Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-07-09
2002-04-30
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06378992
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharging head in which desired liquid is discharged by growth of a bubble generated in liquid by applying thermal energy to the liquid, a head cartridge using such a liquid discharging head, and a liquid discharging apparatus having such a liquid discharging head.
The present invention is applicable to printers for effecting the recording on a recording medium such as a paper sheet, a thread sheet, a fiber sheet, a cloth, a leather sheet, a metal sheet, a plastic sheet, glass, wood, ceramic sheet and the like, copying machines, facsimiles having a communication system, word processors having a printer portion, and to industrial recording apparatuses compositely combined to various processing devices.
Incidentally, in this specification and claims, a term “recording” means not only application of a significant image such as a character or a figure onto a recording medium but also application of a meaningless image such as a pattern onto a recording medium.
2. Related Background Art
There has been proposed an ink jet recording method, i.e., a bubble jet recording method in which change in state of ink including abrupt change in volume of ink (generation of a bubble) is caused by applying thermal energy to the ink and the ink is discharged from a discharge opening by an acting force due to such change in the ink state, thereby forming an image on a recording medium by adhering the ink to the recording medium. As disclosed in U.S. Pat. No. 4,723,129, a liquid discharging head used in such a bubble jet recording method includes discharge openings for discharging ink, ink passages communicated with the discharge openings, and heat generating elements (electro/thermal converters) disposed in the ink passages and acting as energy generating means for generating energy for discharging the ink.
FIG. 33
schematically shows a construction of a conventional liquid discharging head. Now, an arrangement and an assembling method of the conventional liquid discharging head will be briefly explained with reference to FIG.
33
.
A liquid discharging head
200
comprises a heater board (element substrate)
101
on which a plurality of heaters (heat generating resistance elements) for applying thermal energy to ink are disposed, a grooved top plate
150
having a plurality of grooves constituting nozzles and a common liquid chamber communicated with the grooves, and a holding spring
178
. The liquid discharging head
200
includes a chip tank
180
acting as a liquid supply member for the head
200
when connected to an ink tank
190
, and a base plate
170
as a substrate having a circuit board
171
. The liquid discharging head is assembled with the ink tank
190
to form a head cartridge.
In order to assemble these elements, after the heater board
101
is adhered to the base plate
170
, the top plate
150
is temporarily adhered to the heater board
101
with the heaters aligned with the nozzle grooves. Thereafter, in a condition that the top plate is fixed under pressure with the heater board
101
by a press spring, the top plate and the heater board are heat-welded to the base plate
170
, together with the chip tank
180
. Lastly, the chip tank
180
is connected to the ink tank
190
by fitting the base plate
170
onto positioning pins
194
,
195
of the ink tank
190
and heat-welding the base plate to the ink tank.
According to the ink jet recording method using such a liquid discharging head, a high quality image can be recorded at a high speed with low noise.
Further, in the head performing such a recording method, since the discharge openings for discharging the ink can be arranged with high density, not only an image having high resolving power but also a color image can easily be recorded with a compact structure. Thus, the bubble jet recording method has recently been used in various office equipments such as printers, copying machines, facsimiles and the like, as well as industrial systems such as print devices.
However, when the conventional liquid discharging head as shown in
FIG. 33
is assembled, since the number of parts is great and the assembling processes are complicated, the liquid discharging head cannot be manufactured cheaply. Accordingly, the inventors aims to provide a liquid discharging head having a structure which can be assembled and manufactured easily and cheaply.
First of all, a liquid discharging liquid passage structure and a liquid discharging principle applied to a liquid discharging head of the present invention will be explained with reference to
FIGS. 1A
,
1
B,
1
C,
1
D,
2
,
3
,
4
,
5
,
6
,
7
,
8
A and
8
B.
FIGS. 1A
to
1
D are schematic sectional views of a liquid discharging head taken along a liquid passage and showing liquid discharging steps, and
FIG. 2
is a partial sectional perspective view of the liquid discharging head.
The liquid discharging head according to the illustrated embodiment includes an element substrate
1
on which a heat generating element
2
(rectangular heat generating resistance member having a dimension of 40 &mgr;m×105 &mgr;m, in
FIG. 2
) for acting thermal energy on liquid (as discharge energy generating element for generating energy for discharging the liquid) is arranged, and a liquid passage
10
is formed above the element substrate
1
in correspondence to the heat generating element
2
. The liquid passage
10
communicates with a discharge opening
18
and also communicates with a common liquid chamber
13
for supplying the liquid to a plurality of liquid passages
10
, and receives the liquid corresponding to the discharged liquid from the common liquid chamber
13
.
Within the liquid passage
10
, above the element substrate
1
, a movable member
31
formed from material having elasticity such as metal is disposed in a cantilever fashion in a confronting relation to the heat generating element
2
. One end of the movable member
31
is secured to bases (support member)
34
formed by patterning photosensitive resin on walls of the liquid passage
10
and on the element substrate
1
. As a result, the movable member
31
is held in such a manner that the movable member can be displaced around a fulcrum (support portion)
33
.
The movable member
31
has the fulcrum (support portion; fixed end)
33
positioned at an upstream side of large flow of liquid flowing from the common liquid chamber
13
through the movable member
31
to the discharge opening
18
and a free end (free end portion)
32
disposed at a downstream side of the fulcrum
33
, and is disposed in a confronting relation to the heat generating element
2
to cover the heat generating element
2
and is spaced apart from the heat generating element
5
upwardly by about 15 &mgr;m. A bubble generating area is defined between the heat generating element and the movable member. Incidentally, kinds, configurations and dispositions of the heat generating element
2
and the movable member
31
are not limited to the above-mentioned ones, but, the heat generating element and the movable member may be configured and disposed to control growth of a bubble and transmission of bubble pressure, which will be described later. In the present invention, since the free end
32
has an adequate width, growing power of the bubble can easily be directed toward the discharge opening
18
. Incidentally, for the explanation of a liquid flow which will be described later, the liquid passage
10
is explained to have a first liquid passage
14
(at one side of the movable member
31
) directly communicated with the discharge opening
18
and a second liquid passage
16
(at the other side of the movable member) including a bubble generating area
11
and a liquid supply passage
12
.
Heat is applied to the liquid in the bubble generating area
11
between the movable member
31
and the heat generating element
2
by heating the heat generating element
2
, and a bubble is formed in the liquid by a film-boiling phenomenon as disclosed in U.S. Pa
Ikeda Masami
Kashino Toshio
Koyama Shuji
Kudo Kiyomitsu
Masuda Kazuaki
Barlow John
Brooke Michael S.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
LandOfFree
Liquid discharging head, method for manufacturing such... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid discharging head, method for manufacturing such..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid discharging head, method for manufacturing such... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2925111