Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-01-29
2002-12-17
Braun, Fred L. (Department: 2852)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C029S025350, C029S890100
Reexamination Certificate
active
06494566
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a member having ultrafine grooves that can be used in a ip displacement control element, motor, relay, switch, shutter, printer head, pump, fan, ink jet printer, and an ink jet printer head using the same.
Recently, in the field of optics and precision processing, a displacement control element capable of adjusting the optical path length or position in the sub-micron order is demanded, and to meet such demand, various actuators are devised including, for example, those utilizing piezoelectric material and others utilizing static electricity.
More lately, in particular, for use in an ink jet printer head, a small-sized actuator is proposed, in which a ceramic green sheet is formed. Air vents forming ink chambers are formed by a die, and by laminating and baking a part thereof as a diaphragm. A piezoelectric drive section is formed on the surface of the actuator (see Japanese Laid-open Patent No. 4-12678).
The structure of an ink jet printer head is as shown in
FIG. 7
, in which a nozzle plate
23
forming a nozzle
6
, a partition wall
22
forming ink chambers
1
or ink passages, and a diaphragm
21
are fabricated of ceramic green sheet. Thereby a head substrate
2
having ink chambers
1
and nozzles
6
and ink passages (not shown) is obtained. An electrode
4
a,
a piezoelectric element
3
, and an electrode
4
b
are formed on the diaphragm
21
of the head substrate
2
.
By applying a voltage between the electrodes
4
a
and
4
b,
the piezoelectric element
3
is deformed, and this displacement is transmitted to the ink chambers
1
through the diaphragm
21
, so that the ink in the ink chambers
1
can be ejected from the nozzles
6
. The ink jet printer head is required to have higher density and higher precision as the product is reduced in size. For example, the width of the partition wall
22
forming the head substrate
2
is demanded to be fabricated in the order of scores of microns.
In the manufacturing process of the ink jet printer head shown in
FIG. 7
, partition wall
22
is fabricated to form a head substrate
2
by blanking a ceramic green sheet by a die, where the ink chambers
1
and ink passages
6
are formed. Using this process, it is extremely difficult to manufacture the printer head in a such small size yet with high density and high precision. For example, when blanking the green sheet by the die, the sheet may be torn, or the respective position of the different elements with respect to one another may deviate when the diaphragm
21
or the nozzle plate
23
is laminated, thereby making it difficult to manufacture at high density and high precision. Further, it is also difficult and costly to manufacture the die used in such blanking in a small size and at high precision.
The invention, in one or more embodiments, relates to a member for passage having tiny passages of liquid for use in an ink jet head or small-sized pump, and its manufacturing method, and more particularly to an ink jet printer head using the same.
Today, along with the advancement of the multimedia, the demand for personal computers is increasing steadily; and the printer, which is one of the recording media of a personal computer, is required to have higher density and high definition in its performance. In particular, the ink jet system, introduced to replace the existing dot system, has been improved to print more quietly at higher definition and higher density and is now in high demand.
The ink jet system is proposed in various methods, such as the method of discharging ink drops from a nozzle by making use of a piezoelectric material, and the method of generating bubbles in ink by heat and discharging ink drops. In these methods, commonly, the ink is fed into a printer head, the ink is supplied through a passage, and the ink is discharged from an ink discharge port.
Such an ink jet printer head by thermal method is shown in
FIG. 8
, in which a flat plate
111
has plural partition walls
112
, and a substrate
120
is bonded to a member
110
for forming a passage
113
between partition walls
112
, thereby covering each passage
113
. One end of each passage
113
is a discharge port
114
, and the other end communicates with an ink chamber
116
having an ink feed hole
115
. Moreover, at a position corresponding to each passage
113
of the substrate
120
, a heating element
121
and an electrode
122
for energizing it are disposed.
Moreover, as shown in
FIG. 9
, when the passage
113
is filled with the ink
130
and the heating element
121
is energized to generate heat, bubbles
132
are generated in the ink
130
; and by the force of the expansion of volume of these bubbles
132
, ink drops
131
are discharged from the discharge port
113
.
Incidentally, higher definition and higher density are demanded in ink jet printers recently. As such, in passage members
110
for composing the ink jet printer head
101
, the width of the partition wall
112
and passage
113
are demanded to be as narrow as scores of microns.
To manufacture the passage member
110
having such ultrafine passages
113
, various methods have been proposed, including a method of forming a masking in the portion of the partition wall
112
on the flat plate
111
, processing grooves as passages
113
by sand blasting, a method of forming partition walls
112
by repeating screen printing on the flat plate
111
, a method of applying a photosensitive resin in the portion of the partition walls
112
on the flat plate
111
, and forming grooves as passages
113
by photolithography.
However, in the sand-blasting method, since the passages
113
are formed while digging grooves by blowing powder, it is necessary to keep constant the powder blowing force and angle, and it is difficult to process the inner surface of the passages
113
in a specified shape at high precision. In the screen-printing method, it is necessary to print many times, and as a result the partition walls
112
are deformed. In the photolithography method, a slight difference caused by the degree of right angle and depth of the partition walls, due to light illumination angle, time or other condition, can make it difficult to form the passages
113
at high precision. Additionally, in the passage members
110
manufactured using the above-mentioned methods, the inner surface of the passages
113
is not smooth. As a result, the ink flow was disturbed in the passages
113
, and fluctuations were likely to occur in the ink discharge volume, discharge pressure, and response. Thus, a method is needed to allow for the formation of the passages
113
at high precision with smooth inner surfaces.
In one or more embodiments, the invention relates to an ink jet printer head used in an ink jet printer. The ink jet printer is a printer for printing by ejecting ink from the head, and it is widely used recently, owing to low noise and high printing speed. The structure of the ink jet printer head is as shown in
FIG. 12
, in which a head substrate
202
comprises a plurality of ink chambers
201
and ejection ports
206
, and piezoelectric elements, where the piezoelectric elements
203
are bonded to positions corresponding to the ink chambers
201
. The head substrate
202
includes a plate
223
forming ejection ports
206
, a plate
222
forming ink chambers
201
, a diaphragm
221
, and a piezoelectric element
203
bonded on the diaphragm
221
through a lower electrode
205
, whereby a driving electrode
204
is formed thereon.
By deforming the piezoelectric element
203
by applying a voltage between the lower electrode
205
and driving electrode
204
, the diaphragm
221
is deflected, and the pressure in the ink chambers
201
is elevated so that the ink may be ejected from the ejection ports
206
.
The conventional head substrate
202
and others were made of metal materials, but recently it has been proposed to use ceramics (see Japanese Laid-open Patent No. 6-40030 and Japanese Laid-open Patent No. 6-218929). For example, the head substrate
202
can be fo
Ito Keisuke
Kishino Toshikazu
Ohkubo Makoto
Soroi Kazunori
Braun Fred L.
Hogan & Hartson LLP
Kyocera Corporation
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