Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-09-22
2001-11-06
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06312110
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to methods and apparatus for electrohydrodynamic (hereinafter “EHD”) ejection, and specifically to ink jet printers that eject ink via EHD.
2. Background of Related Art
Ink jet printers are playing an increasingly significant role in the printer art. This popularity is due at least in part to their improved resolution and relatively low cost compared to laser technology. Further, the emergence of digital photography has shifted the consumer printing market to low cost, photo-capable color ink jet printers. Higher resolution print heads are required to support market expectations for photographic quality. In fact, it has been estimated that by the year 2002, consumers may purchase more than 15 times as many photo-capable ink jet printers than dedicated photo printers per year.
Thus, an increasingly significant need exists for an ink jet printer that utilizes a high resolution print head.
SUMMARY OF THE INVENTION
It is therefore desirable to provide an ink jet printer that utilizes a high resolution print head. Specifically, it is desirable to provide pumping and ejecting apparatus of an ink jet printer print head that are very small and enable close spacing of nozzles, i.e., that have a fine nozzle pitch. It is further desirable to provide such methods and apparatus that provide consistent and reliable printing, wherein the relatively small ink droplets are satisfactorily controlled.
A high resolution print head in accordance with the invention provides at least some of these advantages by utilizing either an electrostatic field or a combination of electrodynamic and electrostatic fields to induce motion of a fluid, such as ink, within a nozzle of the print head. The motion of the fluid is induced by virtue of the interaction of the electric fields with charges within the fluid.
The nozzle in accordance with the invention can include a concentric ring of electrodes so as to cause directional motion of the ink within the nozzle, thereby providing improved control of the ejected ink stream. Specifically, by using separate electrode rings with different electric biasing, electric field behavior can be manipulated to introduce fluid motion that enhances nozzle performance.
This use of a directional electric field to force fluid down the nozzle in the vertical direction produces little lateral pressure on the sidewalls. Thus, the nozzle in accordance with the invention does not need to have thick silicon walls to handle large lateral fluid pressures, which allows smaller monolithic structures to be fabricated.
The invention also covers methods of manufacturing nozzles, such as via arisotropic etching (sacrificial etch) on silicon manufacturing techniques to yield small nozzle orifices. This process can yield a nozzle pitch of at least 2,000 nozzles per inch.
The apparatus manufactured according to this process can thereby be fabricated as a monolithic device, which obviates bonding several separate modules together and thus reduces the amount of silicon required for manufacture. The apparatus manufactured according to this process also does not have any moving parts, which enhances its operational reliability.
These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.
REFERENCES:
patent: 4316233 (1982-02-01), Chato et al.
patent: 4658269 (1987-04-01), Rezanka
patent: 4801955 (1989-01-01), Miura et al.
patent: 5194880 (1993-03-01), Elrod et al.
patent: 5336062 (1994-08-01), Richter
patent: 5598195 (1997-01-01), Okamoto et al.
patent: 5754205 (1998-05-01), Miyata et al.
patent: 5838349 (1998-11-01), Choi et al.
Dong Ho Choi et al. IS&T Final Program Proceedings, IS&T's Seventh International Congress on“Advances in Non-Impact Printing Technologies” vol. Two, pp. 49-58, 1991.
Dong Ho Choi et al., IS&T Final Program and Proceedings, IS&T's English International Congress on “Advances in Non-Impact Printing Technologies” pp. 334-339, 1992.
Tipler, P.A., Physics, Second Edition, Worth Publishers, Inc., New York, NY, 1982.
Brother International Corporation
Gordon Raquel Yvette
Oliff & Berridg,e PLC
LandOfFree
Methods and apparatus for electrohydrodynamic ejection does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods and apparatus for electrohydrodynamic ejection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods and apparatus for electrohydrodynamic ejection will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2614255