Coating processes – Direct application of electrical – magnetic – wave – or... – Electrostatic charge – field – or force utilized
Reexamination Certificate
1999-12-28
2001-08-28
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Electrostatic charge, field, or force utilized
C427S064000, C427S261000, C427S290000
Reexamination Certificate
active
06280799
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a viscous substance discharging method using a viscous substance dispenser to make a viscous substance adhere to or to apply the viscous substance to a medium, and a pattern forming method using the viscous substance dispenser.
BACKGROUND ART
A generally known dispenser having a container containing a liquid applies pressure to the liquid from behind to force the liquid out of the container and forms a pattern on a medium. The known dispenser is able to discharge a substance having a high viscosity and a substance having a low viscosity and to form patterns on a medium. However, in the known dispenser, it takes a long time for pressure to be propagated and hence the response of a liquid discharge operation to the pressure is not quick enough. Since the size of lines and dots is dependent on the outside diameter of a nozzle, the known dispenser is not suitable for minute patterning.
Another known method applies pressure to a liquid from behind the liquid and vibrates a portion of a dispenser around an outlet to form a liquid drop and attaches the liquid ball to a medium. This method, however, is unable to discharge highly viscous substance.
A pattern forming method that forms a pattern on a medium by discharging an ink from an orifice is known as an ink-jet patterning technique. The ink-jet patterning technique is exercised by a method that produces a bubble by heating a portion of a nozzle to force the ink out of the nozzle by the bubble, and a method that vibrates a piezoelectric ceramic element to force an ink out of a nozzle by a pressure generated by the vibration of the piezoelectric ceramic element. Each of these methods uses a very low force for forcing the ink out of the nozzle and is unable to discharge a highly viscous substance. The size of ink drops discharged from the orifice by the ink-jet patterning method is several times the diameter of the orifice.
This problem will be explained with reference to FIG.
9
. Referring to
FIG. 9
, a highly viscous substance
2
is extruded through an opening formed in the tip of a nozzle
1
by electrostatic attraction or electromechanical pressure. A string
3
of the extruded highly viscous substance
2
of a predetermined length is cut off the tip of the nozzle
1
. Then, the string
3
of the extruded highly viscous substance
2
becomes a spherical drop
4
by its own surface tension, and the spherical drop
4
adheres to a medium
5
in a dot. Therefore, the dot inevitably has a size as large as five to six times the diameter of the orifice of the nozzle
1
.
The diameter of the orifice must be reduced to form a smaller drop. When it is required to discharge an ink containing large particles, the orifice of a small diameter is clogged, offset is abraded by the particles and the life of the discharge device is shortened.
An ink-jet device of an electrostatic attraction type also is unable to discharge a highly viscous substance.
DISCLOSURE OF THE INVENTION
The present invention has been made to solve such problems and it is therefore an object of the present invention to provide a viscous substance discharging method using a viscous substance dispenser, capable of discharging the viscous substance even if the viscous substance contains particles of large particle sizes to make the viscous substance adhere to or to apply the viscous substance in minute patterns, and to provide a method of forming a pattern by the method of discharging a viscous substance.
According to the present invention, a viscous substance discharging method using a viscous substance dispenser comprises the steps of arranging an electrode in a portion or an entire portion of a container of the viscous substance dispenser having a circular orifice or a polygonal orifice of a diameter in the range of 50 &mgr;m to 1 mm in it lower portion and containing a viscous substance having a viscosity in the range of 1,000 to 1,000,000 cps, and making a meniscus of the viscous substance bulge out from the orifice, applying a voltage to the electrode to pull out the viscous substance through the orifice and cutting off a portion of the viscous substance pulled out of the orifice and making the cut portion of the viscous substance adhere to a medium.
The present invention is the method of discharging a viscous substance by a viscous substance dispenser wherein in the step of applying the voltage to the electrode with the meniscus of the viscous substance bulging out from the orifice, and cutting a portion of the viscous substance pulled out of the orifice to make the same adhere to the medium, the positional relation with respect to a horizontal direction between the medium and the orifice is changed according to the voltage.
In the method of discharging a viscous substance by a viscous substance dispenser according to the present invention, the absolute value of the voltage is in the range of 100 to 20,000 V.
In the viscous substance discharging method according to the present invention, the voltage is a pulse voltage.
In the viscous substance discharging method according to the present invention, the portion of the viscous substance is cut by reducing the absolute value of the voltage or by stopping the application of the voltage to the electrode.
The viscous substance discharging method using a viscous substance dispenser according to the present invention forms the meniscus by applying a pressure to the container containing the viscous substance.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the distance between the orifice and the medium is in the range of 0.1 to 10 mm.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the viscous substance contains particles having a particle size not greater than {fraction (1/10)} of the diameter of the orifice.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the viscous substance contains particles of a mean particle size in the range of 0.1 to 10 &mgr;m.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the container containing the viscous substance serves also as an electrode, and the voltage is applied to the container.
The viscous substance discharging method using a viscous substance dispenser according to the present invention forms the meniscus by heating the container containing the viscous substance.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the voltage is a dc voltage.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the voltage is a dc voltage, the voltage is applied to and removed from the electrode, and the pressure is controlled to form lines of the viscous substance in a line width not grater than {fraction (
1
/
2
)} of the diameter of the orifice or dots of the viscous substance in a diameter not greater than ½ of the diameter of the orifice.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the voltage is an ac voltage.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the voltage is an ac voltage, the amplitude of the voltage and the pressure are controlled to form lines of the viscous substance in a line width not greater than ½ of the diameter of the orifice or to form dots of the viscous substance in a diameter not greater than ½ of the diameter of the orifice.
In the viscous substance discharging method using a viscous substance dispenser according to the present invention, the ac voltage has a frequency in the range of 1 Hz to 100 kHz.
According to the present invention, a pattern forming method using a viscous substance dispenser comprises the steps of arranging an electrode in a portion or a entire
Okabe Masato
Tsuchiya Katsunori
Dai Nippon Printing Co. Ltd.
Parkhurst & Wendel L.L.P.
Pianalto Bernard
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