JPH0417244Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an apparatus for separating non-magnetic particles from a mixture of magnetic particles and non-magnetic particles.

(Prior art) For example, when measuring characteristics such as the amount of charge of toner particles used in electrophotographic copying machines, toner particles are There is a need to separate non-magnetic particles, and non-magnetic particle separation devices have been conventionally provided to perform such separation.

As this type of device, for example,
There is one shown in Publication No. 51558. This device is
providing means for forming a magnetic field acting on said mixture and means for forming an electric field acting likewise;
While magnetic particles are attracted by the force of the magnetic field, only non-magnetic particles are repelled by the electric field,
I try to separate them.

The principle used in this device will be explained with reference to FIG. In the figure, 101 is a grounded conductor, and an electrode 1 is placed on the upper surface of this conductor 101.
An insulator 103 in which 02 is embedded is provided. Then, an equal voltage is applied to each electrode 102 by an AC power source 104, thereby forming an unequal alternating electric field schematically shown by dotted lines between the electrode 102 and the conductor 101. are doing. When a particle P exists in the electric field formed in this way, the particle P receives a repulsive force in the direction of the arrow, and the electrode 10
It scatters in the direction away from 2.

Therefore, for example, magnetic particles can be attached to the insulator 10 using a magnet or the like.
3 and scattering only the non-magnetic particles using the action of the electric field, it is possible to separate the non-magnetic particles from the mixture.

However, since the electric field is formed on the opposite side of the conductor 101 with respect to the electrode 102, that is, on the back surface of the electrode 102, as is clear from the electric lines of force shown in FIG. The drawbacks were that the repulsive force generated was small and the energy efficiency (separation efficiency of non-magnetic particles) was poor.

(Purpose of the invention) The present invention is to eliminate the above-mentioned drawbacks, and is to provide a device for separating non-magnetic particles from a mixture using an electric field, which can improve the efficiency of separating non-magnetic particles by the electric field. The purpose is to provide a separation device.

(Structure of the invention) The present invention is a device for separating non-magnetic particles from a mixture of magnetic particles and non-magnetic particles, and consists of an insulator provided on the outer periphery of a magnetic roll driven to rotate, and an insulator disposed on the circumferential surface of the magnetic roll. A conductor is provided, and a wire is embedded in the insulator and extends in the axial direction of the magnetic roll. so that an electric field is formed outside the conductor to exert a repulsive force on the non-magnetic particles.
An alternating current voltage is applied between the conductor and the wire, and a communication portion is provided in the insulator and the conductor to connect the wire to the outside of the conductor.

According to such a configuration, only the non-magnetic particles of the mixture moving on the conductor as the magnetic roll rotates are scattered by the electric field formed between the conductor and the wire, thereby separating the non-magnetic particles from the mixture. can do. Moreover, since an electric field is formed between the conductor outside the insulator and the wire connected to the outside of the conductor, non-magnetic particles moving on the conductor are effectively repelled. Force can be applied.

(Example) Embodiments of the present invention will be described with reference to FIGS. 1 to 4.

In these figures, A is a non-magnetic particle separating device according to the present invention, and this separating device A and measuring device B constitute the toner charge amount measuring device shown in FIGS. 1 and 2.

Separation device A includes a magnetic roll 1 having a plurality of magnetic poles that are rotationally driven, and an insulator 2 made of a non-magnetic material such as aluminum provided on the outer periphery of the magnetic roll 1.
A conductor 3 is provided on the circumferential surface of the insulator 2, and a plurality of wires 4 are embedded in the insulator 2 in the axial direction of the magnetic roll 1. On the conductor 3,
A two-component developer 6 (mixture) consisting of toner (non-magnetic particles) and carrier (magnetic particles) is attracted by the magnetic force of the magnetic roll 1, and the toner is electrostatically attracted to the magnetic carrier by frictional charging. There is. The entire structure is such that the developer 6 thus attracted is moved on the conductor 3 by the rotation of the magnetic roll 1.

In the conductor 3 and the insulator 2, the surface of the portion where the wire 4 is buried is cut out, thereby allowing the wire 4 to communicate with the outside of the conductor 3,
A communicating portion a to be exposed is formed. Furthermore, by applying an alternating current voltage 5 between the wire 4 and the conductor 3, an alternating electric field (its electric lines of force E are shown in FIG. 4) is formed outside the conductor 3. There is. This alternating electric field causes a repulsive force to act on the toner in a direction away from the conductor 3. Note that the conductor 3 is grounded to prevent charge from being injected into the developer 6 moving on the conductor 3.

Between the toner separating section A and the measuring device B, slits 7 and 8 (one slit 8 is omitted from illustration in FIG. 1) are arranged in a direction perpendicular to the axial direction of the insulator 2. ing.

The measuring device B includes a pair of parallel electrode plates 9 and 10 facing in the axial direction of the insulator 2, and a receiving plate 11 made of a glass plate or the like disposed below the electrode plates 9 and 10, A DC power supply 12 is applied between the electrode plates 9 and 10 to form a horizontal parallel electric field between the electrode plates 9 and 10.

In the above configuration, the two-component developer 6 adsorbed onto the conductor 3 moves on the conductor 3 as the magnetic roll 1 is rotated. When the developer 6 moving in this manner is subjected to the repulsive force of the alternating electric field formed between the conductor 3 and the wire 4, charged toner particles are scattered from the conductor 3. At this time, the carrier remains on the conductor 3 because it is attracted by the magnetic force of the magnetic roll 1, and thereby the toner in the two-component developer 6 can be separated from the carrier.

The toner particles scattered as described above are subjected to a force in the left-right direction perpendicular to the axial direction of the magnetic roll 1 based on the above-mentioned electric field distribution, and fall naturally while spreading as shown in FIG.

Slits 7 and 8 are arranged corresponding to this spread, and the toner particles pass through these slits 7 and 8 and are guided between electrode plates 9 and 10 of measuring device B.
In this horizontal parallel electric field, the toner particles receive a horizontal force H (FIG. 2) depending on the amount of charge on the toner particles, and the toner particles land on the receiving plate 11. In this way, since the toner particles fall while being subjected to the horizontal force H and the vertical gravity V, the mass of the particles and
Toner particles are dispersed at positions corresponding to the amount of charge.
From the distribution of the falling positions of the toner particles, the toner charge amount distribution is calculated by image processing.

According to the above configuration, in the separation device A, an electric field is formed between the conductor 3 provided outside the insulator 2 and the wire 4 communicating with the outside, so that the separation device A shown in FIG. As can be seen by comparing the electric lines of force shown in FIG. 5, the repulsive force generated by the electric field can be applied more effectively to the toner particles, and the separation efficiency can be improved.

Note that the device to which the present invention is applied is not limited to the toner charge amount measuring device as in the above embodiment, but can be used to separate non-magnetic particles from a mixture of magnetic particles and non-magnetic particles. Just use it. Furthermore, the mixture to be separated is not limited to the developer consisting of toner and carrier.

(Effects of the invention) As described above, the present invention provides a device for separating magnetic particles and non-magnetic particles by using an alternating electric field, in which a conductor is provided outside the insulator, and
Since the wire embedded in the insulator is communicated with the outside of the conductor, the electric field formed can be applied to the non-magnetic particles more effectively than in conventional non-magnetic particle separation devices. Therefore, the repulsive force acting on the non-magnetic particles can be strengthened, and the separation efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a toner charge amount measuring device to which the non-magnetic particle separating device of the present invention is applied, FIG. 2 is a cross-sectional view of the same measuring device, FIG. 3 is a cross-sectional view of the above-mentioned separating device, and FIG. 4 5 is a cross-sectional view showing lines of electric force of an electric field formed in the separation apparatus, and FIG. 5 is a cross-sectional view showing lines of electric force of an electric field formed in a conventional separation apparatus for non-magnetic particles. A...Nonmagnetic particle separation device, a...Communication part,
E... Lines of electric force, 1... Magnetic roll, 2... Insulator, 3... Electric conductor, 4... Wire, 5... AC power supply, 6... Developer (mixture).

Claims (1)

[Scope of utility model registration request] A device for separating non-magnetic particles from a mixture of magnetic particles and non-magnetic particles, which comprises: an insulator provided on the outer periphery of a rotationally driven magnetic roll; a conductor provided on the circumferential surface; a wire embedded in the conductor and extending in the axial direction of the magnetic roll, and configured such that the mixture adsorbed on the conductor moves on the conductor by rotational driving of the magnetic roll,
An alternating current voltage is applied between the conductor and the wire so that an electric field that exerts a repulsive force on the non-magnetic particles is formed outside the conductor, and the wire is applied to the insulator and the conductor. 1. A device for separating non-magnetic particles, characterized in that it is provided with a communication portion that communicates with the outside of a conductor.