Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-08-19
2003-12-09
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S020000, C347S044000, C347S056000, C347S047000
Reexamination Certificate
active
06659588
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head for discharging liquid and forming a flying liquid droplet thereby effecting recording, and formation of discharge opening (also called orifice) for discharging liquid. The present invention is applicable to an apparatus such as a printer for recording on a recording medium such as paper, yarn, fiber, fabrics, leather, metal, plastics, glass, timber, ceramics etc., a copying apparatus, a facsimile apparatus having communicating function, or a word processor having a printer unit, or an industrial recording apparatus combined in complex manner with various processing apparatus.
In the present invention, “recording” means not only providing the recording medium with a meaningful image such as a character or graphics but also providing with a meaningless image such as a pattern.
2. Related Background Art
The ink jet recording apparatus, effecting recording by discharging recording liquid (ink) from the orifice of the liquid discharge head, is already known to be excellent in low noise and high speed recording.
Such ink jet recording method has been proposed in various systems, some of which are already commercialized and some are still under development for commercialization.
The liquid discharge head for such recording method is for example composed, as shown in
FIGS. 6 and 7
, of an orifice plate
40
having an orifice for discharging the liquid, a ceiling plate
400
for forming a liquid path
401
communicating with the orifice, and a substrate
100
constituting a part of the liquid path and provided with an energy generating element
101
(hereinafter called heater) for generating energy for ink discharge.
The orifice plate
40
is provided with a small orifice
41
for discharging ink, and the orifice
41
constitutes an important element governing the discharging performance of the liquid discharge head. The orifice plate
41
of the liquid discharge head
40
is required to be satisfactorily workable in order to form the small orifice, and to have satisfactory ink resistance as it is in direct contact with the ink.
For meeting these requirements, there has conventionally been employed a metal plate such as of SUS, Ni, Cr or Al, or a resinous film material easily and inexpensively available in a desired thickness such as of polyimide, polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide or polypropylene.
On the other hand, with the recent progress in the recording technology, there has been required recording with a higher speed and a higher definition, and, for this reason, the orifices
41
are being formed with a smaller size (orifice diameter) and with a higher density. As a result, there have been devised various methods for forming the orifice
41
, and, in case of using the resinous film, the orifice is formed with a laser beam which is suitable for fine working. Also in case of employing a metal plate, the orifice
41
is formed for example by electroforming.
However, it is extremely difficult to adjoin the orifice plate
40
having a small orifice and the corresponding liquid path
401
without a gap to the neighboring orifice
41
.
For this reason, there has been employed a method of adhering the resinous film for forming the orifice to the main body of the head and then forming the orifice with the laser beam as disclosed in the Japanese Patent Application Laid-open No. 2-187342, or of employing a dry film or the like for the orifice plate, pressing the dry film in a softened state by heating into the adhering face of the main body of the head thereby pressing the softened orifice plate into the liquid path and forming the orifice by a photolithographic process or with a laser beam, as disclosed in the Japanese Patent Application Laid-open No. 2-204048.
The orifice of the liquid discharge head preferably has so-called tapered shape in which the diameter gradually decreases from the liquid path side to the discharge opening side, but, if the orifice plate after formation of the orifice of such tapered shape is adhered by applying adhesive resin for example by transfer method, such adhesive resin may intrude into the orifice to very the tapered shape thereof, thereby resulting in a drawback such as fluctuation in the direction of discharge. Also a bubble inclusion caused by defective contact induces insufficient adhesion in the partition to the neighboring orifice, thus resulting in defective liquid discharge.
Consequently, there is also adopted a method of forming a step in the vicinity of the orifice, in order that the adhesive resin does not intrude into the liquid path and the orifice, as disclosed in the Japanese Patent Application Laid-open No. 5-330061.
Furthermore, in case of adhering the orifice plate having the orifice to the adhering face of the main body of the head, the positional aberration may take place by the contraction of the adhesive resin at the hardening thereof. Therefore, as disclosed in the Japanese Patent Application Laid-open No. 2-78560, there is also adopted a method of forming surface irregularities on the adhering face of the orifice plate, in order to prevent the influence caused by the contraction of the adhesive resin at the hardening.
Also the main body of the liquid discharge head, to be adhered to the above-mentioned orifice plate, can be prepared for example by the following method. On a silicon substrate, discharge energy generating elements are formed, and photosensitive resin for forming the liquid path walls is laminated thereon. Thereafter the photosensitive resin is patterned to form the desired liquid path walls. After the formation of the liquid path walls, a ceiling plate, composed for example of a glass plate, is laminated thereon to complete the liquid paths. Then the obtained laminated body is cut for example with a diamond blade to separate the liquid paths and to adjust the length thereof. Then the orifice plate is adhered for example an adhesive material in such a manner that the orifices communicate with the liquid paths to obtain the desired liquid discharge head.
FIG. 39
is a perspective view showing a conventional example of the liquid discharge head and
FIG. 40
is a plan view thereof.
In the liquid discharge head shown in
FIGS. 39 and 40
, liquid path walls
1301
and electrothermal converting elements
1303
serving as the discharge energy generating elements are formed on a silicon substrate
1309
, and a ceiling plate
1310
composed for example of a silicon substrate is adhered thereon. The laminated body is cut off with a diamond blade for the purpose of adjusting the position of the liquid paths
1302
, and an orifice plate
1307
is adhered with adhesive
1306
for example epoxy resin.
Also in such liquid discharge head, there has been a drawback that the adhesive employed for adhering the orifice plate enter and clog the liquid path. For this reason, there is adopted the method of forming a step in the vicinity of the orifice thereby preventing intrusion of the adhesive into the liquid and the orifice as disclosed in the Japanese Patent Application Laid-open No. 5-330061.
However, the above-described conventional configurations have been associated with the following drawbacks.
In pressing the softened resin into the liquid path at the adhering operation of the orifice plate to the main body of the head, the intruding amount of resin into the liquid path is difficult to control. As the orifices become smaller in diameter and higher in density, the resin intruding into the liquid path significantly influences the discharge performance, resulting in fluctuations of the discharge amount among the nozzles.
Also, with an increase in the density of the orifices and with the recovery operation of the orifice face surface, the distance between the orifices becomes shorter, and, if the step structure is formed in the vicinity of the orifices in order to prevent intrusion of the adhesive resin therein, the adhesive strength between the orifices is lowered thereby deterior
Ikegame Ken
Ito Miki
Kashino Toshio
Koyama Shuji
Mihara Hiroaki
Canon Kabushiki Kaisha
Do An H.
Fitzpatrick ,Cella, Harper & Scinto
Meier Stephen D.
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