Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-10-24
2004-02-17
Brooke, Michael S (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S063000, C347S065000
Reexamination Certificate
active
06692112
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet printhead. More particularly, the present invention relates to a monolithic ink-jet printhead having a hemispheric ink chamber and working in a bubble-jet mode, and a method for manufacturing the same.
2. Description of the Related Art
In general, ink-jet printheads eject small ink droplets for printing at a desired position on a paper and print out images having predetermined colors. Ink ejection methods for ink-jet printers include an electro-thermal transducer method (bubble-jet type) for ejecting an ink droplet by generating bubbles in ink using a heat source, and an electromechanical transducer method for ejecting an ink droplet according to a variation in the volume of ink caused by the deformation of a piezoelectric body.
In a bubble-jet type ink ejection mechanism, as mentioned above, when power is applied to a heater comprised of a resistance heating element, ink adjacent to the heater is rapidly heated to about 300° C. Heating the ink generates bubbles, which grow and swell, and thus apply pressure in the ink chamber filled with the ink. As a result, ink adjacent to a nozzle is ejected from the ink chamber through the nozzle.
There are multiple factors and parameters to consider in making an ink-jet printhead having an ink ejecting unit in a bubble-jet mode. First, it should be simple to manufacture, have a low manufacturing cost, and be capable of being mass-produced. Second, in order to produce high quality color images, the formation of undesirable satellite ink droplets that usually accompany an ejected main ink droplet must be avoided during the printing process. Third, cross-talk between adjacent nozzles, from which ink is not ejected, must be avoided, when ink is ejected from one nozzle, or when an ink chamber is refilled with ink after ink is ejected. For this purpose, ink back flow, i.e., when ink flows in a direction opposite to the direction in which ink is ejected, should be prevented. Fourth, for high-speed printing, the refilling period after ink is ejected should be as short a period of time as possible to increase the printing speed. That is, the driving frequency of the printhead should be high.
The above requirements, however, tend to conflict with one another. Furthermore, the performance of an ink-jet printhead is closely related to and affected by the structure and design, e.g., the relative sizes of ink chamber, ink passage, and heater, etc., as well as by the formation and expansion shape of the bubbles.
FIGS. 1A and 1B
illustrate a conventional bubble-jet type ink-jet printhead according to the prior art.
FIG. 1A
is an exploded perspective view illustrating the structure of a conventional ink ejecting unit.
FIG. 1B
illustrates a cross-sectional view of the ejection of an ink droplet from the conventional bubble-jet type ink-jet printhead illustrated in FIG.
1
A.
The conventional bubble-jet type ink-jet printhead shown in
FIGS. 1A and 1B
includes a substrate
10
, a barrier wall
12
formed on the substrate
10
for forming an ink chamber
13
to be filled with ink
19
, a heater
14
installed in the ink chamber
13
, and a nozzle plate
11
in which nozzles
16
, from which an ink droplet
19
′ is ejected, are formed. The ink chamber
13
is filled with ink
19
through an ink channel
15
. The nozzle
16
, which is in flow communication with the ink chamber
13
, is filled with ink
19
due to a capillary action. In the above structure, if current is supplied to the heater
14
, the heater
14
generates heat. The heat forms a bubble
18
in the ink
19
in the ink chamber
13
. The bubble
18
swells applies pressure to the ink
19
in the ink chamber
13
, and the ink droplet
19
′ is pushed out through the nozzle
16
. Next, the ink
19
is absorbed through the ink channel
15
, and the ink chamber
13
is refilled with the ink
19
.
In the conventional printhead, however, the ink channel
15
is connected to a side of the ink chamber
13
, and a width of the ink channel
15
is large. Therefore, back flow of the ink
19
easily occurs when swelling of the bubble
18
appears. In order to manufacture a printhead having the above structure, the nozzle plate
11
and the substrate
10
should be separately manufactured and bonded to each other, resulting in a complicated manufacturing process and often causing misalignment when the nozzle plate
11
is bonded to the substrate
10
.
FIG. 2
illustrates a cross-sectional view of the structure of another conventional ink ejecting unit according to the prior art.
In the conventional ink-jet printhead shown in
FIG. 2
, ink
29
passes over the edges of a substrate
22
through an ink channel
25
formed in a print cartridge body
20
from an ink reservoir and flows into an ink chamber
23
. When the heater
24
generates heat, bubbles
28
formed in the ink chamber
23
swell, and thus the ink
29
is ejected through nozzles
26
in a droplet form.
Even in the printhead having the above structure, however, a polymer tape
21
, in which the nozzles
26
are formed, should be bonded to a top end of the print cartridge body
20
using an adhesive seal
31
, and the substrate
22
, on which the heater
24
is mounted, is installed in the print cartridge body
20
. Then the substrate should be bonded to the polymer tape
21
by placing a thin adhesive layer
32
between the polymer tape
21
and the substrate
22
. As with the first conventional printhead manufacturing process, the above printhead manufacturing process is complicated, and misalignment may occur in the bonding process of the elements.
SUMMARY OF THE INVENTION
In an effort to solve the above problems, it is a feature of an embodiment of the present invention to provide a bubble-jet type ink-jet printhead having a hemispheric ink chamber, in which the elements of the ink-jet printhead and a MOS integrated circuit are formed monolithically on a substrate, and a method for manufacturing the same.
Accordingly, to provide the above feature, according to one aspect of the present invention, there is provided a monolithic ink-jet printhead including a substrate on which a manifold for supplying ink, an ink chamber filled with ink to be ejected, the ink chamber having a hemispheric shape, and an ink channel for supplying ink to the ink chamber from the manifold are formed monolithically, a silicon oxide layer, in which a nozzle for ejecting ink is formed in a position corresponding to a center of the ink chamber, the silicon oxide layer being deposited on the substrate, a heater formed on the silicon oxide layer to surround the nozzle, and a MOS integrated circuit mounted on the substrate to drive the heater, the MOS integrated circuit including a MOSFET and electrodes connected to the heater. The silicon oxide layer, the heater, and the MOS integrated circuit are formed monolithically on the substrate.
It is preferable that a coating layer formed of diamond-like carbon (DLC) is formed on an external surface of the printhead. The DLC coating layer has high hydrophobic property and durability.
Preferably, the MOSFET includes a gate, formed on a gate oxide layer using the silicon oxide layer as the gate oxide layer, and source and drain regions, formed under the silicon oxide layer. It is also preferable that the heater and the gate of the MOSFET are formed of the same material. It is also preferable that a field oxide layer thicker than the silicon oxide layer is formed as an insulating layer around the MOSFET.
Further, it is also preferable that a first passivation layer is formed on the heater and on the MOSFET, and a second passivation layer is formed on the electrodes. Also preferably, the first passivation layer includes a silicon nitride layer and the second passivation layer includes tetraethylorthosilicate (TEOS) oxide layer.
Preferably, a nozzle guide extended in a direction of the depth of the ink chamber from the edges of the nozzle is formed on an upper portion of the ink chamber.
The manifold is preferably formed
Baek Seog Soon
Kim Hyeon-cheol
Kuk Keon
Lee Chang-seung
Lee Sang-hyun
Brooke Michael S
Lee & Sterba, P.C.
Samsung Electronics Co,. Ltd.
LandOfFree
Monolithic ink-jet printhead does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Monolithic ink-jet printhead, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Monolithic ink-jet printhead will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3320962