JPS62200376A - Developing device - Google Patents

Abstract

PURPOSE:To execute sufficiently the electrification of a non-magnetic one component toner, and to equalize a toner layer formed on a developing roller, by specifying the surface roughness of a toner supplying roller. CONSTITUTION:A surface roughness Rmax of a toner supplying roller 4 consisting of a conductive material such as Al, etc. is formed to 5S-20S. When this roller 4 is rotated, a toner T of a toner containing part 9 is induced between a mesh material 6 and the roller 4 and moved by rubbing against the material 6, electrified negative, stuck thinly to the surface of the roller 4 and carried to a developing roller 3. To the roller 3, a developing bias is applied, therefore, the toner T is attracted by the roller 3, controlled to a proper quantity by a collecting member 5, and a latent image of an image holding body 1 is developed. According to such constitution, the toner T is electrified enough by one rotation of the roller 4, and stuck to the roller 3 sufficiently and uniformly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a developing device using a non-magnetic fractional developing method, and more specifically, to a developing device that uses a non-magnetic fractional developing method, and more specifically, it relates to a developing device that uses a non-magnetic fractional developing method. A developer is applied to a developed roller (referred to as the first roller), and a fiber brush, metal surface, or other surface coated with the developer is brought into contact with the image carrier or brought close to it in a non-contact state to form an electrostatic latent image. The present invention relates to a developing device for developing images.

[Conventional technology]

Conventionally, various methods have been known or proposed for developing apparatuses that apply -g type developing materials.

Among these, there is the fur brush development method, in which a developer is attached to a cylindrical brush made of soft bristles such as beaver hair, and the fur brush development method uses a developing roller whose surface is made of fibers such as velpet. An impression development method (such as US Pat. No. 3,152,012) in which an agent is attached is a well-known development method. When developing electrostatic latent images, these developing methods do not use expensive developers containing all magnetic powder, and use carrier particles to maintain a constant ratio of developer (toner) particles to carrier particles. This is a developing method that does not require the complicated equipment that is typical when using a two-component developer that must be maintained at a high There were drawbacks such as poor fixation during heat fixing and the need to add magnetic material to the toner itself, making it impossible to use color toner, but the non-magnetic bottom development method has the advantage of not having these problems. There is.

[Problem that the invention seeks to solve]

However, in a developing method using a developing roller using a one-component developer (magnetic toner) as a practical developing method for commercial copying machines, the magnetic toner on the developing roller supplied from the toner storage section is stored inside the developing roller. By simply passing the magnet through a doctor blade provided close to the developing roller, a uniform, predetermined thickness of toner can be applied onto the peripheral surface of the developing roller.

On the other hand, when using non-magnetic toner, even if a similar doctor is used, it is not possible to uniformly apply one layer of toner on the circumferential surface of the developing roller (first roller), resulting in uneven coating. A defect occurs in the form of density unevenness in an image copy obtained by development.

Furthermore, since non-magnetic single-component toner is made of a uniform resin component, it does not become charged due to mutual friction, and if it is used as it is, the charge meter will be almost zero during development, so fogging will be severe and it will not be possible to develop it properly. Not only is it impossible to obtain an image, but also undesirable phenomena such as toner scattering tend to occur.

The present invention has been made in view of the above points, and it is possible to sufficiently charge toner for one bottom portion by an inexpensive and simple means in a non-magnetic one-component developing device, and to form a uniform layer of toner on the developing roller. The purpose is to provide a device that allows

[Means to solve the problem]

The above object is to provide a developing device having a first roller that conveys non-magnetic one-component toner to an image carrier and performs development, and a second roller that performs frictional electrification of the toner and supplies the toner to the first roller. Roller surface roughness Rm
This is achieved by a developing device characterized in that ax is in the range of 5S to 20S.

〔Example〕

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention. 1
2 is an image carrier made of an electrophotographic photoreceptor, etc.; 2 is a developing device;
3 is a first roller that conveys toner to the image carrier 1 and performs development; 4 is a second roller that supplies toner to the first roller 3;
Reference numeral 5 denotes a collecting member such as an etching plate for collecting excess toner on the circumferential surface of the first roller 3; 6 is a mesh material made of polyamide or the like; 7 is a rubber blade; 8 is a sponge; 9 is a toner storage section. , 10 is a bias power supply device, and T is a non-magnetic one-component toner.

The first roller 3 is a fur brush roller to which a developing bias of 150 to 300 V is applied by a bias power supply 10, and is made of, for example, 3.8 d (denier) insulating rayon (trade name) with a hair length of 3 mm and a density of 2. 30,000F/in
The peripheral surface is made of a brush made of woven fabric of No. 2 or 7D insulating nylon 6 (trade name) with a hair length of 3 mm and a density of 34,000 F/in. 1 rotates in the direction of the arrow (clockwise) at a circumferential speed of 134 mm/sec, and the three first rollers rotate in the direction of the arrow (counterclockwise) with a circumferential speed of 1 to 3 times the circumferential speed of the image holder 1. ).

The gap DSD between the image holder 1 and the conductive cylindrical portion of the first roller 3 with flocked hair is maintained at 1 mm. Note that a brush with a hair length of 1.5 to 3 mm can be used, and a brush with a density of 30,000 to 1,000 F/in'' can be used.

The second roller 4 is a cylindrical body made of a conductive material such as aluminum, and is grounded.
It rotates at the same circumferential speed as roller 3.

In addition to polyamide resin, the mechanization material 6 may be made of a resin higher in the charging series, glass fiber, or the like. The mesh material 6 is overlapped with the rubber blade 7 as shown in FIG.
It is pressed against the circumferential surface of the roller 4 with an appropriate pressing force. When the second roller 4 rotates clockwise in FIG. 1, the toner T in the toner storage section 9 is attracted between the mesh material 6 and the second roller 4, moves while rubbing against the mesh material 6, and becomes negatively charged. , adhered to the surface of the second roller 4 in a thin layer to form the first
It is carried to roller 3. Since the developing bias is applied to the first roller 3 as described above, the negatively charged toner T is transferred to the first roller 3.
It is attracted by the roller 3.

The toner T transferred to the first roller 3 in this way is regulated to an appropriate number by the collection member 5, and is transported to the developing area, where the gap D
The latent image on the image carrier 1 is developed using SD.

In the apparatus described above, experiments were conducted using non-magnetic toner T2 with an average particle size of 1 μm, fixing the mesh degree of the mesh material 6 constant, and varying the surface roughness and material of the city roller 2. As a result, we were able to obtain the data shown in Table 1.

In the experiments shown in Table 1, the surface roughness of the second roller, which is the toner supply roller, was smoothed and sandblasted to meet JIS B 0601-1970. Select the maximum height Rmax defined by 5 μm, 120 μm, and 550 μm, respectively (these are 58, 208, 508
The above smooth surface was 2S,
) Furthermore, experiments were conducted with a mesh material of polyamide resin with a mesh degree of 508 or a smooth surface sheet material of polyamide resin adhered to the surface of the second roller, or with the second roller changed to a conductive rubber roller, sponge roller, etc. did. According to past experience, if the amount of toner is in the range of 0.8 to 1.2 m9/cd, proper development will occur, but if it is less, uneven density or insufficient density will occur. If the amount is too large, toner scattering and a decrease in the amount of charge will occur.

Furthermore, it is sufficient that the amount of charge on the toner is -2 μC/i.
Table 1 shows the type of second roller that satisfies the above conditions and provides a uniform layer of toner: aluminum, surface roughness 5S~
It is said that it is for 2OS.

The above has described an example in which a fur brush roller is used as the developing roller, but the above conditions are not limited to this, and the above conditions can also be applied when a metal roller or other developing roller is used. It can also be applied to a device using a roller.

〔Effect of the invention〕

As explained above, in the non-magnetic one-component toner developing device, the surface roughness of @2 rollers Rmax f5 S -
By setting the toner in the range of 20S, sufficient toner charging and toner adhesion amount to the roller can be obtained with one rotation of the roller, and the uniformity is also good.

Since a sufficiently charged layer of toner can be obtained by rotating the roller, copying speed can be increased without unnecessary rotation of the roller, and the toner layer can be uniformly charged and uniform in quantity. As a result, toner scattering does not occur, sufficient toner is replenished, and there is no difference in image quality between the leading edge and trailing edge of the image, and a good image without fogging can be obtained, which is extremely effective. There is something.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts of an embodiment of the present invention. ■ Image carrier 2 Development device 3 First roller 4 Second roller 5... Recovered parts 6.
...Mesh material 7...Rubber blade 8...Sponge 9...Toner storage section 10...Bias power supply device T.
...Toner applicant: Konishiroku Photo Industry Co., Ltd. Figure 1

Claims (1)

[Claims] The first stage conveys the non-magnetic one-component toner to the image carrier and performs development.
The roller and the toner are frictionally charged and the first
In a developing device having a second roller that supplies toner to the roller, the surface roughness Rmax of the second roller is set to 5S to 5S.
A developing device characterized by having a range of 20S.