Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-06-04
2001-03-06
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06196666
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to an electrode assembly, and production method, incorporated in image recording apparatuses, such as copy machines, printers, plotters, and facsimile machines, for use in the recording processes.
2. Description of Related Art
In general, an electrode assembly used in a recording process comprises a plurality of apertures, and the same number of control electrodes positioned so as to face the associated apertures. This type of electrode is called an aperture electrode. It is typically used in toner jet image recording apparatuses, in which toner particles travel in an electric field toward a recording medium to form an image on the recording medium. An example of an image recording apparatus using an aperture electrode is disclosed in Japanese Patent Application Laid-open No. 6-155798. In this publication, a predetermined voltage, based on the image data, is applied to each of the control electrodes to control the passage of toner particles (i.e., the charged particles) through the corresponding aperture. The toner particles that pass through the apertures form an image on a recording medium based on the image data.
The electrode assembly comprises an insulating film made of, for example, polyimide; control electrodes formed on the top surface of the insulating film; a top coating layer covering both the control electrodes and the insulating film; and apertures formed with the control electrodes therearound penetrating through the top coating layer and the insulating film. The top coating layer is provided for the purpose of protecting the control electrodes which are formed along the minute interconnection pattern on the insulating film. This coating layer is an insulator formed from, for example, Yupicoat (Trademark), which is a polyimide coating material manufactured by UBE Industries, Ltd., by a screen printing method through the printing, drying, and baking steps.
However, because the top coating layer is an insulating layer, this layer becomes charged during the operation of the conventional image recording apparatus having recording electrodes, which adversely affects the toner particles that pass through the apertures and fly to the recording medium.
For example, if the polyimide of the top coating layer is negatively charged, an electrostatic field repulsing the negatively charged toner particles is formed over the entire surface of the aperture electrode assembly. The leakage electric field is also formed in the apertures, which prevents the toner particles from passing through the apertures.
If the polyimide is positively charged, an electrostatic field that attracts the negatively charged toner particles is formed over the entire surface of the aperture electrode assembly, and its leakage field is formed in the apertures. This causes the negatively charged toner particles to attach to and accumulate in the apertures, which results in choked apertures.
SUMMARY OF THE INVENTION
Therefore, it is an object of the invention to overcome these problems in the prior art, and to provide an electrode assembly, used in the recording process and apparatuses, which allows for high-quality image formation over a long span of time.
In order to achieve the object, in one aspect of the invention, a recording electrode assembly that controls ejection of charged particles toward a recording medium is provided. The recording electrode assembly is positioned between a charged particle supply unit for supplying the charged particles and a rear electrode device that attracts the charged particles. The recording electrode has an insulating sheet, and a plurality of passages formed in the insulating sheet, through which the charged particles are ejected. Control electrodes are also provided on the insulating sheet in order to control the charged particles passing through the passages. The control electrodes are covered with a coating layer which is made of a material containing an anti-electrification agent.
The coating layer may be baked so as to be hardened.
The coating layer is made of a mixture of an insulating material and a conductive material, one of which being a base material, the other being an additive. The additive is mixed or dispersed into the base material prior to forming the coating layer.
The additive is, for example, a conductive material having a diameter of 1 &mgr;m or smaller. Alternatively, the additive may be conductive carbon particles, such as artificial graphite. Preferably, the conductive material as the additive has a diameter equal to or smaller than one tenth of the charged particle.
The insulating material is, for example, polyimide resin.
The conductive material can also be one selected from a group including aluminum, molybdenum, nickel, and chromium.
If carbon is used as the conductive material, and if polyimide is used as the insulator, it is preferable to disperse the carbon to be equal to or more than 0.05 weight parts and less than 0.10 weight part into 1 weight part of solid polyimide resin.
More preferably, 0.07 weight parts of carbon is dispersed into 1 weight part of solid polyimide resin.
The recording electrode assembly may further comprise a back coating layer that is formed so as to face the charged particle supply unit. The back coating layer may be adhered to the back surface of the insulating sheet by an adhesive which contains an anti-electrification agent. Preferably, the back coating layer contains an anti-electrification agent, a lubricant, and an electric charge adjusting agent. The anti-electrification agent is one selected from a group including carbon, polypyrrole, polyacetylene, and polythiophene. The lubricant is one selected from a group including silica, alumina, silicon fine-grain, titanium oxide, and zinc oxide. The electric charge adjusting agent is one selected from a group including quaternary ammonium salt (+), azo dye (−), and azine compound (+).
The coating layer is formed by the steps of dispersing the conductive material in the binder, applying the binder in which the conductive material is dispersed onto the insulating sheet and the control electrodes so as to cover both the insulating sheet and the control electrodes, and baking the binder in order to harden the coating layer.
When forming the back coating layer, an anti-electrification agent, a lubricant, and an electric charge adjusting agent are added into a binder and stirred with the binder. The binder containing the anti-electrification agent, the lubricant, and the electric charge adjusting agent is applied onto a board. Then, the binder and the board are baked. After baking, the binder is removed from the board. Finally, the binder is attached, as the back coating layer, onto the back surface of the insulating sheet.
The recording electrode assembly according to the invention can prevent electrification of the coating layer and, therefore, the passage of the charged particles through apertures can be accurately controlled by application of the voltage to the control electrodes. Because the recording electrode assembly of the invention can prevent the charged particles from accumulating in the passages, a stable and high-quality image recording operation can be maintained over a long span of time.
The coating layer is made of a mixture of an insulator and a conductive material, which is stable in structure.
Since the diameter of the conductive material contained in the coating layer is 1 &mgr;m or less, even if the particles of the conductive material come to the surface of the coating layer, they do not prevent ejection of the charged (toner) particles. For the same reason, the diameter of the conductive particles of the coating layer may be set equal to or smaller than one tenth of the diameter of the charged toner particle. This allows a highly precise recording operation without affecting ejection of the charged particles.
Using conductive carbon particles as the conductive material allows the anti-electrification material to be manufactured at a low cost. Artificial
Kagayama Shigeru
Kitamura Tetsuya
Barlow John
Brother Kogyo Kabushiki Kaisha
Gordon Raquel Yvette
Oliff & Berridg,e PLC
LandOfFree
Electrode assembly, and method for producing, used in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrode assembly, and method for producing, used in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrode assembly, and method for producing, used in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2468350