Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-12-03
2002-10-15
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S065000
Reexamination Certificate
active
06464342
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head for use in a printer or video printer which is used as an output terminal for a copying machine, facsimile apparatus, word processor or host computer, a manufacturing method for said liquid discharge head, a head cartridge having said liquid discharge head mounted thereon, and a liquid discharge apparatus. In particular, this invention relates to a liquid discharge head comprising a substrate formed with electrothermal converting elements for producing heat energy for use as the energy for recording, which performs the recording by discharging the recording liquid (ink or the like) as flying liquid droplets from the discharge openings (orifices) onto the recording medium, a manufacturing method for said liquid discharge head, a head cartridge having said liquid discharge head mounted thereon, and a liquid discharge apparatus.
Note that “recording” in this invention means applying meaningful images such as characters or figures, as well as other images such as patterns, onto the recording medium.
2. Related Background Art
An ink jet recording method or so-called bubble jet recording method has been conventionally well-known, which forms the image by applying the heat energy to cause the state change accompanying rapid volume change to occur in the ink and discharging the ink from the discharge openings using working force by this state change of ink. A recording apparatus relying on this bubble jet recording method is typically provided with discharge openings for discharging the ink, and ink flow channels in communication with these discharge openings, and heating elements (electrothermal converting elements) as energy generating means for discharging the ink disposed in the ink flow channels, as disclosed in U.S. Pat. No. 4,723,129.
With such recording method, a high quality image can be recorded at high speed and with low noise, and because the head for this recording method allows the discharge openings for discharging the ink to be arranged at high density, there are many good advantages such as easily producing a recording image of high resolution, or, further, a color image, with a small apparatus. Therefore, this bubble jet recording method has been recently utilized for many types of office equipment such as printers, copying machines, and facsimile apparatus, and further has come into use for industrial systems such as printing machines.
Development of this bubble jet technology into a variety of products has raised the following various demands in recent years.
For example, examining the request to improve the energy efficiency includes regulating the thickness of the protective film in the heating element. This examination is effective in improving the efficiency of transferring the produced heat to liquid.
In order to obtain a high quality image, there have been proposed the driving conditions to provide a liquid discharge method which is capable of discharging the ink excellently based on the stable production of bubbles, with high rate of discharging the ink, and from the viewpoint of high speed recording, the improved shape of liquid flow channels to obtain a liquid discharge head with high rate of filling the ink to be discharged into the liquid flow channels.
Turning back to the principle of discharging the liquid, careful research has been made to provide a novel liquid discharge method using the bubbles that have never been obtained conventionally, and a head for use therewith, as proposed in Japanese Patent Application Laid-Open No. 9-201966.
In the following, a conventional liquid discharge method and a head for use therewith as disclosed in Japanese Patent Application Laid-Open No. 9-201966 will be described with reference to
FIGS. 19A
to
19
D.
FIGS. 19A
to
19
D are views for explaining the discharge principle in a conventional liquid discharge head, or a cross-sectional view taken in a direction of liquid flow channels. Also,
FIG. 20A
is a perspective view, partially broken, of the liquid discharge head as shown in
FIGS. 19A
to
19
D. The liquid discharge head as shown in
FIGS. 19A
to
19
D is the most fundamental constitution for enhancing the discharge power or discharge efficiency by controlling the propagation direction of pressure caused by bubble or the growth direction of bubble in discharging the liquid.
Note that “upstream” and “downstream” as used in the following description are taken with respect to the flow direction in which liquid passes from a liquid supply source via above a bubble producing region (or movable member) to the discharge openings.
The term “downstream” in respect of a bubble itself is represented by the portion of bubble on the discharge opening side which is supposed to directly take effect in the discharging of a liquid droplet. More specifically, it means the bubble produced in the heating element downstream in the flow direction as above or the constitutional direction relative to the center of bubble, or in the downstream region from its areal center.
Furthermore, “comb tooth” refers to the shape having the support of a movable member as a common member and its free end opened.
In an example of
FIGS. 19A
to
19
D, a liquid discharge head is provided with a heat generator
1102
for applying heat energy on the liquid, as the discharge energy generating element to discharge the liquid, on an element substrate
1101
, a liquid flow channel
1103
being disposed, corresponding to the heat generator
1102
, above this element substrate
1101
. The liquid flow channel
1103
is in communication with a discharge opening
1104
, as well as a common liquid chamber
1105
for supplying the liquid to a plurality of liquid flow channels, from which the liquid in an amount corresponding to the liquid discharged from the discharge opening
1104
is received.
On the element substrate
1101
in this liquid flow channel, a planar movable plate
1106
made of elastic material such as metal is provided opposed to the heat generator
1102
and in cantilever form. This movable plate
1106
is fixed at its one end to a plate base (support member)
1107
formed by patterning photosensitive resin on a wall of the liquid flow channel
1103
or the element substrate
1101
. Thereby, the movable plate
1106
is held on the plate base
1107
, with a fulcrum (support portion)
1108
.
By making the movable plate
1106
like a comb-tooth, it can be fabricated simply and easily, and the alignment for the plate base
1107
can be made easily.
This movable plate
1106
is disposed at a position facing and covering the heat generator
1102
, about 15 &mgr;m away, so as to have the fulcrum (support portion: fixed end)
1108
upstream in the great flow passing from the common liquid chamber
1105
via above the movable plate
1106
to the discharge opening
1104
by operation of discharging the liquid, and the free end downstream of this fulcrum
1108
. A bubble producing region
1110
is between this heat generator
1102
and the movable plate
1106
.
By generating heat with the heat generator
1102
and applying that heat to the liquid in the bubble producing region
1110
between the movable plate
1106
and the heat generator
1102
, a bubble
1111
is produced in that liquid, based on the film boiling phenomenon as described in U.S. Pat. No. 4,723,129 (see FIG.
19
B). The pressure caused by the produced bubble
1111
will act predominantly on the movable plate
1106
, to displace the movable plate
1106
around the fulcrum
1108
to be open toward the discharge opening
1104
, as shown in
FIGS. 19B
,
19
C or
FIGS. 20A and 20B
. By displacement of the movable plate
1106
or displaced state, the pressure caused by produced bubble
1111
is propagated or the growth of bubble
1111
itself led to the discharge opening
1104
. At this time, the top end portion of the free end
1109
has a width, which makes it easier to lead bubbling power of the bubble
1111
to the discharge opening
1104
, with radical improvements in the d
Imanaka Yoshiyuki
Kashino Toshio
Kubota Masahiko
Mochizuki Muga
Ozaki Teruo
Barlow John
Stephens Juanita
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