Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-06-07
2004-01-27
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06682180
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an ink jet head having a plurality of nozzles which discharge ink supplied from an ink supply unit, that is, an ink jet head suitable for use in a print head of an ink jet printer, for example, and a printer apparatus having the ink jet head.
BACKGROUND ART
The ink jet printer is a printer apparatus in a system that discharges drops of ink from an ink jet head having a plurality of nozzles to make to directly adhere the ink drops to a recording medium such as a printing paper or the like. For instance, the ink jet printer prints on a printing paper by conveying the printing paper in a direction perpendicular to a direction of moving the ink jet head while reciprocally moving the ink jet head in a direction of the width of the printing paper.
FIGS. 34 and 35
are diagrams illustrating the structure of a known ink jet head.
FIG. 34
is an exploded perspective view for illustrating the structures of essential parts of a known ink jet head disclosed in Japanese Patent Laid-Open Publication No. H6-99580.
FIG. 35
is a diagram for illustrating a wiring method in the ink jet head.
The known ink jet head is disclosed in, for example, Japanese Patent Laid-Open Publication No. H6-99580, which comprises a nozzle plate
310
in which a plurality (
64
in the drawing) of nozzles
312
are cut and formed, and a substrate
311
having a plurality (
64
in the drawing) of ink chambers
313
formed correspondingly to the respective nozzles
312
, as shown in
FIGS. 34 and 35
.
In the substrate
311
formed are an ink supply port
318
which communicates with an ink tank not shown, and ink supply channels
314
which link and connect the ink supply port
318
to ink chambers
313
.
The nozzle plate
310
is adhered to a surface on a side (the upper side in
FIG. 34
) where the ink chambers
313
on the substrate
311
are formed. By adhering the nozzle plate
310
to the substrate
311
, ink can be filled inside each of the ink chambers
313
and the ink supply channels
314
. The ink supplied from the ink tank can be thereby supplied to each of the ink chambers
313
through the ink supply channel
314
.
In the substrate
311
, a surface of each of the ink chambers
313
opposite to the nozzle plate
310
is formed by a vibrating plate not shown, so that each of the ink chambers
313
is formed as a space sandwiched between the vibrating plate and the nozzle plate
310
. A peizoelectric element
315
is disposed on the opposite side (the lower side in
FIG. 34
) of each of the vibrating plates to the ink chamber
313
. The vibrating plate and the piezoelectric elements
315
form a bimorph layered body.
An individual electrode (not shown) is formed on a surface (the lower side in
FIG. 34
) of each of the piezoelectric elements
315
opposite to the vibrating plate. The individual electrodes are electrically connected to FPCs (Flexible Printed Circuit Boards)
316
A through
316
D by wire bonding using wires
317
. Incidentally, the above vibrating plate is made of a member having conductivity, as well.
Each of the FPCs
316
A through
316
D is connected to a printing signal generator through a connector or the like not shown. A printing signal is transmitted from the printing signal generator to each of the individual electrodes and the vibrating plates, so that each of the piezoelectric elements
315
applies pressure to the ink chamber
313
, and ink is discharged from each of the nozzles
312
.
Since the individual electrode of each of the piezoelectric elements
315
is connected to the FPC
316
A,
316
B, . . . ,
316
D or by wire bonding using the wire
317
in the known ink jet head, it is necessary to secure a space to wire the wire
317
by wire-bonding on the upper side of each of the individual electrodes, that is, on the opposite side to a surface of the substrate
311
to which the nozzle plate
310
are adhered. This leads to problems that the packaging density of the nozzles
312
cannot be increased, and the size of the ink jet head cannot be decreased.
Since the wires
317
are connected by air wiring (wire bonding), short circuit might occur between the wires
317
, and the piezoelectric element
315
or the like might be damaged when each of the piezoelectric elements
315
and the FPC
316
A,
316
B, . . . , or
316
D are connected by wire bonding.
In the ink jet head in a multiple nozzle structure having plural rows of nozzles, it is necessary to form a row of electric contacts for each row of the nozzles (individual electrodes), and to connect the wires
317
for each row of the electric contacts. This leads to a low fabrication efficiency of the ink jet head.
Further, the wire bonding has a limitation of reduction the contact pitch. For example, when the contact pitch is not larger than about 60 &mgr;m (not less than 450 dpi as a nozzle pitch), the fabrication stability might decrease in case of mass production.
A method of directly soldering the FPCs
316
A through
316
D to the individual electrodes is also generally known, which has the similar problems that the above method employing wire bonding has.
In the light of the above problems, objects of the present invention are to facilitate connecting to external connection wiring members, to improve the fabrication efficiency and the reliability, and to decrease the size of the ink jet head and the printer apparatus.
DISCLOSURE OF THE INVENTION
The present invention therefore provides an ink jet head having a plurality of nozzles discharging ink supplied from an ink supply unit comprising a head main body including a plurality of pressure chambers provided for the nozzles, respectively, in which ink is filled, and a plurality of pressure units provided for the pressure chambers, respectively, each of the pressure units applying pressure to the pressure chamber to discharge the ink in the pressure chamber from the nozzle, an individual electrode provided for each of the pressure units to drive the pressure unit, at least one contact connected to an external connection wiring member supplying a signal for controlling the pressure unit, and a wiring pattern formed into a thin film to electrically connect the individual electrode to the contact.
Accordingly, each of the individual electrodes and the external connection wiring member can be electrically connected readily, which improves the fabrication efficiency of the ink jet head. Further, the individual electrode and the contact can be electrically connected certainly, which improves the reliability. Still further, a space for wire bonding (air wiring) becomes unnecessary, which allows reduction of the size of the ink jet head and the printing apparatus.
Since a wiring pattern electrically connecting the individual electrode to the contact is formed into a thin film, a space above the individual electrode for laying a wire connecting the individual electrode to the external connection wiring member becomes unnecessary. Hence, freedom can be given to the shape of the ink jet head, and the size of the ink jet head can be reduced.
The individual electrode, the contact and the wiring pattern may be integrally formed into a thin film on the same surface from the same material. This allows the ink jet head to be fabricated at a low cost and readily.
The ink jet head may further comprise a joint formed to project from the head main body so that the ink supply unit is mounted to the head main body. It is thereby possible to mount the ink supply unit to the head main body readily and certainly, and improve the rigidity of the head main body.
The head main body may be formed on a substrate, and the joint may be formed as a remaining part of the substrate on the head main body by partially removing the substrate from the head main body. It is thereby possible to form the joint readily and certainly in the course of substrate forming, thus the fabrication cost can be decreased.
The joint may be formed to enclose the individual electrodes on a surface on which the individual electrodes, the contacts and the wiring patterns are form
Koike Shuji
Osada Toshihiko
Otani Seigen
Sakamoto Yoshiaki
Shingai Tomohisa
Armstrong Kratz Quintos Hanson & Brooks, LLP
Fujitsu Limited
Meier Stephen D.
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