Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-12-03
2002-12-10
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06491380
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharging head for discharging liquid by generating bubbles by virtue of thermal energy being acted on the liquid and a liquid discharging apparatus using the liquid head. The present invention also relates to a novel liquid discharging method associated with displacement of a removable member and bubble growth, and a liquid discharging head and a liquid discharging apparatus for performing thereof.
The present invention is applicable to such apparatus as a printer, a copier, a facsimile having a communication system, a word processor having a printer, or the like for recording on a recording medium such as paper, yarn, fiber, woven fabric, leather, metal, plastic, glass, wood, ceramic, or the like, and further to an industrial recording apparatus compositely combined with various kinds of processing apparatuses. In this invention, “recording” means not only providing a meaningful image of a character or a picture onto a recording medium but also providing a meaningless image such as a pattern or the like.
2. Related Background Art
Conventionally, an ink jet recording method for producing an image first by providing energy such as heat or the like to ink to cause a state change associated with abrupt volume change and generation of bubbles, and then discharging the ink from a discharging port by means of active force originated from the state change to adhere the ink onto the recording medium, or so-called a bubble jet recording method. To the bubble jet recording method, a discharging port for discharging ink, an ink flow path communicating with the discharging port, and an electrothermal converting element as a means for generating energy for discharging ink disposed in the ink flow path are provided, as disclosed in official gazettes such as the specification of U.S. Pat. No. 4,723,129 and the like.
According to such recording method, as a high quality image can be recorded in high speed and with reduced noise, and a discharging port for discharging ink can be arranged in high density on a recording head by the method, the method has a plenty of advantages such that a high resolution recorded image can be produced by a compact apparatus, and even a color image can be obtained with ease. Therefore, in recent years, the bubble jet recording method has been used in a multiplicity of office apparatuses such as printers, copiers, facsimiles and the like, and further even in industrial systems such as textile printing apparatuses and the like.
With the spread use of the bubble jet technique in a variety of products, a variety of demand such as follows has further been increasingly made in recent years. As an example, optimization of a heating element such as adjustment of the thickness of a protective film is consideration to the demand for improvement in energy efficiency. This method has an advantage to improve conductive efficiency of generated heat into liquid. Further, in order to obtain a high quality image, a driving condition for providing a liquid discharging method and the like in which ink discharging speed is fast, and which can discharge ink attributable to stabilized bubble generation in a good condition have been proposed, and in order to obtain a liquid discharging head which is fast in speed in refilling discharged liquid into a liquid flow path, from a stand point of high speed record, an apparatus having improved liquid flow path shape has been proposed.
Among the flow path shape, the flow path construction and the head manufacturing method described in Japanese Patent Application Laid-Open No. 63-199972 and the like are inventions taking notice of a back wave (pressure toward the direction reverse to the direction toward the discharging port, or pressure toward a liquid chamber) which is generated in association with the generation of bubbles. The back wave is known as energy loss, as the energy is not directed to the discharging direction. A head disclosed in Japanese Patent Application Laid-Open No. 63-199972 has a valve located apart from a bubbling region of bubbles produced by a heating element and opposite to a discharging port relative to the heating element. The valve has an initial position as if stuck to a ceiling of the flow path because of the manufacturing method by use of plate material or the like, and hangs down into the flow path in association with generation of the bubbles. The invention discloses that energy loss can be controlled when a part of the above described back wave is controlled by the valve.
However, in the construction, as can be seen if behavior in the flow path before and after generation of bubbles in the flow path which retains liquid to be discharged, partial inhibition of the back wave by a valve can be understood not necessarily practical for liquid discharging. Originally, the back wave itself is not directly related with the liquid discharging. Therefore, even if a part of the back wave is inhibited, the liquid discharging cannot be greatly influenced.
Further, in order to improve ink refilling and obtain a head which is excelled in frequency responsibility, a head of a structure in which heater neighborhood of a nozzle is communicated with a subordinate flow path has conventionally been proposed. When refilling ink, ink is refilled as well from the subordinate flow path into the nozzle to reduce refilling time. However, the head of the structure has a fear that reduction in discharging efficiency may be caused, as a part of the discharging force generated at the time of bubbling escapes to the subordinate flow path.
SUMMARY OF THE INVENTION
A major object of the present invention is to improve fundamental discharging characteristic in a method for producing bubbles (more particularly, bubbles associated with film boiling) in a liquid flow path to discharge liquid, to such a level unthinkable and unpredictable from the conventional standpoint.
Some of the inventors of the present invention previously came back to principles of liquid droplet discharging, and devotedly studied to provide a novel liquid droplet discharging method using bubbles which had conventionally been unobtainable, and a head and the like to be used therefor. More particularly, a first technical analysis which is originated from operation of a movable member in a liquid flow path such as analysis of the principle of structure of a movable member in a flow path, and a second technical analysis which is originated from the principle related to liquid droplet discharging by bubbles, and further a third technical analysis which is originated from bubble producing region of a heating member for producing bubbles have been performed.
As a result of these analyses, a completely novel technique for positively controlling the bubbles has come to be established by disposing the movable member facing to the heating member or the bubble generating region. Another feature of the present invention is, based on knowledge that use of downstream growth component of a bubble is the greatest contributing factor in significantly improving the discharging characteristic, if energy given to the discharging volume by the bubbles per se is considered, to efficiently convert the downstream growth component of the bubbles toward the discharging direction. By the conversion, improvement in the discharging efficiency and the discharging speed can be realized.
The present invention is to provide a novel discharging method and a novel discharging principle which further improve the above described epoch-making discharging principle. In other words, the present invention seeks after a discharging principle which enables further improvement in the discharging efficiency and refilling properties, by considering relation between the displacement of a free end of the movable member and the growth of bubbles obtained from the bubble generating region, and further, arrangement of the movable member and a structural element of the liquid flow path.
One of the objects of the present inventio
Hiroki Tomoyuki
Ikeda Masami
Imanaka Yoshiyuki
Ishinaga Hiroyuki
Kashino Toshio
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Gordon Raquel Yvette
Stephens Juanita
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