JPS63216079A - Developing device - Google Patents

Abstract

PURPOSE:To miniaturize a copying machine, to make a color distinct, and to realize a full color by providing a member for preventing a variation of a soft and elastic surface of a toner carrying body. CONSTITUTION:Variation preventive members 4-10, 4-11 of the surface of a toner carrying body are installed to a position which is as near possible to a developing device being a contact part of a toner carrying body 4-1 and charge latent image carrying body 1. In order to display satisfactorily its variation preventive effect, it is desirabed that an angle made by a line for connecting a contact of the variation preventive member 4-10 and the toner carrying body 4-1, and the rotation center of the toner carrying body, and a line for connecting the developing position and the rotation center of the carrying body is <=90 deg.C, especially <=60 deg.. By a deformation of a softened layer of the toner carrying body 4-1 and a vibration transfer from the outside, a cylinder vibrates complicatedly in the developing part, but when such a vibration preventive member is provided, the vibration preventive member works like a supporting point, the vibration of the cylinder in the developing part is suppressed, and an uneven image can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device, and particularly to a developing device provided with a member for preventing fluctuations in the surface of a toner carrier having an elastic surface.

Traditionally, developing devices for two-component developers have been the mainstream, but they have drawbacks such as being complex, expensive, large and heavy, and full-color copying machines are not equipped with multiple developing devices. It was necessary to do so, and it was large and expensive.

In addition, as a process using a -component developer, technology using magnetic toner has been commercialized, but since the magnetic agent is mixed into the toner, the color is dominated by the color of the magnetic agent and is not clear. full-color imaging was difficult.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device for a one-component non-magnetic developer that does not have the drawbacks of the conventional ones and realizes miniaturization of copying machines, sharper colors, and full color reproduction. .

As a result of intensive research to achieve the above object, the inventors of the present invention have developed an elastic toner that develops an electrostatic latent image on the electrostatic latent image bearing member by contacting or in close proximity to the electrostatic latent image bearing member. In a developing device including a toner carrier having a surface, the toner carrier is located close to the developing section.

It has been found that the above object can be achieved by providing a developing device characterized by providing a member that comes into contact with the surface of the toner carrier and prevents fluctuation of the surface of the toner carrier in the developing section.

In order to cope with particularly hard electrostatic latent image bearing drums,
It is desirable that the toner carrier of the developing device has an elastic surface as soft as possible.

In order to have a soft elastic surface, the toner carrier has a softening layer made of foam such as sponge rubber or urethane foam.

Due to the softening, the toner carrier is easily deformed, and especially when eccentric rotation occurs due to the deformation during development, image unevenness occurs. In order to solve this problem, the present invention provides a member that prevents the soft elastic surface of the toner carrier from fluctuating.

Preferably, such a fluctuation prevention member is a plate-shaped member that uniformly contacts the toner carrier in parallel with the rotational axis direction,
The plate member may also serve as a toner regulating member.

Furthermore, the fluctuation prevention members may be provided on both sides of the developing section, if necessary.

The fluctuation prevention member may be a static eliminating member that has conductivity and removes charges accumulated on the surface of the toner carrier after development.

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1, 2, 3, and 4.

FIG. 1 is a schematic diagram showing the configuration of a copying machine including a developing device of the present invention. 1 is a photoreceptor (electrostatic latent image carrier), which is an organic photoreceptor, Se-based, amorphous silicon-based, C
dS based photoconductor-insulating binder systems and the like are advantageously used.

2 is a corona charger for imparting photosensitivity to the photoreceptor 1, and 3 is an exposure optical system for performing image exposure. The system 3 forms an electrostatic latent image corresponding to the density of the original (not shown).

The electrostatic latent image formed as described above is developed with toner by the developing device 4 and made visible.

In the developing section W4, 4-1 is a toner carrier.

4-2 is a toner supplying member, and 4-3 is a toner further regulating member. The developer used here is conveniently a one-component non-magnetic developer. - Component non-magnetic developer is a developer consisting of toner that does not contain carrier particles that function to charge and transport the toner, and does not contain a magnetic agent in the toner,
If necessary, external additives are included to improve performance, such as improving the fluidity of the toner and the ability to clean transfer residual toner on the latent image carrier. The components constituting the toner include a thermoplastic resin such as a styrene resin or a polyester resin as a main resin, a colorant, and optionally a function imparting agent such as a charge control agent and a fixability improving agent.

Due to the rotational movement of the toner supply member 4-2, the toner 4-6
is supplied onto the toner carrier 4-1, and the supplied toner 4-6 is electrostatically held and conveyed at an appropriate thickness on the toner carrier, and is formed into a uniform thin layer by the toner layer regulating member 4-3. Normally, the toner layer on the toner carrier 4-1 that is regulated and thinned by the toner regulating member 4-3 is a single layer of toner, and the toner regulating member 4-3 Between it and the toner carrier 4-1, it is uniformly charged to a polarity opposite to that of the electrostatic charge image formed on the photoreceptor 1. The toner thus uniformly formed into a thin layer and charged on the toner carrier 4-1 is conveyed to the developing section 4-7, and is exposed to an electrostatic charge image on the photoreceptor 1 in accordance with the amount of electrostatic charge. By being deposited on the body 1, a toner image is formed.

Note that the surface of the photoreceptor 1 and the surface of the toner carrier 4-1 in the developing section 4-7 are in contact with or are close to each other, thereby enabling toner development. However, when developing in close proximity, by applying a high frequency bias of an appropriate magnitude, the toner 4-6 is made to fly away from the toner carrier 4-1, and the electrostatic charge image on the photoreceptor 1 is can be developed. After passing through the developing section 4-7, the toner on the toner carrier 4-1 is neutralized by a neutralizing brush 4-5 and reused.

4-5 is a static eliminating member, and after development, toner charger 4-1
At the same time, the inappropriate charge existing on the toner is removed, the charge on the toner is weakened, and the effect of scraping off the remaining toner from the toner supply member 4-2 is enhanced.

Reference numeral 4-4 denotes an agitator, which also functions to prevent the toner 4-6 from becoming blocked, to make an appropriate amount of toner adhere to the toner supply member 4-2, and to improve the toner supply performance of the toner supply member 4-2.

As mentioned above, the toner image formed on the photoreceptor 1 after passing through the developing section 4-7 is corona-transferred onto the transfer paper 10 by the transfer pole 5, and the transfer paper is photosensitive by the alternating current corona generated by the 1-separation pole 6. The toner image is separated from the transfer drum 1 and a toner image is formed on the transfer paper 10. Transfer paper 10 carrying a toner image
After being separated from the photoreceptor 1, the toner is conveyed to a fixing device (not shown) and permanently fixed.

After the transfer, the static charge and toner remaining on the photoreceptor 1 pass through the removal electrode 7 and the cleaning section 8 and are cleaned, thereby making the photoreceptor 1 ready for reuse.

In addition, 9 is a paper feed unit, 9-1 is a paper feed cassette, 9-2 is a paper feed roller, and 9-3 is a register 1 to roller system. 6 FIG. 2 shows the toner carrier shown in FIG. 1. The structure of 4-1 is shown.

In order to accommodate the hard drum-type latent image carrier 1,
The conductive shaft portion 4-1 has a softer elastic surface.
-1 has a softening layer 4-1-2 around it.

Softening layer materials include various rubbers and various sponge rubbers such as urethane sponge rubber.

Various types of elastic foams may be used, such as urethane foam, which is an extremely soft and elastic material and is a convenient material.

4-1-3 is a cylinder covering the softening layer 4-1-2, and 4-1-4 is an electrode layer for applying a bias to the toner carrier.

As the material for the cylinder 4-1-3, an electroformed nickel cylinder, a resin cylinder such as polyester, vinyl chloride, polycarbonate, or fluorine-containing resin is conveniently used.

However, if the cylinder is conductive, such as a resin cylinder containing conductive fine powder such as electroformed nickel or carbon black, the electrode layer 4-1-4 is not necessarily necessary because the cylinder itself has the function of an electrode layer. I don't.

The electrode layer 4-1-4 is usually coated with a resin in which conductive fine powder such as carbon black is dispersed.

4-1-5 is a toner carrying layer coated with a material that can conveniently triboelectrically charge the toner and transport it by electrostatic attraction. polyester, polyurethane, polyamide,
In addition to various resins such as acrylic, silicone resins and fluorine-containing resins are also convenient materials for the toner carrying layer. In addition, these resins contain carbon black, Tie, Sin, various metal powders, various fibers, etc. to adjust the image quality.

It can be included for purposes such as improving wear resistance.

FIG. 3 shows a variation preventing member on the surface of a toner carrier according to the present invention.

In FIG. 3, 1 is a charged latent image carrier, 4 is a developing device, and a one-component non-magnetic toner is used.

4-1 is a toner carrier, 4-2 is a toner supply member, 4
-3 is a toner further regulating member, 4-4 is an agitator, 4-5
4-10.4-11 is a static eliminating member, and 4-10.4-11 is a toner carrier surface fluctuation prevention member of the present invention.

The fluctuation prevention member on the surface of the toner carrier is the toner carrier 4-1.
A developing device which is a contact portion between the charge latent image carrier 1 and the charged latent image carrier 1! 4-7
It is desirable to install it as close as possible to the In order for the fluctuation prevention effect of the present invention to be well exhibited, it is necessary to connect the line connecting the contact point between the fluctuation prevention member 4-10 and the toner carrier 4-1 with the rotation center of the toner carrier, and the development position 4-7. The angle (α) between this and the line connecting the center of rotation of the toner carrier is 9
It is preferably within 0°C, particularly within 60°.

Due to the deformation of the softening layer of the toner carrier 4-1 and the transmission of vibrations from the outside, the cylinder vibrates in a complex manner in the developing section, but when the vibration prevention member of the present invention is provided, the vibration prevention member acts as a fulcrum. The parts closer to the anti-vibration member vibrate less than the parts further away.

When vibration occurs in the developing section, the rubbing width between the latent image carrier and the developing roll changes, causing unevenness in the image. Vibration of the cylinder is suppressed, and image unevenness can be prevented.

The effect of preventing uneven development due to this anti-vibration effect is achieved by the pressing force of the vibration-preventing member being applied toward the center of the toner carrier in the vicinity of the developing section, and the pressing force is the same as described above. This is effective when the angle α is set within 90°, preferably within 60°.

It is necessary to select the shape of the tip of the fluctuation prevention member 4-10.4-11 depending on whether the fluctuation prevention member 4-11 makes light contact through which the toner on the surface of the toner carrier can pass, or how the fluctuation prevention member is set on the toner carrier. .

FIG. 4 shows some examples of how to set the fluctuation prevention member to the toner carrier.

In FIG. 4A, a curved surface is provided at the tip of the fluctuation preventing member 4-10 to facilitate the passage of toner.

In FIG. 4B, the abdomen of the fluctuation prevention member 4-10 is applied.

In this case, it is advantageous if the fluctuation preventing member is elastic.

Desirable materials for the fluctuation prevention member include thin elastic metal plates such as stainless steel and phosphor bronze, resin plates such as polyethylene, polyester resin, acrylic resin, epoxy resin, polycarbonate, fluorine-containing resin, and silicone resin. Base resin is a desirable material because it has excellent non-adhesive properties and prevents toner from sticking due to contact with the rotating surface of a toner carrier carrying toner.

It is also desirable to provide a fluctuation prevention member by providing a fluorine-containing resin on the metal plate or resin plate in the form of a coat or film.

Further, the above-mentioned toner carrier surface fluctuation prevention member 4-10.
4-11 is a toner further regulating member 4-3 and a static eliminating member 4-
5 is also preferable in terms of simplifying the structure of the developing device.
However, since the setting position of the toner single layer regulating member is set for the purpose of image quality depending on the uniformity of forming a thin layer and the charging property of the toner, it varies depending on the developing system, and is not always effective for achieving the above-mentioned vibration prevention effect. It does not match the location, setting angle, or pressure.

In a developing device that uses a one-component non-magnetic developer, softening the toner carrier is particularly effective when used with a hard latent image carrier on a drum. Reduces the toner scraping effect during the process and achieves high quality images. However, as the toner carrier is made highly soft, its surface becomes more likely to fluctuate, causing image unevenness. However, by using the fluctuation preventing member of the present invention, fluctuations in the surface of the toner carrier can be prevented. This allows for stable image quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a copying apparatus including a developing device. FIG. 2 is a schematic diagram of a soft type toner carrier. FIG. 3 is a schematic diagram of a developing device provided with the fluctuation preventing member of the present invention. FIGS. 4A and 4B are schematic diagrams showing how the fluctuation prevention member of the present invention is used. 1...Photoreceptor 2...Corona charger 3...Exposure optical system 4...Developer 5...
Transfer pole 6...Separation pole 7...Removal electrode
8... Cleaning section 9... Paper feeding section 10... Transfer paper 4-1... Toner carrier 4-2... Toner supply member 4-3...
Toner further regulating member 4-4...Agitator-4-5
... Static elimination brush 4-6 ... Toner 4-7
...Development section 9-1...Paper feed cassette 9
-2... Paper feed roller 9-3... Registration roller 4-1-1... Shaft portion 4-1-
2... Soft layer 4-1-3... Thin wall cylinder
4-1-4... Electrode layer 4-1-5... Toner carrying layer 4-10. 4-11... Fluctuation prevention member Fig. 1 Fig. 2 ■

Claims (1)

[Claims] 1. In a developing device including a toner carrier having an elastic surface, which develops an electrostatic latent image on the electrostatic latent image carrier with toner in contact with or in close proximity to the electrostatic latent image carrier, 1. A developing device comprising a member that contacts the surface of the toner carrier and prevents the surface of the toner carrier from changing in a developing section.