Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-07-10
2002-09-10
Beatty, Robert (Department: 2852)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S065000, C347S085000
Reexamination Certificate
active
06447093
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head for discharging the desired liquid due to a bubble produced by applying heat energy to the liquid, a head cartridge using the liquid discharge head, and a liquid discharge apparatus, and more particularly to a liquid discharge head having a movable member which is displaceable using the produced bubble, a head cartridge using the liquid discharge head, and a liquid discharge apparatus.
Also, this invention is applicable to a printer for recording onto the recording medium such as paper, thread, fiber, cloths, leather, metal, plastics, glass, wood, and ceramics, a copying machine, a facsimile apparatus having a communication system, a word processor having a printer unit, as well as an industrial recording apparatus in combination with a variety of processors.
By the term “recording” as used in this invention is meant depositing not only a significant image such as a character or figure onto the recording medium, but also a less significant image such as a pattern thereon.
2. Related Background Art
Conventionally, an ink jet recording method, a so-called a bubble jet recording method, has been well known wherein an image is formed on the recording medium in such a manner as to apply the thermal energy to the ink to bring about a state change in the ink which will cause a steep volume change (or produce a bubble) in the ink, and discharge the ink from the discharge ports under the working force produced by this state change. A recording apparatus using this bubble jet recording method has integrally arranged therein a discharge port for discharging the ink, an ink flow passage communicating to this discharge port, and an electricity-heat converter as energy generating means for discharging the ink which is disposed within an ink flow passage, as disclosed in U.S. Pat. No. 4,723,129.
With such a recording method, there are a number of advantages that a high-quality image can be recorded at high speed and with low noise, and a high resolution image or a color image can be easily recorded by a compact apparatus, because a head for use with this recording method can have discharge ports for discharging the ink arranged at high density. Therefore, this bubble jet recording method has been recently applied to numerous office equipments such as a printer, a copying machine, and a facsimile, as well as even an industrial system such as a printing apparatus for cloths.
Thus, as the bubble jet technology has been utilized in various fields of products, numerous requirements as described below have been further raised in recent years.
For example, to cope with the requirements for higher energy efficiency, the optimization of a heat generating member by adjusting the thickness of a protective membrane can be considered. This method is effective in improving the efficiency of transferring generated heat to the liquid.
Also, to obtain a high-quality image, a drive condition for effecting a liquid discharge method with which the ink discharge can be excellently made at high speed of ink discharge and based on stable production of bubble has been proposed, or from the viewpoint of high speed recording, there has been proposed a liquid discharge head having an improved shape of flow passage to attain a higher speed of refilling the discharged liquid into liquid flow passages.
Of the shapes of flow passage, a flow passage structure as shown in
FIGS. 63A and 63B
, has been described in Japanese Patent Application Laid-open No. 63-199972. The flow passage structure or head manufacturing method as described in this patent paid attention to a back wave (pressure propagating in a direction opposite to the direction toward the discharge port, i.e., pressure toward a liquid chamber
2012
) which is yielded with the production of bubble. This back wave is well known as a loss energy as this wave does not propagate in the discharge direction.
The invention as illustrated in
FIGS. 63A and 63B
discloses a valve
2010
located away from the area of producing a bubble to be formed by a heating element
2002
, and opposite the discharge port
2011
with respect to the heating element
2002
.
In
FIG. 63B
, this valve
2010
is disclosed as having an initial position where it is attached to a ceiling of a flow passage
2003
according to a manufacturing method using a plate, and this valve is hung down in the flow passage
2003
with the production of bubble. This invention is disclosed as suppressing the energy loss by controlling part of the back wave as above mentioned with the valve
2010
.
However, it will be understood that with this constitution, it is not practical for the discharge of liquid to suppress part of the back wave with the valve
2010
, by investigating when the bubble is produced within the flow passage
2003
holding the liquid to be discharged.
The back wave as such is not directly involved in discharging, as previously described. At the time when this back wave occurs within the flow passage
2003
, the pressure of bubble directly involved in discharging is ready to discharge the liquid from within the flow passage
2010
, as shown in FIG.
63
A. Accordingly, it is clear that suppressing part of the back wave has no significant effect on the discharge.
On the other hand, in the bubble jet recording method, because the heating is repeated in the state where the heat generating member is in contact with the ink, there occur deposits on the surface of the heat generating member, due to burning of the ink, but a large amount of deposits might occur, depending on the type of ink, thereby resulting unstable production of bubble, which made it difficult to perform excellent ink discharge. Also, a method is desired wherein even when the liquid to be discharged is likely to degrade due to heat, or is not sufficiently bubbled, the ink can be discharged excellently without changing the quality of the light to be discharged.
From such a viewpoint, a method wherein using the liquid for bubbling due to heat (bubbling liquid) and the liquid for discharging (discharge liquid) which are different, the discharge liquid is discharged by transferring a pressure due to bubbling to the discharge liquid has been disclosed in Japanese Patent Application Laid-open No. 61-69467, Japanese Patent Application Laid-open No. 55-81172, and U.S. Pat. No. 4,480,259. In these patents, the ink which is the discharge liquid and the bubbling liquid are completely separated via a flexible membrane of e.g. silicone rubber to prevent the discharge liquid from making direct contact with the heat generating member, and the pressure due to bubble generation of the bubbling liquid is transferred to the discharge liquid owing to deformation of the flexible membrane. By such constitution, to prevent the deposits on the surface of heat generating member can be attained, with a greater degree of freedom in selecting the discharge liquid.
However, in a head in which the discharge liquid and the bubbling liquid are completely separated, as previously described, the pressure due to bubbling will be considerably absorbed by the flexible membrane as the pressure in bubbling is transferred to the discharge liquid, owing to expansion and deformation of flexible membrane. Also, there was a risk that the energy efficiency or discharge power may be lowered, because the deformation of flexible membrane is not very great, even though there is any effect in separating the discharge liquid and the bubbling liquid.
As above described, in a liquid discharge head for discharging the liquid due to a pressure caused by a bubble produced, it is important to bring about film boiling evenly. If there is any dispersion in forming the bubble, the discharge of liquid will become unstable.
Also, the liquid flow passage is divided into two portions for the discharge liquid and the bubbling liquid, a bubble is produced in the bubbling liquid by generating the heat with the heat generating member in the liquid flow passage for the bubbling liquid, an
Asakawa Yoshie
Ishinaga Hiroyuki
Kashino Toshio
Kudo Kiyomitsu
Nagashima Akira
Beatty Robert
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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