JPH08323248A - Method for electrostatic flocking and apparatus therefor - Google Patents

Abstract

PURPOSE: To obtain a densely flocked surface at a high charge rate using highly insulating short fibers and to electrostatically flock uniformly irrespective of the unevenness of a flocking surface. CONSTITUTION: A main discharge electrode 2 for applying DC high voltage is installed, a pulse discharge electrode 3 is placed oppositely to the main discharge electrode 2, the polarity of both electrode are made equal, DC pulse high voltage with base potential of grounding potential is applied to generate corona discharge 42 between both electrodes, and short fibers 5 are passed between both electrodes to charge the fibers 5 by adsorbing ions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electrostatic flocking, and more particularly to electrostatic flocking using highly insulating short-hair fibers, and more particularly to electrostatic flocking for products having an uneven surface. .

[0002]

2. Description of the Related Art Problems and problems of the prior art: Electrostatic flocking is a technique for charging short hair fibers (hereinafter simply referred to as fibers) and flocking them by electrostatic force, and has been widely used since ancient times.
The principle of electrostatic flocking is that for grounded flocked objects,
Usually, a grid electrode to which a positive DC high voltage is applied is arranged above it, and the fiber is passed through the mesh. In that case, if the fiber has an appropriate conductivity, it is positively charged mainly by contact charging. The charged fiber flies toward the hair plant by Coulomb force, collides with and adheres to the surface of the hair plant vertically, and the surface-like hair plant is arranged horizontally. At this time, the hair is evenly and densely planted. Therefore, when the highly insulating fiber is used, the conductive treatment is performed in advance in order to increase the conductivity. However, the conductive treatment of the fiber not only increases the cost, but when an electrolyte is used to improve the conductivity, it reacts with the adhesive and deteriorates its quality.Therefore, the conductive treatment is required even for the highly insulating fiber. Not charging is desired.

By the way, as a method of charging the fiber, in addition to contact charging, there is a method of adsorbing ions generated by corona discharge, which does not require conductivity of the fiber, to charge the fiber. When non-charged fibers are generated, whether by contact charging or corona discharging, dense flocking cannot be obtained because they do not collide vertically with the object to be transplanted. However, when the corona discharge method is used for electrostatic flocking, the flocked material is covered with an insulating adhesive, so the discharge current does not flow sufficiently, and therefore the amount of ions generated is small and a large amount of fibers are evenly distributed. It was difficult to charge. When a large number of discharge electrodes are used to charge a large amount of fibers, it becomes difficult to form an unequal electric field, which makes it difficult to generate corona discharge and makes uniform charging difficult. Therefore, the electrification of the fiber has to be the contact electrification using a narrow mesh grid electrode. Therefore, when highly insulating fibers are used, they must be subjected to a conductive treatment to increase the conductivity of the fibers. On the other hand, even if the fibers are uniformly charged, if there is unevenness on the surface of the transplanted object, dense flocking can be obtained in the horizontal part, but the electric force line concentrates on the convex part, so it can not be applied evenly was there. In particular, in the case of a box-shaped product, a problem arises that the slope becomes thin because electric lines of force concentrate on the tip. This is
Even if the movable electrode is used, the concentration of the lines of electric force does not move, so that it is extremely difficult to electrostatically flock the inside of the box-shaped product.

Therefore, an object of the present invention is to provide a charging method having a good charging rate even when a large amount of highly insulating fibers are dropped, and at the same time, in electrostatic flocking, the line of electric force is applied. An object of the present invention is to provide an electrostatic flocking method and an electrostatic flocking device capable of uniformly flocking an uneven surface or a slope such as a dish-shaped product by preventing the concentration of particles.

[0005]

Means for solving the problem is to provide a main discharge electrode for applying a DC high voltage formed by a thin conductive wire and a conductive wire having a wide width in parallel with the main discharge electrode. A pulse discharge electrode formed of a body is provided, a ground potential is used as a base potential for the pulse discharge electrode, a DC pulse high voltage having the same polarity as that of the main discharge electrode is applied, and a corona discharge is periodically applied between both electrodes. Is formed, and short hair fibers passing between the both electrodes are electrically charged and hair is transplanted.

[0006]

When electrostatic flocking is performed by the above means, for example, when a negative DC high voltage is applied to the main discharge electrode and the pulse voltage of the pulse discharge electrode is not excited, that is, when it is at ground potential, As shown in FIG. 1, a line of electric force 41 extending from the main discharge electrode 2 to the pulse discharge electrode 3 and a corona discharge 42 are formed. Therefore, the fibers 5 fall across the corona discharge 42, and a large amount of fibers are surely adsorbed and charged with the negative ions. A part of the charged fibers 5 adhere to the pulse discharge electrode 3, but most of the fibers 5 fall by gravity, and then, due to gravity, the charges of the fibers 5 themselves and the Coulomb force of the hair-to-be-polished 8, the hair-to-be-polished. Head to Object 8. Next, when the pulse discharge electrode 3 is excited to have a negative polarity, the potential difference between the main discharge axis 2 and the pulse discharge electrode 3 disappears, and the electric force line 43 from the electrode toward the hair transplant 8 is formed. Therefore, the fibers 5 flying toward the hair transplant 8 change the flight direction by the electric force lines 43. Further, the fibers attached to the pulse discharge electrode 3 lose the adhesive force due to the repulsive force from the pulse discharge electrode 3 and head for the hairs 8 to be transplanted. The above operation is performed by the pulse discharge electrode 3
Since it repeats periodically according to the pulse frequency of
When the pulse frequency of the fiber 5 that is flying toward is high, for example, when the pulse frequency is 50 times or more per second, that is, when the pulse frequency is 50 pps or more, excitation and release are performed several times during the flight, and thus the fiber 5 Changes in direction occur several times during flight. That is, the fiber 5 advances toward the hair transplant 8 while vibrating. Therefore, the fiber 5 as a whole has the hair transplant 8
Heading to, even if the shape of the hair transplant 8 is uneven,
Apply evenly without concentrating on the convex part. Further, when applied to electrostatic flocking of a box-shaped product, the fibers 5 fly while vibrating, so that the inner slope can also be flocked without concentrating on the tip of the box-shaped product.

Since the charging rate improving effect and the vibration effect due to the change of the direction of the lines of electric force using the main discharge electrode 2 and the pulse discharge electrode 3 in the present invention vary depending on the pulse frequency and the pulse width, they will be described below. The details of the electrostatic flocking according to the present invention will be described based on examples.

[0008]

EXAMPLE FIG. 1 shows an example of a down type electrostatic flocking apparatus for a box type product. The dish-shaped to-be-planted object 8 is the connecting means 3
It is fixedly mounted on the carrier stand 32 that is grounded by 1, and is carried by the carrying means 30 continuously or intermittently. Fiber 5
Is supplied by the supply means 7 in the same manner as in the case of the normal down type. The main discharge electrode 2 faces the grounded hair transplant 8 and is formed of a copper wire. The distance from the tip of the main discharge electrode 2 to the pulse discharge electrode 3 may be 3 to 10 cm. A high direct current voltage is applied to the main discharge electrode 2 by a direct current power source 12 according to a standard method, but it can be set lower than in the conventional method. The polarity of the voltage applied to the main discharge electrode 2 may be positive, but it is preferable because corona discharge with stable negative polarity can be obtained. The pulse discharge electrode 3 is formed of a thin copper plate, and the portion facing the main discharge electrode 2 is covered with an insulating material 4. As a result, an unequal electric field is formed at the tip of the main discharge electrode 2, and a corona discharge 42 is formed when the pulse discharge electrode 3 is not excited, that is, at the ground potential.
Reference numeral 20 is an example of a power supply circuit applied to the pulse discharge electrode 3, which includes a pulse capacitor 23, a load resistor 25, and a gap switch 24. In the pulse circuit 20, when the switch 24 is short-circuited, the high voltage from the DC power source 21 is applied to the pulse discharge electrode 3, the potential difference from the main discharge electrode 2 disappears, and the fiber 5 attached to the pulse discharge electrode 3 disappears.
Peel off, and ride on the electric force line 43 toward the hair transplant 8. Also, when the switch 24 is cut off, the corona discharge current from the main discharge electrode 2 passes through the pulse discharge electrode 3 and the load resistance 25,
Since it flows to the earth circuit, the corona discharge 42 is the main discharge electrode 2.
And the pulse discharge electrode 3 are formed. Therefore, the fiber 5 is reliably charged when passing between the main discharge electrode 2 and the pulse discharge electrode 3. The higher the voltage applied to the pulse discharge electrode 3, the greater the effect on the change in the direction of the lines of electric force. However, it is not necessary to make the voltage higher than that of the main discharge electrode, and it is usually preferable to make the voltage substantially equal to the voltage applied to the main discharge electrode. The pulse waveform applied to the pulse discharge electrode 3 is not limited to this, but a vibration wave having a pulse width of 1 to 20 μsec and a pulse frequency of 50 to 200 pps can be used. The shorter the pulse width is, the longer the duration of the corona discharge 42 is, and therefore the charging rate is improved. Therefore, the pulse width is usually preferably 20 μsec or less. Preferably.
Further, the pulse frequency is preferably 50 pps or more, because if the frequency is too low, the adhesion of fibers to the electrodes increases. However, it is usually not necessary to increase the pulse frequency too much. The voltage to the pulse discharge electrode 3 is applied in a pulse shape,
Therefore, the corona discharge 42 is formed intermittently, but if the pulse width is shorter than the time for the fiber 5 to pass through the corona discharge 42, the fiber 5 [actually crosses the corona discharge and is charged.

Although this embodiment is a down type in which fibers are dropped by gravity, it can be used as a portable type if fibers are conveyed by an air flow. Further, although the present invention is applied to fibers having a high electric resistance value for uniform flocking, it goes without saying that there is no problem even if it is used for fibers having a relatively low electric resistance value.

[0010]

According to the present invention, since the fibers are charged by the ion adsorption, highly insulating fibers can be used. Therefore, the conductive treatment is not always necessary, resulting in a significant cost reduction. Further, since the direction of corona discharge and the flight direction of the fiber intersect, the ion and the fiber surely come into contact with each other, and the negative ion is adsorbed and charged. Therefore, even if the amount of the fibers 5 is large, the electrification rate becomes extremely good, and dense flocking becomes possible. Moreover, since the direction of the electric force line formed by the main discharge electrode 2 and the pulse discharge electrode 3 can be periodically changed, the fibers fly toward the flocked object while vibrating. Therefore, uniform electrostatic flocking is performed regardless of the irregularities of the flocked object, and the inner corners of the box-shaped product can be flocked.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle and embodiment of the present invention.

[Explanation of symbols]

 2, main discharge electrode 3 pulse discharge electrode 5, short hair fiber 42, corona discharge

Claims (2)

[Claims] 1. A main discharge electrode for applying a high DC voltage formed of a thin conductive wire, and a pulse discharge electrode formed of a wide conductor are arranged in parallel with the main discharge electrode, and the pulse is formed. The earth potential is used as a base potential for the discharge electrode, a DC pulse high voltage having the same polarity as that of the main discharge electrode is applied to periodically form a corona discharge between both electrodes, and a short hair fiber passing between the both electrodes is formed. Electrostatic flocking method performed by charging 2. A main discharge electrode formed of a thin conductive wire to which a high DC voltage is applied, and a DC pulse high voltage which is arranged in parallel with the main discharge electrode and has the same polarity and whose base potential is earth potential. Electrostatic flocking device having a pulse discharge electrode to which is applied