Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-02-12
2002-04-02
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06364462
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to methods for recording images and apparatuses for recording images such as copying machine, facsimile and printer, and more particularly, to a method and an apparatus for recording images by intermittently allowing colorant particles to be ejected on a recording medium, thereby selectively applying on or permeating the particles into the medium to form images thereon.
2. Description of the Background Art
A conventional image recording apparatus has been proposed, by which colorant is evaporated, then ionized, and ejected intermittently based on an electrical signal corresponding to image data to be recorded, whereby the colorant is applied on or permeated into a recording medium to provide images. Such an image recording apparatus is for example disclosed by Japanese Patent Laying-Open No. 8-300803. The image recording apparatus will be now described.
FIG. 8
is a view for use in illustration of an example of a conventional image recording apparatus. In
FIG. 8
, the image recording apparatus includes a printing head
1
. Printing head
1
is formed by integrating a heating device
10
to heat and evaporate colorant, a charging device
30
to charge the evaporated colorant, and an ejecting device
50
to intermittently eject the charged colorant based on an electrical signal corresponding to image data to be recorded.
Heating device
10
includes an electrical heater
10
B. Charging device
30
includes an ionization electrode portion
30
A having a needle shape for example, and a counter electrode portion
30
B having a plate shape. In ejecting device
50
, a back plate electrode portion
50
C is provided at the back of a recording medium RM in order that the charged colorant through an ejecting outlet
90
onto recording medium RM for ejection with electrostatic force, an intermediate electrode portion
50
A (
50
A
1
,
50
A
2
,
50
A
3
) is provided around ejecting outlet
90
, and an intermediate electrode driving control portion
50
E is also provided. Intermediate electrode portion
50
A (
50
A
1
,
50
A
2
,
50
A
3
) has a so-called shutter function to physically or electrically control the ejection of the colorant. Intermediate electrode driving portion
50
E outputs a driving signal corresponding to an input electrical signal corresponding to image data and controls intermediate electrode portion
50
A (
50
A
1
,
50
A
2
,
50
A
3
) in a shutter manner. An insulating plate
50
D is provided around intermediate electrode portion
50
A (
50
A
1
,
50
A
2
,
50
A
3
).
In printing head
1
, powder ink IP is previously stored. Heating device
10
to heat ink IP is provided at the lower half of printing head
1
. At the upper half of printing head
1
, a wire electrode from 50 &mgr;m to 80 &mgr;m is provided as charging device
30
to charge heated and evaporated ink IPG. At the upper part of printing head
1
, an ejecting outlet
90
of &phgr;300 &mgr;m to allow evaporated ink IPG to be ejected therethrough is provided, and intermediate electrode portion
50
A (
50
A
1
,
50
A
2
,
50
A
3
) having an inner diameter of &phgr;300 &mgr;m is provided to surround ejecting outlet
90
.
The operations of the image recording apparatus shown in
FIG. 8
will be now described. During printing, ink IP is heated to 200°C. and evaporated. When colored inks are used, the colorant may include as a base, anthoraisothiazole, quinophthalone, pyazolonazo, pyiidone azo, styryl or the like for yellow, anthraquinone, dicyanoimidazole, thiadiazoleazo, tricyanovinyl, or the like for magenta, and azo, anthraquinone, naphthoquinone, indoaniline, or the like for cyan. Evaporated ink IPG is ionized by applying a voltage at +5 kV to charging device
30
. Ionized evaporated ink IPG is controlled to be ejected on recording medium RM in response to application of a prescribed voltage to back plate electrode portion
50
C and intermediate electrode portion
50
A (
50
A
1
,
50
A
2
,
50
A
3
).
The image recording apparatus shown in
FIG. 8
however suffers from the following disadvantage. When ink is ionized by a strong electric field in the vicinity of ionization electrode portion
30
A, the ionization efficiency is low, i.e., the efficiency of transporting of evaporated ink IPG into a possible ionization area and the efficiency of ionization of evaporated ink IPG thus transported in total are low, therefore the ratio of effective evaporated ink which can be controlled for ejection is small, and the recording speed is low. If an electric field to ionize evaporated ink IPG is generated, air in the vicinity of ionization electrode portion
30
A is also ionized. Therefore, the ions act as a driving force to cause a flow of ionized air, evaporated ink IPG present in the area where the ionized air flows is brought by the flow and sticks to counter electrode portion
30
B. As a result, the percentage of evaporated ink IPG which can be used for recording is low.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and an apparatus for recording images, which allows for increase in the charging efficiency of colorant particles, the charge amount, the use efficiency and the recording speed and permits good picture qualities to be provided.
In order to achieve this object, an image recording method according to the present invention includes the following characteristics. More specifically, the method includes the steps of generating colorant particles from ink colorant, charging the generated colorant particles, and intermittently ejecting the charged colorant particles onto a recording medium by electrostatic force based on an electrical signal corresponding to prescribed image data.
The colorant particles are transported sequentially from the generating step to the charging step and to the ejecting step.
The generating step may further include the steps of heating and evaporating ink colorant, cooling, solidifying and agglomerating the evaporated ink colorant, thereby granulating the colorant into colorant particles.
In the image recording method as described above, the colorant particles generated in the generating step are transported sequentially from the generating step to the charging step and the ejection step, and therefore the colorant particles may securely gone through each step, so that the use efficiency of the colorant in image recording may be improved and the charge amount may become even.
Since the colorant particles are transported while controlling the flow of air including the colorant particles in the above image recording method, the colorant particles generated in the generating step are transported surely to the following steps in the flow of air. The airflow is controlled, and therefore the colorant particles will not be attached in an undesired location in the flow path or the amount of ejection in the ejection step will not be uneven. Thus, the colorant particle density may be improved to increase the recording speed as a result.
In order to achieve the above-described object of the present invention, an image recording apparatus according to the present invention records prescribed images on a recording medium using ink colorant has the following characteristics. More specifically, the apparatus includes a generating portion which generates colorant particles from ink colorant, a charging portion which charges the generated colorant particles, an ejecting portion which intermittently ejects the charged colorant particles onto the recording medium by electrostatic force based on an electrical signal corresponding to prescribed image data, and a transport portion which sequentially transports the colorant particles from the generating portion to the charging portion and the ejecting portion.
Therefore, the generated colorant particles are surely passed through each portion, the use efficiency of the colorant is improved and the charge amount may become even.
In the above image recording apparatus, the generating portion may include a heating portion for
Furukawa Kazuhiko
Kakiwaki Shigeaki
Okuda Tohru
Dike Bronstein Roberts & Cushman IP Group
Gordon Raquel Yvette
Hartnell, III Geroge W.
Sharp Kabushiki Kaisha
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