Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-04-20
2003-09-23
Vo, Anh T.N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C029S025350
Reexamination Certificate
active
06623110
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to an ink jet recording head, production methods therefor, and a printer apparatus, and particularly relates to the ink jet recording head which jets ink using jet energy generation part to vibrate a vibrator provided as a wall of a pressure chamber, production methods therefor, and a printer apparatus therewith.
Recently, a printer apparatus has been widely used as an output device for a personal computer. The printer apparatus is generally based on a wire driving method or an ink jet method.
An ink jet recording head used in an ink jet type printer apparatus generates less noise than a head that prints by magnetically driving wires to pressurize a platen through an ink ribbon and a sheet of paper, drawing attention as appropriate for office use.
DESCRIPTION OF THE BACKGROUND ART
A conventional ink jet recording head comprises nozzles, ink chambers, ink supply systems, ink tanks and transducers, recording letters and images onto such a recording media as paper by jetting ink particles from the nozzles by transferring displacements or pressures originated at the transducers to the ink chambers.
A widely known method is to use a thin plate of a piezoelectric device that has one surface thereof completely bonded to an external wall of the ink chamber as the transducer. A voltage pulse is applied to the piezoelectric device to bend the compound plate of the piezoelectric device and the external wall of the ink chamber. The displacement/pressure caused by the bend is transferred into the ink chamber through the external wall of the ink chamber.
FIG. 1
is a side view of a printer apparatus (an ink jet recording apparatus) provided with an ink jet recording head
2
. In the drawing, a recording media
1
is subjected to printing or the like by the printer apparatus. An ink jet recording head
2
jets ink to the recording media
1
. An ink tank
3
provides the ink to the ink jet recording head
2
. On a carriage
4
, the ink jet recording head
2
and the ink tank
3
are mounted.
A transporting roller
5
and a pinch roller
6
transport the recording media
1
to the ink jet recording head
2
by holding it in between. An ejecting roller
7
and a pinch roller
8
transport the recording media
1
to an ejecting direction by holding it in between. A stacker
9
stores the ejected recording media
1
. A platen
10
holds the recording media
1
.
The ink jet recording head
2
is so structured as to jet the ink by a pressure generated by expansion and contraction of a piezoelectric device that is driven by a voltage, thereby printing letters or the like on the recording media
1
.
FIG. 2
is an oblique angle view of the ink jet recording head
2
. As the drawing shows, the ink jet recording head
2
comprises a plurality of piezoelectric devices
11
, individual electrodes
12
formed on the piezoelectric devices
11
, a nozzle plate
13
that is provided with nozzles
17
, a vibrating plate
15
, ink chambers (pressure chambers)
14
that are formed corresponding to each of the nozzles
17
, and a main body
16
made of a metal or resin.
The nozzle
13
and the vibration plate
15
are designed to face with the ink chamber
14
. A portion around the ink chamber
14
of the main body
16
is firmly fixed to the vibrating plate
15
. The vibrating plate
15
is so structured as to bend when a voltage is applied to drive the piezoelectric device
11
, as shown by the dotted lines in the drawing. Further, the structure allows a voltage to be applied to each of the piezoelectric devices
11
based on electrical signals coming from a printer apparatus main body (not shown in the drawing).
In the conventional ink jet recording head
2
, the piezoelectric devices
11
are formed by either pasting plate-like piezoelectric devices
11
on the vibrating plate
15
at a position corresponding to an ink chamber or forming a piezoelectric material on the whole upper surface of the vibrating plate
15
and removing the material except for locations corresponding to the ink chambers to be formed.
In the example shown in
FIG. 2
, the piezoelectric devices
11
are used as a means to displace the vibrating plate
15
. An ink jet recording head that employs thermal elements in place of the piezoelectric devices
11
has been available. The ink jet recording head that employs the thermal elements is structured such that it is provided with thermal elements at the position of the vibrating plate
15
described above, which are made of layers of materials of different thermal expansion coefficients. The thermal expansion generated by heating the elements causes a displacement of the vibration plate
15
, and thereby ink is jetted out. In the following, an item that generates energy to displace the vibrating plate
15
, which includes the piezoelectric elements
11
and thermal elements described above will be called an ink jet energy generating part.
In recent years, there has been a demand for reducing the power consumption of personal computers. Accordingly, reduced power consumption (semiconductor driving voltage of around 20V) is required of printing devices serving as peripheral equipment. Furthermore, higher resolution is required of the printing devices, so that flight particles of the ink jet recording head are made finer and finer.
Specifically, following requirements need to be satisfied to achieve what is required above. That is, in the case of using a piezoelectric element for the ink jet energy generating part:
a) thin-filming of the piezoelectric element (same internal applied electric field);
b) thin-filming of the vibration plate (transferring a minute displacement of the piezoelectric element);
c) stable adherence of the piezoelectric element to the vibrating plate (reducing loss of piezoelectric element displacement);
d) higher flatness of the vibrating plate (ease of bending the vibrating plate); and
e) a minute process of the piezoelectric device and the vibrating plate are required.
In the case of using the thermal element in the ink jet energy generating part,
f) finer wiring of wires connected to the thermal element;
g) shorter heat dissipation time; and
h) thinner protection films of the thermal devices are required.
In the conventional ink jet recording head
2
described with reference to
FIG. 2
, following problems are present. Namely, in the structure where the piezoelectric device is bonded to the vibrating plate,
1) a thin piezoelectric element is susceptible to damages when the piezoelectric device is bonded to the vibrating plate;
2) in the structure where the piezoelectric device is bonded to the vibrating plate, thickness of an adhesive material layer is non-uniform, causing difficulties to obtain a flat vibrating plate, and thereby cases happen wherein it does not displace properly when driven;
3) an adhesive material absorbs displacement of the piezoelectric element when a voltage is applied to the piezoelectric element; and
4) miniaturization is difficult with the structure where the piezoelectric element is bonded to the vibrating plate.
Further, in a structure in which a piezoelectric material provided all over the vibrating plate is divided by a machine process, the problems 1) through 4) described above are encountered in the same manner. Furthermore, the machine process presents problems that it takes a longer processing time and provides a less production efficiency.
When the thermal element is used in the ink jet energy generating part, the board that carries the thermal element thereon may not have proper heat releasing characteristics.
DISCLOSURE OF THE INVENTION
The present invention is made in view of the points described above with an object to provide an ink jet recording head and production methods therefor and a printer apparatus which hold a high reliability while enabling to reduce consumption power.
To achieve the object, the present invention takes a structure wherein at least an ink energy generating part employs the thin film forming technology in an ink jet recording head that co
Koike Shuji
Sakamoto Yoshiaki
Shingai Tomohisa
Fujitsu Limited
Vo Anh T.N.
LandOfFree
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