Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-06-10
2004-04-06
Nguyen, Judy (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06715861
ABSTRACT:
TECHNICAL FIELD
This invention relates to an ink jet head having a plurality of nozzles for discharging ink supplied thereto from an ink supplying part, and more particularly to an ink jet head suitable for use, for example, as a printing head of an ink jet printer and a printing apparatus which includes the ink jet head.
BACKGROUND ART
FIGS. 33 and 34
are views illustrating a configuration of a conventional ink jet head (the official gazette of Japanese Patent Laid-Open No. 148921/1995), and wherein
FIG. 33
is an exploded perspective view showing a configuration of essential part of the ink jet head and
FIG. 34
is a vertical sectional view showing a configuration of essential art of the ink jet head.
As shown in
FIGS. 33 and 34
, the conventional ink jet head includes a pressure generation unit
320
and a flow path unit
340
.
The pressure generation unit
320
includes a communication path substrate
301
, a pressure chamber formation substrate
302
and a diaphragm
304
and is formed such that the diaphragm
304
is adhered to one face side (upper side in
FIGS. 33 and 34
) of the pressure chamber formation substrate
302
and the communication path substrate
301
is adhered to the other face side (lower side in
FIGS. 33 and 34
) of the pressure chamber formation substrate
302
.
A plurality of portions which serve as pressure chambers
303
are formed by punching in the pressure chamber formation substrate
302
, and a plurality of communication paths
309
for communicating the pressure chambers
303
of the pressure chamber formation substrate
302
and ink supplying paths
314
formed in an ink supplying path formation substrate
313
, which is hereinafter described, with each other are formed by perforation in the communication path substrate
301
. Further, a plurality of nozzle communication holes
318
a
are perforated in the communication path substrate
301
in a corresponding relationship to the pressure chambers
303
of the pressure chamber formation substrate
302
.
A plurality of pressure elements
306
are disposed on the face (upper side in
FIGS. 33 and 34
) of the diaphragm
304
opposite to the face adhered to the pressure chamber formation substrate
302
in a corresponding relationship to the pressure chambers
303
of the pressure chamber formation substrate
302
with lower electrodes
305
interposed therebetween. Further, upper electrodes not shown are formed on the opposite side (upper side in
FIGS. 33 and 34
) of the pressure elements
306
to the lower electrodes
305
.
The flow path unit
340
includes a reservoir chamber formation substrate
312
, an ink supplying path formation substrate
313
, and a nozzle formation substrate
311
. The ink supplying path formation substrate
313
is adhered to one face side (upper side in
FIGS. 33 and 34
) of the reservoir chamber formation substrate
312
and the nozzle formation substrate
311
is adhered to the other face side (lower side in
FIGS. 33 and 34
) of the reservoir chamber formation substrate
312
.
A plurality of nozzles
316
are formed in the nozzle formation substrate
311
. A V-shaped ink reservoir chamber
315
is formed by a technique such as punching in the reservoir chamber formation substrate
312
, and nozzle communication paths
318
c
are perforated at positions of the reservoir chamber formation substrate
312
corresponding to the nozzles
316
formed in the nozzle formation substrate
311
.
A plurality of ink supplying paths
314
for communicating and connecting the ink reservoir chamber
315
and the communication paths
309
of the communication path substrate
301
with and to each other are formed in the ink supplying path formation substrate
313
. Further, nozzle communication paths
318
b
are perforated at positions of the ink supplying path formation substrate
313
corresponding to the nozzle communication paths
318
c
formed in the reservoir chamber formation substrate
312
. Furthermore, an opening
317
for communicating and connecting an ink tank not shown and the ink reservoir chamber
315
with and to each other is formed in the ink supplying path formation substrate
313
.
The pressure generation unit
320
and the flow path unit
340
are adhered to each other by a bonding agent or the like. Consequently, as shown in
FIG. 34
, the nozzle communication paths
318
a
of the communication path substrate
301
, the nozzle communication paths
318
b
of the ink supplying path formation substrate
313
and the nozzle communication paths
318
c
of the reservoir chamber formation substrate
312
are communicated with the nozzles
316
formed in the nozzle formation substrate
311
. Further, the pressure chambers
303
and the ink reservoir chamber
315
are communicated with each other through the ink supplying paths
314
and the communication paths
309
.
In the configuration described above, ink supplied from the ink tank not shown is supplied into the ink reservoir chamber
315
through the opening
317
and further supplied into the pressure chambers
303
through the ink supplying paths
314
and the communication paths
309
.
Then, driving signals are supplied to the upper electrodes (not shown) and the lower electrodes
305
from a driving circuit not shown to deform the pressure elements
306
thereby to displace the diaphragm
304
to raise the ink pressure in the pressure chambers
303
so that drops of the ink are discharged from the nozzles
316
through the nozzle communication holes
318
a
to
318
c
to form an image on a recording medium.
In such a conventional ink jet head as described above, while ink is supplied from the ink tank not shown to the ink reservoir chamber
315
through the opening
317
, since the opening
317
must be formed with a greater size as the amount of ink consumed by the ink jet head increases, it is required for the opening
317
to have a greater opening area as the number of nozzles
316
formed in the nozzle formation substrate
311
increases. Consequently, the conventional ink jet head has a subject to be solved that the degree of integration of the ink jet head cannot be raised and, since the ink jet head cannot be miniaturized, a high production cost is required as well.
Meanwhile, in order to improve the print quality of the ink jet printer, it is necessary to make the ink jetting characteristic from the nozzles
316
uniform. In order to make ink jetting from a nozzle
316
on the upstream side and another nozzle
316
on the downstream side along an ink supplying path uniform, stabilized ink supply is required, and it is necessary to lower and make the fluid resistances of the ink supply paths for the individual nozzles to ink uniform.
In the conventional ink jet head described above, in the substrates which form the ink jet head, the ink reservoir chamber
315
for supplying ink supplied thereto from the opening
317
into the pressure chambers
303
is formed, and the pressure chambers
303
are communicated with and connected to the ink reservoir chamber
315
through the ink supplying paths
314
and the communication paths
309
.
Generally, in order to miniaturize an ink jet head, it is a common practice to form it with a reduced thickness. However, in order to lower the resistance to ink in the ink reservoir chamber
315
, the supplying path length for ink must be reduced and the sectional area must be increased. Accordingly, it is necessary to make the sectional shape of the ink reservoir chamber
315
wide. Consequently, also this gives rise to a subject to be solved in that improvement of the degree of integration and/or miniaturization of the ink jet head are obstructed and a high production cost is required as well.
The present invention has been made in view of such subjects as described above, and it is an object of the present invention to devise the shape and so forth of an ink supplying path to each pressure chamber to make the ink supply to the pressure chambers uniform and make it possible to raise the degree of integration of an ink jet head thereby to miniaturize the ink jet h
Koike Shuji
Sakamoto Yoshiaki
Shingai Tomohisa
Armstrong Kratz Quintos Hanson & Brooks, LLP
Fujitsu Limited
Nguyen Judy
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