Photocopying – Contact printing – Light boxes
Patent
1994-02-03
1995-07-25
Pendegrass, Joan H.
Photocopying
Contact printing
Light boxes
355260, 430117, G03G 1510
Patent
active
054367069
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates generally to development apparatus and more particularly to latent image development apparatus in electrophotographic imaging systems.
BACKGROUND OF THE INVENTION
The method of developing a latent image formed on a photoconductive surface by means of electrophoretic transfer of liquid toner is well known in the art. In this method, charged particles suspended in a non-polar insulating carrier liquid migrate under the influence of an electrostatic field and concentrate in image forming configuration upon relatively charged or discharged areas of a photoconductive surface. The latent image so developed is then transferred to a substrate, such as paper, either directly or by means of one or more intermediate transfer members.
In U.S. Pat. No. 4,504,138 a different method for the developing of a latent image is described. The method described involves applying a thin viscous high density layer of toner particles on the circumferential surface of a roller and bringing the layer so formed to the photoconductive surface. Transfer of selected portions of the toner layer onto the photoconductive surface then occurs as a function of the electric field strength of the latent image.
In Canadian Patent 990589, a method of developing electrostatic images is described which involves producing a film of liquid toner on a first applicator and bringing the applicator in contact with the final substrate which carries a latent image, thereby to develop the image. A second applicator bearing a layer of carrier liquid is then brought into contact with the substrate to remove background deposits and to squeegee out excess liquid. The film of liquid toner described in Canadian Patent 990589 has between 2-4 per cent of toner concentrate dispersed within the carrier liquid.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide simplified apparatus for the development of latent images in electrophotographic imaging systems by the direct transfer of concentrated liquid toner. There is therefore provided imaging apparatus including: electrostatic image, the latent electrostatic image including image regions at a first voltage and background regions at a second voltage; second voltages and having a second surface adapted for resilient engagement with the first surface at a first, transfer, region; region; carrier liquid to the second region, thereby forming on the second surface a thin layer of liquid toner containing a relatively high concentration of charged toner particles; of the layer of liquid toner from the second surface to the first surface at the first region to form a developed image on the first member; and substrate.
There is further provided in a preferred embodiment of the invention imaging apparatus including: electrostatic image, the latent electrostatic image having image regions at a first voltage and background regions at a second voltage; second voltages and having a second surface adapted for resilient engagement with the first surface; thin layer of liquid toner containing a relatively high concentration of charged toner particles; the layer of liquid toner from the surface of the second member to the photoconductive surface of the first member, the portions remaining on the surface of the second member constituting the desired image; and
Either or both of the first and second surfaces are preferably formed of resilient material.
In one preferred embodiment of the invention the third member is a roller with an elastomer surface, in another it is a resilient blade. In a third preferred embodiment the third member is a spring-mounted wire-wrapped solid rod. Alternatively the third member is an extrusion coating head.
Alternatively, in a preferred embodiment of the invention, the third member includes a metallic-screen hollow drum containing liquid toner and a squeegee blade urged against the inner surface of the metallic-screen, preferably also including a doctor blade in engagement with the second surface. Preferably the metallic-s
REFERENCES:
patent: 3758204 (1973-09-01), Mochizuki
patent: 3814054 (1974-06-01), Tajihi
patent: 4271785 (1981-06-01), DiNallo, Sr. et al.
Chatow Ehud
Landa Benzion
Lior Ishaiau
Indigo N.V.
Pendegrass Joan H.
LandOfFree
Latent image development apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Latent image development apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Latent image development apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-743491