Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-08-25
2002-09-03
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06443562
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from the inventor's application METHOD FOR MANUFACTURING A DRIVING PART OF AN INK JETTING APPARATUS filed with the Korean Industrial Property Office on Nov. 4, 1999 and there duly assigned Ser. No. 48546/1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet apparatus, such as an inkjet printer or a facsimile machine. More particularly, the invention concerns an integrally formed driving module of an electrostatic attraction type inkjet apparatus, and a method for manufacturing the module.
2. Description of the Related Art
Generally, an ink jet apparatus is employed in a print head of an output device, such as an inkjet printer or and a facsimile machine. The apparatus forces a jet of ink from an ink chamber through a nozzle. Such fluid jet apparatus types include a thermal type, an electrostatic-attraction type, a piezoelectric type, and a thermo-compression type, the type depending on the method for applying physical force to the fluid.
An example of an electrostatic attraction type fluid jet apparatus is shown in FIG.
1
. The fluid jet apparatus includes a driving module
20
and a nozzle module
40
.
Driving module
20
includes a substrate
15
, an oxide layer
14
laminated on substrate
15
, a working fluid barrier
25
having a working fluid chamber
27
, a lower electrode
17
disposed in working fluid chamber
27
, a membrane
30
disposed on the upper portion of working fluid chamber
27
, and an upper electrode
37
disposed on the upper portion of membrane
30
. Working fluid chamber
27
is either kept in a vacuum state, or is filled with a working fluid having a high permittivity, to accelerate the generation of the electrostatic force which will be described below.
Nozzle module
40
includes an ink chamber barrier
45
having an ink chamber
57
, and a nozzle plate
47
connected to the upper portion of ink chamber barrier
45
. On the upper side of nozzle plate
47
, a nozzle
49
is formed to permit the ink in ink chamber
57
to be forced therethrough. The ink is constantly supplied to ink chamber
57
from an ink supply (not shown in the drawings).
As the voltage is applied to upper and lower electrodes
37
and
17
, a potential difference is generated between upper and lower electrodes
37
and
17
. Membrane
30
is deformed toward the working fluid chamber
27
. The force deforming the membrane
30
is obtained by the following formula:
F=eAV
2
/2
D
2
where e is the permittivity of the working fluid reserved in working fluid chamber
27
, A is the area of upper electrode
37
, V is the potential difference between upper and lower electrodes
37
and
17
, and D is the distance between upper and lower electrodes
37
and
17
.
Membrane
30
lowers pressure in ink chamber
57
, causing the ink to be sucked into ink chamber
57
from the ink supply (not shown). When the application of the voltage ceases, membrane
30
recovers its initial state. Accordingly, pressure in ink chamber
57
then increases, so that the ink in ink chamber
57
is forced out through nozzle
49
.
The driving module
20
of the above-described electrostatic attraction type ink jet apparatus is made by the following processes:
FIGS. 2
to
9
show the manufacturing processes for driving module
20
of a conventional electrostatic attraction type ink jet apparatus. The method for manufacturing driving module
20
includes the steps of making membrane
30
and various other modules, separately, and then connecting separately made membrane
30
and the other modules.
Membrane
30
is made by the following processes: As shown in
FIG. 2
, membrane
30
of a polyamide material is applied on substrate
60
by a spin coater. An oxide layer
61
is then vapor-deposited on substrate
60
. Then, as shown in
FIG. 3
, an O-ring
63
made of quartz glass is attached to membrane
30
. Then, as shown in
FIG. 4
, substrate
30
and oxide layer
61
are separated from membrane
30
.
Working fluid barrier
25
is made by the following processes: As shown in
FIG. 5
, a lower electrode
17
is formed on a substrate
15
by a photo etching process. Then, an oxide layer
14
is vapor-deposited on substrate
15
. Then, as shown in
FIG. 6
, working fluid barrier
25
is made as the polyamide is applied on oxide layer
14
by the spin coater, and then the central portion thereof is etched by a photo etching process.
When working fluid barrier
25
is completed, as shown in
FIG. 7
, membrane
30
shown in
FIG. 4
is attached to the upper portion of working fluid barrier
25
. Membrane
30
is then turned over so that O-ring
63
is located at a lower position. Then, as shown in
FIG. 8
, O-ring
63
is removed, and an upper electrode
37
is vapor-deposited on membrane
30
as shown in FIG.
9
. As a result, driving module
30
is completed. After that, nozzle module
40
, which is obtained through a separate manufacturing process, is attached to driving module
30
. That completes a conventional electrostatic attraction type ink jet apparatus.
The above-described conventional ink jet apparatus, however, has the following shortcoming. The membrane
30
is separately made from the other modules, and it takes several processes to complete membrane
30
, such as attaching O-ring
63
, and separating the substrate
60
. Accordingly, additional processes are needed for attaching membrane
30
to working fluid barrier
25
. Also, an additional wafer is needed to manufacture membrane
30
.
In order to overcome the shortcoming of the conventional ink jet apparatus, another electrostatic attraction type inkjet apparatus has been suggested in which ink chamber barrier
45
of nozzle module
40
is integrally formed with membrane
30
during the manufacturing of nozzle module
40
. Such an ink jet apparatus saves manufacturing processes since ink chamber barrier
45
and membrane
30
are integrally formed (i.e., as a unitary product) by one process. Such an inkjet apparatus employs a method of doping the area corresponding to the membrane to provide conductivity, however, because it is hard to make upper electrode
37
to generate an electrostatic attraction with lower electrode
17
.
This suggested ink jet apparatus, however, has a further shortcoming in that it is difficult to maintain a fine gap between lower electrode
17
and membrane
30
. According to the above-mentioned formula (F=eAV
2
/2D
2
), the electrostatic attraction is increased as the gap between lower and upper electrodes
17
and
37
is narrowed. In the above ink jet apparatus, however, the gap between lower and upper electrodes
17
and
37
is relatively large, so a higher potential difference is needed to generate an appropriate electrostatic attraction for deformation of membrane
30
. Moreover, it is difficult to make thin membrane
30
. Accordingly, higher force is required to deform the membrane
30
, and thus the product requires a higher degree of electrostatic attraction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved method for manufacturing a driving module for an electrostatic attraction type ink jet apparatus. The method of this invention makes membrane integral with a driving module. The membrane is not made separately. The resulting membrane is capable of generating electrostatic attraction efficiently, and performing a smooth jet operation.
The improved method for manufacturing a driving module of an ink jet apparatus includes the steps of: forming a working fluid chamber by etching a wafer; vapor-depositing a lower electrode in the working fluid chamber; attaching a polyamide sheet to the wafer; forming a membrane by etching the polyamide sheet; and vapor-depositing an upper electrode on the membrane. The working fluid chamber is formed by a wet etching process, and the membrane is formed by a dry etching process.
REFERENCES:
patent: 5870121 (1999-02-01), Chan
Bushnell , Esq. Robert E.
Gordon Raquel Yvette
Samsung Electronics Co,. Ltd.
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