JPH0415568A - One-component toner charge amount distribution measurement method - 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 a method for measuring the charge amount distribution of one-component toner particles.

[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 toner particles used here, particularly the amount of charge and the particle size, are important factors for 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.

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 1 to 1 particle from the degree of deflection and vibration phase of toner particles in a constant velocity airflow, an electric field, and a vibration wave. 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 1 to 1 particles from the carrier particles of a two-component developer, Japanese Patent Application Laid-Open Nos. 57-79958 and 63-263475 disclose methods of separating toner particles from carrier particles using compressed air. A method of separation has been proposed. 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. 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, 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.

The method for measuring the toner charge distribution described so far has been proposed for two-component developers consisting of carrier particles and toner particles, and it is thought that there is a problem with measuring the charge distribution of single-component toner particles. It will be done. In other words, it is difficult to accurately measure the charge amount distribution of one-component toner particles using methods that mainly use airflow as described above.

Measuring the charge distribution of one-component toner particles avoids the problem of separation of toner particles and carrier particles as in two-component developers, but the friction of toner particles during development in an actual electrophotographic system, etc. It is more difficult to measure the charge amount distribution that corresponds to the charge than in the case of a two-component developer. That is, when an air stream or the like is used as a means for separating a one-component toner coated in a thin layer onto a toner particle carrier, the toner layer coated in a thin layer is blown onto the toner carrier, and the toner is separated from the toner particle carrier. This may cause problems such as recharging with the surface of the carrier, or a non-uniform toner coating layer that changes the charge amount distribution.Secondly, the toner particles are not separated from the toner carrier, but rather the toner is supported. The toner particles may slip on the body and may not be properly conveyed to the measurement unit.

In contrast to this method of separating toner particles using air flow,
A method for separating toner particles using only an electric field was published in Japanese Patent Application Laid-open No. 62-5.
This is proposed in Publication No. 81.75. 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, in this method, the sleeve used is special, and not only is it difficult to correspond to the actual developing system, but the applied alternating electric field is essentially generated inside the sleeve, resulting in separation. The toner particles exposed to the toner particles are subjected to the force of the leaked electric field, and there is a possibility that the toner particles have a biased charge distribution even before measurement. Furthermore, since a stronger electric field is required to separate all the toner particles, creeping discharge may occur on the sleeve surface.

Furthermore, in Japanese Patent Application Laid-Open No. 63-135874, an electrode is provided so as to surround the lower part of the toner particle carrying roller, and an electric field formed between the electrode and the toner particle carrying roller causes toner particles to be transferred from a two-component developer. It has been proposed to measure the charge amount distribution of toner particles by separating the toner particles and measuring the charge amount of the separated toner particles corresponding to the electric field strength.

However, with this method, it is difficult to accurately measure the charge amount distribution of a magnetic toner, which is a typical one-component toner and whose toner particles contain a magnetic material. That is,
Since magnetic toner particles are coated on the toner particle carrying roller by magnetic force in addition to electrostatic adhesion force, the strength of the magnetic force of the magnetic roller inside the toner particle carrying roller causes the magnetic toner particles to be coated on the toner particle carrying roller even in the same electric field. The amount of charge on the toner particles to be separated differs, and there may be cases where the electric field and the amount of charge on the toner particles cannot be matched. Therefore, it is not possible to obtain a correct charge amount distribution.

As described above, no method has yet been proposed for accurately measuring the charge amount distribution of -component toners, especially magnetic toners.

Therefore, the present inventors developed a method using direct current in order to peel off the toner particles from the toner particle carrier and measure the charge amount distribution without disturbing the thin toner coating layer on the toner particle carrier. Although a method of applying a voltage has been proposed, there is a strong desire to increase the yield of toner particles and measure the charge amount distribution with high accuracy.

[Problems to be Solved by the Invention] In other words, in view of the problems of the prior art described above, the present invention aims to: It shall be possible to measure the charge amount distribution of one-component toner particles. (2) Charge the toner particles on the toner particle carrier while maintaining a thin and uniform 1 to 1 coat layer on the toner particle carrier. It is an object of the present invention to provide a one-component toner charge amount distribution measuring method that achieves the following: (1) the charge amount distribution of magnetic toner particles can be measured in a form similar to that in a developing system;

[Means and Operations for Solving the Problems] The present invention is characterized by supporting one-component toner particles on a toner particle carrier and generating an electric field between the toner particle carrier and an electrode facing the toner particle carrier. In the toner charge amount distribution measuring method, the toner charge amount distribution measuring method includes peeling off the charged toner particles from the toner particle carrier, and measuring the charge amount distribution of the peeled charged toner particles in a measuring section. It is provided between the charge amount distribution measuring section and the separated charged toner particles to fly.

That is, in the charge amount distribution measurement of one-component toner particles, the one-component toner particles coated in a thin layer on a toner particle carrier are provided between the toner particle carrier and the entrance of the charge amount distribution measuring section. A direct current voltage is applied between the electrode facing the toner particle carrier and the toner particle carrier, the generated electric field causes each henna particle to be peeled off, and the charge amount distribution is measured to determine the toner yield. This makes it possible to measure the charge amount distribution of a one-component system 1 to 2 with high accuracy.

[Example] Embodiments according to the present invention will be described below based on the drawings.

Actual Example 2 FIG. 1 is a schematic diagram of a method for measuring the charge amount distribution of a one-component toner according to the present invention. In the figure, one-component toner 1
This is a device that regulates and charges electricity by a regulating member 3. Here, 2 is a toner carrier, and 6 is a magnetic pole. The one-component toner used here is an insulating one-component magnetic toner containing a magnetic material.

A in the figure is a charged toner peeling part for peeling off the charged toner 1a from the toner carrier 2 by an electric field, B in the figure is a charged toner moving part for sending the charged toner to the measuring section, and C in the figure is a charging part. This is the charge amount distribution measurement part that measures the particle size and charge amount of toner.

An electric field is generated by a DC voltage applied by a power source 10 between the toner carrier 2 and a counter electrode 4 facing the toner carrier 2 . 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 carrier 2. Therefore, by applying a predetermined voltage depending on the charging polarity of the charged toner 1a, it becomes possible to separate the charged toner particles 1a from the toner particle carrier 2. The separated charges 1 to 1a fly in the direction of the counter electrode 4 due to the force caused by the two-layer electric field. The flying charged toner 1a is accelerated by the electric field and moves downward due to the addition of gravity, so that most of the toner particles are not captured by the electrode 4 (and do not enter the measuring section).

At this time, the shape of the electrode 4 is such that the flying toner particles 1a
For example, if the toner particle carrier side forms an acute angle, the cross-sectional area of the electrode in the toner flight direction is smaller, and the distance between the electrode 4 and the entrance of the measuring section is wide, then the conventional The toner particles 1a can be collected much more efficiently than a flat plate electrode in the entrance of the measuring section.

In addition, due to improved collection efficiency, if the electric field is reversed, the amount collected is smaller than before (which could not be fully investigated).
It has become possible to easily measure the charge amount distribution of minute amounts of oppositely charged toner particles.

A measuring device 21 measures a predetermined physical quantity of the charged toner 1a that has been conveyed to the measuring section C, and a calculating section 22 converts the physical quantity into a charge amount and a particle size.

Therefore, by measuring a plurality of charged toners 1a through the above process, it is possible to obtain the charge amount distribution with respect to particle size.

FIG. 2 shows an example of the above measuring device. What is shown in FIG. 2(a) is a method of measuring the amount of charge and particle size using the laser Doppler method. 211a in the diagram
, 2], 1b is a vibrating electrode, and 2]2 is a vibration generator.

As is well known, microparticles existing in an air field vibrating 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 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 this embodiment, a laser generator 213 and a laser receiver 214 are arranged, and the laser Doppler method is used to measure the phase delay of the charged toner 1a with respect to air vibration and the shift speed due to the electric field. The particle size and charge amount of the charged toner 1a are obtained by calculating the amount in the calculation unit 22 in FIG.

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

In other words, the laser generator 213 generates a laser, the generated laser passes through the window 217 and enters the laser receiver 214, and the speed of the charged toner 1a in the air flow direction is determined by
Measured by laser Doppler method.

As is well known, the diameter of a particle can be determined by measuring the relative falling speed of a microparticle falling in an airflow with respect to the airflow. Therefore, the relative falling speed of the charged toner 1a is determined by the laser Doppler method,
The particle size of the charged toner 1a can be obtained by calculation by the calculation unit 22(a).

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

In the actual IL system, in place of the electrode member 4 of the first embodiment,
As shown in FIG. 3, a funnel-shaped electrode 4 was used.

Even with such means, the collection efficiency and measurement accuracy were able to be improved.

In this embodiment, a curved and inclined member was used as the electrode 4, as shown in FIG.

Even with this method, it was possible to improve the collection efficiency and measurement accuracy.

q [Effects of the Invention] As explained above, according to the method for measuring toner charge amount distribution of the present invention, it is possible to transport most of the charged toner present in the vicinity of the counter electrode to the measurement section, and to measure the charge amount distribution. can be done efficiently and fairly accurately.

In addition, conventionally, in a charging system similar to an actual developing system, reversely charged toner, which is charged in the opposite direction to the normal charge, has a correlation with background stains, such as stains around a single character, and it is difficult to know the charge amount distribution. Although it was thought that toner was important, the amount of toner was small and it was not possible to capture it properly. However, using the method of the present invention, the amount of toner to be collected can be significantly increased. It is possible to know the charge amount distribution of reverse polarity toner.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus used for charge distribution measurement that best represents the features of the present invention. 3 and 4 are schematic diagrams showing other embodiments of the electrode according to the present invention. 1. One-component toner 10. DC power supply 1a.
...One-component system 1-ner particles 21...Measurement section 2
. . . toner particle carrier 3 . . . layer thickness regulating member 4 . . . electrode 5 . a, 211b --- Vibrating electrode plate 212... Vibration generator 213... Laser generator 2] 4... Laser receiving section 217... Window 218... Detecting electrode C... Measuring section D ...Charging part

Claims (1)

[Claims] (1) One-component toner particles are supported on a toner particle carrier, and an electric field is generated between the toner particle carrier and an electrode facing the toner particle carrier to separate the charged toner particles from the toner particle carrier, and the peeling is performed. In the toner charge amount distribution measuring method of measuring the charge amount distribution of the charged toner particles in a measuring section, the electrode is provided between the toner particle carrier and the charge amount distribution measuring section, and the separated charged toner particles are caused to fly. A one-component toner charge amount distribution measuring method characterized by: