JPH0415574A - Toner charge amount distribution measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for measuring the charge amount distribution of toner particles based on component (1).

[Prior Art] In recent years, with the spread of image forming apparatuses such as electrophotography, electrostatic recording, and electrostatic printing, their uses have become widespread, and quality requirements for images have become stricter. The characteristics of the individual toner particles used, particularly the charge amount and particle size, are important factors in electrophotographic 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 the amount of charge, but this method alone is not sufficient to provide information on electrophotographic characteristics. In other words, the amount of charge of each toner particle is important for electrophotographic characteristics.

Some proposals have been made as a method for measuring the charge amount distribution of such 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 sometimes have a wide particle size distribution, and unless the correspondence with the particle size is 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. Although this is a very effective method, the most important point of these measurement methods is to measure the amount of charge of the charged toner in a manner close to the developing system. Therefore, it is important to separate the charged toner from the developer in a form close to the developing system and convey it to the measuring section. Since the above method is premised on measuring the charged toner after being separated, it may not correlate with actual development.

Therefore, as a method for separating toner particles from carrier particles of a two-component developer, Japanese Patent Laid-Open No. 57-79958 discloses a method for separating toner particles from carrier particles of a two-component developer.
Japanese Unexamined Patent Publication No. 63-263475 proposes a method of separating toner particles from carrier particles using compressed air. However, in these methods, it is difficult to separate all 1 to 1 particles from the carrier particles because there are toner particles that are hidden by the carrier particles and compressed air does not work effectively on them. That is difficult.

Furthermore, Japanese Patent Application Laid-open No. 60-8758 proposes a method of separating toner particles from carrier particles by using a mesh below the developer container. The toner particles are so fine that when they pass through the mesh, they are recharged due to friction with the mesh, which may make it difficult to accurately measure the charge amount distribution.

As a method to solve such problems, Japanese Patent Application Laid-Open No. 64809
No. 69 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 air flow for the 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 requires a very small developing machine, so it is particularly suitable for small machines, but due to improvements in the developing machine, it is also being used in high-speed machines that can process about 80 sheets per minute. However, , 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 things.In particular, insulation 1
In the component development method, since toner 1 to toner is thinly coated on the surface of the toner carrier, separation of the toner particles becomes more difficult. For example, when an air stream is used as a means of separation, a thin coated toner layer is blown onto the toner carrier, causing recharging with the surface of the toner carrier, or creating an uneven toner coating layer. Inconveniences such as a change in the charge amount distribution occur. Furthermore, the toner particles may slip on the toner carrier and may not be conveyed to the measurement unit.

In contrast to this method of separating toner particles using air flow, a method of separating toner particles using only an electric field was proposed in Japanese Patent Application Laid-Open No. 1986-62.
This 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 developer supported on the surface of the insulating sleeve by this alternating electric field.
This is to measure the charge amount distribution of toner particles by allowing them to fall freely to a measuring section.

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

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

Therefore, in measuring the charge amount distribution of a one-component toner, the present inventors investigated how one-component toner particles coated in a thin layer on a toner particle carrier having a conductive member were mixed with a toner particle carrier and the toner particle carrier. We proposed a device that measures the charge distribution by peeling off the body using a DC electric field generated between electrodes placed opposite each other at precisely controlled positions with respect to the body.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional examples, particularly in the method of separating the electric field using a counter electrode, the counter electrode itself becomes an obstacle when conveying the peeled charged toner, and the efficiency is reduced. It was difficult to convey the sample to the charge amount measuring section.

Therefore, it was not possible to accurately measure the charge amount distribution.

In other words, it is an object of the present invention to provide a one-component toner particle charge amount distribution measuring device that can transport as many exfoliated charged toner particles as possible to a measuring section and improve measurement accuracy. be.

[Means and effects for solving the problems] The present invention is characterized by a toner carrying member carrying one-component toner particles, and a member regulating the layer thickness of the toner particles on the L/Q carrying member. and a counter electrode member disposed opposite to the toner carrying member, and an electric field is generated between the toner carrying member and the counter electrode member for peeling the charged toner particles from the toner carrying member and causing them to fly in the direction of the counter electrode member. a DC power supply as a voltage applying means to cause the charged toner particles to flow, a device for controlling the distance between the toner carrying member and the counter electrode member; and a measuring device capable of measuring at least a value related to the charge amount, wherein the counter electrode member has a grid shape and is configured to allow charged toner particles to pass through. be.

Another feature of the present invention is that the counter electrode member is formed into a lattice shape using conductive wires or a lattice shape by etching the conductive member.

In other words, since the counter electrode member has a lattice shape, the area covered by the electrode is expanded, and charged toner particles attracted toward the electrode do not adhere to the electrode as much, and many particles reach the charge amount distribution measuring section. It was designed to be guided.

Hereinafter, the structure and operation according to the present invention will be explained in detail using examples.

[Example] Actual Example 2 FIG. 1 is a schematic diagram of a one-component toner charge amount distribution measuring device according to the present invention. The middle figure shows a device that regulates and charges the one-component toner 1 with a regulating member 3. Here, 2 is a toner carrying member. A in the figure is a charged toner peeling part for peeling off the charged l/toner 1a from the toner carrying member 2 by a DC electric field, and B in the figure is a charged toner moving part for sending the charged toner to the measuring section. C is a charge amount distribution measurement part that measures the particle size and charge amount of Charge 1 to Toner.

A power source 1 is connected between the toner carrying member 2 and the grid-like counter electrode 4.
An electric field is generated by the DC voltage applied by 0.

As a result, a force in the same direction as the electric field acts on the charged toner 1a in the toner carried on the toner carrying member 2''. Therefore, by applying a predetermined DC voltage in accordance with the charging polarity of the charged toner 1a, it becomes possible to separate the charged toner 1a from the toner carrying member 2.

The separated charged toner 1a flies in the direction of the lattice-shaped counter electrode 4 due to the force caused by the DC electric field. The number of toner particles 1a is the same as that of the lattice-shaped counter electrode 4.
It passes through the space and is guided to the measurement section at the rear (.

The charged toner 1a guided to the measuring section C is transferred to the measuring device ^';
21), a constant physical quantity is measured, and the calculation unit 22 converts the physical quantity into a charge amount and a particle size.

Therefore, by measuring a plurality of charged toners 1a according to the process described below, 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! , two things. What is shown in FIG. 2(a) is a method of measuring the amount of charge and particle size using the laser Doppler method. 2 in the diagram
1], a, 211b are vibrating electrodes, and 212 is 1
It is a pulse generator.

As is well known, microparticles existing in an air temperature that vibrates at a constant frequency vibrate following the air vibrations. At this time, due to the inertial force of the grains, the large grains vibrate with a delay from the standard vibration. Further, when a voltage is applied to the electrode, the particles are shifted in the direction of the electric field depending on the particle size, the amount of charge, and the electric field caused by the applied voltage. Therefore,
By measuring the phase delay of the vibration of the grains relative to the air vibrations and the degree of deviation due to the electric field, the grain size and electric charge of the grains are determined.1.
-, +A-sign.

That is, in this embodiment, the laser generator 21
3 and an L norther light receiving device 214, and by using a laser Doppler, the phase retardation of the charged toner 1a with respect to the air oscillation and the shift speed due to the electric field are measured. By performing calculations in the numbing unit 22 in FIG. 1, the particle diameters and charge amounts of the charges 1 to 1a are obtained.

In addition, the measurement method is not limited to the one shown in Fig. 2 (a), but may also be used, for example, as shown in Fig. 2 (1). Now, the generated laser is introduced into the laser receiver 214 through the window 217, and the velocity of the charged toner 1a in the air flow direction is measured by the laser Doppler method. The particle diameter can be determined by measuring the relative falling speed of the charged toner 1a with respect to the air flow. Therefore, the relative falling speed of the charged toner 1a is determined by the laser Doppler method, and the calculation unit 22(a) calculates the relative falling speed of the charged toner 1a. By performing the calculation 1, the particle size of the charged toner 1a can be obtained.

In addition, by measuring the charge induced in the detection electrode 218 by the charge 1-1a using the charge measuring device 22(b), the amount of charge on the charged toner 1a can be measured.

In this example, instead of the counter electrode in Example 1,
As shown in FIG. 3(b), the counter electrode 4 was constructed by etching a conductive member.

Even in this configuration, the same effects as in Example 1 were obtained.

In this embodiment, as shown in FIG. 3(C), a plurality of pipes made of conductive material were arranged to constitute the counter electrode 4.

Even in this configuration, effects similar to those of the above embodiment could be obtained.

[Effects of the Invention] As explained above, according to the toner charge amount distribution measuring device of the present invention, by forming the counter electrode in a grid shape, it is possible to efficiently send the toner peeled off by the electric field to the measuring section. This made it possible to measure the charge amount distribution with higher accuracy.Reproducibility was also improved.

[Brief explanation of drawings]

FIG. 1 shows a schematic cross-sectional view of a charge distribution measuring device that best represents the features of the present invention. FIGS. 2(a) and 2(b) are schematic diagrams showing means for measuring the amount of charge and particle size using the laser Doppler method. FIGS. 3(a), 3(b), and 3(c) show grid-like counter electrodes according to the present invention. 1... One-component toner 2... Toner carrying member 3
...Toner layer thickness regulation sound 4--Grid counter electrode 5...Position control device 10...DC power supply 21
... Charge amount detection device (measuring section) 22.22 (
a), 22 (b)... Arithmetic unit 211, a, 21
1b... Vibrating electrode plate 212... Vibration generator 21
3 ... Laser generator 214 ... Laser receiver 217 ・ Chamber Δ ... Stripping section C ... Measuring section 218 ... Detection electrode B ... Moving section ]) ... Charging section

Claims (3)

[Claims] (1) A toner carrying member that carries one-component toner particles, a member that regulates the layer thickness of the toner particles on the toner carrying member, a counter electrode member disposed opposite to the toner carrying member, and a toner carrying member that supports charged toner particles. a DC power supply as a voltage applying means for generating an electric field between the toner carrying member and the counter electrode member to cause the toner to be peeled off from the toner carrying member and flying toward the counter electrode member; and the toner carrying member and the counter electrode member. a device for controlling the distance between the electrodes;
A toner charge amount distribution measuring device comprising a measuring device capable of measuring at least a value related to the charge amount of the charged toner particles, the counter electrode member having a grid shape and allowing the charged toner particles to pass through the toner charge amount distribution measuring device. A toner charge amount distribution measuring device characterized by: (2) The toner charge amount distribution measuring device according to claim 1, wherein the counter electrode member is formed in a grid shape on a conductive wire. (3) The toner charge amount distribution measuring device according to claim 1, wherein the counter electrode member is formed in a grid shape by etching a conductive member.