Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-07-13
2002-12-03
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06488364
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a recording method and a recording apparatus having a process step by which a bubble produced by thermal energy communicates with ambience, more particularly to a recording method and apparatus such as a printer for recording images or characters on paper or cloth (recording material) in accordance with a recording signal, a copying machine, a facsimile machine having an information transmitting system, an electronic typewriter having a keyboard, a wordprocessor, or a compound system or the like.
Among various recording methods which have been put into practice for various printers, an ink jet system as disclosed in U.S. Pat. Nos. 4,723,129, 4,740,796 or the like, which uses thermal energy to produce film boiling, is advantageous. In one of the types a liquid passage is not blocked by the bubble in U.S. Pat. No. 4,410,899.
The prior art is applicable to various recording systems, but they do not disclose or teach, to the practical level, the system wherein the created bubble communicates with the ambience. This system will be called “ambience communication system”.
As one type of the ambience communication system, there is a system in which the bubble explodes. However, since the liquid ejection is not stabilized, it is not practical. Japanese Laid-Open Patent Application No. 161935/1979 discloses a cylindrical nozzle provided with an internal cylindrical heater in which the nozzle is blocked by the bubble, although the ejection principle is not known, but it splashes a great number of fine ink droplets as well as the relatively large major droplet.
Japanese Laid-Open Patent Application No. 185455/1986 discloses that liquid ink is filled in a small clearance between a heat generating head and a plate member having small openings and is heated by the heat generating head to create a bubble to eject a droplet of the ink through the fine opening. Also, the gas forming the bubble is ejected through the fine opening. By doing so, an image is formed on a recording material.
Japanese Laid-Open Patent Application No. 20 249768/1986 discloses that a bubble is formed by application of thermal energy to liquid ink. By the expansion force of the bubble, a small droplet of the ink is formed and ejected. Simultaneously, the gas forming the bubble is ejected through a large opening into the atmosphere. By doing so, an image is formed on the recording material. The system of this publication is characterized by the absence of the wall.
These two publications at most, disclose the ambience communication system by simply stating so or by simply expressing in the drawing. The details of the bubble are not considered.
Japanese Laid-Open Patent Application No. 197246/1986 discloses recording apparatus using thermal energy, in which the ink is supplied into plural bores and is heated by a recording head having heat generating means to the temperature of 150-200° C., by which a droplet of the ink is ejected onto the recording material. However, in the recording apparatus of this type, it is difficult to completely closely dispose the heat generating element and the recording medium, and therefore, the thermal efficiency is not as good as expected, and therefore, it is not suitable for a high speed recording, as the case may be. This publication discloses ejection of the ink using the pressure of the created bubble, but it does not disclose the specific principles of ejection. Therefore, any solution to the problem is not even suggested. This publication shows in its
FIG. 3
the growth of the bubble, in which the bubble growth from a point, and therefore, it is understood that the bubble is created by an extension of the nucleate boiling. In addition, the communication between the bubble and the air occurs in a space away from the ejection outlet, and therefore, the ejection behavior is not stabilized in addition, the ink remains around the ejection outlet.
SUMMARY OF THE INVENTION
The present invention is intended to provide a practical solution to the problems with the ambience communication system ink jet recording apparatus. The present invention is based on new investigations and analysis as to the preferable conditions under which the bubble communicates with the ambience.
Accordingly, it is a principal object of the present invention to provide a recording method and apparatus wherein the splashing of the liquid due to the explosion of the bubble is suppressed.
It is another object of the present invention to provide a recording method and apparatus wherein the liquid droplet formation is stabilized.
It is a further object of the present invention to provide a recording method and a recording apparatus wherein the bubble communicates with the ambience under preferable conditions.
It is a further object of the present invention to provide a recording method and apparatus wherein the bubble communicates with the ambience under such a condition that the volume and the speed of the ejected droplet are stabilized.
It is a further object of the present invention to provide an on-demand recording method and a on-demand type recording apparatus wherein plural ejection outlets are arranged at a high density without the problem of undesirable temperature rise.
It is a further object of the present invention to provide an on-demand recording method and an on-demand recording apparatus which is excellent in the image quality and in the high frequency response.
It is a further object of the present invention to provide a recording method and a recording apparatus having a long service life.
It is a further object of the present invention to provide a recording method and a recording apparatus which is stable in the recording operation.
It is a further object of the present invention to provide a recording method and a recording apparatus which have plural liquid passages with good refilling property.
According to an aspect of the present invention, there is provided a liquid jet recording method, comprising: applying thermal energy to liquid in a liquid passage to produce film boiling of the liquid to produce a bubble; permitting the bubble to communicate with ambience; wherein the liquid passage is not blocked in the communicating step.
According to another aspect of the present invention, there is provided a liquid jet recording method wherein ink is heated to create a bubble which is effective to eject at least a part of the ink, the improvement resides in that the bubble communicates with ambience under the condition that an internal pressure of the bubble is lower than a pressure of the ambience.
According to a further aspect of the present invention, there is provided a recording method using a recording head including an ejection outlet for ejecting ink, a liquid passage communicating with the ejection outlet and an ejection energy generating means for generating thermal energy contributable to ejection of the ink by creation of a bubble in the liquid passage, wherein the bubble communicates with the ambience when
l
a
/
l
b
≧1 is satisfied, where
l
a
is a distance between an ejection outlet side end of the ejection energy generating means and an ejection outlet side end of the bubble, and
l
b
is a distance between that end of the ejection energy generating means which is remote from the ejection outlet and that end of the bubble which is remote from the ejection outlet.
According to a yet further aspect of the present invention, there is provided a liquid jet method using a recording head having an ejection outlet for ejecting ink, a liquid passage communicating with the ejection outlet and an ejection energy generating element for generating thermal energy contributable to the ejection of the ink by creation of a bubble in the liquid passage, wherein a first order differential of a movement speed of an ejection outlet side end of the created bubble is negative, when the bubble created by the ejection energy generating means communicates with the ambience through the ejection outlet.
These and other objects, features a
Asai Akira
Inui Toshiharu
Miyagawa Masashi
Nakajima Kazuhiro
Ohkuma Norio
Barlow John
Fitzpatrick ,Cella, Harper & Scinto
Stephens Juanita
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