Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-04-11
2002-11-19
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06481834
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet recording head that jets ink particles through nozzle holes by applying pressure to the ink contained in pressure chambers by pressure producing elements.
2. Description of the Related Art
Generally, an ink-jet recording head includes an ink reservoir connected to an external ink tank, a plurality of pressure chambers communicating with the ink reservoir by means of ink inlets, pressure producing elements, such as piezoelectric vibrators or heating means, and a nozzle plate provided with nozzle holes through which the ink is jetted in ink particles.
FIG. 10
is a vertical sectional view of a conventional ink-jet recording head provided with longitudinal oscillation mode piezoelectric vibrators and
FIG. 11
is a cross-sectional view taken on line A—A in FIG.
10
.
Referring to
FIG. 10
, a conventional ink-jet recording head includes a passage forming plate
60
, a nozzle plate
61
disposed on the front surface
60
a
of the passage plate
60
, a casing member
62
disposed on the back surface
60
b
of the passage plate
60
, and a sealing plate
63
held between the back surface
60
b
of the passage plate
60
and the casing member
62
.
A plurality of pressure chambers
64
are formed in the passage forming plate
60
. A plurality of nozzle holes
65
communicating with the pressure chambers
64
, respectively, are formed in the nozzle plate
61
. An ink reservoir
66
for containing ink to be supplied to the pressure chambers
64
is formed in the passage forming plate
60
. The pressure chambers communicate with the ink reservoir
66
by means of ink inlets
67
, respectively. The ink inlets
67
adjust the flow of the ink into the pressure chambers
64
. The sealing plate
63
is attached hermetically to the back surface of the passage forming plate
60
to close the open back ends of the pressure chambers
64
, the ink inlets
67
and the ink reservoir
66
.
A plurality of piezoelectric vibrators
68
are housed in the casing member
62
so as to correspond to the plurality of pressure chambers
64
, respectively. The piezoelectric vibrators
68
are held fixedly by a holding member
69
on the casing member
62
.
The sealing plate
63
has a thick part
71
including a plurality of lands
70
connected to the plurality of piezoelectric vibrators
68
, respectively, and a thin part
73
including elastically deformable parts
72
surrounding the lands
70
, respectively. As shown in
FIGS. 10 and 11
, the thin part
73
is provided with a thin compliant part
74
of a shape substantially resembling that of the ink reservoir
66
. An ink supply pipe
75
carries the ink into the ink reservoir
66
. The ink supply pipe
75
penetrates the sealing plate
63
and opens into the ink reservoir
66
. the ink supply pipe
75
is connected to a middle part of the elongate ink reservoir
66
in order that the ink supplied into the ink reservoir
66
is able to flow through the shortest possible distance to the extremities of the ink reservoir
66
and resistance against the flow of the ink is reduced to the least possible extent.
In this conventional ink-jet recording head, the sealing plate
63
must provide a part through which the ink supply pipe
75
extends and hence the thin compliant part
74
has a break in a middle part thereof, which affects adversely to the compliance of the compliant part
74
.
Since the ink reservoir
66
is formed in the passage forming plate
60
, the depth of the ink reservoir
66
cannot exceed the thickness of the passage forming plate
60
. Therefore, if the ink-jet recording head is provided with a large number of nozzles and has a big length and the ink reservoir
66
has a big length, the width of the ink reservoir
66
needs to be increased to reduce resistance against the flow of the ink flowing toward the extremities of the ink reservoir
66
. Consequently, the size of the ink-jet recording head is inevitably large.
SUMMARY OF THE INVENTION
The present invention has been made in view of the aforesaid problems and it is therefore an object of the present invention to provide an ink-jet recording head having high compliance and capable of being formed in a small size.
According to the present invention, an ink-jet recording head comprises: a passage forming plate provided with a plurality of pressure chambers; a nozzle plate disposed on one surface of the passage forming plate and provided with a plurality of nozzle holes respectively communicating with the plurality of pressure chambers; a plurality of pressure producing elements for applying pressure to ink contained in the plurality of pressure chambers; a casing member disposed on a side of the other surface of the passage forming plate and provided with an ink reservoir for containing the ink to be supplied to the plurality of pressure chambers; and a sealing plate disposed between the other surface of the passage forming plate and the casing member and connected to the plurality of pressure producing elements; wherein the sealing plate is provided with a plurality of through holes respectively communicating with both the plurality of pressure chambers and the ink reservoir.
Preferably, the plurality of through holes connected to the ink reservoir via a plurality of ink inlets, respectively, and wherein the ink inlets are capable of adjusting flow of ink between the ink reservoir and the pressure chambers.
Preferably, the sealing plate has a thick part including a plurality of lands connected to the piezoelectric vibrators, respectively, and a thin part including elastic parts capable elastic deformation and surrounding the lands.
Preferably, the plurality of ink inlets are formed in the thin part of the sealing plate.
Preferably, the sealing plate is formed by laminating a metal sheet and a polymer film, and the elastic parts are formed in the polymer film.
Preferably, the plurality of ink inlets are formed by etching the metal sheet.
Preferably, the plurality of through holes are formed by laser-machining portions of the polymer film corresponding to etched parts of the metal sheet.
Preferably, the sealing plate is formed by processing a plate member which can be elastically deformable at least by thinning.
Preferably, the plate member is a metal sheet, and the plurality of through holes are formed in the metal sheet by subjecting the metal sheet to press working.
Preferably, the plate member is a metal sheet, and the plurality of through holes are formed by etching the metal sheet.
Preferably, the plurality of ink inlets are recesses formed in a surface, which faces the sealing plate, of the casing member.
Preferably, the plurality of through holes are capable of adjusting flow of ink between the ink reservoir and the pressure chambers.
Preferably, the sealing plate has a thick part including a plurality of lands connected to the piezoelectric vibrators, respectively, and a thin part including elastic parts capable elastic deformation and surrounding the lands.
Preferably, the sealing plate is formed by laminating a metal sheet and a polymer film, and the elastic parts are formed in the polymer film.
Preferably, the plurality of through holes are formed by subjecting the sealing plate to press working.
Preferably, the plurality of through holes are formed by etching the metal sheet and laser-machining the polymer film.
Preferably, the sealing plate is formed by processing a plate member which can be elastically deformable at least by thinning.
Preferably, the plate member is a metal sheet, and the plurality of through holes are formed in the metal sheet by subjecting the metal sheet to press working.
Preferably, the plate member is a metal sheet, and the plurality of through holes are formed by etching the metal sheet.
Preferably, the ink reservoir has an outlet opening opened in a surface, which faces the sealing plate, of the casing member, a compliant part is formed in a part, corresponding to the outlet opening of the ink reservoir, of the sealing plate, and a compliance space is
Nakamura Takashi
Takahashi Tomoaki
Seiko Epson Corporation
Sughrue & Mion, PLLC
Vo Anh T. N.
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