Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-07-09
2002-10-01
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06457816
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid jet head for discharging a desired liquid by causing thermal energy to act upon liquid for the creation of air bubbles, a head cartridge using such liquid jet head, a liquid jet apparatus, a method for manufacturing liquid jet heads, a liquid discharging method, a recording method, and recorded objects obtained by utilizing such liquid discharging method.
More particularly, the present invention relates to a liquid jet head provided with movable members displaceable by the utilization of the creation of air bubbles, a head cartridge using such liquid jet head, and a liquid jet apparatus or the invention relates to a liquid discharging method for discharging liquid by displacing. movable members by the utilization of the creation of air bubbles, and a recording method.
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 also, 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 discharging 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 is disclosed in the specification of Japanese Patent Application Laid-Open No. 63-199972 as shown in
FIGS. 47A and 47B
. The structure of the liquid flow paths and the method for manufacturing disclosed in the specification thereof 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.
The invention represented in
FIGS. 47A and 47B
discloses a valve
55
, which is arranged away from the air bubble generating area formed by the heat generating element
2
, and which is positioned on the side opposite to the discharge port
18
with respect to the heat generating element
2
.
As shown in
FIG. 47B
, this valve
55
is set at the initial position thereof such as adhesively bonded to the ceiling of the liquid flow path
10
by method of manufacture utilizing a plate material or the like. In the disclosure, the valve is described as such to be caused to hang down in the liquid flow path
10
along the creation of air bubble. It is also referred to in the disclosure that the invention is designed to control the aforesaid back waves partly by the provision of the valve
55
in order to suppress the energy loss.
However, with respect to the structure thus disclosed, it is clearly understandable that the partial suppression of the back waves by means of the valve
55
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 as shown in FIG.
47
B. 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 of the back waves.
Also, in the specification of Japanese Patent Application Laid-Open No. 63-199972, an invention of the head is disclosed. This head is made excellent in the frequency response by improving the refilling of recording liquid. In accordance with such invention, a sub-flow path is arranged, and this path is connected with the corresponding nozzle in the vicinity of the heater. At the time of refilling, ink is also supplied from this sub-flow path, thus attempting to make the refilling period shorter.
However, with the head thus structured, part of the discharging power generated at the time of bubble generation escapes to the sub-flow path, and there is a fear that the discharging efficiency is lowered inevitably. 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 mak
Ishinaga Hiroyuki
Kashino Toshio
Sugama Sadayuki
Sugiyama Hiroyuki
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Stephens Juanita
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