Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-06-28
2004-11-30
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S086000, C347S087000, C347S092000
Reexamination Certificate
active
06824255
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording device that ejects ink from nozzles to record on sheets and the like.
2. Description of the Related Art
One conventional ink jet recording device includes a head unit with an ink cartridge and an ink jet head. The ink cartridge holds ink and the ink jet head ejects the ink onto a sheet, for example, to record images on the sheet. The ink cartridge and the ink jet head are brought into fluid communication by a tube through which ink flows from the ink cartridge to the ink jet head. This can be referred to as a tube-supply type ink jet recording device.
FIG. 1
shows a conventional tube-supply type ink jet recording device. The device includes a head unit
1
, a carriage
20
that supports the head unit
1
, a subtank
26
, and an ink cartridge
31
for supplying ink to the head unit
1
.
The head unit
1
includes a head holder
2
, an ink jet head
3
, a buffer tank
4
, tubes
15
,
16
, and a head-side joint member
5
.
The ink jet head
3
includes an actuator
6
and a manifold
7
. The actuator
6
is formed with a plurality of ejection channels (not shown) for ejecting ink from a nozzle surface
8
. The manifold
7
is connected to the upper end portion of the actuator
6
and is formed with an upwardly protruding ink-inflow port
10
. The manifold
7
distributes ink from the ink-inflow port
10
to each of the ink channels in the actuator
6
. The actuator
6
changes volume in the ink channels to eject ink vertically downward from the nozzle surface
8
.
The head holder
2
is supported by the carriage
20
with a substantially horizontal orientation. The head holder
2
supports the ink jet head
3
through an attachment plate
11
that is fixedly attached to the manifold
7
. The head holder
2
includes a head cover
9
that covers the ink jet head
3
in a condition with the nozzle surface
8
exposed facing vertically downward.
The buffer tank
4
serves as a vessel for temporarily holding ink. The buffer tank
4
is supported by the head holder
2
at a position above the ink jet head
3
. The buffer tank
4
is formed at its lower portion with a downwardly protruding ink-outflow port
14
, and at its upper side with an upwardly protruding ink-supply port
12
and an upwardly protruding ink-return port
13
. The ink-outflow port
14
is connected to the ink-inflow port
10
of the manifold
7
. With this configuration, ink held in the buffer tank
4
is supplied from the ink-outflow port
14
to the manifold
7
through the ink-inflow port
10
. The ink-supply port
12
is connected to the inner supply tube
15
and the ink-return port
13
is connected to the inner-return tube
16
.
The head-side joint member
5
includes a head-side-supply joint
18
and a head-side-return joint
19
that are aligned next to each other on, and that protrude vertically upward from, the head holder
2
. The head-side-supply joint
18
and the head-side-return joint
19
are each formed in a hollow-tube shape. The head-side-supply joint
18
and the head-side-return joint
19
are connected at the top end to the inner supply tube
15
and the ink-return port
13
, respectively, and are open downward.
The carriage
20
includes a casing
21
and a carriage-side joint member
22
. The casing
21
houses the head unit
1
and supports the head unit
1
and the carriage-side joint member
22
with substantially a horizontal orientation. The carriage-side joint member
22
is provided on the casing
21
and includes a carriage-side-supply joint
23
and a carriage-side-return joint
24
. The carriage-side-supply joint
23
and the carriage-side-return joint
24
are formed in a hollow-tube shape and protrude vertically upward. The carriage-side-supply joint
23
and the carriage-side-return joint
24
are inserted in the head-side-supply joint
18
and the head-side-return joint
19
, respectively, to connect to the head-side-supply joint
18
and head-side-return joint
19
.
The carriage-side-supply joint
23
is connected to subtank
26
through an outer-supply tube
27
and the carriage-side-return joint
24
is connected to the subtank
26
through an outer-return tube
28
. A circulation pump
29
is provided along the outer-return tube
28
.
When the circulation pump
29
is driven, ink held in the subtank
26
is supplied to the buffer tank
4
through the outer-supply tube
27
, the carriage-side-supply joint
23
, the head-side-supply joint
18
, the inner supply tube
15
, and the ink-supply port
12
. Simultaneously with this, ink held in the buffer tank
4
is returned to the subtank
26
through ink-return port
13
, the inner-return tube
16
, the head-side-return joint
19
, the carriage-side-return joint
24
, and the outer-return tube
28
. Bubbles generated in the ink are collected in the subtank
26
with the ink, and naturally separate from the ink by the difference between weight of the bubbles and the ink in the subtank
26
. The circulation pump
29
is normally not driven. Rather, the amount of ink that is ejected by the ink jet head
3
is naturally supplied from the subtank
26
to the buffer tank
4
through the outer-supply tube
27
by force of capillary action that operates in the nozzle portion of the actuator
6
.
The ink cartridge
31
is connected to the subtank
26
through a supplementary tube
30
. Also, a liquid-feed pump
32
is provided along the supplementary tube
30
. The liquid-feed pump
32
normally supplies ink from the ink cartridge
31
into the subtank
26
in accordance with reduction in the amount of ink held in the subtank
26
.
SUMMARY OF THE INVENTION
The head-side-supply joint
18
and the carriage-side-supply joint
23
, and the head-side-return joint
19
and the carriage-side-return joint
24
, extend in substantially the same direction in which the ink jet head
3
ejects ink, and moreover, are connected in a vertical direction that is substantially perpendicular to the direction in which the head unit
1
is supported on the casing
21
. Therefore, the tubes
15
and
16
need to be bent around at an approximately 180° angle in order to connect the tubes
15
and
16
to the joints
18
and
19
. For this reason, the tubes
15
and
16
need to be made from an extremely flexible material. This places an inconvenient limitation on materials that can be used to form the tubes
15
and
16
.
Also, the tubes
15
and
16
need to be rather long because the distance between connection ends of the tubes
15
and
16
increases when the tubes
15
and
16
are bent around at an approximately 180° angle. As a result, more material is required to produce the tubes
15
and
16
, so material costs increase. Also, the amount of ink that needs to be circulated increases. Production costs increase because a more powerful pump is required and running costs increase because the more powerful pump requires more energy to run. Also, because flexible tubes are normally semi permeable to air, a great amount of air penetrates through the walls of the tubes
15
and
16
because the tubes
15
and
16
are so long. More bubbles are generated so the possibility of defective ejections in the ink jet head
3
also increases.
Because the joints
18
and
19
are aligned next to each other on, and protrude vertically upward from, the head holder
2
, it is impossible to secure a sufficient pressure head, even though the head-side joint member
5
is supported on the head holder
2
at a position that is higher than the ink jet head
3
. Ink can be drip out from the joints
18
and
19
after the joints
23
,
24
detach from the joints
18
and
19
when the head unit
1
is detached from the carriage
20
.
Because the joints
18
and
23
, and the joints
19
and
24
, have a substantial vertical orientation when connected to each other, the head holder
2
and the carriage
20
need to be wider by an amount equal to the width of the joints
18
,
23
,
19
, and
24
. Therefore, the silhouette of the head unit
1
is larger, so that the ink j
Brother Kogyo Kabushiki Kaisha
Meier Stephen D.
Oliff & Berridg,e PLC
Tran Ly T
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