Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-07-14
2001-07-17
Beatty, Robert (Department: 2852)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06260958
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a liquid ejecting head wherein liquid is ejected by generation of a bubble created by application of thermal energy to the liquid, more particularly to such a head having a movable member displaced by the generation of the bubble.
In this specification, “recording” means not only forming an image of letter, figure or the like having specific meanings, but also includes forming an image of a pattern not having a specific meaning.
An ink jet recording method of so-called bubble jet type is known in which an instantaneous state change resulting in an instantaneous volume change (bubble generation) is caused by application of energy such as heat to the ink, so as to eject the ink through the ejection outlet by the force resulted from the state change by which the ink is ejected to and deposited on the recording material to form an image formation. As disclosed in U.S. Pat. No. 4,723,129 and so on, a recording device using the bubble jet recording method comprises an ejection outlet for ejecting the ink, an ink flow path in fluid communication with the ejection outlet, and an electrothermal transducer as energy generating means disposed in the ink flow path.
With such a recording method is advantageous in that, a high quality image, can be recorded at high speed and with low noise, and a plurality of such ejection outlets can be posited at high density, and therefore, small size recording apparatus capable of providing a high resolution can be provided, and color images can be easily formed. Therefore, the bubble jet recording method is now widely used in printers, copying machines, facsimile machines or another office equipment, and for industrial systems such as textile printing device or the like.
With the increase of the wide needs for the bubble jet technique, various demands are imposed thereon, recently.
For example, adjustment of a thickness of a protecting film is considered to optimize the heat generating element to meet the demand for the improvement in the ejection efficiency. This method is effective in that propagation efficiency of the generated heat to the liquid is improved.
In order to provide high quality images, driving conditions have been proposed by which the ink ejection speed is increased, and/or the bubble generation is stabilized to accomplish better ink ejection. As another example, from the standpoint of increasing the recording speed, flow passage configuration improvements have been proposed by which the speed of liquid filling (refilling) into the liquid flow path is increased.
Japanese Laid Open Patent Application No. SHO-63-199972 and so on discloses a flow passage structure shown in
FIG. 6
, (
a
), (
b
). The flow passage structure or the head manufacturing method disclosed in this publication has been made noting a backward wave (the pressure wave directed away from the ejection outlet, more particularly, toward a liquid chamber
12
) generated in accordance with generation of the bubble.
FIG. 6
, (
a
) and (
b
) disclose a valve
10
spaced from a generating region of the bubble generated by the heat generating element
2
in a direction away from the ejection outlet
11
.
In
FIG. 6
, (
b
), the valve
55
is manufactured from a plate and has an initial position as if it is stuck on the ceiling of the liquid flow path
10
. It lowers into the liquid flow path
10
by generation of the bubble.
Japanese Laid Open Patent Application No. SHO-63-199972 discloses a head wherein refilling of the recording liquid is improvement so that frequency responsivity is high.
On the other hand, in the bubble jet recording method, the heating is repeated with the heat generating element contacted with the ink, and therefore, a burnt material is deposited on the surface of the heat generating element due to burnt deposit of the ink. However, the amount of the deposition may be large depending on the materials of the ink. If this occurs, the ink ejection becomes unstable. Additionally, even when the liquid to be ejected is the one easily deteriorated by heat or even when the liquid is the one with which the bubble generated is not sufficient, the liquid is desired to be ejected in good order without property change.
Japanese Laid Open Patent Application No. SHO-61-69467, Japanese Laid Open Patent Application No. SHO-55-81172 and U.S. Pat. No. 4,480,259 disclose that different liquids are used for the liquid generating the bubble by the heat (bubble generating liquid) and for the liquid to be ejected (ejection liquid). In these publications, the ink as the ejection liquid and the bubble generation liquid are completely separated by a flexible film of silicone rubber or the like so as to prevent direct contact of the ejection liquid to the heat generating element while propagating the pressure resulting from the bubble generation of the bubble generation liquid to the ejection liquid by the deformation of the flexible film. The prevention of the deposition of the material on the surface of the heat generating element and the increase of the selection latitude of the ejection liquid are accomplished, by such a structure.
However, with this structure in which the ejection liquid and the bubble generation liquid are completely separated, the pressure by the bubble generation is propagated to the ejection liquid through the expansion-contraction deformation of the flexible film, and therefore, the pressure is absorbed by the flexible film to a quite high degree. In addition, the deformation of the flexible film is not so large, and therefore, the energy use efficiency and the ejection force are deteriorated although the some effect is provided by the provision between the ejection liquid and the bubble generation liquid.
Further improvement of liquid ejecting head is desired.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a liquid ejecting head wherein back wave is suppressed by a valve mechanism of a movable member, and a resistance applied to the ejection liquid by the liquid flow path is reduced to improve the refilling performance.
It is another object of the present invention to provide a liquid ejecting head or the like wherein an inertia, due to a backward wave, in a direction opposite from the liquid supply direction is suppressed, and simultaneously therewith, a meniscus retraction amount is reduced by a valve function of a movable member, so that refilling frequency is increased, and therefore, the printing speed or the like is improved.
It is a further object of the present invention to provide a liquid ejecting head wherein when the valve mechanism of the movable member operates by the generation of the bubble, the resistance applied by the liquid flow path is reduced to improve the ejection efficiency.
It is a further object of the present invention to provide a liquid ejecting head wherein the heat accumulation in the liquid on the heat generating element is significantly reduced, and the residual bubble on the heat generating element can be reduced, while the ejection efficiency and the ejection pressure are improved.
It is a further object of the present invention to provide a liquid ejecting head and so on wherein deposition of residual material on the heat generating element is reduced, and the range of the usable liquid is widened, and in addition, the ejection efficiency and the ejection force are significantly increased.
It is a further object of the present invention to provide a liquid ejecting method, a liquid ejecting head and so on, wherein the choice of the liquid to be ejected is made greater.
It is a further object of the present invention to provide a manufacturing method for a liquid ejecting head with which such a liquid ejecting head is easily manufactured.
It is a further object of the present invention to provide an inexpensive liquid ejecting head and a manufacturing method therefor wherein the number of parts constituting the liquid ejecting head is small.
According to an aspect of the present invention, there is provided a liquid
Asakawa Yoshie
Fukai Hisashi
Hayasaki Kimiyuki
Ishinaga Hiroyuki
Kashino Toshio
Beatty Robert
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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