JPH03231776A - Powder electrifying device and powder coating device - Google Patents

Abstract

PURPOSE:To uniformly and stably execute electrostatical charging of powder and to make it fly with a sufficient quantity of electrostatical charge by introducing gas such as oxygen to a side opposite to a powder carrying side partitioned by an ionic conducting body. CONSTITUTION:A carrying unit 14 for a plain sheet 14 and a supplying unit 10 for a developer 8 are provided in this powder coating device 20. The supplying unit 10 is constituted of a hopper 15 housing the granular developer 8, a carrying roller 6, a developer supplying roller 7 auxiliarily provided so as to allow the developer 8 to be carried on the carrying roller 6, and a removing blade 9 for removing the excessive developer 8 carried on the carrying roller 6. The carrying roller 6 is constituted of a stabilized zirconia 30 to be a solidstate electrolyte and its inside is a cavity so that the gaseous oxygen can introduced. In such a case, the powder is disposed on the outer peripheral surface of the carrying roller 6 and the concentrated gas of the oxygen, etc., is introduced to the cavity inside the carrying roller 6. Thus, the powder can be uniformly and stably electrostatically charged and can be made to fly with a sufficient quantity of the charge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a powder charging device and a powder coating device.

[Prior Art] Conventionally, in the developing process of attaching toner to an electrostatic latent image in a copying machine and making the latent image visible, it is necessary to charge the toner in advance in order to make the toner fly using electrostatic force.・This was done by contact charging and corona charging, and the charged toner was made to fly.

[Problems to be Solved by the Invention] However, in such conventional powder charging devices, there are problems such as a stable corona not being generated in corona charging, and in friction/contact charging, individual particles are separated from each other. Because they are charged by friction and contact with the particles, one side is positively charged and the other is negatively charged, and in this state there is an equal number of toners of opposite polarity, which results in a problem of reduced transfer efficiency. . Furthermore, since toner with a small amount of charge is difficult to fly, there is also the drawback that it cannot be used unless the amount of charge is increased with a charge control agent or the like.

The present invention has been made in order to solve the above-mentioned problems, and is intended to uniformly and stably charge powder and make the powder fly with a sufficient amount of charge.

[Means for Solving the Problems] In order to achieve this object, the powder charging device of the present invention supports powder on the front or back side of an ionic conductor, and uses the ionic conductor as a partition wall to support the powder. A diluted or concentrated gas such as oxygen is introduced on the opposite side.

Further, it is preferable that the ion conductor is a cylindrical support roller.

Further, the supporting roller has a hollow interior, and it is desirable to introduce a concentrated gas such as oxygen into the interior.

The powder coating device of the present invention uses the powder charging device described above to coat charged powder onto a support supported by opposing electrode rollers.

[Function] The powder charging device of the present invention having the above-mentioned configuration supports powder on the outer circumferential surface of the support roller, which is an ionic conductor such as a solid electrolyte, and concentrates oxygen, etc. in the cavity inside the support roller. Introduce gas. As a result, ions are stably, uniformly and sufficiently attached to the powder, and the powder is uniformly charged.

The powder coating device of the present invention applies sufficiently charged powder using the powder charging device to a support supported by opposing electrode rollers.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

First, a solid electrolyte used as an embodiment of the powder charging device of the present invention will be briefly explained.

Solid electrolytes are ionic conductors, the most typical of which is stabilized zirconia, which is currently used as an oxygen sensor to measure oxygen concentration. FIG. 1 explains the principle of an oxygen sensor using stabilized zirconia. If stabilized zirconia is used as a partition wall between two gas atmospheres having different oxygen partial pressures, and the left side of FIG. 1 has a high oxygen partial pressure, oxygen will move from left to right. As mentioned above, stabilized zirconia is an ionic conductor, so when it enters the stabilized zirconia partition wall from the high oxygen partial pressure side, it receives electrons and becomes oxygen ions. Oxygen ions move within the stabilized zirconia partition wall toward the lower oxygen partial pressure side. Then, when going out from the stabilized zirconia partition wall, electrons are released and become oxygen molecules. Therefore, a positive charge is generated on the high oxygen partial pressure side and a negative charge is generated on the low oxygen partial pressure side. In this way, a potential difference is generated between both ends of the wall, and if the oxygen concentration of one side is known, the oxygen concentration of the other side can be determined from that potential difference. This is the principle of an oxygen sensor.

The present invention utilizes the above principle for charging, and one embodiment of the present invention is shown in FIG. This shows a powder coating device that uses a solid electrolyte in a carrier roller that carries powder.

The powder coating device 2o is a device for coating plain paper 4 as a support with a color developer 8 to form a color developing paper, and a conveying unit for the plain paper 4 is located on the left side of the powder coating device 20. 1
4, and a supply unit 10 for a color developer 8 are provided on the right side. On the outer wall of the powder coating device 20,
An insertion opening 12 on the lower side for inserting the plain paper 4 and an ejection opening 11 on the upper side for taking out the plain paper (color developer paper) 4 after applying a color developer to the plain paper 4 are opened. ing.

The conveying unit 14 includes an electrode roller 1, a pair of conveying rollers 3, and an endless conveying belt 2 that is passed between the rollers 1 and 3. The plain paper 4 inserted from the insertion port 12 is conveyed while being attracted to the conveyor belt 2, and is discharged from the take-out port 11 after being coated with the color developer 8. The electrode roller 1 is connected to a DC power supply 5 as a voltage applying means, and a predetermined high voltage is applied to the plain paper 4 via the electrode roller 1.

The supply unit 10 also includes a hopper 15 storing powdery color developer 8, a carrier roller 6, and a color developer supply roller auxiliary provided to carry the color developer 8 on the carrier roller 6. 7, and a removing blade 9 for removing excess color developer 8 carried on the carrying roller 6.

Then, the supply unit 10 faces the carrier roller 1,
They are arranged with a predetermined gap d in between. Note that a portion of the carrier roller 6 is exposed from the opening of the hopper 15 and forms a transfer area 13. Further, the removal blade 9 is provided below the carrier roller 6 and is grounded.

In this embodiment, as shown in FIG. 3, the carrier roller 6 is made of stabilized zirconia 30 which is a solid electrolyte, and the interior of the carrier roller 6 is hollow so that oxygen gas can be introduced thereinto. An oxygen inlet 32 is provided at one end of the carrier roller 6, and the other end is sealed, and the inner wall surface is covered with an electrode 31 made of metal, and the electrode 31 is grounded.

Next, the operation of the powder coating apparatus 20 of the above embodiment will be explained.

In FIG. 2, a drive motor (not shown) rotates the carrier roller 6 and the developer supply roller 7 in contact with the carrier roller 6 in the counterclockwise direction in the figure. In this way, the developer 8 stored in the hopper 15 is supplied to the carrier roller 6 via the developer supply roller 7, and is supported on the carrier roller 6 by frictional force, image force, etc. Since the color developer 8 is usually made of a dielectric material, individual particles or aggregates of the color developer 8 are charged by contacting or rubbing against other particles or aggregates. However, in this state, the amount of charge is small and there are approximately the same number of color developers 8 of opposite polarity, so either they are neutralized and become cello, or oxygen is supplied to the carrier roller 6 from an oxygen supply device (not shown). As a result, the color developer 8 is charged in the following manner. In FIG. 3, when oxygen gas is supplied from the gas inlet 32 at the left end of the carrying roller 6, the oxygen concentration inside the carrying roller 6 becomes higher than that outside the carrying roller 6, and as described above, the oxygen inside the carrying roller 6 generates electrons. The oxygen ions become oxygen ions and move inside the stabilized zirconia 31 from the inside of the support roller 6 to the outside. The oxygen ions that have moved to the surface of the carrier roller 6 come into contact with the powder that has been previously supported on the surface of the carrier roller 6, and as shown in FIG. 4, are released as oxygen ions or when the oxygen ions become oxygen molecules. Electrons attach (adsorb) to the color developer 8, and as a result, the color developer 8 is all uniformly negatively charged. Although the electrons in the stabilized zirconia are consumed over time, they are constantly supplied from the ground through the electrode 31 on the inner wall of the carrier roller 6.

In this way, the color developer 8 is carried by the carrying roller 6, charged, and conveyed toward the transfer area 13.

By the way, the plain paper 4 to which the color developer 8 is applied is inserted into the insertion slot 1.
After being inserted into the coating device 20 from 2, it is held by the conveyance belt 2 and conveyed to a position facing the transfer area 13 as the electrode roller 1 and the conveyance roller 3 rotate. Electrode roller 1
is made of metal, and a high voltage is applied by the DC power source 5, so that an electric field is formed around it including the transfer region 13. The charged color developer 8 carried by the carrying roller 6 exists in the transfer area 13 and is attracted toward the electrode roller 1 by electrostatic attraction according to the electric field. At this time, as mentioned above, since the color developer 8 is strongly charged, the color developer 8 is easily attracted to the electrode roller 1, and a large amount of the color developer 8 is applied to the plain paper 4 on the electrode roller 1. Ru. After that, if there is a small amount of color developer 8 on the carrier roller 6 that was not attracted to the electrode roller 1 even by electrostatic attraction, it will be completely removed by contacting the grounded removal blade 9. Charges are also neutralized.

The plain paper 4 coated with the color developer 8 in this manner is conveyed according to the operation of the conveyance unit 14 and is discharged from the discharge port 11 to the outside of the casing 17 .

Although the powder coating device equipped with the powder charging device of the present invention has been described above, modifications can be made without departing from the spirit of the present embodiment. For example, in this embodiment, a solid electrolyte is used for the carrier roller and is charged on the carrier roller, but the hopper containing the powder may be made of a solid electrolyte. Furthermore, although oxygen was used in this example, other gases may be used if the ion conductor is selected appropriately, and by doing so, it is possible to charge the powder either positively or negatively.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, it is possible to uniformly and stably charge powder and make the powder fly with a sufficient amount of charge. .

[Brief explanation of drawings]

1 to 4 show embodiments embodying the present invention, and FIG. 1 is an explanatory diagram showing the principle of an oxygen sensor similar to the principle of the powder charging method of the present invention, FIG. 2 is a schematic configuration diagram of the powder coating device, and FIG. 3 is an enlarged view of the carrying roller. FIG. 4 is an explanatory diagram showing how the powder is charged. 1... Electrode roller 3... Conveyance roller 5... DC power source 7... Supply roller 9... Removal plate 11... Output port 10 2... Conveyance belt... Plain paper ... Carrying roller ... Color developer ... Supply unit ... Insertion port 13 ... Transfer area 15 ... Hopper 20 ... Powder coating device 31 ... Electrode 14 ... Transport unit 16...Casing 30...Stabilized zirconia 32...Oxygen inlet

Claims (1)

[Claims] 1. Powder is supported on the front or back side of an ionic conductor, and a diluted or concentrated gas such as oxygen is introduced to the side opposite to the side on which the powder is supported, using the ionic conductor as a partition wall. A powder charging device featuring: 2. A powder charging device, wherein the ion conductor according to claim 1 is a cylindrical carrier roller. 3. A powder charging device according to claim 2, wherein the carrying roller has a hollow interior, into which a concentrated gas such as oxygen is introduced. 4. A powder coating device, characterized in that the powder charged using the powder charging device according to any one of claims 1, 2 and 3 is applied to a support supported by opposing electrode rollers.