JPS63188043A - rubber molded products - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to rubber molded products such as paper feed rollers for electrophotographic copying machines and platen rollers for thermal printers.

(Technical background of the invention and its problems) A paper feed roller, which is a rubber molded product, has a structure having a rubber layer on a core metal, and feeds the recording paper to the transfer side so as to overlap the toner image on the photosensitive drum. .

By the way, the rubber layer of the paper feed roller has conventionally been formed of chloroprene rubber, silicone rubber, or the like. but,
When forming a rubber layer using such a rubber material, there is a drawback that a discharge action occurs between the rubber layer and the recording paper due to the charging phenomenon, making it impossible to obtain a clear image. Because the paper wraps around the paper, it becomes impossible to feed the paper smoothly.

It is also possible to fill the rubber material with a large amount of conductive carbon such as acetylene black to maintain conductivity in the rubber layer, but in this case, the hardness of the rubber layer increases and printing accuracy decreases. There was a problem with it.

Conventionally, polynorbornene rubber is used as the rubber material, and a large amount of petroleum-based softener or plasticizer is mixed with this rubber material to form the rubber layer of the paper feed roller. However, simply adding petroleum-based softeners and plasticizers will cause oil and plasticizers to bleed onto the surface of the rubber layer.
In addition to contaminating the recording paper, it also has the disadvantage that the recording paper adheres to the rubber layer due to stickiness.

(Object of the Invention) An object of the present invention is to provide a rubber molded product that does not cause bleeding.

(Summary of the invention) The present invention is based on the general formula 2Ca○・3SiOz fistn5i02・mH with respect to 100 parts by weight of rubber to which compounding agents are added.
A rubber molded product is formed by filling 1 to 30 parts by weight of petal-shaped calcium silicate represented by zo (where n and m are positive numbers, and n is 0.1 to 10).

Rubber materials used in rubber molded products include polynorbornene rubber (trade name Ninosolex, manufactured by Nippon Zeon Co., Ltd.), EPDM (ethylene, propylene, diene ternary copolymer) rubber, and rubber kneaded with these rubbers. There are other materials such as silicone rubber.

Compounding materials include petroleum softeners, plasticizers, anti-aging agents, stearic acid, inorganic fillers, etc., and these are added to improve the physical properties of the rubber material and increase its weight. As the petroleum softener, naphthenic oil, aromatic oil, paraffin oil, etc. can be used.

Further, as the plasticizer, phthalic acid-based or phosphoric acid-based ester plasticizers, aromatic polyether, etc. can be used.

Then, the general formula 2CaO* 3S ioz ・nS i
02 φmHz O (however, n and m are positive numbers, and n is 0
．． The details of the petal-shaped calcium silicates shown in 1 to 10) are shown in Japanese Patent Publication No. 60-29643. That is, this calcium silicate has porous petals, has a significantly large bulk specific volume or oil absorption φ, and has a function as an adsorption carrier. Therefore, when this calcium silicate is filled into a rubber material, it adsorbs and fixes compounding agents such as petroleum-based softeners and softeners, so that bleeding of the compounding agents can be reliably prevented.

The above calcium silicate is commercially available under the trade name "Fluorite" (manufactured by Tokuyama Soda Co., Ltd.).

By the way, if the above-mentioned calcium silicate is 1 part by weight or less based on 10011i parts of rubber, hardly any adsorption/supporting effect will occur and bleeding will occur. Furthermore, if the above-mentioned calcium silicate is 30 parts by weight or more, the rubber hardness of the rubber molded article becomes extremely high, and the adsorption and support function does not improve much.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Example 1] FIG. 1 shows a paper feed roller according to the present invention, and this paper feed roller includes a core metal 1 and a rubber layer 2 provided on the core metal 1. . The core metal 1 has an outer diameter of 25 mm and a length of 60 mm, and the rubber layer 2 has a wall thickness of 15 mm.

Now, the rubber layer 2 is formed with the following compounding ratio.

Polynorbornene rubber too 11 parts "Nosolex" EPDM rubber manufactured by Nippon Zeon Co., Ltd.
20 parts by weight "Nisprene 505" Sumitomo Chemical (
MT Carbon Black manufactured by Co., Ltd. 50 parts by weight Naphthenic oil 300 parts by weight Antioxidant 4 parts by weight Zinc oxide
5 parts by weight stearic acid
1 part by weight Vulcanization accelerator Tsukusela TT 1 part by weight/I
TBT 1 part by weight // DT
1 part by weight accelerator TL
O, 5 parts by weight/l NA-220, 5 parts by weight Sanfel-R 2 parts by weight Fluorite J 10 parts by weight A rubber composition manufactured by Tokuyama Soda Co., Ltd. or above was kneaded in a Banbury mixer and then formed into a sheet with a thickness of 15 mm. The paper feed roller of the present invention was obtained by molding it into a shape, disposing it on the core metal 1, and press-vulcanizing it.

The rubber layer 2 of this paper feed roller is JIS A scale 20.
It has a hardness of ', and no bleeding occurred even when it was left in an atmosphere at a temperature of 25° C. and a humidity of 50 to 60% for 180 days.

[Comparative example]

In the above Example 1, a rubber composition was prepared without being filled with "fluorite", and the above-mentioned paper feed roller was obtained. When this paper feed roller was left in an atmosphere under the above conditions, bleeding occurred in 3 days. [Comparative Example] In Example 1 above, instead of "Fluorite", another adsorption carrier was used. A rubber composition was prepared by filling 10 parts by weight of silica (Nipsil VN3 J, manufactured by Nippon Silica Co., Ltd.) to obtain the above paper feed roller. This paper feed roller was left in an atmosphere under the above conditions. , bleed occurred in 60 days.

[Example 2] Fig. 2 shows a platen roller according to the present invention, and this platen roller has an outer diameter of 20 mm and a length of 280 mm.
It consists of a core metal 3 with a thickness of 20 mm and a rubber layer 4 provided on the core metal 3 with a thickness of 20 mm.

The rubber layer 4 is formed with the following compounding ratio.

EPDM rubber 100 parts by weight "Nisprene 502" carbon manufactured by Sumitomo Chemical Co., Ltd.
5 parts by weight "Geast S" naphthenic oil manufactured by Tokai Carbon Co., Ltd. 110 parts by weight Antioxidant 1 part by weight Zinc oxide
5-fold stearic acid
1 part by weight calcium carbonate (filler) 1
80 parts by weight Vulcanization accelerator Tsukusela TT 0, 5 parts by weight tt
M 1 part by weight // CZ
G, 5$j part sulfur
1.2 parts by weight "Fluorite"
The platen of the present invention is produced by kneading 10 parts by weight or more of a rubber composition manufactured by Tokuyama Soda Co., Ltd. in a Banbury mixer, forming it into a sheet with a thickness of 20 mm, placing it on the core bar 3, and press-vulcanizing it. Got Laura. The rubber layer 4 of this platen roller has a hardness of JIS A scale 30', and the temperature is 25°C and the humidity is 50-60.
% atmosphere for 180 days, no bleeding occurred.

[Comparative example]

In the above Example 2, a rubber composition was prepared without being filled with "fluorite", and the above platen roller was obtained. When this platen roller was installed in a thermal printer and printing was performed, bleeding occurred within three days and the recording paper was contaminated.

The present invention can be applied not only to paper feed rollers and platen rollers, but also to paper conveyance rollers and various belts, and in short, to rubber molded products containing compounding agents.

(Effects of the Invention) According to the present invention, by filling 1 to 30 parts by weight of petal-shaped siliceous calcium that functions as an adsorption carrier with respect to 100 parts by weight of the rubber into which the compounding agent is mixed, Bleed can be reliably prevented. Therefore, it is possible to provide rubber molded products such as paper feed rollers and platen rollers that do not contaminate recording paper.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a paper feed roller according to the present invention, and FIG. 2 is a cross-sectional view of a platen roller according to the present invention. 1.3---1---core metal,

Claims (1)

[Scope of Claims] 1. A rubber molded product containing a compounding agent, which has the general formula 2CaO・3SiO_2・nSiO based on 100 parts by weight of rubber.
_2・mH_2O (however, n and m are positive numbers, and n is 0.
Petal-shaped calcium silicate shown by 1 to 10) 1 to 30
A rubber molded product characterized by containing a weight part. 2. The rubber molded article according to claim 1, wherein the rubber is polynorbornene rubber containing a petroleum-based softener.