Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-11-24
2001-08-21
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06276779
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an improved acoustic fluid emission head, e.g. an acoustic ink printhead, and a method of forming or assembling same. More particularly, the invention is directed to an acoustic ink printhead that advantageously incorporates elastomer gaskets to replace epoxy joints in the printhead and a corrugated spacer to provide focal gap control in the printhead. A related method for forming the printhead includes folding and spot-welding the aperture plate of the printhead to maintain the elastomer gaskets in place and, consequently, control the focal gap.
While the invention is particularly directed to the art of acoustic ink printing, and will be thus described with specific reference thereto, it will be appreciated that the invention may have usefulness in other fields and applications. For example, the invention may be used in any application where acoustic emitters are used.
By way of background, acoustic ink printing involves the emission of a droplet of ink from a pool of ink toward a print medium. Sound waves are generated and focussed toward the surface of the ink pool to emit the droplet therefrom. While acoustic ink printing elements may take various forms, such elements typically include a piezoelectric transducer, a lens, a cover plate having apertures formed therein to allow emission of the ink, and corresponding wiring. It is to be appreciated that approximately one thousand (1,000) or more of these elements may be disposed on a single printhead. It should also be appreciated that other fluids may be emitted such as molten metal, etc. rather than ink.
More particularly, as shown in
FIG. 1
, a single acoustic element
10
includes a glass layer
12
having an electrode layer
14
disposed thereon. A piezoelectric layer
16
, preferably formed of zinc oxide, is positioned on the electrode layer
14
and an electrode
18
is disposed on the piezoelectric layer
16
. Electrode layer
14
and electrode
18
are connected through a surface wiring pattern representatively shown at
20
and cables
22
to a radio frequency (RF) power source
24
which generates power that is transferred to the electrodes
14
and
18
. On a side opposite the electrode layer
14
, a lens
26
, preferably a concentric Fresnel lens, is formed. Spaced from the lens
26
is a liquid level control plate
28
, having an aperture
30
formed therein. Ink, or fluid,
32
is retained between the liquid level control plate
28
and the glass layer
12
, and the aperture
30
is aligned with the lens
26
to facilitate emission of a droplet
34
from surface
36
. The surface
36
is, of course, exposed by the aperture
30
.
The lens
26
, the electrode layer
14
, the piezoelectric layer
16
, and the electrode
18
are formed on the glass layer
12
through known photolithographic techniques. The liquid level control plate
28
is subsequently positioned to be spaced from the glass layer
12
to establish a focal gap. The ink
32
is fed into the space between the plate
28
and the glass layer
12
, e.g. the focal gap space, from an ink supply (not shown).
Acoustic ink printheads of the type incorporating emitting elements as described above typically have components that are bonded together with epoxy material. Epoxy bonded heads have the disadvantages of 1) experiencing epoxy delamination by the ink and 2) requiring increased manufacturing time resulting from the excessive cure time inherent in use of epoxy materials. Moreover, many types of epoxy materials are simply not compatible with the types of ink used in acoustic ink printing. Another disadvantage of the heretofore known types of acoustic emission heads is that, in such heads, it is difficult to maintain a uniform focal gap, i.e. the gap between the control plate
28
and the glass layer
12
shown in
FIG. 1
, across the entire emitting surface of the head. Controlling the focal gap is important for purposes of precision in emitting fluid.
It would, therefore, be advantageous to provide a head that is assembled without the use of epoxy. Such a head would be easier to assemble and would avoid the problems associated with the lack of compatibility of certain epoxy materials and the ink. It would also be advantageous to provide a head with improved focal gap control.
The present invention contemplates a new guleless acoustic ink printhead and a method of assembling the printhead that resolves the above-referenced difficulties and others.
SUMMARY OF THE INVENTION
A method and apparatus relating to an improved acoustic fluid emitting head, e.g. an acoustic ink printhead, are provided.
In one aspect of the invention, the apparatus comprises a glass substrate having lenses with emitters positioned thereon, a first frame positioned to support the glass substrate—the first frame having a flange extending therefrom, a first plate having a first portion with apertures defined therein, a second portion and a third portion—the apertures being positioned in alignment with the lenses of the glass substrate and separated from the lenses by a predetermined distance to establish a focal gap, a second frame positioned to support the first plate, a first sealing member disposed between the first plate and the second frame, a second sealing member disposed between the flange of the first frame and the second frame, a second plate positioned between the second portion of the first plate and the glass substrate—the second plate having corrugations defined therein, wherein the third portion of the first plate is disposed at an angle relative to the first and second portions and is connected to the second frame, and further wherein the flange of the first frame is connected to the second frame such that the glass substrate is maintained in a position between the first frame and the first plate.
In another aspect of the invention, the apparatus comprises an elastomer cushion and seal member positioned between the first frame and the glass substrate.
In another aspect of the invention, the flange is a deformable spring plate.
In another aspect of the invention, the apparatus comprises a fold between the second and third portions of the first plate.
In another aspect of the invention, the first sealing member is an elastomer gasket.
In another aspect of the invention, the second sealing member is an elastomer gasket.
In another aspect of the invention, the second frame includes a recess into which the elastomer gasket is disposed.
In another aspect of the invention, the second frame includes a recess into which the elastomer gasket is disposed.
In another aspect of the invention, the corrugations of the second plate are disposed to facilitate fluid flow.
In another aspect of the invention, the apparatus comprises a spot weld to connect the third portion of the first plate to the second frame.
In another aspect of the invention, the apparatus comprises a spot weld to connect the flange of the first frame to the second frame.
In another aspect of the invention, the apparatus comprises a fluid path extending between the first and second frames and through the corrugations of the second plate and the focal gap.
In another aspect of the invention, the apparatus comprises a tab positioned to align the glass substrate on the first frame.
In another aspect of the invention, the method comprises steps of folding the first plate such that a fold demarcates the second portion from the third portion, positioning the first sealing member in the first recess of the second frame, connecting the first plate to the second frame such that the first sealing member is compressed between the third portion of the first plate and the second frame, positioning the glass substrate to be supported by the first frame, maintaining the position of the glass substrate relative to the first frame with tabs extending from the first frame, positioning the second sealing member in the second recess of the second frame, positioning the second plate on a second portion of the glass substrate, positioning the first plate over the glass substrate and the
Fay Sharpe Fagan Minnich & McKee LLP
Le N.
Vo Anh T. N.
Xerox Corporation
LandOfFree
Acoustic fluid emission head and method of forming same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Acoustic fluid emission head and method of forming same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Acoustic fluid emission head and method of forming same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2545195