Thermal-compression type fluid jetting apparatus using ink

Details Thermal-compression type fluid jetting apparatus using ink Thermal-compression type fluid jetting apparatus using ink

2000-09-18

2002-04-30

Barlow, John (Department: 2853)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S065000

Reexamination Certificate

active

06378991

ABSTRACT:

BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a paper-copy output apparatus such as an inkjet printer or facsimile machine. More particularly, the invention concerns a thermal-compression type of fluid jetting apparatus employed in a print head of such a print output apparatus. The invention also concerns a method of making paper copies by means of such an apparatus.
DESCRIPTION OF THE RELATED ART
Generally, a fluid jetting apparatus employed in a print head of an output apparatus such as an inkjet printer or a facsimile machine, ejects ink in from ink chamber outward through a nozzle by exerting physical force to the ink chamber. Such fluid jetting apparatuses include thermal type, piezoelectric, and thermal-compression devices to exert the physical force to eject the fluid.
One thermal-compression fluid jetting apparatus of the prior art is shown in FIG.
1
. The fluid jetting apparatus includes a driver module
20
, a membrane
30
, and a nozzle module
40
.
Driver module
20
includes a substrate
15
, a fluid chamber subassembly
25
having a plurality of working fluid chambers
27
, a plurality of heating elements
16
disposed within the respective working fluid chambers, and a plurality of electrodes
17
connected with the respective heating elements.
Nozzle module
40
includes an ink chamber subassembly
45
having a plurality of ink chambers
57
, and a nozzle plate
47
connected to an upper side of the ink chamber. Nozzle holes
49
are formed on the upper side of the nozzle plate, corresponding in location to the respective ink chambers.
Membrane
30
is disposed between the ink chamber and the fluid chamber. The membrane serves the function of partition between the working fluid chambers and the ink chambers.
Substrate
15
, fluid chamber subassembly
25
, membrane
30
, and ink chamber subassembly
45
have correspondingly located ink feeding holes
11
,
21
,
31
, and
41
, which intercommunicate with one another. Ink feeding hole
41
of the ink chamber communicates with the ink chambers via an ink feeding passage
59
. Ink feeding hole
11
of substrate
15
communicates with an external ink source (not shown). Accordingly, the ink is fed from the external ink source into the ink chambers through the feeding holes
11
,
21
,
31
, and
41
, and ink feeding passage
59
.
Nozzle plate
47
, ink chamber
45
, membrane
30
, and fluid chamber member
25
have corresponding fluid feeding holes
53
,
43
,
33
, and
23
, which communicates with one another. Fluid feeding hole
23
of the fluid chamber intercommunicates with the working fluid chambers through a fluid feeding passage
29
. The working fluid is charged in the working fluid chambers through fluid feeding holes
53
,
43
,
33
, and
23
, and fluid feeding passage
29
. Fluid feeding hole
53
of the nozzle plate is sealed to be air-tight by a sealing member
55
, after working fluid is charged in the working fluid chambers
27
, fluid feeding passage
29
and fluid feeding holes
23
,
33
, and
43
.
When electricity is applied to electrodes
16
, heating elements
17
generate heat. The working fluid in the working fluid chambers is heated, forming bubbles. The bubbles increase the volume of the working fluid chambers, upwardly pressing and curving membrane
30
. Accordingly, the ink in the ink chambers is pushed and jetted through nozzle holes
49
.
The foregoing conventional fluid jetting apparatus, however, has a shortcoming of complicated manufacturing processes. It requires a process for separately preparing the ink and the working fluid, and a sealing process after the working fluid is discharged into the working fluid chambers. Further, since the working fluid employs an organic solvent such as a heptane which is apt to evaporate easily, there is a likelihood of having unnecessary space in the working fluid chambers. When the space is formed in the working fluid chambers, the intensity of the pressure exerted on membrane
30
during the heating of heating elements
16
becomes insufficient, so that the quantity of the jetted ink can not be precisely controlled.
In order to solve the problem of the conventional fluid jetting apparatus, the same applicant has previously disclosed a ‘Thermal-compression type fluid jetting apparatus’, which utilizes ink as the working fluid as shown in FIG.
2
.
As shown in
FIG. 2
, a substrate
115
, a fluid chamber subassembly
125
, a membrane
130
, and an ink chamber subassembly
145
have corresponding ink feeding holes
111
,
121
,
131
, and
141
which intercommunicate. Ink feeding hole
141
of the ink chamber subassembly communicates with ink chambers
157
through an ink feeding passage
159
. Ink feeding hole
121
of fluid chamber subassembly
125
communicates with working fluid chambers
127
through an ink feeding passage
129
. Accordingly, ink chambers
157
and working fluid chambers
127
communicate with one other.
Ink feeding hole
111
of substrate
115
communicates with an external ink source. The ink is fed from the ink source to working fluid chambers
127
and ink chambers
157
through ink feeding holes
111
,
121
,
131
, and
141
, and ink feeding passages
129
and
159
. The ink fed into the working fluid chambers
127
is the working fluid.
As electricity is applied to electrodes
116
, heating elements
117
generate heat. As described earlier, the ink in the ink chambers is pushed, and is then jetted out through the nozzle holes by the deformation of the membrane. In such an ink jetting apparatus, since the ink is used as the working fluid, there is no need to separately prepare the working fluid, and also no need for the sealing process. Also, the malfunction of the ink jetting apparatus is prevented.
The above-described ink jetting apparatus utilizing the ink as the working fluid, however, has the following problem: While the ink in working fluid chambers
127
is pushed out by the expansion of the bubble produced due to the heating of the heating elements, there is no constant supply of ink thereto. Accordingly, the pressure of the ink jetting decreases, and the quantity of the jetted ink becomes insufficient. As a result, the print quality deteriorates, especially in continuous performance of the printing operation.
Further, the repetitive heating of the heating elements
117
increases the temperature in the working fluid chambers, and the durability of the fluid jetting apparatus is shortened due to the excessive heat.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a fluid jetting apparatus having a consistently high print quality by maintaining a constant ink jetting pressure, and also having longer durability by preventing excessive heat.
The above object is accomplished by a thermal compression type fluid jetting apparatus including a nozzle part, a driving part, and a membrane. The nozzle part includes an ink chamber for reserving the ink, and a nozzle hole for permitting the ink in the ink chamber to be jetted therethrough. The driving part has a heating element received in the working fluid chamber, forming a working fluid chamber. The membrane serves as a partition between the ink chamber and the working fluid chamber. During the heating operation of the heating element, the membrane is curved by the increased pressure in the working fluid chamber, and thus pressurizes ink in the ink chamber. The working fluid chamber includes an ink feeding hole formed thereon for receiving ink from an external ink source, and the ink chamber includes an intercommunicating passage which communicates with the working fluid chamber. Accordingly, the ink fed into the working fluid chamber is fed into the ink chamber through the intercommunicating passage.
In the ink jet process of the present invention, the ink is constantly fed into the working fluid chamber. As a result, the possible pressure decrease and excessive heat in the working fluid chamber are prevented.


REFERENCES:
patent: 5097275 (1992-03-01), Takita
patent: 5635966 (1997-06-01), Keefe

Affiliated with

Also associated with

Rating

Thermal-compression type fluid jetting apparatus using ink does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Thermal-compression type fluid jetting apparatus using ink, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermal-compression type fluid jetting apparatus using ink will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2903966