Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-06-30
2003-01-28
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06511162
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention and Related Art
This invention relates to a liquid discharge head for injecting liquid and forming flying liquid droplets to thereby effect recording, and a method of manufacturing the liquid discharge head. Also, the present invention is an invention which can be applied apparatuses such as a printer for effecting recording on a recording medium such as paper, yarn, fiber, cloth, leather, metals, plastics, glass, wood or ceramics, a copier, a facsimile apparatus having a communication system, and a word processor having a printer, and further an industrial recording apparatus compositely combined with various processing apparatuses.
The term “recording” in the present invention means not only imparting meaningful images such as characters and figures to a recording medium, but also imparting meaningless images such as patterns to a recording medium.
An ink jet recording apparatus for discharging recording liquid (ink) from the orifices of a liquid discharge head to thereby effect recording is known as a recording apparatus excellent in such points as low moise and high-speed recording.
With regard to this ink jet recording method, various systems have heretofore been proposed and improved, and some of them have been commercialized and some of them continue to be subjected to the effort to put them into practical use.
The liquid discharge head of this kind, as shown, for example, in
FIG. 10
of the accompanying drawings, is comprised of an orifice plate
1040
having orifices
1041
for discharging ink, a top plate
1400
for forming flow paths
1401
communicating with the respective orifices, and a substrate
1100
having energy generating elements
1101
(hereinafter referred to as the heaters) constituting a part of the flow paths and generating energy for discharge.
The orifice plate
1040
has minute orifices
1041
for discharging the ink, and these orifices are important elements governing the discharging performance of the liquid discharge head. That is, such advantages as good workability and good ink resistance, because of the direct contact with the ink, are required of the orifice plate
1040
of the liquid discharge head because the minute orifices
1041
are formed therein.
As a material satisfying the above-mentioned advantages, use has heretofore been made of a metal plate such as SUS, Ni, Cr or Al, or a resin film material such as polyimide, polysulfone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide or polypropylene which can be obtained easily and inexpensively.
On the other hand, with the recent advance of the recording technique, high-speed and highly minute recording is coming to be required and therefore, the orifices
1041
have become minute in the size (orifice diameter) thereof and have come to be formed highly densely. As the result, various contrivances have been made in the method of working the orifices
1041
, and when resin film is used, a laser beam is suited for minute working and therefore, a laser beam is used for the orifice working of the resin film. Also, when a metal plate is used, the orifices
1041
are formed by a method such as electrocasting.
However, it is very difficult to join the orifice plate
1040
formed with the minute orifices and the flow paths
1401
corresponding thereto together without any gap with respect to the adjacent orifices
1041
.
Therefore, there have been adopted a method of joining resin film as the material of an orifice plate to a head body, and thereafter orifice-working it, as disclosed in Japanese Patent Application Laid-Open No. 2-187342, etc., and a method of using dry film or the like as an orifice plate, bringing it in its softened state by heating into pressure contact with the joined surface of a head body, bringing the softened orifice plate into flow paths, and thereafter working orifices by the photolithography process or laser working, as disclosed in Japanese Patent Application Laid-Open No. 2-204048, etc.
It is desirable that the shape of the orifices of a liquid discharge head be a so-called tapered shape in which the diameter thereof becomes smaller from the flow path side toward the discharge port side, but if after the orifices of the tapered shape are formed in the orifice plate, adhesive resin is applied by a transferring method or the like and is hardened with the orifice plate stuck, there occurs the inconvenience that the adhesive resin goes into the orifices and the shape of the orifices formed in the tapered shape is changed and irregularity arises in the discharging direction. Also, the entry of a bubble due to bad close contact makes the adhesion to the adjacent orifices insufficient and causes bad discharge.
Therefore, there has also been adopted a method of providing a level difference near orifices so that adhesive resin may not go into flow paths and orifices, as disclosed in Japanese Patent Application Laid-Open No. 5-330061, etc.
Also, when the orifice plate formed with the orifices is to be adhesively secured to the joined surface of the head body, positional deviation during hardening occurs due to the hardening and contraction of the adhesive resin. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 2-78560, etc., a method of forming unevenness on the joined surface of an orifice plate is also adopted in order to prevent the influence of the hardening and contraction of the material used for joint.
Also, as a method of manufacturing a liquid discharge head body to be joined to such an orifice plate, there is, for example, the following method. Discharge energy generating elements are first formed on a silicon substrate, and then photosensitive resin forming flow path walls is laminated. Thereafter, the photosensitive resin is patterned to thereby form desired flow path walls. After the flow path walls have been formed, a top plate formed of glass or the like is layered, and flow paths are formed. Further, the layered body is cut by a diamond blade or the like, whereby the adjustment and separation of the length of the flow paths are effected. Then, the orifice plate is joined through an adhesive agent or the like so as to communicate with the flow paths, and a desired liquid discharge head is manufactured.
FIG. 11
of the accompanying drawings is a perspective view showing another example of the liquid discharge head according to the prior art, and
FIG. 12
of the accompanying drawing is a plan view thereof. The liquid discharge head shown in
FIGS. 11 and 12
has flow path walls
1301
and electrothermal conversion elements
1303
as discharge energy generating elements provided on a silicon substrate
1309
, and a top plate
1310
comprising, for example, a silicon substrate is joined thereto. An orifice plate
1307
cut by the use of a diamond blade in order to adjust the positions of flow paths
1302
, and provided with orifices
1308
is joined to the top plate by an adhesive agent such as epoxy resin.
Again such a liquid discharge head has suffered from the problem that the adhesive agent used when the orifice plate is joined goes into and clogs in the flow paths. Therefore, again here, as described in Japanese Patent Application Laid-Open No. 5-330061, there is adopted a method of providing a level difference near the orifices to thereby prevent the entry of the adhesive agent into the flow paths and the orifices.
However, the prior art described above has suffered from various problems as discussed below.
A first problem is the problem that when the orifice plate is formed of resin or a metal such as stainless steel, the pitch deviates by the heating of the orifice plate and the head body during adhesion due to the difference between the coefficients of thermal expansion of the two and therefore, a load enough to suppress this deviation of the pitch must be applied, and this leads to the bulkiness of a manufacturing apparatus and the necessity of extending the production tact. Also, still after the orifice plate has been joined to the head body, expansion and contraction are
Ikeda Masami
Kashino Toshio
Koyama Shuji
Mihara Hiroaki
Miyagawa Masashi
Feggins K.
Le N.
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