Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2003-01-15
2004-07-27
Eickholt, Eugene H. (Department: 2854)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S108000, C347S085000, C347S063000, C029S890100
Reexamination Certificate
active
06767079
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the image rendering arts. It finds particular application in conjunction with thermal ink jet printheads, and will be described with particular reference thereto. However, it is to be appreciated that the present invention is also amenable to other like applications.
Typically, the manufacturing of thermal ink jet printheads involves numerous complicated steps both inside and outside of a clean room. Among the process steps are a plurality of precise adhesive placements and position alignments are performed in the clean room. More specifically, constituent components of the printhead assembly have adhesives applied, are aligned and pressed together, and the adhesives cured in a heater. Typically, each separate component is bonded and cured in a separate step.
More specifically to the prior art, U.S. Pat. No. 6,229,114 to Andrews, et al. describes the construction of a thermal ink jet printhead, and is herein incorporated by reference. First, in the clean room, a die bond epoxy is applied to the bottom side of a die module
1
. The die module
1
is then precisely aligned and assembled to a substrate
2
, in the case of Andrews, a heat sink. Next, the die bond is cured in an oven for approximately 45 minutes or longer. After the die bond is set, wire bonds
3
are applied between a printed wiring board
4
on said substrate
2
and an electrical contact portion of the die module
1
. An adhesion promoter is applied to the top surface of die module
1
. A tack fluid seal
5
is precisely located and applied to one surface of the ink manifold assembly
6
. The die module
1
and substrate
2
assembly and the manifold
6
an fluid seal
5
assembly are then precisely located to each other and are merged together and a UV adhesive is applied and cured The tack fluid seal is cured in an oven for approximately 45 minutes or longer. An encapsulation adhesive is then injected into the assembly to protect the wire bonds
3
from oxidation. A faceplate
7
is adhered to the operative surface of the printhead.
Once assembled, the printhead is subjected to an additional final cure, along with a series of integrity tests.
U.S. Pat. No. 4,601,777 to Hawkins, et al. describes an alternate method for constructing a thermal ink jet printhead, and is herein incorporated by reference. With reference to
FIGS. 2 through 5
of the present application, aspects of existing manufacturing processes are illustrated. In
FIG. 2
, a daughter board
10
carries a thermal ink jet printhead
12
. A portion of daughter board electrodes
14
are carried entirely on the facing side of the daughter board
10
, and another portion of the electrodes
14
are carried partially on the reverse side of the daughter board
10
, switching sides at inversion points
15
. As seen in
FIG. 3
, daughter board electrodes
14
are connected to individual printhead electrodes
16
. The printhead electrodes
16
are carried upon a substrate
18
, as best seen in
FIGS. 4 and 5
. Wire bonds
20
are used to connect between each daughter board electrode
14
and its corresponding printhead electrode
16
counterpart. The wire bonds are installed with a standard wire bonding process as is known in the art.
Each printhead electrode
16
is connected to a heating element
22
(FIG.
5
). A plurality of heating elements
22
are situated side by side along a front edge
24
of the substrate
18
. An etched manifold
26
is precision aligned with the substrate
18
such that etched grooves
28
in the manifold
26
align precisely with the heating elements
22
, defining ink jet channels between the manifold
26
and the substrate
18
. Internal pathways and capillaries within the manifold allow ink from a supply aperture
30
to flow into each of the ink jet channels.
The present invention is suited for applications wherein a heat sink substrate is not needed and thermal control of the printhead is accomplished through other means known in the art. The present invention contemplates a new and improved method and apparatus that replaces the wire bonds, and condenses other bonding steps with a single step or process, overcoming the above referenced problems, and others.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with one aspect of the present invention, a method of assembling an ink jet printhead is provided. A printed wiring board is attached to an ink jet manifold. A die module is simultaneously attached to the manifold and the printed wiring board. Adhesives used to bond the die module to the printed wiring board and the manifold are simultaneously cured.
In accordance with another aspect of the present invention, a method of constructing an ink jet cartridge is provided. A fluid seal is dispensed on a first portion of a die module. An isotropic conductive adhesive is dispensed on a second portion of the die module containing a series of bumped electrical contacts. A single component is aligned with the die module, the component including a first, ink jet manifold section and a second, printed wiring board section. The die module and single component are moved into engagement, whereby a fluid seal connection is made, and an electrical connection is made in a single processing step.
In accordance with another aspect of the present invention, a thermal ink jet cartridge is provided. The cartridge includes a manifold and a printed substrate attached to the manifold. A die module single component that includes the manifold and the substrate is attached to at least a printed daughter board, the die module being at least partially attached with a flip chip bumping process.
One advantage of the present invention resides in simplified construction of an ink jet printhead.
Another advantage of the present invention resides in a more robust electrical bond.
Another advantage resides in reduced manufacturing costs.
Still further advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
REFERENCES:
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patent: 4532530 (1985-07-01), Hawkins
patent: 4579469 (1986-04-01), Falcetti
patent: 4601777 (1986-07-01), Hawkins et al.
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patent: 5297336 (1994-03-01), Burolla
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patent: 5850234 (1998-12-01), Kneezel et al.
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patent: 6229114 (2001-05-01), Andrews et al.
patent: 6388231 (2002-05-01), Andrews
patent: 6548895 (2003-04-01), Benavides et al.
Deborah S. Patterson,A Comparison of Popular Flip Chip Bumping Technologies,Flip Chip Technologies, 3701 E. University Drive, Phoenix, AZ 85034.
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