Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1996-03-22
2002-10-29
Vu, Bao Q. (Department: 2838)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S068000, C347S071000
Reexamination Certificate
active
06471341
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet head used for an ink jet printer or the like, and more specifically, it relates to an ink jet head allowing highly dense arrangement of nozzles.
2. Description of the Related Art
An ink jet head of interest to the present invention is disclosed, for example, in Japanese Patent Laying-Open No. 6-64163.
FIG. 10
is a perspective view of the ink jet head disclosed in this laid-open patent application. Referring to
FIG. 10
, there are a plurality of nozzle openings
101
a
,
101
b
, . . . formed in a nozzle forming member
102
. A pressure chamber forming member
103
is provided adjacent to nozzle forming member
102
. An oscillating plate
104
is adhered to pressure chamber forming member
103
. Electrodes are formed on both sides of oscillator
107
. One electrode is connected to oscillating plate
104
and the other electrode is connected to a driving circuit by means of an anisotropic conductive film
108
or the like. Oscillating plate
104
also serves as a GND electrode. At a portion surrounded by nozzle forming member
102
, pressure chamber forming member
103
and oscillating plate
104
, there are formed a pressure chamber
110
and an ink outlet
111
, filled with ink. When a voltage is applied between electrodes, a unimorph constituted by oscillating plate
104
and oscillator
107
is bent, pressing pressure chamber
110
, so that ink drops are emitted from nozzle openings
101
a
,
101
b
, . . . In the figure, the reference character
112
represent a common ink pool, and
117
represents a flexible print circuit (FPC).
The conventional ink jet head was structured as described above. However, as the oscillating plate is formed of a metal, it has a problem that reactive force is considerably large. A piezoelectric element is used for the oscillator. When a voltage is applied to the piezoelectric element by a signal from the driving circuit, the oscillating plate is displaced because of unimorph effect with the oscillating plate. That the oscillating plate has high rigidity means there is large reactive force preventing displacement of the oscillating plate. Therefore, displacement of the oscillating plate is suppressed, change in volume of the pressure chamber becomes smaller and the efficiency in emitting ink is degraded. Accordingly, it is necessary to enlarge the area of the oscillator or to apply a high voltage to the oscillator to obtain energy necessary for the emission. However, if the area of the oscillator is enlarged, degree of integration of nozzles becomes lower, the head becomes larger and hence the apparatus as a whole cannot be made compact. Further, if a high voltage is applied to the oscillator to ensure an amount of deformation of the oscillator, power consumed by the head is undesirably increased.
FIG. 11
a
is a cross sectional view taken along the XI direction of the ink jet head shown in
FIG. 10
, and
FIG. 11
b
is a side view of
FIG. 11
a
. Referring to
FIGS. 11
a
and
11
b
, in the conventional head, the dimensions of an elastic plate
105
and oscillator
107
oscillating the sidewall of the pressure chamber are smaller than the dimension of the corresponding wall surface of the pressure chamber.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an ink jet head which allows higher degree of integration of nozzles.
Another object of the present invention is to provide an ink jet head which can be made compact.
A still another object of the present invention is to provide an ink jet head allowing reduced power consumption.
The above described objects of the present invention can be attained by the ink jet head in accordance with the present invention in which oscillation is caused in a pressure chamber communicated with nozzles so as to partially bent a wall surface of the pressure chamber and to emit ink thereby, including an oscillating plate formed of resin provided at least on a part of the wall surface of the pressure chamber, and a unimorph including an elastic plate and an oscillator provided on the oscillating plate. The dimension of the bending portion provided by the unimorph is larger than the dimension of the wall surface of the pressure chamber corresponding to the unimorph.
The dimension of the bending portion provided by the unimorph is made larger than the dimension of the wall surface of the pressure chamber corresponding to the unimorph, whereby the dimension of the oscillator constituting the unimorph is made close to the channel pitch corresponding to the dimension between wall surfaces of the pressure chamber. Accordingly, highly dense arrangement of nozzles becomes possible.
More preferably, the ink jet head further includes a conductive film provided on the oscillator. The oscillator is adhered to the elastic plate by means of a first adhesive layer, and adhered to the conductive film by means of a second adhesive layer. The first adhesive layer is thicker than the second adhesive layer.
The thickness of the adhesive layer in contact with the oscillator is made thinner than on the side opposite to the oscillating plate, that is, on the side of the conductive film. Therefore, the problem that the adhesive layer on the side opposite to the oscillating plate binds the oscillator and prevents deformation of the oscillating plate, can be prevented.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4199769 (1980-04-01), Fischbeck
patent: 4455560 (1984-06-01), Louzil
patent: 4520374 (1985-05-01), Koto
patent: 4550325 (1985-10-01), Viola
patent: 5359350 (1994-10-01), Nakano et al.
patent: 5360943 (1994-11-01), Mori et al.
patent: 5575577 (1996-11-01), Kawakami et al.
patent: 5660486 (1997-08-01), Okuda et al.
Patent Abstracts of Japan, vol. 18, No. 065, Feb. 3, 1994.
Patent Abstracts of Japan, vol. 17, No. 201, Apr. 20, 1993.
Patent Abstracts of Japan, vol. 16, No. 471, Sep. 30, 1992.
Patent Abstracts of Japan, vol. 18, No. 115, Feb. 24, 1994.
Patent Abstracts of Japan, vol. 17, No. 679, Dec. 14, 1993.
Patent Abstracts of Japan, vol. 18, No. 304, Jun. 10, 1994.
Patent Abstracts of Japan, vol. 17, No. 576, Oct. 20, 1993.
Patent Abstracts of Japan, vol. 17, No. 595, Oct. 29, 1993.
Patent Abstracts of Japan, vol. 18, No. 398, Jul. 26, 1994.
Patent Abstracts of Japan, vol. 94, No. 011.
Patent Abstracts of Japan, vol. 16, No. 195, May 12, 1992.
Patent Abstracts of Japan, vol. 18, No. 025, Jan. 14, 1994.
Koyama Kazuya
Tsurui Kohji
Yoshimura Hisashi
Sharp Kabushiki Kaisha
Vu Bao Q.
LandOfFree
Ink jet head allowing highly dense arrangement of nozzles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet head allowing highly dense arrangement of nozzles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet head allowing highly dense arrangement of nozzles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2920597