Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-07-30
2003-02-04
Hallacher, Craig (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S094000
Reexamination Certificate
active
06513914
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharging head which discharges a desired liquid by generating bubbles with thermal energy or the likes a method for manufacturing liquid discharging head, and a liquid discharging apparatus, and particularly relates to a liquid discharging head using a movable separation film which is displaced using the generation of bubbles.
Note that with the present invention, the term “record” refers not only to applying meaningful images such as characters or shapes to recording media, but also to applying images without any particular meaning, such as patterns, to recording media
Also, with the present invention, the term “not yet driven” refers to the state of an article which is to be sequentially driven, but the time for this article to be driven has net yet come.
2. Description of the Related Art
There conventionally is known the so-called bubble jet recording method which is an ink-jet recording method wherein, with a recording device such as a printer or the like, energy such as thermal energy or the like is applied to liquid ink in a channel to cause bubbles therein, thereby discharging ink from discharging orifices due to an operating force based on the sudden change in volume due to the bubbles generated, the discharged ink adhering to a recording medium to form images. As disclosed in U.S. Pat. No. 4,723,129, recording apparatuses using this bubble jet recording method generally comprise discharging orifices for discharging ink, channels connecting to the discharging orifices, and electro-thermal converters serving as energy generating means for discharging ink disposed within the channels.
According to such a recording method, high-quality images can be recorded a high speed with little noise, and also, and the discharge orifices for discharging ink can be arrayed at high density with heads for this recording method, so this method is advantageous in many ways, such as yielding high-resolution recorded images with small apparatuses and also facilitating color image recording. Accordingly, in recent years, bubble jet recording devices have come to be used with many sorts of office equipment, such as printers, photocopiers, facsimile devices, and so forth, and even with industrial systems such as textile printing machines.
As bubble jet technology has come to be used in products in various fields, various types of demands have come to be made, as described next.
Driving conditions for providing liquid discharging methods or the like whereby suitable ink discharge based on stable bubble generation can be provided with high-speed ink discharging have been proposed, and improved channel shapes for obtaining liquid discharging heads with fast refilling speed (i.e., channels which have discharged ink are speedily refilled with ink for the next discharge) from the perspective of high-speed printing, have been proposed, in order to obtain high-quality images.
In addition to such heads, an invention has been disclosed in Japanese Patent Laid-Open No. 6-31918, which takes note of back waves (pressure directed toward the opposite direction of the discharge orifices) generated at the time of generating bubbles, and provides a structure which prevents back waves which are lost energy in the discharging action. The invention disclosed here has a triangular portion of a triangular plate member facing a heater which generates bubbles with this invention, the back waves can be temporarily suppressed, though slightly, with the plate member. However, no mention whatsoever is made of the relation between growth of the bubble and the triangular portion, and no thought has been given thereto, so the above invention has the following problems.
That is to say, with the invention disclosed in the above publication, the heater is situated at the base of a recess and there is no linear connection state with the discharging orifice, so the droplet form is unstable, and further growth of the bubble is permitted from around the apex portion of the triangle, so the bubble grows from one side of the triangular plate member to the other side, i.e., over the entirety, and consequently a normal bubble grows to its full size in the liquid as if the plate member did not even exist. Accordingly, the plate member is unrelated to the grown bubble. Conversely, the entirety of the plate member is surmounted by the bubble, is in the stage of the bubble shrinking, disturbances are generated in the process of refilling ink to the heater situated in the recess, resulting in minute bubbles being accumulated therein, and eventually disturbing the principle of discharge based on growing bubbles itself.
Next, EP Patent Laid-Open No. 436047A1 discloses an invention wherein a first valve is disposed between the discharge orifice area and the bubble generating portion for closing these off, and a second valve is disposed between the bubble generating portion and the ink supplying portion for completely closing these off, the first and second valve being alternately opened and shut (
FIGS. 4 through 9
in EP 436047A1). However, this invention sections these three chambers into two each, so at the time of discharging the ink following the droplet causes massive tailing, so the number of satellite dots is far greater than with a normal discharge method which performs bubble growth, reduction, and dissipation (it is assumed that meniscus regression during to dissipation of the bubble will not be usable). Also, at the time of refilling, the liquid is supplied to the bubble generating portion as the bubble dissipates, but liquid cannot be supplied to the discharging orifice area until the next bubble generation starts, so not only are the irregularities in discharged liquid droplets great, but also the discharge response frequency is extremely great, and accordingly this invention is not at a practical level.
On the other hand, the present assignee has proposed many inventions using movable members (plate-shaped members having a free end closer to the discharge orifice side than the fulcrum) which are completely different from the above-describe conventional art and effectively contribute to discharging of liquid droplets. Of such inventions, Japanese Patent Laid-Open No. 9-48127 discloses an invention wherein the upper limit of displacement of the moving member is restricted, in order to prevent slight disturbance in the behavior of the aforementioned movable member. Also, Japanese Patent Laid-Open No. 9-323420 discloses an invention wherein the position of the common liquid chamber upstream from the movable member is shifted toward the free end side of the movable member using the advantages of the movable member, i.e., shifted downstream, thereby increasing the refilling capability. These inventions were based upon the conception of temporarily enveloping the growth of the bubble with the movable member and then from that state discharging the bubble all at once toward the discharging orifice side, and accordingly, various individual elements relating to formation of droplets by the entire bubble and relations thereof were not noted.
As a next stage, the present assignee has disclosed in Japanese Patent Laid-Open No. 10-24588 an invention wherein a part of the bubble generating area is released from the movable member, as an invention taking note of bubble growth due to pressure wave propagation (acoustic wave) as an element relating to liquid discharge. However, this invention also only focuses on the growth of the bubble at the time of discharging liquid, and accordingly various individual elements relating to formation of droplets by the entire bubble and relations thereof are not noted.
While it is known that the front portion of bubbles (edge shooter type) with conventionally-known film boiling greatly affects discharging, there have conventionally been no inventions taking note of using this portion to effectively contribute to formation of discharging droplets, so the present inventors have diligently studied this matter to re
Ishinaga Hiroyuki
Misumi Yoshinori
Sugiyama Hiroyuki
Taneya Yoichi
Brooke Michael
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hallacher Craig
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