Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-07-07
2003-07-22
Williams, Hezron (Department: 2855)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06595625
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharging method, a liquid jet head, and a liquid jet apparatus for discharging a desired liquid by the creation of air bubbles brought about by causing thermal energy to act upon liquid. More particularly, the invention relates to a liquid discharging method, a liquid jet head, and a liquid jet apparatus provided with a movable member to be displaced by the utilization of the air bubble creation.
The present invention is also applicable to a printer for recording on a recording medium, such as paper, thread, fabric, cloth, leather, plastic, glass, wood, or ceramics, and to a copying machine, a facsimile equipment provided with communication systems, a word processor and other apparatuses having a printing unit therefor. Further, the present invention is applicable to a recording system for industrial use, which is complexly combined with various processing apparatuses.
Here, the term “recording” in the description of the present invention means not only the provision of images having characters, graphics, or other meaningful representation, but only the provision of those images that do not present any particular meaning, such as patterns.
2. Related Background Art
There has been known the so-called bubble jet recording method, which is an ink jet recording method whereby to form images on a recording medium by discharging ink from discharge ports using acting force exerted by the change of states of ink brought about by the abrupt voluminal changes (creation of air bubbles) when thermal energy or the like is applied to ink in accordance with recording signals. For the recording apparatus that uses the bubble jet recording method, it is generally practiced to provide, as disclosed in the specifications of U.S. Pat. No. 4,723,129 and others, the discharge ports that discharge ink, the ink paths conductively connected to the discharge ports, and electrothermal transducing elements arranged in each of the ink paths as means for generating energy for discharging ink.
In accordance with such recording method, it is possible to record high quality images at high speeds with a lesser amount of noises. At the same time, the head that executes this recording method makes it possible to arrange the discharge ports for discharging ink in high density, with the excellent advantage, among many others, that images are made recordable in high resolution, and that color images are easily obtainable by use of a smaller apparatus. In recent years, therefore, the bubble jet recording method is widely adopted for many kinds of office equipment, such as a printer, a copying machine, a facsimile equipment. Further, this recording method is utilized even for industrial systems, such as a textile printing, among others.
Along the wider utilization of bubble jet technologies and techniques for various products in many different fields, there have been increasingly more demands in recent years as given below.
For example, as to the demand on the improvement of energy efficiency, the adjustment of the thickness of protection film has been studied to optimize the performance of heat generating elements. A study of the kind has produced effects on the enhancement of transfer efficiency of generated heat to liquids.
Also, in order to obtain high quality images, there has been proposed a driving condition under which a liquid discharging method or the like is arranged to be able to execute good ink discharges at higher ink discharging speeds with more stabilized creation of air bubbles. Also, from the viewpoint of a high-speed recording, there has been proposed the improved configuration of liquid flow paths that makes it possible to obtain a liquid jet head capable of refilling liquid to the liquid flow paths at higher speeds in order to make up the liquid that has been discharged.
Of the various configurations of liquid flow paths thus proposed, the structure of liquid flow paths and a method for manufacturing heads, which are disclosed in the specification of Japanese Patent Application Laid-open No. 63-199972, are the inventions devised with attention given to the back waves (the pressure directed opposite to the direction toward the discharge ports, that is, pressure exerted in the direction toward the liquid chamber). The back waves are known as energy loss because such energy is not exerted in the discharging direction.
However, with respect to the structure as disclosed, it is clearly understandable that the partial suppression of the back waves is not practical for liquid discharge when studies are made on the condition under which the air bubbles are created in the liquid flow path that retains the discharging liquid in it.
Fundamentally, the back waves themselves are not related directly with discharging as described above. Of the pressures exerted by the air bubble, those directly related with discharging have already acted upon liquid so that the liquid is in the state of being discharged from the liquid flow path the moment the back waves are generated in the flow path. Therefore, even if the back waves are suppressed, it is clear that no significant influence is exerted on the liquid discharge, not to mention the partial suppression as described earlier.
On the other hand, for the bubble jet recording method, each of the heat generating elements repeats heating, while being in contact with ink. As a result, deposit is accumulated on the surface of each heat generating element due to burning of ink. Depending on the kinds of ink, such deposit is made in a considerable quantity, and results in the instabilized creation of air bubbles, hence making it difficult to perform ink discharges in good condition. Also, it is desired to provide a method for performing discharges in good condition without changing the quality of discharging liquid even when the liquid used has the nature such as to be easily deteriorated by the heat application or such as to make sufficient bubbling difficult.
Here, with this in view, there has been proposed a method for discharging liquid by transferring pressure exerted by bubbling to discharging liquid, while arranging means for separating the liquid used to create air bubbles by the application of head (bubbling liquid) and the liquid for use of discharges (discharging liquid) as different liquids, such as disclosed in the specifications of Japanese Patent Application Laid-Open No. 61-69467, Japanese Patent Application Laid-Open No. 55-81172, U.S. Pat. No. 4,480,259, among some others. In accordance with these disclosures, the structure is arranged to completely separate ink serving as discharging liquid, and bubbling liquid by use of silicon rubber or some other flexible film so as not to allow the discharging liquid to be directly in contact with the heat generating elements, and at the same time, to transfer pressure exerted by bubbling of the bubbling liquid to the discharging liquid by means of the deformation of the flexible film. With a structure of the kind, it is attained to prevent the deposit from being accumulated on the surface of each heat generating element, the improvement of selection range of discharging liquids, or the like.
However, the structure that completely separates discharging liquid and bubbling liquid as described above is the one whereby to transfer pressure exerted at the time of bubbling to discharging liquid by means of the deformation of the flexible film brought about by its expansion and contraction. Therefore, the pressure exerted by the deforming thereof is absorbed by the flexible film to a considerable extent. Also, the amount of deformation of the flexible film is not large. As a result, although it is possible to obtain effect that discharging liquid and bubbling liquid are made separable, there is a fear that energy efficiency and discharging power are lowered after all.
SUMMARY OF THE INVENTION
The applicant hereof has filed an application for a patent of such an extremely high technical standard as compared with the conventio
Asai Akira
Ishinaga Hiroyuki
Kashino Toshio
Kudo Kiyomitsu
Sugama Sadayuki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Williams Hezron
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