JPS61281975A - Measuring instrument for distribution of toner electric charge quantity - Google Patents

Abstract

PURPOSE:To measure the particle size distribution and the charge quantity distribution of toner particle units with a high precision by gathering toner particles of low natural drop speed onto the surface of a filter easily. CONSTITUTION:Electrodes 1 and 2 are provided in parallel with the Z direction, and air alminar streams in Y and X directions are formed in the electric field which is formed by applying a certain DC voltages to these electrodes. Charged toner particles 4 are dispersed in particle units and are dropped naturally from a toner drop tube 3 provided above the position between electrodes 1 and 2. Particles 4 are moved with a certain speed component in the X direction by air alminar streams and are gathered on a filter 7. Toner particles receive the force of the electric field in the Y direction and the gravity in the Z direction to move with components in individual directions while moving in the X direction. Displacements in Y and X directions of particles 4 are proportional to the square of the particle size and the charge quantity per unit particle size. Thus, the particle size and the charge quantity of particles 4 are obtained inversely in accordance with YZ coordinates of particles 4 gathered on the filter 7.

Description

[Detailed Description of the Invention] (Summary) This is a toner charge amount distribution measuring device, which measures the difference in the distance that toner particles naturally fall per unit time due to the difference in particle size, and the particle size and charge of toner particles. Utilizing the fact that there is a difference in the amount of movement per unit time in the direction of the electric field due to the difference in the amount,
By arranging the filter in a plane perpendicular to the direction of the laminar air flow, the time it takes for toner particles to be collected by the filter can be made constant, and the charge amount distribution and particle size distribution of each toner particle can be adjusted at the same time. This allows for easy measurement.

[Industrial application field]

The present invention relates to a toner charge distribution measuring device, and more particularly to a toner charge distribution measuring device that has been improved so as to be able to measure the charge amount in units of toner particles with high accuracy and to make the device compact.

In the electrophotographic process, it is necessary to know the amount of charge on the toner in order to analyze the development process.Especially in recent years, it has become increasingly important to measure the amount of charge on each toner particle and determine the distribution of the amount of charge on the toner in the developer. It is requested.

(Prior Art) Conventionally, as a device for measuring the amount of charge on toner particles, a device typified by Japanese Patent Application Laid-Open No. 116542/1983 has been proposed.

As shown in the schematic diagram of Figure 4, this device operates in the direction of gravity (Z
A constant DC voltage is applied between two parallel electrode plates 1 and 2 that are arranged parallel to each other in the direction (direction) to form a uniform electric field between the electrodes 1 and 2.

In addition, a laminar air flow is generated in a direction (X direction) parallel to the two electrode plates 1 and 2 and perpendicular to the direction of gravity, and the toner disposed above between the two electrode plates 1 and 2 is Charged toner particles 4 are allowed to naturally fall from a drop tube 3 onto a measurement plate 5 placed perpendicular to the direction of gravity.

The toner particles 4 falling from the toner drop tube 3 are moved in the X direction due to the difference in falling speed depending on the size of the particles and the difference in electric force depending on the amount of charge on the particles.

It falls onto the measurement plate 5 with a displacement in the Y direction.

Therefore, it is possible to determine the particle size and charge amount distribution of the toner particles from the X and Y coordinates of the toner on the measurement plate 5.

[Problem that the invention seeks to solve]

Generally used toner particles have a density of 1.0g/
The particle diameter is around lOμ corner around cff13, and the natural falling speed in the air is extremely small at about 0.3 cIl/Sec when calculated based on Stokes' theorem.

Therefore, in order to collect and measure toner separated into particles using conventional equipment, it is necessary to reduce the toner falling distance in two directions, to minimize the speed of the air flow, or to measure the toner in the X direction of the equipment. It is necessary to lengthen the possible range, leading to deterioration in measurement accuracy or an increase in the size of the device.

Therefore, in practice, this device can only measure the average charge amount distribution for each aggregation of several tens to hundreds of toner particles and the distribution of the degree of aggregation of dropped toner.
It was difficult to measure the charge amount distribution and particle size distribution of each toner particle.

The present invention was created in view of these points, and provides a toner charge amount distribution measuring device that can simultaneously and easily measure the charge amount distribution and particle size distribution of each toner particle with a simple configuration. is intended to provide.

[Means for solving problems]

FIG. 1 shows a sectional view of the toner charge amount distribution measuring device of the present invention.

In FIG. 1, the apparatus is a wind tunnel consisting of a measuring section A, a rectifying section B, and an airflow generating section C.

The measurement section A includes a toner drop tube 3 that drops toner particles 4, an electrode 1.2 that forms a uniform electric field perpendicular to the direction of gravity, and a direction of laminar air flow, as shown in the schematic diagram of FIG. The filter 7 is disposed in a plane perpendicular to the direction X and collects the toner particles 4 introduced into the laminar air flow.

The airflow generating section C is a suction section 9 that sucks air from the rear of the device.
and a regulator 8 that adjusts the amount of air sucked into the suction unit 9.

The rectifying section B is composed of a grid-like rectifying plate 6 that forms a laminar air flow in the wind tunnel in the horizontal direction (X direction), and is provided on both sides of the measuring section A.

[Effect]

The regulator 8 in the airflow generation section C adjusts the amount of air flowing in the wind tunnel to an optimal value, and the lattice rectifier plate 6 in the rectification section B forms a horizontal laminar air flow to increase the velocity of the toner particles 4 in the X direction. The toner particles 4 are moved by a filter 7 whose composition is constant and which is arranged in a plane perpendicular to the direction X of the laminar air flow.
I am trying to collect the following.

The present invention makes it possible to make the time required for toner particles to be collected by a filter constant, and to simultaneously and easily measure the charge amount distribution and particle size distribution of each toner particle.

〔Example〕

FIG. 1 is a sectional view of a toner charge amount distribution measuring device according to an embodiment of the present invention.

In FIG. 1, the device is composed of a measuring section A, a rectifying section B, and an airflow generating section C. Air is sucked from the rear of the device by a suction section 9, and a predetermined flow rate is adjusted by adjusting a regulator (valve) 8. It is a type of wind tunnel that obtains a flow velocity and forms a laminar air flow in the horizontal direction (X direction) using rectifier plates 6 arranged in a grid pattern.

FIG. 2 is a diagram schematically showing the structure of the measuring section of the present device.

In Fig. 2, two parallel electrode plates 1.2 are installed parallel to the direction of gravity (two directions), and in the electric field formed by applying a constant DC voltage to these two electrode plates, The airflow generation section C and the rectification section B form an airflow in a direction perpendicular to the direction of the electric field (Y direction) and perpendicular to the direction of gravity (X direction).

Next, the charged toner particles 4 are dispersed in particle units and allowed to fall freely from the toner drop tube 3 provided above between the two electrodes 1 and 2.

Here, the origin is the drop port 3-1 of the toner drop tube 3, and x
, y, z coordinate system.

The toner particles 4 move with a constant velocity component in the X direction due to the laminar air flow, and are collected on the filter 7. The filter 7 uses filter paper that has good air permeability and a surface rough enough to retain toner particles.

The time T until the toner particles 4 that have started falling from the drop port 3-1 of the toner drop tube 3 reach the filter 7 surface is determined by the distance E from the drop port 3-1 of the toner drop tube 3 to the filter 7 surface.
, the velocity of the laminar air flow is Vx, then T-1/Vx (1).

Further, while moving in the X direction, the toner is subjected to the force of an electric field in the Y direction and gravity in two directions, and moves with components in each direction.

Assuming that the toner particles are spheres with density p and diameter d, and the displacements in the Y and Z directions within time T are y and z, the following equation is obtained by omitting the higher-order minute quantities from Stokes' theorem: It is expressed as

y=(ρg/18y)xTxd ------(2) Z
-(E/ 3 ff W) XTX (q/d)
--(3) where g is the gravitational acceleration and η is the viscosity coefficient of air.

E is the electric field strength, q and the amount of charge held by the toner particles.

Equations (2) and (3) are, in other words, the Y direction of the toner particles, the
This shows that the displacement in the direction is proportional to the square of the particle size d, the amount of charge per unit particle size, and q/d, respectively. Therefore, from the YZ coordinates of the toner particles collected on the filter, the particle size of the toner particles can be calculated in reverse. and the amount of charge can be determined.

FIG. 3 is an example of equal particle diameter lines 9 equal charge amount lines of toner particles collected on the filter obtained based on equations (2) and (3).

As shown in Figure 3, since the origin of the yz coordinate is the point where both the particle size and the amount of charge are zero, toner particles with a small falling velocity can be captured near the origin 0, and the distribution of each particle can be measured. can be done reliably. In addition, the equal particle diameter line is a horizontal straight line, and the second equal charge amount line is a group of straight lines perpendicular to the equal particle diameter line. can be known very easily.

In this embodiment, the charge amount per unit particle diameter of the toner particle, q/d, is used as the charge amount, but it is also possible to determine the charge amount q per toner particle light.

In addition, the adjustment unit 8 adjusts the air volume to optimize the flow velocity, and the lattice-shaped rectifier plate 6 forms a uniform laminar air flow in the horizontal direction. Obtaining toner particle distribution.

〔Effect of the invention〕

As explained above, according to the present invention, toner particles having a low natural falling speed can be easily collected on the filter surface, so that the particle size distribution and charge amount distribution of each toner particle can be measured with high precision. This has the effect that the size of the device can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the toner charge amount distribution measuring device of the present invention, FIG. 2 is a schematic diagram of the measuring section of the present invention, FIG. 3 is an example of equal particle diameter lines and equal charge amount lines, and FIG. 4 1 is a schematic diagram of a measuring section of a conventional toner charge amount distribution measuring device. In the figure, 1 and 2 are electrodes, 3 is a toner drop tube, and 3-1
Reference numeral 4 indicates a falling port, 4 indicates a toner particle, 5 indicates a measuring plate, 6 indicates a grid rectifying plate, 7 indicates a filter, 8 indicates a regulator, and 9 indicates a suction section. Ji invention fan T-O 萄 1 meritorious eyebrow setting device 禮訝 柝斊 FIRST CAUSE i Shot 1 to Gun 4 Hard Ga jump @ 2m

Claims (1)

[Claims] Toner particles (4) are dropped into a space in which a horizontal laminar air flow and a uniform DC electric field in a horizontal direction perpendicular to the direction of the laminar air flow are formed, and the particle size distribution of the toner particles (4) is determined. and a toner charge amount distribution measuring device that measures the charge amount distribution from the deflection displacement of toner particles collected on a plane, with the plane for collecting the toner particles being perpendicular to the filter (7) surface with respect to the laminar air flow. A toner charge amount distribution measuring device, characterized in that: