Incremental printing of symbolic information – Electric marking apparatus or processes – Electrostatic
Reexamination Certificate
1998-06-03
2001-02-06
Pendegrass, Joan (Department: 2852)
Incremental printing of symbolic information
Electric marking apparatus or processes
Electrostatic
C347S141000, C347S158000
Reexamination Certificate
active
06184911
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to electrographic recording apparatus and methods wherein an electrographic writer establishes electrical fields that are used to selectively develop toner into an image.
2. Description Relative to the Prior Art
In the art of electrographic recording, it is well known to provide an electrographic writer or writehead that has a series of electrodes that can be selectively activated to selectively deposit charge and thereby record an electrostatic image on an insulative recording member. The electrostatic image is then advanced to a development station wherein the electrostatic image is developed to be visible by selectively attracting visible marking particles such as liquid or dry toner particles to deposit on the insulative recording member. The developed toner image is then transferred and fused to a receiver member such as plain paper or plastic to form a permanent record of the image.
A problem with electrographic recording on an insulative recording member using an ionographic recorder is that it is difficult to control position or placement of a charge pixel on the recording member and thus the recording images are not as well defined as in electrophotographic recording. Electrographic recording is distinguishable from electrophotographic recording in that the image is not required to be formed on a light sensitive member and light is not used in recording the image.
In order to improve upon electrographic recording there has recently been described by Oce Nederland B. V. a direct imaging electrographic writer that features a rotatable cylindrical writehead in the form of a drum. The drum has imbedded ring electrodes that are selectively provided with a voltage to attract toner in a development station. As the writer drum rotates, the voltages on the ring electrodes change in accordance with image data to form a toned image on the writehead. The toned image on the writehead is then transferred to a heated transfer roller and then simultaneously transferred to paper and fused.
A problem associated with development of toner images on the writehead itself is the buildup of contamination on the writehead which affects adversely the quality of the images formed thereon.
It is therefore an object of the invention to provide an improved electrographic apparatus and method that reduces the contamination problem and avoids the problem of having to place the electrostatic image well upstream of the development station and does not require use of an electrophotoconductive member.
SUMMARY OF THE INVENTION
The invention and its objects and advantages are achieved in accordance with a first aspect of the invention by an electrographic recording apparatus comprising a primary image forming member (PIFM) moving in a process direction; an electrographic writehead having a row of spaced electrodes arranged with the row being transverse of the process direction, the electrodes being selectively activated to establish respective electrical fields for recording of a respective row of pixels on the PIFM, the writehead facing a first surface of the PIFM and positioned in contact with or closely adjacent the first surface to establish the respective electrical fields through the PIFM; a development station including electrostatically charged toner particles in the form of a nap that selectively deposits the toner particles on a second surface of the PIFM directly opposite the series of spaced electrodes so that the toner particles are electrostatically selectively attracted by the respective electrical fields to develop the respective pixels to form a toner image on the second surface of the PIFM, the second surface being opposite the first surface; and wherein the PIFM moves relative to the writehead and the development station.
In accordance with a second aspect of the invention, there is provided an electrographic recording method comprising moving a primary image forming member (PIFM) in a process direction; providing an electrographic writehead having a row of spaced electrodes arranged with the row being transverse of the process direction, selectively activating the electrodes to establish respective electrical fields for recording of a respective row of pixels on the PIFM, the writehead facing a first surface of the PIFM and positioned in contact with or closely adjacent the first surface to establish the respective electrical fields through the PIFM; providing a development station including a nap of electrically charged toner particles; selectively depositing the particles on a second surface of the PIFM directly opposite the series of spaced electrodes by electrostatically selectively attracting the toner particles by the respective electrical fields to develop the respective pixels to form a toner image on a second surface of the PIFM, the second surface being opposite the first surface; and wherein the PIFM moves relative to the writehead and the development station.
In accordance with a third aspect of the invention, there is provided A color electrographic recording method comprising providing a plural number of color separation image forming modules, each module including a primary image forming member (PIFM), and an electrographic writehead and a development station; in each module forming a respective color separation image on the PIFM by operating the respective writer to establish selective recording electrical fields across a process direction while moving the PIFM in the process direction past a development station having a nap of electrically charged toner particles of the respective color, the nap being presented to one surface of the PIFM while the recording electrical fields are established through the PIFM with the writehead positioned adjacent a second surface of the PIFM and directly opposite the nap; and moving a receiver sheet into contact with a PIFM of each module to transfer respective color separation images in registration to form a multicolor image on the receiver sheet, wherein colors other than that of the respective toner particles are formed by superposition of toner particles of different colors.
REFERENCES:
patent: 3743411 (1973-07-01), Krekow et al.
patent: 4118710 (1978-10-01), Tomita et al.
patent: 4568955 (1986-02-01), Hodoya et al.
patent: 4748464 (1988-05-01), Pannekoek et al.
patent: 5483269 (1996-01-01), Van Stiphout et al.
patent: 5793401 (1998-08-01), Peter
patent: 2-130159 (1990-05-01), None
Oce' Technology Info; Oce' Direct Imaging is a True Digital Technology; 1996.
Hard copy observer; Apr. 1996; pp. 27-32.
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