Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-12-07
2001-03-06
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S063000, C347S056000
Reexamination Certificate
active
06196667
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liquid discharging head for discharging desired liquid by the creation of bubbles caused by making heat energy act on the liquid, a method of manufacturing the liquid discharging head, a head cartridge carrying the liquid discharging head thereon and a liquid discharging apparatus. The invention particularly relates to a liquid discharging head having a movable member displaceable by the utilization of the creation of bubbles, a method of manufacturing the liquid discharging head, a head cartridge carrying the liquid discharging head thereon and a liquid discharging apparatus.
The word “recording” in the present invention means not only imparting images having meanings such as characters and figures to a recording medium, but also imparting images having no meaning such as patters to the recording medium.
2. Related Background Art
There is known an ink jet recording method, i.e., a so-called bubble jet recording method of giving energy such as heat to ink to thereby create in the ink a state change resulting in a steep volume change (creation of a bubble), discharging the ink from a discharge port by an acting force based on the state change, causing the ink to adhere onto a recording medium and effecting image formation. A recording apparatus using this bubble jet recording method, as disclosed in Japanese Patent Publication No. 61-59911 and Japanese Patent Publication No. 61-59914, is generally provided with a discharge port for discharging ink therefrom, an ink flow path communicating with this discharge port, and a heating member (electro thermal converting member) as energy generating means disped in the ink flow path for discharging the ink.
According to the recording method as described above, images of high dignity can be recorded at a high speed and with low noise and also, in a head for carrying out this recording method, discharge ports for discharging the ink therefrom can be disposed highly densely, and this leads to many excellent points that recorded images of high resolution and further, color images can be easily obtained by a compact apparatus, etc. In recent years, this bubble jet recording method has been utilized in many office instruments such as printers, copying apparatuses and facsimile apparatuses, and has come to be utilized even in an industrial system such as a textile printing apparatus.
So, some of the inventors have returned to the principle of liquid discharge and have energetically carried out researches to provide a novel liquid discharging method utilizing bubbles which could heretofore not be obtained and a head or the like used therein, and filed Japanese Patent Laid-Open Application No. 9-201966, etc.
A prior-art liquid discharging method disclosed in Japanese Patent Laid-Open Application No. 9-201966, etc. and a head used therein will now be described with reference to
FIGS. 12A
to
12
D, etc. of the accompanying drawings.
FIGS. 12A
to
12
D illustrate the principle of discharge in the prior-art liquid discharging head, and is a cross-sectional view in the direction of a liquid flow path.
FIG. 13
is a fragmentary broken-away perspective view of the liquid discharging head shown in
FIGS. 12A
to
12
D. The liquid discharging head shown in
FIGS. 12A
to
12
D and
FIG. 13
is of the most basic construction in which when liquid is to be discharged, the direction of propagation of pressure based on a bubble and the direction of growth of the bubble are controlled to thereby improve discharging force and discharging efficiency.
The words “upstream” and “downstream” used in the following description are represented as expressions with respect to the direction of flow of liquid going from a supply source of liquid toward discharge ports via above a bubble creating area (or a movable member), or with respect to the direction in this construction.
The “downstream side” with respect to the bubble itself represents the discharge port side portion of the bubble which is regarded as directly acting on chiefly the discharge of a liquid droplet. More specifically, it means a bubble created at the downstream side with respect to the direction of flow or the direction in the construction, relative to the center of the bubble, or an area downstream of the center of the area of a heat generating member.
Further, “comb-teeth” means a shape in which the fulcrum portion of the movable member is a common portion and the front of the free end thereof is opened.
In the example shown in
FIGS. 12A
to
12
D, the liquid discharging head is such that as a discharge energy generating element for discharging the liquid, a heating member
102
for making heat energy act on the liquid (in the present example, a heat generating resistance member of a shape of 40 &mgr;m×105 &mgr;m) is provided on an element substrate
101
and liquid flow paths
103
are disposed on the element substrate
101
correspondingly to the heating member
102
. The liquid flow paths
103
communicate with discharge ports
104
and also communicate with a common liquid chamber
105
for supplying the liquid to the plurality of liquid flow paths
103
, and receive from this common liquid chamber
105
an amount of liquid corresponding to the liquid discharged from the discharge ports
104
.
On the element substrate
101
for these liquid flow paths
103
, a plate-like movable member
106
formed of a resilient material such as a metal and having a flat portion is provided in a cantilever fashion so as to be opposed to the aforementioned heating member
102
. One end of this movable member
106
is fixed to a pedestal (support member)
107
or the like formed by patterning photosensitive resin or the like on the wall of the liquid flow paths
103
or the element substrate
101
. Thereby, the movable member
106
is held on the pedestal
107
, and a fulcrum (fulcrum portion)
108
is constituted.
Also, by making the movable member
106
comb-teeth-like, the movable member
106
can be made simply and inexpensively, and the alignment thereof with the pedestal
107
can be done easily.
This movable member
106
is disposed at a distance of the order of
15
um from the heating member
102
in such a manner as to cover the heating member
102
at a location facing the heating member
102
so as to have the fulcrum (fulcrum portion: fixed end)
108
upstream of a great flow flowing from the common liquid chamber
105
to the discharge port
104
side via above the movable member
106
by the discharging movement of the liquid, and have a free end (free end portion)
109
downstream with respect to the fulcrum
108
. The space between the heating member
102
and the movable member
106
provides a bubble creating area
110
.
The heating member
102
is caused to generate heat to thereby make the heat act on the liquid in the bubble creating area
110
between the movable member
106
and the heating member
102
, thus causing the liquid to create a bubble
111
based on a film boiling phenomenon as described in U.S. Pat. No. 4,723,129, etc. (see FIG.
12
B). Pressure based on the creation of the bubble
111
and the bubble
111
preferentially act on the movable member
106
, which is thus displaced so as to be greatly opened toward the discharge port
104
side about the fulcrum
108
, as shown in
FIGS. 12B and 12C
or FIG.
13
. By the displacement or displaced state of the movable member
106
, the propagation of the pressure based on the creation of the bubble
111
or the growth of the bubble
111
itself is directed to the discharge port
104
side. Also, at this time, the bubbling power of the bubble
111
becomes easy to direct to the discharge port
4
side because the tip end portion of the free end
109
has a width, and a fundamental improvement in the discharging efficiency and discharging force or discharging speed of a liquid droplet can be achieved.
As described above, the technique disclosed in Japanese Patent Laid-Open Application No. 9-201966, etc. is the technique of positively controll
Hiroki Tomoyuki
Ikeda Masami
Imanaka Yoshiyuki
Ishinaga Hiroyuki
Kubota Masahiko
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Mouttet Blaise L
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