JPH04118565A - Measuring device for charge quantity distribution - Google Patents

Abstract

PURPOSE:To correctly measure the charge quantity distribution of charged one-component system toner particles in a shape near to a development system by separating and flying toner particles, coated in a thin layer on a holding member, by the force of an electric field, and moreover sucking the toner particles with an air flow generating device through a measuring device. CONSTITUTION:An electric field is produced by voltage, applied with a power source 10, between a toner particle holding member 2 and a counter electrode 3, and toner particles 1 are separated from the holding member 2. The separated toner particles 1 are flown in the counter electrode 3 direction by force by the electric field, and are carried to the introduction part of a charge quantity distribution measuring part B by an air flow produced with an air flow generating device 31. In the toner particles 1 carried to the charge quantity distribution measuring part B, a given physical quantity is measured with a measuring device 21, and is converted into a charge quantity and a particle diameter with an operation part 22. This can accurately measure the charge quantity distribution of charged one-component system toner particles coated in a thin layer in a shape near to a development system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for measuring the charge amount distribution of monocomponent toner particles.

[Prior Art] In recent years, with the spread of image forming apparatuses such as particle photography, electrostatic recording, and electrostatic printing, their uses have become widespread, and quality requirements for images have become increasingly strict.

The characteristics of the individual toner particles used, especially the charge amount and particle size, are important factors in particle photographic characteristics because they greatly affect the image density, sharpness, fog, etc. of the final copied image.

Conventionally, the blow-off method is well known for measuring 18:coulometric capacity, but this method alone is not sufficient to provide information on particle photographic characteristics. In other words, the amount of charge of each toner particle is important for particle photographic characteristics. Several proposals have been made as methods for measuring the charge amount distribution of toner.

For example, Japanese Patent Application Laid-open No. 57-79958 proposes a method in which toner particles in a constant velocity airflow are deflected by an electric field and the toner charge distribution is measured from the amount of deflection after a certain period of time. However, toner particles have a wide particle size distribution depending on the case, and if the correspondence with the particle size is not known, it cannot be said that the charge amount distribution is effective.

As a method to solve such problems, Japanese Patent Application Laid-Open No. 61-2
No. 77071 has been proposed. This method determines the charge amount distribution corresponding to the particle size of toner particles from the degree of deflection and vibration phase of toner particles in a constant velocity airflow, electric field, and vibration waves. This is a very effective method, but the most important point in these measurement methods is whether all of the toner is being charged in a manner close to the development system and whether all of the toner is being measured.

Therefore, as a method for separating toner particles from carrier particles of a two-component toner, Japanese Patent Application Laid-Open No. 57-79958 discloses
Japanese Unexamined Patent Publication No. 63-263475 proposes a method of separating toner particles from carrier particles using compressed air. However, it is difficult to separate all the toner particles from the carrier particles because some toner particles are hidden by the carrier particles and cannot be effectively affected by compressed air, making it difficult to measure the charge distribution of all toner particles. It is. Also, in Japanese Patent Application Laid-Open No. 60-8758,
A method has been proposed in which toner particles are separated from carrier particles by using a mesh below the developer container, but in this method, the mesh is fine to collect the carrier particles, and the toner particles pass through the mesh. In some cases, friction with the mesh may cause recharging, making it difficult to accurately measure the charge amount distribution.

As a method to solve such problems, JP-A-64-80
No. 969 has been proposed. This method uses an electric field to weaken the Coulomb force between toner particles and carrier particles, and in this state, blows an air stream to separate the toner particles from the carrier particles. However, since this method relies on airflow for final separation of toner particles, it is difficult to separate all toner particles, and therefore it may be difficult to accurately measure the charge amount distribution of toner particles.

As described above, the method for measuring the charge amount distribution is still not sufficient.

Furthermore, in recent years, one-component developing method has been increasingly used instead of two-component developing method. The one-component developing method is particularly suitable for small machines because the developing machine can be made very small, but due to improvements in the developing machine, it is now possible to process 80 sheets per minute (also used in high-speed machines for leprosy). , the charge amount of single-component toner, especially the charge amount distribution, has not yet been fully analyzed, and it is thought that further improvements can be made by analyzing these.In particular, the insulation property 1
In the component development method, the toner particles are coated in a thin layer on the surface of the toner particle supporting member, making it even more difficult to separate the toner particles.For example, when an air stream is used as a means of separation, the toner particles are coated in a thin layer. Since the toner particles are blown onto the toner particle carrying member, problems arise such as recharging with the surface of the toner particle carrying member, or creating an uneven toner coating layer and changing the charge amount distribution.Furthermore, toner particles However, the toner particles may slip on the toner particle supporting member and the toner particles may not be properly conveyed to the measuring section.

In contrast to this method of separating toner particles using air flow, a method of separating toner particles using only an electric field was developed in Japanese Patent Application Laid-Open No. 1983-1999.
This method is proposed in Japanese Patent No. -58175. In this method, an alternating electric field is applied between two electrodes embedded inside a sleeve made of an insulator, and the toner particles are separated from the two-component toner supported on the surface of the insulating sleeve by this alternating electric field. This method measures the charge amount distribution of toner particles that are dropped.

However, the sleeve used in this method is special, and it cannot be said that it measures the charge amount distribution of toner particles that actually contribute to development.

As described above, an apparatus for measuring the charge amount distribution of toner particles in the insulating one-component development method has not yet been established.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems. That is, the purpose is to measure the IF charge amount distribution of charged one-component toner particles in a form similar to the developing system in an image forming apparatus such as an actual particle photography system. Another object of the present invention is to prevent recharging of toner particles while maintaining a thin and uniform toner coating layer on the toner particle carrying member, and to measure the IF charge distribution of all toner particles on the toner particle carrying member. Furthermore, it is necessary to accurately measure the charge amount distribution of magnetic toner particles in a form close to that of the developing system.

[Means and effects for solving the problem] The means taken by the present invention is to form a thin layer of toner particles on a toner particle supporting member having a conductive member in a method for measuring the charge amount distribution of one-component toner particles. The regulating member to be coated, the toner particle carrying member, and the opposing t8i! installed opposite to the toner particle carrying member. a power supply that applies a voltage between the toner particles, a measuring device that can measure at least a value related to the amount of charge of the toner particles, an air flow generating device, and a device that controls the distance between the toner particle carrying member and the opposing electrode. The charge amount distribution measuring device is characterized in that the regulating member is composed of a magnetic plate, or the regulating member is composed of an elastic rubber blade. This is a charge amount distribution measuring device characterized by:

Furthermore, the device for measuring the charge amount distribution of one-component toner according to the present invention has the following effects. Toner particles are coated in a thin layer on a toner particle carrying member in a form similar to that of a developing system.
A voltage is applied between the toner particle carrying member and the counter electrode with a controlled distance, and the electric field generated by the voltage causes the toner particles to be peeled off from the toner particle carrying member, and the toner particles are further separated by the electric field and air flow. By conveying the toner particles to the measuring section, almost all of the toner particles can be separated from the toner particle carrying member and measured. At this time, the direction of the air flow may be the same as the direction of the electric field, and must be at least ±30° with respect to the electric field. If the angle is larger than that, all the toner particles on the toner particle carrying member cannot be conveyed to the measuring section. Furthermore, if the air flow is too strong, an air flow perpendicular to the electric field will occur on the toner particle supporting member.
It is not possible to accurately measure the charge amount distribution.

In particular, since single-component magnetic toner is restrained by magnetic force on the toner particle supporting member, there is a large proportion of magnetically aggregated toner, and the method of the present invention allows measurement in a state in which the aggregates are loosened, which is very effective. It is valid. Furthermore, in recent years, technology has progressed toward higher image quality, and toner particle diameters have become smaller and smaller. This has increased the powder cohesive force of toner particles, making it difficult to measure the charge amount distribution of toner particles. The method of the present invention is also very effective in this respect.

[Example] Hereinafter, an example according to the present invention will be described based on the drawings.

Example 1 FIG. 1 is a schematic cross-sectional view of a charge amount distribution measuring device according to the present invention. In the figure, A is a peeling/conveying section for peeling toner particles 1 from the toner particle carrying member 2 using an electric field and transporting the peeled toner particles 1 to measurement section B. In the figure, B is the particle size and charging of toner particles 1. This is a charge amount distribution measuring section that measures the amount of charge.

First, the toner particle carrying member 2 containing the magnet 5 rotates,
The toner particles 1 regulated by the regulating member 4, which is a magnetic blade, are coated in a thin layer on the toner particle carrying member 2.

A power source 1 is connected between the toner particle supporting member 2 and the counter electrode 3.
The voltage applied by 0 causes an electric field to be generated. At this time, in the case of an arbitrary voltage, the toner particle carrying member 2 moves back and forth on the rail 7 with the wheels 6 with respect to the counter electrode 3, moves to a distance where the toner particles 1 are separated by the force of the electric field, and is fixed. be done. The electric field strength at that time is below the discharge limit according to Paschen's law.

Therefore, a force in the same direction as the electric field acts on the toner particles 1 supported on the toner particle supporting member 2.
The toner particles 1 can be peeled off from the toner particle supporting member 2.

The peeled off toner particles 1 fly in the direction of the counter electrode 3 due to the force caused by the electric field. In the vicinity of the counter electrode 3, an air flow generator 31 generates an air flow of 3000 cm'/wi.
A uniform air flow set at n leads in the direction of the arrow. Therefore, the toner particles 1 flying near the counter electrode 3 are conveyed to the introduction section of the charge amount distribution measuring section B by the air flow.

In the present invention, the toner particles 1 coated in a thin layer on the toner particle carrying member 2 by the regulating member 4 are peeled off and flown by the force of an electric field, and are further sucked by the air flow generator 31 passing through the measuring device. Creates a uniform airflow,
It can be transported to the charge amount distribution measuring section B.

The toner particles 1 conveyed to the charge amount distribution measuring section B have a predetermined physical quantity measured by the measuring device 21, and are transferred to the calculating section 22.
The physical quantities are converted into charge amount and particle size.

Therefore, by the above process, a plurality of toner particles 1 are
By measuring, it is possible to obtain the charge amount distribution with respect to the particle size.

FIG. 2 shows an example of the above measuring device. FIG. 2(a) shows a method of measuring the amount of charge and particle size using the laser Doppler method. 211a, 21 in the figure
1b is shaking! 1J electrode plate, and 212 is a vibration generator. As is well known, minute particles existing in an air base that vibrates follow the air vibrations. At this time, due to the inertia of the grains, the large grains vibrate with a delay from the standard vibration. Also, the above shake! I] When a voltage is applied to the electrode plates 211a and 211b, the particles change due to their particle size, amount of charge, and electric field due to the applied voltage.
Shifts in the direction of the electric field. Therefore, by measuring the phase delay of the vibration of the particles relative to the air vibration and the degree of deviation due to the electric field, the particle size and charge amount of the particles can be determined.

In the present invention, a laser generating section 213 and a laser receiving section 214 are arranged, and by using the laser Doppler method, the phase delay of the toner particles 1 with respect to air vibration and the shift speed due to the electric field are measured, and the measured quantity is The particle size and charge amount of the toner particles 1 are obtained by calculating them in the calculating section 22 in FIG.

Further, the measuring method is not limited to that shown in FIG. 2(a), but may be, for example, as shown in FIG. 2(b).

That is, the laser generator 213 generates a laser, and the generated laser passes through the window 217 to the laser receiver 2.
14, and the velocity of the toner particles 1 in the air flow direction is measured by the laser Doppler method. As is well known, the diameter of a particle can be determined by measuring the relative falling speed of a minute particle falling in an air stream with respect to the air stream. Therefore, the relative falling speed of the toner particles 1 is determined by the laser Doppler method and calculated by the arithmetic unit 22(a).
particle size can be obtained.

In addition, as is well known, the charge measurement device 22 (
By measuring in b), the amount of charge on the toner particles 1 can be measured.

Embodiment 2 The present invention is not limited to the above-mentioned embodiment. For example, as shown in the schematic diagram of FIG. 3, the regulating member 4 may be formed into a thin layer using a non-magnetic plate.

Embodiment 3 Furthermore, as shown in FIG. 4, the regulating member 4 may be made of a thin layer of elastic rubber blade.

[Effects of the Invention] As described above, according to the present invention, the IF charge distribution of charged monocomponent toner particles coated in a thin layer in a manner similar to that of a developing system can be measured with higher accuracy.

In particular, since most of the toner particles on the toner particle carrying member can be peeled off from the toner particle carrying member, reproducibility is also improved.

Furthermore, since most of the toner particles peeled off from the toner particle supporting member can be measured, efficiency is also high.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of the present invention, FIG. 2 is a schematic diagram of a measuring section used in the present invention, and FIG. 4 is a third schematic diagram of a chess game system of another embodiment of the present invention. It is a diagram. 1: Toner particles 3: Opposing electrode 5: Magnet 7: Rail 21: Measuring device 22 (a): Arithmetic device 31/air flow generator 212: Vibration generator 214: Laser receiver 218: Detection electrode B: Charge amount distribution Measuring section 2: toner particle carrying member 4, regulating member 6, wheel 10, variable voltage power source 22: calculating section 22 (b): charge measuring device 211a, 211b: vibrating electrode plate 213: laser generating section 217: window A: peeling・Transportation section

Claims (3)

[Claims] (1) In measuring the charge amount distribution of one-component toner particles,
Applying a voltage between a regulating member that coats a thin layer of toner particles on a toner particle carrying member having a conductive member, and a counter electrode disposed opposite to the toner particle carrying member and the toner particle carrying member. A charge amount distribution measuring device comprising: a power supply for measuring at least a value related to the charge amount of the toner particles; a measuring device capable of measuring at least a value related to the charge amount of the toner particles; an air flow generating device; and a device controlling the distance between the toner particle carrying member and the counter electrode. . (2) The charge amount distribution measuring device according to claim (1), wherein the regulating member is constituted by a magnetic blade. (3) The charge amount distribution measuring device according to claim (1), wherein the regulating member is constituted by an elastic rubber blade.