Recorders – Markers and/or driving means therefor – With ink supply to marker
Patent
1990-07-23
1992-06-23
Fuller, Benjamin R.
Recorders
Markers and/or driving means therefor
With ink supply to marker
3461531, 101DIG37, B41J 206, B41J 2385
Patent
active
051247291
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a recording apparatus which realizes recording by electrostatically absorbing ink from a member impregnated with the ink and the adhereing ink on a recording medium.
BACKGROUND OF THE INVENTION
The principle of recording by absorbing ink with an electrostatic force and adhering the ink to a recording medium such as a recording sheet is disclosed in Published Japanese Patent No. 36-13768.
In these years, a variety of methods have been proposed to realize a) a reduction in size of a recording apparatus of this type and b) high resolution as explained in the Japanese Laid-open Patent Nos. 55-164175, 61-211048 and 62-44457, wherein countless number of fine holes of a mesh member are filled with ink. This ink is absorbed by electrostatic force and it is then injected and adhered onto a recording sheet.
However, since the holes of the mesh members are filled with the ink in these methods, a gap must be provided between the mesh member and the recording sheet, resulting in a problem that a recording voltage as high as 2.about.3 kV is required. Moreover, a high application voltage sometimes generates a leak between the adjacent electrodes and thereby gives a limit on high resolution.
Considering the problems mentioned above, it is therefore an object of the present invention to provide a recording apparatus which realizes recording only with a low recording voltage and high resolution.
DISCLOSURE OF THE INVENTION
According to the present invention, a recording apparatus provided thereby includes a thin plate member providing fine holes, an ink reserving member which is closely provided on one side of the thin plate member and is impregnated with conductive ink, and electrode members which are provided on the other side of the thin plate member in such a manner as to interpose a recording medium and to effectuate an electrostatic force to absorb conductive ink through the holes.
FIG. 1 is a diagram for explaining the recording principle of a recording apparatus of the present invention.
As shown in FIG. 1, a structure provides an electrode 1, a recording medium 100, a thin plate member (mesh) 2 having a through hole 3 extending in the thickness direction thereof and an ink (layer) 8. When the thin plate member 2 is kept dry from the ink 8 (contact angle .theta..gtoreq.90.degree.), the ink 8 cannot enter the hole 3 if pressure is not applied (the pressure can be adjusted depending on the surface tension).
When the ink is given conductivity and a voltage is applied across the ink and electrode 1, an electrostatic force is generated between the recording sheet 100 (in the hole 3) and electrode 1 through the air layer. When the electrostatic force is larger than the surface tension of ink 8, the ink 8 enters the hole 3 and adheres to the recording medium 100.
The voltage required for such an event will then be explained hereunder.
First, the effect of surface tension of the ink is considered.
A wet angle .theta. between the hole 3 formed like a pipe having a radius r, and the ink 8 is considered as 90.degree. and the surface tension of the ink is .gamma.. The surface tension affectuates in the direction of interfering with the inflow of the ink as the force (pressure) p expressed as follows.
When r=70 .mu.m, .gamma.=60 dyne/cm, the pressure p becomes equal to 1.7 .times.10.sup.4 (dyne/cm.sup.2) and when a pressure higher than p is applied, the ink enters the hole.
An electrostatic force f is considered next. When a thickness of recording medium 100 is assumed as d.sub.1, a dielectric constant thereof is .epsilon..sub.1, the thickness of hole 3 (air layer) is d.sub.2 and the dielectric constant thereof is .epsilon..sub.2, the electrostatic force f can be expressed as follows: ##EQU1##
When d.sub.1 =60 .mu.m, r.sub.1 (specific dielectric constant of the recording medium)=3, d.sub.2 =50 .mu.m and r.sub.2 (specific dielectric constant of air)=1, V.sub.p for p=f becomes equal to 1.67.times.10.sup.3 (V).
Namely, recording can be realized by applying a voltage hig
REFERENCES:
patent: 3834301 (1974-09-01), Croquelois et al.
patent: 3843381 (1974-10-01), Matsumoto et al.
patent: 4069759 (1978-01-01), Endo et al.
patent: 4205320 (1980-05-01), Fujii
patent: 4263601 (1981-04-01), Nishimura et al.
Japanese Patent Abstract No. 61-219658, Y. Hosaka, Sep. 30, 1986, vol. 11, No. 64 (M-565) (2511, Feb. 26, 1987).
Japanese Patent Abstract No. 63-34149, M. Okubo, Feb. 13, 1988, vol. 12, No. 247 (M-717) (3094) Jul. 13, 1988.
Kiyota Kohei
Nakazawa Akira
Nonoyama Shigeo
Ozaki Mitsuo
Takada Noboru
Bobb Alrick
Fujitsu Limited
Fuller Benjamin R.
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