KR910008070B1 - Developing system for electronic photograph copymachine - Google Patents

Abstract

The developer for preventing dispersing of the toner and controlling the toner quantity selectively includes an electromagnet (20) placed at inner side of a rotating sleeve (15). The different voltages are applied to the coil wound around each yoke of the electromagnet to control the intensity of the electromagnetic force selectively so that the image with good quality is reproduced.

Description

Developing method of electrophotographic copier

1 is a schematic diagram of a general copier.

2 is a conventional one-component or two-component developing apparatus.

3 is another embodiment of the conventional two-component phenomenon.

4 is an embodiment of the rotation direction of the photosensitive drum 10, the sleeve 15, the magnetic roller 16 to improve the characteristics of the conventional phenomenon.

5 is a developing apparatus according to the present invention.

6 is a specific view of the electromagnet 20 of FIG. 5 according to the present invention.

* Explanation of symbols for main parts of the drawings

13 developing part 14 toner powder

15: sleeve 16: magnetic roller

10: photosensitive drum 19: braid

20: electromagnet

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a developer in an electrophotographic coying apparatus, and more particularly, to the scattering of toner by adjusting the intensity of the electromagnet with an applied bias voltage by using a magnetic roller of the developing device as an electromagnet roller. The present invention relates to a developing method of an electrophotographic copier, which can prevent and improve the developing efficiency.

In general, a copying apparatus forms an electrostatic latent image corresponding to an original on a photoconductor, and develops an electrostatic latent image formed on the photosensitive drum with a toner to visualize an image. Had been making. That is, referring to FIG. 1, a general copier function will be described. Part of the main charger 4 is evenly charged on the photosensitive drum 10 by the corona discharge, and the portion charged by the rotation of the photosensitive drum 10 is a halogen lamp. It is exposed by the light reflected from the original on the document glass by the light source of (2). This exposure produces a latent image, such as an image of the original, on the photosensitive drum 10, at which time the toner is sprayed and turned into a visible image while passing through the developing unit 5, and then a transfer unit ( Passing the fixing unit 7 while the visible image on the photosensitive drum 10 is moved to the copy paper 11 in 6), the image of the original is fixed on the copy surface to make a desired copy.

On the other hand, residual toner and a latent image exist on the drum passing through the transfer unit 6, where the toner is removed by the cleaner 8, and the latent image is removed by the latent image removal lamp 9.

It is generally known that it is a developing device that greatly influences copy performance in a copying apparatus or a printer as described above.

Accordingly, in order to improve the radiation performance, various development apparatuses such as FIG. 2 and FIG.

For example, the first and second components are classified according to the presence or absence of carriers in the developer as shown in FIGS. 2 and 3, and the materials have been used in various ways depending on magnetic properties, nonmagnetic, malleability, and conductivity. .

Specifically, the conventional developing apparatus such as FIG. 2 and FIG. 3 will be frictionally charged to the toner powder 14 due to the friction between the toner powder 14 and the rotating sleeve 15 inside the developer. The toner powder 14 is transported by the magnetic roller 16 made of a permanent magnet on the rotating sleeve 15 by such frictional charging. At this time, the toner powder 14 buried on the sleeve 15 in the photosensitive drum 10 is transferred under the influence of the magnetic roller 16, thereby making a copy.

However, since the magnetic roller 16 is made of a permanent magnet, the part giving the frictional power to the toner powder 14 and the developing part are made of the same continuous strength, so that the toner powder 14 is always constantly supplied. There are limitations in the control of the radiation image density, and there is a drawback that the characteristics of the phenomenon cannot be improved depending on the situation.

Accordingly, in order to solve the drawback, as shown in FIG. 4, the rotational direction of the photosensitive drum 10, the sleeve 15, and the magnetic roller 16 is changed to adjust the amount of toner supply according to the respective rotational directions. In addition, since the magnetic roller 16 is made of permanent magnet, the magnetic force is weakened due to the change in the hardness (Hardness Variaty) according to the use time, which changes the strength of the magnet and requires considerable precision and attention in reassembly. Was in issue.

Accordingly, an object of the present invention is to improve the development efficiency by preventing the toner from scattering by adjusting the intensity of the electric field differently for each yoke of the electromagnet by using the magnetic roller as an electromagnet, and increasing the developing efficiency in proper harmony with the charging part of the photosensitive drum In providing.

Therefore, the invention for carrying out the above object in the printer or copier using an electrophotographic copying apparatus, it is possible to selectively adjust the amount of toner on the sleeve according to the intensity of the electromagnet by installing the electromagnet in the sleeve of the developer and rotating the sleeve It is characterized by the configuration.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

)에 바이어스 전압(V₁,V₂,V₃)을 달리 인가하여, 슬리브(15)의 회전에 따라 상기 전자석(20)의 세기 조절에 따른 슬리브(15)상의 토너가루(14)가 감광드럼(10)의 가시상으로 이송되도록 구성된다.5 is a developing device according to the present invention, in which a bias voltage V _T is applied to the photosensitive drum 10 and the sleeve 15 in the developing portion 13, and is viewed from a side cross-section inside the sleeve 15. A coil electromagnet 20 is installed, and coils are wound around each yoke formed in the electromagnet 20 so that the strengths of different electromagnets 20 are generated at each yoke.

By applying different bias voltages (V ₁ , V ₂ , V ₃ ) to the toner powder 14 on the sleeve 15 as the intensity of the electromagnet 20 is adjusted as the sleeve 15 is rotated. And to be conveyed in the visible image of 10.

FIG. 6 is a specific view of the electromagnet 20 of FIG. 5 according to the present invention. The yoke is formed by winding the coil in a side cross-sectional view of the yoke, and the number of yokes may be configured differently depending on the purpose of use.

Therefore, a specific embodiment of the present invention will be described in detail with reference to FIGS. 5 and 6 described above, and the electromagnet 20 is applied with the bias voltage V _T applied between the photosensitive drum 10 and the sleeve 15. The sleeve 15 is rotated around. At this time, when the friction force acts between the sleeve 15 and the toner powder 14, the polarity of the triboelectric charge is generated in the toner powder 14, and the coil bias voltages V ₁ and V ₃ of the electromagnet 20 are increased. The toner powder 14 is grown on the rotating sleeve 15. Subsequently, the toner powder 14 is cured to a certain height by the blade 19 to which the toner powder 14 is fixed by the rotation of the sleeve 15. When the rotating sleeve 15 approaches the latent image generated on the photosensitive drum 10, the bias voltage V ₃ is applied to a voltage different from the bias voltages V ₁ and V ₂ to apply the applied voltage. By adjusting the intensity of the electromagnet 20 by generating a low-lens force (Loretz Force) to the electromagnet 20.

If you look at the application of the lens lens

* Q = amount of charge due to toner polarity

=바이어스 전계

= Bias electric field

=슬리브내 마그네틱 롤러의 자속세기에 의한 힘

= Force by magnetic flux strength of magnetic roller in sleeve

When the bias electric field V ₃ , that is, the applied voltage V ₃ is large, as shown in Equation (1), the magnetic flux of the electromagnet 20 becomes stronger because the linkage flux of the yoke of FIG. 6 of the electromagnet 20 increases. The toner powder 14 of the sleeve 15 becomes heavily toner on the latent image of the photosensitive drum 10, resulting in a high image density, and when the applied voltage V ₃ is low, the density becomes shallow.

Therefore, by adjusting the magnetic field strength of the electromagnet 20, the toner powder 14 of the sleeve 15 can be adjusted by the magnetic field to freely adjust the concentration of the radiant image.

In addition, by controlling the intensity of the electromagnet 20 by the bias voltage, it is possible to remove the scattering by the toner powder 14.

As described above, the portion in which the friction charge between the sleeve and the toner is generated inside the developing unit 13 can adjust the strength of the electromagnet separately from the developing portion, thereby preventing the toner from scattering and making good quality radiation. Therefore, the state of the phenomenon can be adjusted and the general-purpose integrated circuit (IC) can easily configure the applied voltage control unit, which has the advantages of ease of design and cost reduction.

Claims (1)

In the developing method of an electrophotographic copying machine having a sleeve 15, an electromagnet 20 is installed in the rotating sleeve 15, and a coil is wound around each yoke to apply different voltages to the electromagnet 20. The developing method of the electrophotographic copier characterized in that the intensity of the electromagnet 20 is partially adjusted to the applied voltage to suit the situation, thereby preventing the toner powder 14 from scattering and selectively adjusting the amount of toner.

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