JP2009254972A - Electrostatic spray apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic spray apparatus in which the deposition mist on a counter electrode is prevented with simple structure. <P>SOLUTION: The electrostatic spray apparatus for charging mist and spraying the charged mist is structured so as to prevent the deposition of the mist 6 on the counter electrode 4 by applying ultrasonic vibration on the counter electrode 4 by an ultrasonic transducer 8 or to prevent the deposition of the mist on the counter electrode by incorporating a heater in the counter electrode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic spraying device for performing printing by charging and spraying mist.

  Conventionally, an electrostatic spraying method is known as a method of spraying mist. In the apparatus using this electrostatic spraying method, the mist generated by means such as spraying is charged by induction to charge and efficiently adhere to the object (for example, see Patent Document 1). .

JP 2005-305883 A

  However, in the electrostatic spraying device described above, when the operation is continued, the charged mist adheres to the induction electrode, resulting in a problem that the charging efficiency is lowered.

  The present invention has been made in view of such circumstances, and prevents the mist from adhering to the counter electrode for charging or the like when electrostatically spraying the mist with a simple structure, thereby improving the charging efficiency. It aims at obtaining the electrostatic spraying apparatus which can prevent a fall.

  In order to meet such an object, an electrostatic spraying device according to the present invention (the invention according to claim 1) is an electrostatic spraying device that sprays by charging a mist. It is characterized by being configured to prevent adhesion.

  The electrostatic spraying device according to the present invention (the invention described in claim 2) is configured to prevent the mist from adhering in the electrostatic spraying device that charges and sprays the mist and incorporates a heater in the counter electrode. It is characterized by that.

  The electrostatic spraying apparatus according to the present invention (the invention described in claim 3) is the electrostatic spraying apparatus according to claim 1 or 2, wherein the counter electrode is provided with a water repellent coat when the mist is aqueous and a hydrophilic coat when the mist is oily. It is characterized by.

  As described above, according to the electrostatic spraying apparatus according to the present invention, when the mist is charged and sprayed, ultrasonic vibration is applied to the counter electrode to prevent the mist from adhering. It becomes possible to remove the mist adhering to the induction electrode which was a problem. As a result, the electric field between the charging electrode and the nozzle tip is stabilized, so that a stable charging mist can be created. As a result, the mist is stably supplied to the non-adherent matter and the required printing or the like is performed. There is an advantage that you can.

  Further, according to the electrostatic spraying apparatus according to the present invention, when the mist is charged and sprayed, a heater is built in the counter electrode to prevent the mist from adhering. Therefore, it is possible to create a stable charging mist. Thereby, it becomes possible to supply mist stably to a non-adhering matter.

  Here, when the mist described above is aqueous, a water repellent coat is applied to the counter electrode, and when the mist is oil based, a hydrophilic coat can be applied to the counter electrode.

  1 to 3 show an embodiment of an electrostatic spraying device according to the present invention. In these drawings, FIG. 1 is a schematic cross-sectional view of an electrostatic atomizing device used in the present invention.

  Briefly explaining this, the water sent through the hose 5 from a pressurizing device (not shown) reaches the spray nozzle 1. In addition, the induction electrode 4 arranged in a cylindrical shape is held by the insulating member 3 arranged in a cylindrical shape, and a charging voltage is applied to the induction electrode 4 as shown in FIG.

  The nozzle tip 2 is formed of a conductor and is grounded. Then, the water that has reached the nozzle 1 becomes mist 6 by passing through the nozzle tip 2. The mist 6 is inductively charged by the electric field acting between the charging electrode 4 and the nozzle tip 2 at the same time as it is ejected from the nozzle tip 2.

  In the example shown in FIG. 2, since the polarity applied to the charging electrode 4 is (+), the mist is charged to (−). Thereafter, the charged mist 6 flies and adheres to the object.

Here, in such an apparatus, when the mist formation is continued, there is a problem that the charged mist 6 adheres to the charging electrode 4. When the mist adheres to the charging electrode 4, the electric field acting between the charging electrode 4 and the nozzle tip 2 becomes weak, causing a problem that the amount of charge on the mist 6 is reduced. Moreover, when the charge amount of mist 6 falls, the problem that the adhesion amount to the target object of mist 6 falls arises.
This is presumably because the mist 6 adheres to the charging electrode 4 due to the Coulomb force because the charging polarity of the mist 6 and the applied polarity of the charging electrode 4 are opposite.

The present invention is characterized in that adhesion of the mist 6 to the charging electrode 4 is prevented by applying ultrasonic vibration to the charging electrode 4.
The vicinity of the charging electrode 4 is enlarged and shown in FIG.

  More specifically, the induction electrode 4 has the gap 9 disposed so that only both ends are held by the insulating member 3 and easily vibrate. The ultrasonic vibrator 8 is made of PZT, for example, and is bonded to the charging electrode 4 with the insulating member 7 interposed therebetween. When a signal is applied to the ultrasonic vibrator 8 from a circuit (not shown), the induction electrode 4 vibrates due to the vibration of the ultrasonic vibrator 8.

  Then, when the charging electrode 4 vibrates, cavitation occurs in the mist adhering to the induction electrode 4. The mist is atomized by cavitation and disappears from the induction electrode 4. As a result, it is possible to remove the mist adhering to the charging electrode 4 which has been a problem until now, so that it is possible to create a stable charging mist.

  For example, FIG. 4 shows the charge amount measurement result when water is sprayed for 30 seconds when the charging electrode 4 at a position 5 mm from the nozzle tip 2 is arranged and the charging electrode 4 is formed with a diameter of 8 mm.

  Here, the amount of charge increases as the applied voltage to the charging electrode 4 increases, but the amount of charge does not increase halfway. When the induction electrode 4 was seen, many mists adhered, the electric field between the induction electrode 4 and the nozzle tip 2 weakened, and efficient mist charging was not performed.

On the other hand, FIG. 5 shows the charge amount measurement result when the charging electrode 4 is vibrated by the ultrasonic vibrator 8. In this case, the ultrasonic transducer 8 vibrates at about 2 MHz.
Then, as shown in FIG. 5, the voltage applied to the induction electrode 4 increases, and at the same time, the charge amount also increases. Further, it was confirmed that the mist 6 did not adhere to the surface of the charging electrode 4.

Here, even when the charge amount of the mist 6 is low, if the operation time is long, the mist 6 adheres to the charging electrode 4 to cause a problem of lowering the charge amount. Therefore, it is necessary to remove the mist on the charging electrode 4 even under all charging conditions.
As described above, the mist adhering to the charging electrode 4 can be removed by atomization by ultrasonic vibration. For this reason, the electric field acting between the charging electrode 4 and the nozzle tip 2 is stabilized, and the charge amount of the mist 6 is stabilized.

  According to the above configuration, since it is possible to remove the mist adhering to the induction electrode 4 which has been a problem until now, the electric field between the charging electrode 4 and the nozzle tip 2 is stabilized, and a stable charging mist is obtained. It can be created. As a result, the mist 6 can be stably supplied to the non-adherent matter.

FIG. 6 and FIG. 7 show different embodiments of the present invention. In these drawings, the same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
In other words, in this embodiment, the heating electrode 10 such as a heater is attached to the charging electrode 4 to prevent the mist from adhering to the charging electrode 4.

As shown in FIG. 6, the heating element 10 is attached to the charging electrode 4.
The charging electrode 4 is heated by the heat generated by the heating element 10. The mist adhering to the charging electrode 4 can be evaporated by heating, and the mist 6 is removed from the charging electrode 4. Thereby, since the electric field between the charging electrode 4 and the nozzle tip 2 is stably formed, the mist 6 is stably charged.

  In addition, as shown in FIG. 7, the heating element 10 and the ultrasonic vibrator 8 can be simultaneously installed on the charging electrode 4.

  In this case, since the temperature of the heating element 10 and the vibration condition of the ultrasonic vibrator 8 can be set according to the solvent conditions, finer settings can be made, and mist adhesion to the charging electrode 4 can be further prevented. It becomes easy to do.

  And according to these structures, since mist adhesion on the charging electrode 4 can be prevented, it becomes possible to create a stable charging mist. Thereby, it becomes possible to stably supply the mist 6 to the non-adherent matter.

  In addition, this invention is not limited to the structure demonstrated by embodiment mentioned above, It cannot be overemphasized that the shape of each part which comprises an electrostatic spraying apparatus, a structure, etc. can be deform | transformed and changed suitably.

  In the above-described embodiment, the induction charging method is described as the device of the present invention, but the present invention can also be implemented in the corona charging method.

  Further, in the above-described embodiment, although not particularly described, the water repellent coat is applied to the counter electrode 4 when the mist 6 described above is aqueous, and the hydrophilic coat is applied to the counter electrode 4 when oily. Experiments have confirmed that the effect can be further exhibited.

It is typical sectional drawing which shows one Embodiment of the electrostatic spraying apparatus which concerns on this invention. It is a typical schematic diagram showing another example of an electrostatic spraying device. It is an expanded sectional view showing the neighborhood of a charging electrode characterizing the present invention. It is a graph which shows the charge amount measurement result of the conventional apparatus at the time of spraying water for 30 seconds when a charging electrode is arrange | positioned in the position of 5 mm from the nozzle front-end | tip, and a charging electrode is formed with a diameter of 8 mm. 6 is a graph showing a charge amount measurement result when a charging electrode is vibrated by an ultrasonic vibrator in the device of the present invention. It is an expanded sectional view of the charging electrode vicinity which shows another embodiment of the electrostatic spraying apparatus which concerns on this invention. It is an expanded sectional view of the charging electrode vicinity which shows another embodiment of the electrostatic spraying apparatus which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Spray nozzle, 2 ... Nozzle tip, 3 ... Insulating member, 4 ... Charge electrode, 5 ... Hose, 6 ... Mist, 7 ... Insulating member, 8 ... Ultrasonic vibrator, 9 ... Air gap, 10 ... Heating element.

Claims (3)

In an electrostatic spraying device that charges and sprays mist,
Apply ultrasonic vibration to the counter electrode,
An electrostatic spraying device configured to prevent adhesion of mist. In an electrostatic spraying device that charges and sprays mist,
Built-in heater on the counter electrode,
An electrostatic spraying device configured to prevent adhesion of mist. In the electrostatic spraying device according to claim 1 or 2,
An electrostatic spraying device characterized in that a water repellent coat is applied to the counter electrode when the mist is aqueous, and a hydrophilic coat is applied to the counter electrode when it is oily.

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