JPS61239266A - Developing method - Google Patents

Abstract

PURPOSE:To prevent a carrier from sticking to the surface of a sensitive material by arranging a donor roll and a magnet roll and supplying a two-component developer, which has a microcarrier having a prescribed average particle size, to the magnet roll. CONSTITUTION:After a developer 3 in a developing vessel 5 is attracted and stuck to a magnet roll 4, the quantity of the carried developer 3 is limited by a developer control member 6, and this developer is carried to a developer transfer area between the magnet roll 4 and a donor roll 2. In the developer transfer area, a toner powder of the developer 3 is transferred to the surface of the donor roll by a uniform electric field formed between the magnet roll 4 and the donor roll 2 to develop uniformly the donor roll 2. The uniformly developed donor roll 2 is rotated to develop a latent image on the surface of a photosensitive drum 1. The two-component developer which has the microcarrier having 10-40mum average particle size is used as the developer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an electrophotographic developing method, and particularly to an improvement in a nine-component developing method using a two-component developer.

(Prior Art) Conventionally, one-component developers and two-component developers have been known as developers used in electrophotographic copying machines.

These developers have properties that are contradictory to each other. That is, a one-component developer tends to aggregate, has poor fluidity, and tends to cause poor conveyance. Furthermore, since the toner charge is lower than that of a two-component system, adhesion to the surface of the photosensitive material becomes unstable. On the other hand, with two-component developers, the flow between the toner and the carrier is important, and if the amount of toner is too large, the background of the copy will be smeared, and if there is too little, the image density will be insufficient, so there is an allowable range of toner density. Moreover, repeated use over a long period of time causes changes in its triboelectric properties, resulting in deterioration of the properties, and therefore requires replacement with a new developer from time to time.

In order to improve these drawbacks mentioned above, for example, particle size of 10~
A two-component development method using 40 μm microcarriers is already known.

That is, in a two-component developer using microcarriers, the total surface area ratio of carrier particles to toner particles is greatly increased by 1,
The toner density latitude is expanded, the developer life is extended, and the stability of the density of the developed image is improved. However, fluidity was still not fully satisfied.

In order to compensate for the liquidity of
A complex mechanism, as disclosed in Japanese Patent No. 955, in which a developing sleeve and a multipolar magnet are rotatably provided in the same direction, and the influence of the moving force on the culm developer due to the rotation of the multipolar magnet is set to be reduced. In order to prevent carrier adhesion to the non-latent image surface of the photosensitive material caused by the use of a developing device or lack of fluidity, it has been necessary to use a magnet with high magnetic force or a magnet with a special shape.

(Problems to be Solved by the Invention) The present invention was made in view of the above-mentioned drawbacks. 1. A two-component developer having microcarriers is used to ensure a wide allowable range of toner concentration and a long lifespan. Another object of the present invention is to provide a developing method that can simplify the structure of the apparatus, improve fluidity, and prevent the carrier from adhering to the sensitive material.

(Means for Solving the Problems) That is, the above-mentioned object of the present invention is to provide an electrophotographic developing method using a two-component developer; A mag roll for developing is arranged, and the average particle size is 10 to 4 on the mag roll.
Development method 1'' characterized by supplying a two-component developer having microcarriers of 0 μm: 9tBz%
7. ,.

(Example) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a developing device 1 used for carrying out the developing method of the present invention.

This developing device includes a donor roll 2 that is disposed close to the surface of a rotating photoreceptor drum 1 and forms a development area A between it and the photoreceptor drum 1, and a mag roll 4 that supplies developer 6 to the donor roll 2. are arranged inside the developing container 5.

The donor roll 2 is made of a non-magnetic conductive material and is formed into a cylindrical shape.The donor roll 2 is arranged at a distance of 600 μm from the photoreceptor drum 1, which is rotatable in a clockwise direction. It is rotatably provided.

Further, a voltage having a polarity opposite to the charging voltage of the photoreceptor drum 1 is applied to the donor roll 2 .

This voltage is a variable DC voltage superimposed on an AC voltage.
In the device of this embodiment, 1000 V AC and +20 V DC are applied.

The mag roll 4 is disposed close to the donor roll 2 along the circumferential surface, and has the same configuration as a conventionally known one. It is configured by providing a non-magnetic sleeve 4b that is fitted into and rotates.

The sleeve 4b rotates counterclockwise to move the developer 3 supplied on the sleeve clockwise, and transfers the developer 6 onto the surface of the donor roll 2 by a uniform electric field, which will be described later. Develop.

That is, a DC voltage of opposite polarity to the donor roll 2 is applied to the mag roll 4, and a voltage of 400 V is applied to the device of this embodiment.
A uniform electric field E is formed between the mag roll 4 and the donor roll 2.

Further, a developer regulating member 6 is provided adjacent to the circumferential surface of the mag roll 4 on the side retreating from the developer transfer area between the mag roll 4 and the donor roll 2, and prevents the conveyance of more than a predetermined amount of developer. There is.

Next, a toner replenishment roll 7 for replenishing new developer is disposed above the developer container 5.

Furthermore, the two-component developer used in the developing device configured as described above has an average particle size of 11, which is the same as the conventional two-component toner.
1#rL toner powder and 70 parts by weight of magnetite are contained in styrene-acrylic resin, and the average particle size is 10 to 40.
It consists of prrL microcarriers.

With the start of the developing process, the developer 3 in the developing container 5
After being suctioned and adhered to the mag roll 4, the amount of conveyance thereof is restricted by the developer regulating member 6, and the developer is conveyed to the developer transfer area between the developer roll 2 and the donor roll 2.

In the developer transfer region, the toner powder of the developer is transferred to the surface of the donor roll 2 by the uniform electric field E formed between the mag roll 4 and the donor roll 2, thereby uniformly developing the donor roll 2. After uniform development in this manner, the donor roll 2 rotates to form a latent image and rubs against the surface of the photosensitive drum 1 to develop the latent image.

In this development process, when the hole developer 3 supplied to the mag roll 2 is transferred to the donor roll 2, the electric field strength required for the transfer of the toner powder formed between the donor roll and the mag roll is compared to that of a developer with a normal particle size. Transfer of microcarriers to the donor roll is suppressed by greatly affecting the adhesion between the Betoner and the carrier. As a result, adhesion of microcarriers to the photosensitive drum surface is also prevented, and a suitable current g1m can be obtained.

(Effects of the Invention) As described above, according to the present invention, in an electrophotographic developing method using a two-component developer, A mag roll with an average particle diameter of 10 to 10 is placed on the mag roll.
By supplying a two-component developing agent having 40 prrL of microcarriers, adhesion of the carrier to the surface of the photosensitive material is prevented. Additionally, the use of microcarriers allows the developer to be maintained at a very high toner concentration, resulting in a stable trial and thickness of toner layer formed on the donor roll. Furthermore, an apparatus for achieving one aspect of the present invention can be configured to have a simple structure.

First, the microcarrier makes the beans soft and prevents the beans from clumping together on the donor roll.

Moreover, a high-resolution real image can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device used in one embodiment of the present invention. In the figure, reference numeral 1: photosensitive drum, 2: donor roll. 3... Two-component developer, 4... Magroll.

Claims (1)

[Claims] In an electrophotographic development method using a two-component developer, a donor roll that supplies toner powder to a development area and a mag roll that develops this donor roll are arranged, and the mag roll has micro particles having an average particle size of 10 to 40 μm. A developing method characterized by supplying a two-component developer having a carrier.