JPS6123171A - Developing device - Google Patents

Abstract

PURPOSE:To improve the wear resistance and durability of the surface of a developer carrier body and to obtain a sharp image by forming the surface of the developer carrier body of a resin dispersed and reinforced with carbon fibers. CONSTITUTION:The carbon fiber-reinforced layer (a) is the layer formed by dispersing uniformly the carbon fibers into the resin, for example, nylon resin, PBT, ABS, PC, etc. to increase the surface hardness of a sleeve. The conventional known carbon fibers are usable. Any metal having conductivity is usable and metals such as aluminum and stainless steel are more preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device applied to an image forming apparatus such as a copying machine or an information recording device.

Conventionally, a developing image carrier in a developing device includes, for example, a developing sleeve, which has a magnet inside as a magnetic field generating means, carries toner powder on its surface, and transports this toner to a developing area where it is exposed to light. Development is performed by attaching the latent image to a latent image holding member such as a body drum. At this time, if the developing sleeve itself is magnetic, uneven adhesion of toner powder will occur, and unevenness will also appear in the image, so a cylinder made of a non-magnetic material is usually used as the sleeve.

Furthermore, a developing bias is applied to the developing sleeve to prevent toner from adhering to the background portion, so-called fog. For this reason, the sleeve is also generally required to be electrically conductive.

Currently, materials such as aluminum are used as developing sleeves that meet the requirements of non-magnetic properties and electrical conductivity.

However, aluminum has low wear resistance and durability, and
It had the disadvantage that it could only make copies of about 2,000 to 3,000 sheets.

An object of the present invention is to provide a developing device that can perform developer application and development without unevenness by improving the durability of a developer carrier.

The present invention provides a developing device that carries a developer on a developer carrier and performs development by making the developer face a latent image holding member.
This is a developing device that has a resin reinforced by dispersing carbon #li fibers on the surface of a developer carrier.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a schematic cross-sectional view of a developing device to which the present invention is applied. In the figure, ■ is a sleeve as a developer carrier, which moves in the direction of arrow a. Reference numeral 2 denotes a magnet roller as a magnetic field generating means, which is fixedly arranged within the sleeve 1. Of course, the sleeve may be fixed and the magnetic roller may rotate, or both may be arranged so as to rotate in the same or opposite directions to convey the developer. A magnetic toner 3 is stored in a developer container 4 . 5 is a magnetic blade,
It is arranged substantially opposite to the magnetic pole N1 of the magnet roller 2. The blade 5 may be of a type that presses against a non-magnetic material or an elastic material. Reference numeral 6 denotes a photosensitive drum as a latent image holder, on the surface of which a latent image is formed by latent image forming means (not shown), rotates in the direction of the arrow mark, and faces the sleeve 1 in a developing area. 7 is a developing bias power supply, and in this embodiment, a bias voltage in which AC and DC are superimposed is applied between the sleeve l and the photosensitive drum 6. The sleeve-shaped toner 3 formed into a layer thinner than the development gap by the magnetic blade 5 is reciprocated in the gap between the re-drum and the sleeve by this bias, and is developed by so-called jumping development. Incidentally, the bias voltage may be only AC or only DC, and development may be performed by bringing one layer of toner on the sleeve into contact with the drum. Further, the developer may be a non-magnetic toner or a two-component developer consisting of a carrier and a toner. A belt-shaped sleeve/photosensitive drum can also be used.

In FIG. 1, la is a carbon fiber reinforced layer having a layer thickness of about 5w to t, made of resin such as nylon resin, PBT,
This is a layer in which approximately 10 to 60 wt% of carbon fibers are uniformly dispersed in ABS, PC, etc. to strengthen the surface hardness of the sleeve. For example, trading cards (product name: Toshiku Co., Ltd.) are used for carbon #li fibers.
It is possible to use conventionally known ones such as (manufactured by).

The carbon fiber reinforced layer is formed by sprinkling finely cut carbon fibers on the surface of the aluminum sleeve and plasma spraying a resin. In addition, carbon fibers may be dispersed in a resin and then the sleeve surface may be coated. The sleeve base 1 may be made of any material as long as it is non-magnetic and conductive, but metals such as aluminum and stainless steel are preferred.

Alternatively, a cylinder having a wall thickness of 1 to 20 mm may be formed by molding or the like using only a resin in which carbon fibers are dispersed, and this may be used as a sleeve. This has the advantage that the sleeve can be made smaller and lighter.

) What is the difference between a resin with dispersed and reinforced pyrotechnic fibers and a resin without additives?
There are differences in physical properties as shown in Table 1.

Table 1 As is clear from Table 1, since the carbon fiber reinforced resin contains carbon fiber, the volume resistivity is l Q 13~1
019, and the bending elastic modulus also improves by several tens of times. Furthermore, the heat distortion temperature increases by about 3 to 4 times, and the Rockwell hardness (R scale) also increases by 20 to 30%. Carbon fiber-reinforced resins with a volume resistivity of 1 Ω·cm or less have good electrical conductivity and do not cause any problems during development even if they are adhered to the sleeve on the order of several dozen square meters. Furthermore, regarding the provision of tripocharges due to abrasion with toner, the durability is about 10 times that of aluminum used as a developing sleeve, and the durability is almost equivalent to that of austenitic stainless steel mesh. Furthermore, in the case of aluminum or stainless steel sleeves, the sleeve surface is roughened by sandblasting etc. in order to impart a tripo charge to the toner, strengthen the toner conveying force, and prevent toner from fusing to the sleeve. In the case of carbon fiber reinforced resin, an average roughness of 2 to 3 degrees can be formed on the sleeve surface at the same time when the sleeve is formed, so there is an advantage that conventional processes such as blasting are not required. Therefore, it is also sufficiently effective to form the carbon #li fiber reinforced layer of the present invention on the surface of the austenitic stainless steel mesh.

As described above, in the present invention, since the surface of the developer carrier is formed of a resin reinforced with carbon fiber dispersion, the abrasion resistance and magnetism of the developer carrier surface are improved. Further, since the developer is uniformly attached to the developer carrier, a clear image can be obtained. Further, according to the present invention, there is an advantage that the image forming apparatus can be made smaller and lighter.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a developing device showing an embodiment of the present invention. In the figure, 1 is a sleeve, 1a is a carbon fiber reinforced resin layer, 2 is a magnetic roller, 3 is a toner, 4 is a developer container, 5 is a magnetic blade, 6 is a photosensitive drum, and 7 is a developing bias power source.

Claims (1)

[Claims] A developing device that carries a developer on a developer carrier and performs development by facing the latent image holding member, characterized in that the surface of the developer carrier is formed of a resin reinforced by dispersion of carbon fibers. A developing device.