Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1998-03-27
2001-08-07
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06270205
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet print head, employed in an ink-jet printing device, for ejecting liquid ink from nozzles onto a recording paper in order to form desired images on the recording paper.
2. Description of the Related Art
Ink-jet type printing devices are well-known in the art for their relatively simple construction and for their high-speed and high-quality printing capabilities. An ink-jet print head is employed in the ink-jet type printing devices.
SUMMARY OF THE INVENTION
A conceivable structure of the ink jet print head is shown in
FIGS. 1 and 2
. The ink-jet print head includes an actuator
213
and a manifold
215
. The actuator
213
is constructed from a piezoelectric ceramic material, for example, and is formed with a plurality of ejection channels
212
for ejecting droplets of liquid ink from nozzles (not shown). The actuator
213
has an upper end surface
208
, where the plurality of ejection channels
212
are opened to form their inflow ends.
The manifold
215
is attached to the upper end surface (inflow end surface)
208
of the actuator
213
. The manifold
215
is formed with an ink supply channel
214
for supplying liquid ink to the ejection channels
212
. The manifold
215
is further formed with an inflow channel
216
in fluid communication with the ink supply channel
214
. Liquid ink is transferred through the inflow channel
216
from an ink supply source (not shown) to the ink supply channel
214
. Liquid ink is then introduced into the ejection channels
212
of the actuator
213
. The actuator
213
is partially applied with electric fields, thereby being partially transformed. The transformation in the actuator
213
causes variations in the volume of ejection channels
212
desired to be actuated. When the volumes of the ejection channels
212
are decreased, the liquid ink in those channels
212
is ejected in droplets from the nozzles. When the volumes of the ejection channels
212
are increased, on the other hand, ink from the ink supply source is introduced into the ejection channels
212
via the inflow channel
216
and the ink supply channel
214
.
As shown in
FIG. 2
, the ink supply channel
214
has a rectangular cross-section. That is, the manifold
215
is formed with an upper horizontal inner wall
217
and a pair of vertical inner walls
209
for surrounding the ink supply channel
214
. The upper horizontal inner wall
217
is connected to the pair of vertical inner walls
209
with a right angle being formed therebetween.
The manifold
215
is attached to the actuator
213
so that the upper horizontal inner wall
217
is located facing the upper end surface
208
of the actuator
213
and apart therefrom by a predetermined distance. Thus, the ink supply channel
214
is provided to be entirely opened over the inflow ends of all the ejection channels
212
.
As shown in
FIG. 1
, the manifold
215
is further formed with an inner wall surface
220
for defining the inflow channel
216
. The inner wall surface
220
is connected to the inner wall surface
217
. An approximately right angle is formed between the inner wall surface
220
and the inner wall surface
217
. That is, the inner wall surface
220
extends approximately perpendicularly to the inner wall surface
217
. Thus, the ink supply channel
214
extends from and perpendicularly to the inflow channel
216
.
With the above-described structure, when ink is initially introduced into the ink-jet print head from the ink supply source (not shown), ink flows into the inflow channel
216
and then continues flowing in the direction of the inflow channel
216
without slowing down its flowing speed. As a result, the ink forcibly hits the upper end surface
208
of the actuator
213
, causing the formation of air bubbles. These air bubbles can enter ejection channels
212
and can cause ejection problems such as printing imperfections.
In view of the above-described problem, it is an object of the present invention to provide an improved ink-jet print head which has a simple construction, but which is capable of suppressing the generation of air bubbles in the ink supply channel to prevent ejection problems from occurring.
In order to attain the above and other objects, the present invention provides an ink-jet print head comprising: an actuator formed with a plurality of ejection channels, the actuator having a predetermined surface, on which the plurality of ejection channels are opened to have their opened ends; a first wall, in confrontation with the predetermined surface, for defining an ink supply channel for supplying the liquid ink to the plurality of ejection channels through their opened ends; a second wall defining an inflow channel in fluid communication with the ink supply channel, the inflow channel being for supplying ink to the ink supply channel; and a sloped surface formed between the first wall and the second wall for defining an ink flow path for allowing ink to flow from the inflow channel to the ink supply channel, the sloped surface gradually increasing the cross-sectional area of the ink flow path in a direction toward the ink supply channel.
According to another aspect, the present invention provides an ink-jet print head comprising: an actuator formed with a plurality of ejection channels for accommodating a liquid ink and for ejecting drops of the liquid ink, the plurality of ejection channels being arranged in at least one row which extends in a predetermined direction, the actuator having a predetermined surface, on which each of the ejection channels is opened to have an inflow end for receiving the liquid ink flowing into the ejection channel; a manifold joined with the actuator on the predetermined surface, the manifold being formed with an ink supply channel which extends substantially along the predetermined direction in fluid communication with the inflow ends of the ejection channels to supply liquid ink to the ejection channels, the ink supply channel having a top portion which is located farthest away from the predetermined surface and which extends substantially along the predetermined direction, the top portion being located as shifted from a center of at least one ejection channel in a direction normal to the predetermined direction.
According to a further aspect, the present invention provides an ink-jet print head comprising: an actuator formed with a plurality of ejection channels for accommodating a liquid ink and for ejecting drops of the liquid ink, the ejection channels being arranged in at least one row which extends in a predetermined direction, the actuator having a predetermined surface, on which each of the ejection channels is opened to have an inflow end; a manifold joined with the actuator on the predetermined surface, the manifold being formed with an ink supply channel which extends along the at least one row of ejection channels for supplying liquid ink to each of the ejection channels, the manifold being further formed with an inflow channel connected to a first end of the ink supply channel to supply ink to the ink supply channel, the ink supply channel extending substantially in the predetermined direction between a first end and a second end opposite to the first end, the ejection channels in each of the at least one row being arranged so that their inflow ends are exposed in the ink supply channel between the first and second ends, the ink supply channel having a width along the predetermined surface, the width of the ink supply channel at its portion close to the second end decreasing toward the second end.
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patent: 5519425 (1996-05-01), Dietl et al.
patent: 5793396 (1998-08-01), Sasaki
patent: 5808643 (1998-09-01), Tracy et al.
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patent: 0 705 705 A2 (1996-04-01), None
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patent: 8-132639 (1996-05-01), None
patent: 9-66604 (1997-03-01), None
Brother Kogyo Kabushiki Kaisha
Le N.
Nghiem Michael
Oliff & Berridg,e PLC
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