Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-02-19
2002-09-17
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06450615
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
Though the present invention is an apparatus developed for an ink-jet recording head, it can be widely used as an apparatus for forming a conductive film of a small electric circuit or integrated circuit and moreover, performing fine printing in addition to the ink-jet recording head. The present invention relates to the improvement of the art disclosed in Japanese Patent Application Laid-open No. 57963/1997 (hereafter referred to as “older application”) previously applied by the present applicant.
2. Description of the Related Art
The present applicant disclosed a droplet ejection apparatus according to a new theory in the above older application. The droplet ejection apparatus comprises an main chamber having an inlet and an ejection aperture and pressurizing means for applying a pressure to the liquid introduced into the main chamber. The ejection aperture forms surface waves on the surface of the injection liquid contacting the air at the ejection aperture by the pressure and ejects droplets having a diameter smaller than that of the ejection aperture in accordance with the action of the surface waves. To form surface waves on the surface of the liquid at the ejection aperture, the sectional shape illustrated in
FIG. 40
is disclosed.
FIG. 40
is an illustration showing the structure of a ink droplet ejection apparatus. The droplet ejection apparatus is provided with an inlet
1
, an ejection aperture
2
, a vibration plate
3
, a piezoelectric actuator
4
, an main chamber
5
, and an ink supply
6
.
When providing a mechanical displacement for the vibration plate
3
driven by the piezoelectric actuator
4
, the pressure of the ink stored in the main chamber
5
changes and surface waves are produced on the surface of the ink at the ejection aperture
2
. The surface waves move from the circumference of the ejection aperture
2
to the central portion, interfere with each other at the central portion to increase their wave height, and resultingly droplets of the ink separate from the surface of the ink. The ink is fed to the injection chamber
5
from the ink supply
6
after passing through the inlet
1
.
The above phenomenon is conceptually described below. When dropping a drop of water onto a stationary water surface, an annular surface wave expands centering about the drop-of-water fall point. A phenomenon just reverse to the above phenomenon occurs on the ink surface at the injection aperture
2
of the present invention. When producing surface waves bound for the center of the ejection aperture
2
from the circumference of the aperture
2
, the waves concentrate on the center of the ejection aperture
2
and ink droplets separate from the ink surface.
FIG. 41
is a structural drawing for explaining the aperture portion of a printing apparatus provided with a plurality of ink droplet ejection apparatuses. As shown in
FIG. 41
, by arranging a plurality of ejection apertures
2
of droplet ejection apparatuses
14
1
to
14
n
and controlling the ink ejection of each ejection aperture
2
, it is possible to print the paper passing through the front of the ejection aperture ? in the direction of the arrow. Thereby, it is possible to constitute the head of the printing apparatus.
An apparatus according to the new theory makes it possible to eject a droplet having a diameter smaller than that of an ejection aperture. Therefore, even if an ejection aperture having a large diameter is formed by roughly setting a machining accuracy, it is possible to perform high-resolution printing by ejecting small droplets. That is, it is possible to provide a high-resolution apparatus inexpensively and easily. Moreover, because it is possible to increase the diameter of an ejection aperture, clogging with ink does not easily occur, and an apparatus has a high adaptability to the surrounding environmental change. That is, available temperature range and humidity range are expanded. Moreover, there are superior features including the fact that requirements to the composition of a liquid are moderated and thereby, the liquid can be adapted to various types of inks.
The inventor of the present application et al. performed various tests on the droplet injection apparatus according to the new theory. Then, they confirmed through the tests that the droplet ejection apparatus according to the theory was considerably effective. As the standard of a practical printing apparatus, at least a resolution of approx. 300 dpi (dots per inch) or higher is required to print beautiful Japanese characters. In the case of the present invention, study has been progressed by aiming at the development of a practical printing apparatus having a resolution of 300 dpi or higher.
In this case, the most important problem to obtain a practical apparatus is to form surface waves on the surface of an ejection aperture instead of directly discharging an injection liquid from the ejection aperture. Moreover, another important problem is how to constantly stably form the surface waves under environmental conditions including practical temperature and humidity. To solve the problems, it is necessary to consider the following factors: (1) mechanical structures or shape of main chambers and aperture, (2) viscosity, surface tension, density, and other physical properties of liquid, and (3) art for controlling pressure to be applied to main chamber.
SUMMARY OF THE INVENTION
The first invention discloses a condition obtained as the result of performing many tests on the above Item (1) and apparatus structure according to the condition. It is an object of this invention to provide a compact, simple, and high-resolution droplet ejection apparatus. It is another object of this invention to provide a practical printing apparatus having a resolution of 300 dpi or higher. It is still another object of this invention to provide a droplet ejection apparatus which can be widely used as an apparatus for forming a conductive film of a small electric circuit or integrated circuit and moreover performing fine printing.
The second invention discloses a condition obtained as the result of performing many tests on the above Item (2) and an apparatus structure according to the condition.
It is an object of the second invention to provide an apparatus less influencing a liquid and capable of performing stable ejection even if the operating environmental temperatures of the apparatus are changed.
The third and the fourth inventions disclose a condition obtained as the result of performing many tests on the above Item (3) and an apparatus structure according to the condition.
The first invention is a droplet ejection apparatus comprising an chamber having an ejection aperture and pressuring means for applying a pressure to the liquid introduced into the chamber, in which the chamber is formed into a shape for forming surface waves on the surface of the liquid at the ejection aperture with the pressure and ejecting droplets having a diameter smaller than the diameter of the ejection aperture and whose sectional size vertical to the ejecting direction is decreased toward the ejection aperture, wherein the cross section of the chamber vertical to the injecting direction is circular or regular polygonal.
The first invention is characterized by forming the planar sectional shape of the chamber to be circular or regular polygonal. That is, for surface waves to be synthesized at the central potion of an ejection aperture, a circle or regular polygon is suitable for the shape of the ejection aperture. Because the ejection aperture is formed at an end of the wall surface of the chamber, it is proper to form the planar sectional shape of the chamber to be circular or regular polygonal.
It is preferable that the angle &thgr; formed between the wall surface and a plane vertical to the ejecting direction (see
FIG. 1
) is set to 65° or less and the diameter D of the ejection aperture is set to a value 1.25 or more times larger than a desirable diameter of droplets to be injected from the ejection
Kanda Torahiko
Kojima Ryuichi
Nakamura Hirofumi
Okuda Masakazu
Otsuka Yasuhiro
Barlow John
Brooke Michael S
Sughrue & Mion, PLLC
LandOfFree
Ink jet printing apparatus and method using a pressure... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet printing apparatus and method using a pressure..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet printing apparatus and method using a pressure... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2824858