Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-03-21
2004-06-15
Stephens, Juanita (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S065000
Reexamination Certificate
active
06749289
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of liquid ejection apparatus utilized in inkjet recording heads, etc. and, more particularly, relates to a liquid ejection apparatus that is high in production efficiency and yield and, in addition, can realize ejection of liquid droplets with a high accuracy, a method of manufacturing this liquid ejection apparatus, an inkjet printer utilizing this liquid ejection apparatus, and a method of manufacturing this inkjet printer.
Thermal inkjet formed in such a manner that a portion of ink is rapidly vaporized by heating by the use of a heater, so that, by the expansion force thereof, etc., ink droplets are ejected from nozzles, is utilized in various printers (See JP 48-9622 A, JP 54-51837 A, etc.).
Further, there is also known a printer that utilizes an electrostatic type inkjet formed in such a manner that a diaphragm (vibration plate) is vibrated by static electricity, so that, by the energy thereof, ink droplets are ejected from nozzles (See JP 11-309850 A, etc.).
FIGS. 9A and 9B
are schematic diagrams showing an example of a recording head of so-called top shooter type using thermal inkjet, which is one of such inkjets. Of
FIGS. 9A and 9B
,
FIG. 9A
is a view (hereinafter referred to as a plan view) of the recording head as seen from the ink ejection direction, while
FIG. 9B
is a sectional view taken along the line IV—IV in FIG.
9
A.
As shown in
FIG. 9A
, in a recording head
150
, a large number of nozzles
20
for ejecting the ink are formed in a state arranged in one direction (the direction perpendicular to the drawing plane of FIG.
9
B). Further, in the example shown, two rows of such nozzles
20
(hereinafter referred to as nozzle rows) are provided, whereby the recording density is enhanced.
In this recording head
150
, heaters (not shown) as ink ejection devices corresponding to the individual nozzles
20
and driving integrated circuits
14
for driving the respective heaters are formed on an Si (silicon) substrate
12
, and further, on them, a partition wall
15
that defines individual ink flow paths to the respective nozzles
20
(heaters) and the like are laminated. Further, the nozzles
20
are formed through an orifice plate
22
laminated/stuck on the partition wall
15
.
Further, in the Si substrate
12
of the recording head
150
, there are formed an ink groove
152
for feeding the ink to the individual ink flow paths for a plurality of nozzles
20
and ink feed holes
154
for feeding the ink to this ink groove
152
. The ink groove
152
is formed by digging down in the surface of the Si substrate
12
so as to extend in the direction of the nozzle rows, while the ink feed holes
154
are bored so as to be arranged at predetermined intervals in the nozzle row direction in a state connecting the back surface of the Si substrate
12
and the ink groove
152
to each other.
The recording head
150
as such is normally not handled in the state of the Si chip comprised mainly of the Si substrate
12
, but it is mounted in a frame
24
and fitted into a head unit (e.g., a so-called cartridge) or the like of an inkjet printer.
In the frame
24
, there is formed an ink flow path
26
for feeding the ink fed from an ink tank connected to the head unit to the ink feed holes
154
in the recording head
150
.
In the recording head
150
, the ink fed from the ink flow path
26
in the frame
24
flows into the ink feed holes
154
from the back surface side of the Si substrate
12
, and then, the ink is introduced into the ink groove
152
communicating with the ink feed holes
154
, flows from the ink groove
152
into the individual ink flow paths defined by the partition wall
15
so as to lead to the respective nozzles
20
, and is ejected from the nozzles
20
by the heating of the heaters.
The recording head
150
in which ink ejection devices such as heaters (the devices include diaphragms for an inkjet printer of electrostatic type as referred to above apart from heaters for a thermal inkjet printer whose recording head is illustrated in the figures) are formed on the Si substrate
12
can be fabricated by employing the semiconductor manufacturing technology which utilizes film deposition techniques and photolithography.
In the recording head
150
of top shooter type as illustrated in the figures, the provision of ink feed flow paths extending through the Si substrate
12
is indispensable; ordinarily, the ink groove
152
for feeding the ink to the individual ink flow paths for the respective nozzles and the ink feed holes
154
for feeding the ink to the ink groove
152
from the back surface of the Si substrate
12
are formed as illustrated in the figures.
As the methods for the formation of the ink groove
152
and the ink feed holes
154
as such, there are known the etching process, the laser machining process, the sandblasting process, etc, any of which can be used for the processing of the Si substrate
12
.
However, in case of the etching of an Si substrate, both the wet etching and the dry etching are excellent in processing accuracy but have the drawback that their processing efficiency is inferior.
The laser machining has problems that both its processing efficiency and processing accuracy are low and it requires much time since the splashes (work tailings) produced after machining need to be removed.
The sandblast is superior in processing efficiency indeed but it is disadvantageous because its processing accuracy is low and there is even a high possibility that damages such as the breakdown of the Si substrate
12
at the edges of the ink groove
152
be caused, for example, as shown in
FIG. 9B
since it is a grinding process utilizing impact. There is another disadvantage that, in case such damages exist, the flow of the ink does not become uniform, so that it becomes impossible to stably feed a correct amount of ink to each nozzle
20
, and in addition, through the damaged portions, the ink penetrates to break the driving integrated circuits
14
, etc. formed on the Si substrate
12
in some cases.
Further, the formation of the ink groove
152
, etc. is normally made after the fabrication of the driving integrated circuits
14
, etc., but, in case of using the sandblast process, static electricity is produced during processing, so that the insulating layers of the driving integrated circuits
14
are charged with the electricity, whereby the driving integrated circuits
14
, etc. are subjected to electrostatic breakdown in some cases.
Thus, the sandblast is good in processing efficiency but has problems of its low processing accuracy and low production yield.
SUMMARY OF THE INVENTION
It is the object of the present invention to give solutions to the foregoing problems of the known art and, more particularly, to provide a liquid ejection apparatus used in an inkjet recording head or the like that is constituted in such a manner that liquid ejection units such as vibration plates vibrated by static electricity, heaters or the like are formed on a substrate composed of Si or the like, said liquid ejection apparatus having a good productivity and a good production yield, and the necessary portions thereof having a high accuracy, to provide a method of manufacturing this liquid ejection apparatus, to provide an inkjet printer using this liquid ejection apparatus as an inkjet recording head, and to provide a method of manufacturing this inkjet printer.
In order to attain the object described above, the first aspect of the present invention provides a liquid ejection apparatus comprising: a substrate having one side and another side; a plurality of nozzles formed in a member provided on the one side of the substrate; a plurality of droplet ejection units, each corresponding to one of the plurality of nozzles, the plurality of droplet ejection units being formed on a surface of the one side of the substrate; a plurality of individual flow paths, each feeding liquid to one of the plurality of nozzles, the plurality of individual flow paths being formed on th
Matsumoto Nobuo
Mitani Masao
Fuji Photo Film Co. , Ltd.
Stephens Juanita
Whitham Curtis & Christofferson, P.C.
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