Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-08-31
2003-03-18
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S065000
Reexamination Certificate
active
06533400
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head for applying a thermal energy to a liquid to generate a bubble and discharge the liquid, a method of manufacturing the liquid discharge head, and a liquid discharge apparatus using the liquid discharge head.
Moreover, the present invention can be applied to apparatuses for performing recording on recording media such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramic, and the like, such as a printer, a copying machine, a facsimile machine provided with a communication system, and a word processor provided with a printer section, and further to an industrial recording apparatus combined with various processing apparatuses in a composite manner.
Additionally, “recording” in the present invention means not only that a character image, a diagram image or another meaningful image is given to the recording medium, but also that a pattern image or another meaningless image is given.
2. Related Background Art
In conventional recording apparatuses such as a printer, an ink jet recording method, a so-called bubble jet recording method is known which comprises applying heat or another energy to a liquid ink in a flow path to generate a bubble, discharging the ink from a discharge port by an action force based on a steep volume change with the bubble, and attaching the ink to a recording medium to form an image. In a recording apparatus using the bubble jet recording method, as disclosed in U.S. Pat. No. 4,723,129 or the like, the discharge port for discharging the ink, the flow path connected to the discharge port, and an electrothermal converting element as energy generating means, disposed in the flow path, for discharging the ink are usually arranged.
According to the recording method, a high quality level image can be recorded with a high speed and a low noise, and the discharge ports for discharging the ink can be arranged with a high density in a head to perform the recording method, which provides many advantages that a high-resolution recorded image and further a color image can easily be obtained with a small-sized apparatus. Therefore, in recent years the bubble jet recording method has been utilized in many office apparatuses such as a printer, a copying machine, and a facsimile machine, and further in industrial systems such as a textile printing machine.
Various demands have been raised with utilization of such bubble jet technique in products of various fields, and for example, there are proposed drive conditions for providing a liquid discharge method to perform a satisfactory ink discharge with a fast ink discharge speed based on a stable bubble generation in order to obtain a high quality image, or improvement of a flow path configuration to obtain a liquid discharge head fast in refill speed of a discharged liquid into a liquid flow path from a viewpoint of high-speed recording.
Above all, in a head for generating the bubble in a nozzle and discharging the liquid with bubble growth, the bubble growth in a direction opposite to the discharge port and a generated liquid flow are known as factors for deteriorating discharge energy efficiency and refill property, and the invention provided with a structure for enhancing the discharge energy efficiency and refill property is proposed in European Patent Application Laid-Open No. EP0436047A1.
In the invention described in the publication, a first valve, disposed between the vicinity of the discharge port and a bubble generator, for shutting them off, and a second valve, disposed between the bubble generator and an ink supply section, for completely shutting them off are alternately opened/closed (FIGS. 4 to 9 of EP436047A1). For example, in an example of
FIG. 7
of the publication, as shown in
FIG. 23
, a heat generating member
110
is disposed substantially in the middle of an ink flow path
112
between an ink tank
116
and a nozzle
115
on a substrate
125
for forming an inner wall of the ink flow path
112
. The heat generating member
110
lies in a division
120
with an entirely closed periphery inside the ink flow path
112
. The ink flow path
112
is constituted of the substrate
125
, thin films
123
,
126
directly laminated on the substrate
125
, and ligulate pieces
113
,
130
as closing members. The opened ligulate piece is shown by a broken line in FIG.
23
. Another thin film
123
extending in a plane parallel to the substrate
125
and terminating in a stopper
124
shuts off on the ink flow path
112
. When the bubble is generated in the ink, a free end of the ligulate piece
130
in a nozzle area closely attached to the stopper
126
in a stationary state is displaced upward, and the ink liquid is discharged via the ink flow path
112
and nozzle
115
from the division
120
. In this case, since the ligulate piece
113
disposed in an area of the ink tank
116
closely abuts on the stopper
124
in the stationary state, the ink liquid in the division
120
fails to go toward the ink layer
116
. When the bubble in the ink vanishes, the ligulate piece
130
is displaced downward to again abut on the stopper
126
. Moreover, the ligulate piece
113
falls down in the ink division
120
, and accordingly the ink liquid flows into the division
120
.
SUMMARY OF THE INVENTION
In the invention described in EP0436047A1, however, each of three chambers of the vicinity of the discharge port, bubble generator and ink supply section is divided into two, the ink following a liquid droplet trails long during discharge, and the number of satellite dots considerably increases as compared with an ordinary discharge system for performing bubble growth, shrinkage, and bubble vanishing (it is assumed that an effect of meniscus retreat by the bubble vanishing cannot be used). Moreover, the valve on the side of the bubble discharge port causes much loss of discharge energy. Furthermore, during refill (during ink replenishment to the nozzle) the liquid is supplied to the bubble generator with bubble vanishing, but no liquid can be supplied to the vicinity of the discharge port until the next bubbling occurs, therefore a dispersion of discharged liquid droplet is large, further a discharge response frequency is remarkably small, and a practical level cannot be obtained.
In the present invention, there is proposed an invention for enhancing an inhibition efficiency of a bubble growth component in a direction opposite to a discharge port and contrarily for enhancing a discharge efficiency based on a new idea to find out an inventive method for satisfying a highly efficient refill property and a head constitution.
As a result of intensive researches, the present inventor et al. have found that in a nozzle structure of a liquid discharge head for generating a bubble in a linearly formed nozzle and discharging a liquid with bubble growth, a function of a special check valve inhibits the bubble growth in a (rearward) direction opposite to a discharge port, and a rearward discharge energy can effectively be utilized on a discharge port side. Additionally, it has been found that the special check valve function inhibits a rearward bubble growth component, an efficient refill property is provided, and a discharge response frequency can therefore be set to be considerably high.
Specifically, an object of the present invention is to establish an inventive discharge system (structure) for simultaneously enhancing discharge power and discharge frequency by a nozzle structure and discharge method using an inventive valve function and for achieving a high speed, high image quality head of a level which has not been heretofore achieved.
According to the present invention obtained in the process of the aforementioned research, there is provided a liquid discharge head comprising: a plurality of discharge ports for discharging a liquid; communicates with each of the discharge ports and which comprise a bubble generating area for generating a bubble in the liquid; bubble generating means for generating
Ikeda Masami
Inoue Ryoji
Kubota Masahiko
Kudo Kiyomitsu
Saito Takashi
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Stephen Juanita
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