Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-11-18
2002-11-19
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S054000
Reexamination Certificate
active
06481821
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an actuator for an ink jet printer head. In particular, the invention relates an actuator for an ink jet printer head using a shape memory alloy and an insulating film.
2. Description of the Prior Art
FIGS. 1
a
through
1
f
show a conventional manufacturing method of actuator for ink jet printer head using a shape memory alloy.
Photoresist
12
is coated on silicon substrate
10
to form a pattern after which it is etched. Part removed by etching is covered with polysilicon
14
and a shape memory alloy layer
16
is formed in wished pattern upon silicon substrate
10
.
Polysilicon
14
is removed by etching after the shape memory alloy layer
16
formation; and the shape memory alloy layer
16
becomes a cantilever structure by bending deformation as in
FIG. 1
f
after polysilicon
14
removal.
FIGS. 2
a
through
2
d
show the usual manufacturing method of an actuator for ink jet printer head using a shape memory alloy.
Silicon substrate
20
is used for a substrate plate in the actuator for an ink jet printer head using a shape memory alloy.
Insulating film
22
is formed upon silicon substrate
20
upon which film then the shape memory alloy layer
24
is formed.
After shape memory alloy layer
24
has been formed, lower space part is formed by etching the silicon substrate
20
below. Whence insulating film
22
plays the etching interruption layer role.
Bending deformation takes place at insulation film
22
by stress after etching. Then bending deformation takes place also at shape memory alloy layer
24
according to the above bending deformation of insulation film
22
.
Actuator for ink jet printer head using a shape memory alloy manufactured by method described above generally consists of silicon substrate
20
where lower space is formed, insulation film
22
formed to cover lower space part upon silicon substrate
20
, and shape memory alloy layer
24
formed upon the insulation film
22
.
FIG. 3
shows actuator for ink jet printer head using a shape memory alloy, manufactured by method as shown in
FIGS. 2
a
through
2
d
; and
FIG. 4
shows the jet unit part of ink jet printer head applying the actuator.
As shown in
FIG. 4
, chamber
26
and nozzle
28
are formed upon actuator using a shape memory alloy as in FIG.
3
.
If actuator is electrified, shape memory alloy layer
24
of actuator recovers flat state which is mother shape, according to which shape transformation the volume of chamber
26
formed upon shape memory alloy layer
24
is decreased, whereby ink in chamber
26
is jetted through nozzle
28
to execute printing.
In traditional actuator for ink jet printer head using a shape memory alloy as above, initial transformation of shape memory alloy layer is controlled using compressive stress of silicon oxide film as only silicon oxide film is used for insulation film.
There it is difficult to control compressive stress deformation direction and size and also there is problem that fatigue phenomenon arises by repetitive use.
SUMMARY OF THE INVENTION
Purpose of the present invention to solve the above problem is to provide actuator for ink jet printer head using a shape memory alloy, optimized of ink ejection characteristics by shape memory effect of shape memory alloy, by controlling the internal stress by way of material and thickness of insulation film which transforms in multilayer construction with shape memory alloy.
The invention to achieve the above purpose features an actuator for ink jet printer head using a shape memory alloy, the actuator comprising: a lower space part; a silicon substrate where the lower space part is formed; an insulating film formed on the silicon substrate surface and made of silicon nitride film which acts to pull the shape memory alloy film in a direction opposite to nozzle side; and a shape memory alloy layer formed on the insulation film so as to cover the lower space part, whereby initial transformation direction and magnitude are controlled.
And the invention features an actuator for ink jet printer head using a shape memory alloy, the actuator comprising: a lower space part; a silicon substrate where the lower space part is formed; an insulating film formed on the silicon substrate surface and made of a silicon oxide film which acts to push the shape memory alloy film to nozzle side direction and a silicon nitride film which acts to pull the shape memory alloy film in a direction opposite to nozzle side; and a shape memory alloy layer formed on the insulation film so as to cover the lower space part, whereby initial transformation direction and magnitude are controlled.
REFERENCES:
patent: 6130689 (2000-10-01), Choi
patent: 6306671 (2001-10-01), Silverbrook
patent: 63057251 (1988-03-01), None
patent: 02265752 (1990-10-01), None
Choi Hae Yong
Park Sung June
Yun Sang Kyeong
Barlow John
Darby & Darby
Huffman Julian D.
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