Etching a substrate: processes – Forming or treating thermal ink jet article
Reexamination Certificate
2001-02-12
2003-02-18
Mills, Gregory (Department: 1763)
Etching a substrate: processes
Forming or treating thermal ink jet article
C029S890010
Reexamination Certificate
active
06521137
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing a liquid discharge head that discharges liquid by bubbling it. More particularly, the invention relates to a method for manufacturing a liquid discharge head provided with a movable member which is displaceable by pressure exerted at the time of bubbling.
Also, the present invention is applicable to a printer for recording on a recording medium, such as paper, thread, textile, cloths, leather, metal, plastic, glass, wood, ceramics, and some others, as well as to a copying machine, a facsimile equipment having communication systems, and a word processor having a printer unit, among some others. Further, the invention is applicable to a recording apparatus of industrial use, which is complexly combined with various processing apparatuses.
In this respect, the term “recording” used for the invention hereof means not only the provision of characters, graphics, and other meaningful images, but also, that of patterns and other images which are not meaningful.
2. Related Background Art
For a recording apparatus, such as a printer, there has conventionally been known an ink jet recording method, the so-called bubble jet recording method, in which images are formed on a recording medium by adhesion of ink discharged from discharge ports by action based on the abrupt voluminal changes that follow a bubble created by the application of thermal energy or the like to liquid ink in flow paths. A recording apparatus that uses this bubble jet recording method is generally provided with discharge ports for discharging ink; liquid flow paths communicated with the discharge ports; and electrothermal converting devices arranged in the liquid flow paths as means for generating energy used for discharging ink as disclosed in the specification of U.S. Pat. No. 4,723,129 and others.
In accordance with a recording apparatus and recording method of the kind, it is possible to recording high quality images at a higher speed in a lesser amount of noises. At the same time, the head of this recording apparatus makes it possible to arrange discharge ports for discharging ink in high density with many advantages, such as to facilitate obtaining recorded images in high resolution or color images by use of a smaller apparatus. As a result, the bubble jet recording method has been widely utilized for many office equipment including a printer, a copying machine, and a facsimile equipment, and further, utilized for industrial systems, such as textile printing apparatus, in recent years.
Along with the wider utilization of the bubble jet technologies for products in many fields, various demands have been brought increasingly in recent years as given below.
In order to obtain images in higher quality, there has been proposed a liquid discharging method or the like that regulates driving conditions to attain good ink discharges at high ink discharge speed on the basis of stabilized bubble generation or there has been proposed a liquid discharge head the configuration of flow paths of which is improved to make it possible to perform recording at higher speed, as well as to effectuate refilling liquid into flow paths at higher speed after liquid has been discharged.
Besides, such heads as described above, there is an invention disclosed in the specification of Japanese Patent Application Laid-Open No. 6-31918 in which attention is given to the back wave (pressure directed toward the side opposite to the discharge port) generated along with the creation of a bubble (bubbles), which incurs energy loss at the time of discharges, and a head is structured so as to prevent the back waves from being generated. In accordance with the invention disclosed in the specification of this Laid-Open Application, the back wave can be suppressed momentarily and slightly. However, since nothing is taken into consideration at all as to the correlations between the growth of bubble and the triangle portion, nor there is any conception thereof, this invention contains problems as given below.
In other words, a heat generating element is positioned on the bottom of each recessed portion by the invention disclosed in the specification of this Laid-Open Application, thus making it impossible to provide the linearly communicative condition with each discharge port. As a result, the shape of each liquid droplet is not stabilized, and furthermore, owing to the growth of bubble which is allowed to begin with the circumference of each vertex of the triangle portion, the bubble grows up to the entire side opposite to one side of the plate-like portion of the triangle. As a result, the ordinary growth of bubble is completed in liquid as if there was no plate-like member present. Then, for the bubble that has grown, the existence of the plate-like member has no relational effect at all. On the contrary, with the entire body of the plate-like member being surrounded by bubble, the refilling to the heat generating element positioned on the bottom of the recessed portion creates disturbance in the liquid flow, which causes a micro-bubble to be retained inside the recessed portion, leading to disorder in effectuating the principle of discharges itself, which is based on the growth of bubble.
Meanwhile, as disclosed in the specification of European Patent (EP) Application Laid-Open No. 436,047, it has been proposed to provide a first valve which is arranged between the vicinity of discharge port and bubble generating portion to cut them off, and a second valve which is arranged between the bubble generating unit and ink supply portion to cut them off completely, and then, to open and close these valves alternately (
FIG. 4
to
FIG. 9
, EP Laid-Open Application 436,047). However, it is required by this invention to divide three chambers by two, respectively, which results in the creation of large tail that ink trails when it follows a liquid droplet at the time of discharge. Then, the number of satellite dots becomes much more than that of those formed by the discharge effectuated by the ordinary method in which bubble grows, shrinks, and becomes extinct in that order (presumably, this is because the effect of meniscus retraction that follows bubble extinction cannot be used). Also, at the time of refilling, liquid is supplied to the bubble generating portion along with the extinction of bubble. However, as no liquid can be supplied to the vicinity of discharge port until the next bubbling takes place, not only discharging liquid droplets vary greatly, but also, the response frequency of discharges becomes extremely small. Therefore, this invention has not attained the practical level as yet.
In this respect, the applicant hereof has proposed many inventions that use a movable member (a plate member or the like formed in a cantilever fashion, which is provided with the free end from the pivot thereof on the discharge port side) capable of contributing to the discharge of liquid droplets effectively unlike the conventional art described above. In the specification of Japanese Patent Application Laid-Open No. 9-48127, an invention is disclosed wherein the upper limit of the displacement is regulated for a movable member in order to prevent even a slight disorder from being given to the behavior of the movable member. Also, in the specification of Japanese Patent Application Laid-Open No. 9-323420, an invention is disclosed wherein the refilling capability is enhanced by the advantageous utilization of a movable member by shifting the position of the common liquid chamber to the free end side of the movable member, that is, on the downstream side. For these inventions, there is adapted a mode as a prerequisite in which the growing bubble is encircled by the movable member temporarily, and then, it is released from this stage to the discharge port side all at once. As a result, no attention is given to each individual element of the bubble related to the formation of liquid droplet itself as a whole nor any attention is given to the correlations
Inoue Ryoji
Kubota Masahiko
Kudo Kiyomitsu
Takenouchi Masanori
Mills Gregory
Moore Karla
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