Etching a substrate: processes – Forming or treating thermal ink jet article
Reexamination Certificate
1999-12-02
2002-10-22
Gulakowski, Randy (Department: 1746)
Etching a substrate: processes
Forming or treating thermal ink jet article
C216S041000, C438S021000, C347S056000, C347S065000
Reexamination Certificate
active
06468437
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing a liquid discharging head adapted for use in a printer constituting an output terminal for a copying apparatus, a facsimile apparatus, a word processor or a host computer or in a video printer, and more particularly to a method for producing a liquid discharging head having a substrate on which formed is an electrothermal converting element for generating thermal energy to be used for recording. More specifically, it relates to a method for producing a liquid discharging head adapted for use in a liquid discharge recording apparatus which executes recording by discharging recording liquid (such as ink) as a flying droplet from a discharge opening (orifice) and depositing the liquid onto a recording medium.
2. Related Background Art
There is already known so-called bubble jet recording method, namely an ink jet recording method of providing ink with an energy such as heat to cause a state change involving an abrupt volumic change in the ink, discharging ink from the discharge opening by an action force based on such state change and depositing the ink onto a recording medium to form an image. The recording apparatus employing such bubble jet recording method is generally provided, as disclosed in the U.S. Pat. No. 4,723,129, with a discharge opening for discharging ink, an ink path communicating with the discharge opening and an electrothermal converting member provided in the ink path and serving as energy generating means for generating energy for discharging the ink.
Such recording method has various advantages for example of recording an image of high quality at a high speed with a low noise level, and recording an image of a high resolution or even a color image with a compact apparatus since, in the head executing such recording method, the ink discharge openings can be arranged with a high density. For this reason, the bubble jet recording method is recently employed in various office equipment such as printers, copying machines, facsimile apparatus etc., and even in industrial systems such as fabric dyeing apparatus.
With the spreading of the bubble jet technology into various fields, there are appearing various demands explained in the following.
For example, in order to satisfy a demand for improving the energy efficiency, there is conceived optimization of the heat generating member, such as adjustment of the thickness of the protective film for the heat generating member. This method is effective in improving the efficiency of propagation of the generated heat to the liquid.
Also for obtaining the image of high quality, there is proposed a driving method for liquid discharge capable of realizing a faster ink discharging speed and satisfactory ink discharge based on stable bubble generation, and, for achieving high-speed recording, there is proposed an improved shape of the liquid path for realizing the liquid discharge head with a faster refilling speed of the liquid into the liquid path.
Also in relation to the basic principle of liquid discharge, investigations have been made to provide a novel liquid discharging method utilizing the bubble that has not been available and a head adapted for use in such method, and such method and head are disclosed for example in the Japanese Patent Application Laid-open No. 9-201966.
In the following there will be explained, with reference to
FIGS. 21A
to
21
D and
22
, the conventional liquid discharging method and the head therefor disclosed in the Japanese Patent Application Laid-open No. 9-201966.
FIGS. 21A
to
21
D are cross-sectional views along the liquid path, for explaining the discharging principle of the conventional liquid discharge head, and
FIG. 22
is a partially broken perspective view of the liquid discharge head shown in
FIGS. 21A
to
21
D. The liquid discharge head shown in
FIGS. 21A
to
21
D and
22
has a basic configuration of controlling the pressure propagating direction based on the bubble and the growing direction thereof, thereby improving the discharging force and the discharging efficiency.
In the following description, the expression “upstream” or “downstream” refers to the liquid flowing direction from the liquid supply source, then through above a bubble generating area, toward the discharge opening.
The “downstream side” relating to the bubble itself refers to the side of discharge opening of the bubble, considered principally acting on the discharge of the liquid droplet. More specifically, it means the downstream side in the flowing direction mentioned above or the direction in the above-described configuration with respect to the center of the bubble, or means a bubble generated in an area of the heat generating member in the downstream side with respect to the areal center thereof.
Also the “comb-tooth shape” means a shape in which movable members are as a common member at the fulcrum ends thereof and are liberated in front of the free ends thereof.
In the configuration shown in
FIGS. 21A
to
21
D, the liquid discharge head is provided, on an element substrate
1101
, with a heat generating member
1102
as a discharge energy generating element for giving thermal energy to the liquid for the discharge thereof, and a liquid path
1103
is provided on the element substrate
1101
, corresponding to the heat generating member
1102
. The liquid path
1103
communicates with a discharge opening
1104
and also with a common liquid chamber
1105
for supplying plural liquid paths
1103
with the liquid, and receives, from the common liquid chamber
1105
, with the liquid of an amount matching the discharged amount thereof.
On the element substrate
1101
in the liquid path
1103
, a plate-shaped movable member
1106
, composed of an elastic material such as metal and having a flat portion, is formed in the form of a beam supported at an end, so as to face the aforementioned heat generating member
1102
. An end of the movable member
1106
is fixed to a support member
1107
formed by patterning photosensitive resin or the like on the wall of the liquid path
1103
or on the element substrate
1101
, whereby the movable member
1106
is supported by the support member
1107
with a fulcrum
1108
.
The movable members
1106
are constructed in a comb-tooth shape, whereby the movable member
1106
can be prepared easily and inexpensively, and can be easily aligned with the support member
1107
.
The movable member
1106
is so positioned as to be opposed to and to cover the heat generating member
1102
, with a distance of about 15 &mgr;m therefrom, and to have the fulcrum
1108
at the upstream side in the main flowing direction of the liquid, caused by the liquid discharging operation, from the common liquid chamber
1105
through above the movable member
1106
toward the discharge opening
1104
and to have the free end
1109
at the downstream side with respect to the fulcrum
1108
. A space between the heat generating member
1102
and the movable member
1106
constitutes a bubble generating area
1110
.
Heat generation by the heat generating member
1102
applies heat to the liquid in the bubble generating area
1110
between the movable member
1106
and the heat generating member
1102
, thereby generating a bubble in the liquid based on a film boiling phenomenon as described in the U.S. Pat. No. 4,723,129 (see. FIG.
21
B). The bubble
111
and the pressure resulting from the generation thereof are preferentially applied to the movable member
1106
, which in response displaces to open widely toward the discharge opening
1104
about the fulcrum
1108
, as shown in
FIGS. 21B and 21C
or in FIG.
22
. Based on the displacement of the movable member
1106
or the displaced state thereof, and also on a fact that the front end portion of the bubble has a certain width, the pressure resulting from the generation of the bubble
1111
can more easily propagate toward the discharge opening
1104
, whereby a basic improvement can be attained in the discharging efficient of the
Imanaka Yoshiyuki
Kashino Toshio
Kubota Masahiko
Mochizuki Muga
Ozaki Teruo
Ahmed Shamim
Fitzpatrick ,Cella, Harper & Scinto
Gulakowski Randy
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