Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-08-18
2002-06-18
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S092000
Reexamination Certificate
active
06406135
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ink jet cartridge which discharges ink using a pressure produced by a bubble and an ink jet recording apparatus which uses the ink jet cartridge.
RELATED BACKGROUND ART
It has conventionally been known that an ink jet recording apparatus which performs recording by discharging a recording liquid (ink) from an orifice of a liquid ejecting head is a recording apparatus excellent from viewpoints of low noise and high speed recording.
Speaking of recording method which uses this ink jet recording apparatus, various types of methods have hitherto been proposed and improved: some have been placed on the market, whereas endeavors are being made to put others to practical use.
Above all, it is demanded to lower a manufacturing cost and improve discharging performance of a recording head of a type which comprises as an ink jet recording head, a substrate having an energy generating element for generating an ejecting energy and a ceiling plate joined to the substrate for forming a liquid flow path for discharging ink and a liquid chamber.
In order to meet a demand described above, the inventor et al. have manufactured a recording head shown in FIG.
10
.
FIG. 10
is a sectional view taken in a direction of a flow path showing a configurational example of an ink discharge unit constituting a background art of the present invention and
FIG. 11
is an enlarged view of a vicinity of a liquid chamber shown in FIG.
10
. Furthermore,
FIGS. 12A
,
12
B and
12
C are diagrams showing a form of the liquid chamber:
FIG. 12A
being a view as seen from a side of a discharge port,
FIG. 12B
being a top view and
FIG. 12C
being a side view.
As shown in
FIGS. 10 and 11
, the background art is configured by a base plate
1
made of a metal such as aluminum, a heater board
2
which is disposed on the base plate
1
and composed of a silicon substrate or the like on which a heater array for discharging ink is arranged, a printed wiring board
10
for transmitting an electric signal to the heater array on the heater board
2
by way of a bonding wire
11
, a plurality of discharge ports
3
for discharging ink, a plurality of flow paths
4
which communicate with the plurality of discharge ports
3
respectively and supply the ink to the discharge ports
3
, a liquid chamber
5
which communicates with the flow paths
4
and holds the ink to be supplied to the flow paths
4
, a supply path
6
which communicates with an ink tank (not shown) and supplies ink from the ink tank to the liquid chamber
5
, a supply tube
9
which forms the supply path
6
, a grooved ceiling plate
7
which integrally forms the flow paths
4
, the liquid chamber
5
and a portion of the supply path
6
, and a clamp spring
8
which fixes the grooved ceiling plate
7
: the discharge port
3
being formed by a laser boring method after the flow paths
4
, the liquid chamber
5
and the portion of the supply path
6
are formed in the grooved ceiling plate
7
by plastic molding. Furthermore, the liquid chamber
5
is communicated with the supply path
6
by an opening
13
as shown in
FIGS. 12A
,
12
B and
12
C so that the ink is supplied from the ink tank into the liquid chamber
5
by way of the opening
13
.
The opening
13
of the liquid chamber
5
is formed not in a top surface of the liquid chamber
5
but in a rear surface which is opposed to the flow paths
4
. It is desirable to configure the heater board
2
as small as possible in order to reduce a manufacturing cost and a size of the liquid chamber
5
is limited, but since the top surface of the grooved ceiling plate
7
must have an area which is used to fix the grooved ceiling plate
7
with the clamp spring
8
and the supply tube
9
cannot be disposed on the top surface of the liquid chamber
5
, the ink is supplied from behind the liquid chamber
5
.
In the ink jet cartridge which uses the ink discharge unit configured as described above, a sucking operation is first performed by a sucking device (not shown) of an ink jet recording apparatus main unit by way of the discharge port
3
, whereby the ink is supplied from the ink tank into the flow path
4
.
Then, the heaters on the heater board
2
generate heat on the basis of the electric signal transmitted from the printed wiring board
10
, whereby a bubble is produced in the flow path
4
and the ink is discharged from the discharge port
3
under a pressure produced by the bubble.
FIGS. 13A
,
13
B,
13
C and
13
D are diagrams descriptive of a series of operations from ink discharge to suction in the ink jet cartridge which uses the ink discharge unit shown in FIG.
10
.
When a heater
23
on the heater board
2
generates heat on the basis of the electric signal transmitted from the printed wiring board
10
, the ink is heated and boiled by the heat in the flow path
4
, thereby forming a bubble
24
on the heater
23
. The ink is discharged from the flow path
4
through the discharge port
3
under a pressure produced by the bubble
24
(FIG.
13
A). At this time, a small number of small bubbles
26
may be produced upstream of the flow path
4
.
The small bubble (bubbles)
26
produced on the upstream side of the flow path
4
are stagnant in the liquid chamber
5
even after the bubble
24
disappears on the heater
23
(FIG.
13
B).
When the heater
23
on the heater board
2
generates heat once again thereafter on the basis of the electric signal transmitted from the printed wiring board
10
, the ink is heated and boiled by the heat in the flow path
4
and the bubble
24
is produced on the heater
23
, and the small bubble (bubbles)
26
move upstream of the liquid chamber
5
under a pressure produced by the bubble
24
and adhere to a ceiling surface of the liquid chamber
5
together with the small bubble (bubbles)
27
coming from the supply path
6
, thereby forming a bubble
14
(FIG.
13
C).
An ink jet recording apparatus performs a suction recovery at an improper printing time. A bubble is removed by bringing a suction pad
28
into contact with a surface of the discharge port
3
as shown in FIG.
13
D and sucking the ink out of the flow path
4
.
However, the inventor et al. have found that the bubble
14
adhering to the ceiling surface of the liquid chamber
5
is not sucked but remains and a small bubble
30
also remains upstream of the flow path
4
in some cases dependently on kinds of ink since the background art forms in the liquid chamber
5
an ink flow
12
which has a high flow velocity in a region indicated by an arrow and an ink flow
29
which has a low flow velocity in the vicinity of the ceiling surface of the liquid chamber
5
at the suction time.
FIGS. 14A
,
14
B,
14
C and
14
D are diagrams descriptive in detail of the bubble
14
remaining after the operations shown in
FIGS. 13A
,
13
B,
13
C and
13
D:
FIG. 14A
being a sectional view taken in a direction of a flow path of the ink jet cartridge,
FIG. 14B
being a view of the liquid chamber
5
as seen from a side of the discharge port,
FIG. 14C
being a top view of the liquid chamber
5
and
FIG. 14D
being a side view of the liquid chamber
5
. The opening
13
of the liquid chamber
5
is disposed in the rear surface of the liquid chamber
5
and has a trapezoid or rectangular shape as shown in FIG.
14
B. The opening
13
must have a height nearly equal to that of the liquid chamber
5
in order to reserve a sufficient sectional area without narrowing an ink flow path. Accordingly, the ink flow
12
which flows from the opening
13
into the liquid chamber
5
at the suction recovery time has a portion of a maximum flow velocity in the vicinity of a center of the opening
13
as shown in FIG.
14
D and other portions of flow velocities which are slowed down outward.
Even after the above described sucking operation is performed, bubbles
14
-
1
and
14
-
2
may adhere to the ceiling surface of the liquid chamber
5
and remain as shown in
FIGS. 14A
,
14
B,
14
C and
14
D.
The remaining bubble
14
may gradually expand due to a temp
Saito Akio
Sato Yohei
Watanabe Kenjiro
Yoshinari Taiji
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Stephen Juanita
LandOfFree
Ink jet recording head and recording apparatus using the same 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 recording head and recording apparatus using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet recording head and recording apparatus using the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2949259