for forming a multicolor proof print from at least two light transmitting color separations.
2. Description of the prior art
FIG. 1 shows a schematic frontal view of the mutual position of the different constituent parts of the arrangement in accordance with the invention;
FIG. 2 provides a view in the direction of the arrow 2;
FIG. 3 provides a view in the direction of the arrow 3;
When preparing a series of proof prints from the same originals using coatings sensitive to glare phenomena the exposures for a certain color separation preferably are effected with equal light quantities throughout the series.
When performing the method of the invention with certain types of photoconducting coatings, such as zinc oxide coatings, the quality of the toner image is improved when the coating is moistened with a toner dispersant prior to the application of toner.
To obtain good results, it is advantageous to moisten the surface of the photoconductive coating with a suitable solvent after transfer of the toner to the receptor surface and prior to further charging of the photoconductive coating. Thereafter, the applied solvent is sucked off. Any residual charge on the photoconductive coating will flow away after transfer of the toner to the receptor surface and prior to further charging of the photoconductive coating. As a result, the respective consecutive images all are of high quality. The quality is even better if, prior to transfer of toner, the receptor surface is moistened and thereafter dried after transfer of toner.