JPH0692136B2 - Seamless non-static roller and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a lightweight and seamless (seamless) having a non-charging function as a platen roller of a printer attached to a computer terminal or an OA equipment and a roller for carrying electronic components. None) The present invention relates to a non-chargeable roller and a manufacturing method thereof.

[Conventional technology]

Most conventional rollers are made of rubber,
This is a technology that requires many man-hours such as casting, vulcanization, curing, and grinding after release. Further, an injection molding method using a thermoplastic resin in a small part is also used. As a related technology, JP-A-60
-190317, JP-A-59-12879, JP-A-55-65580 and the like.

[Problems to be solved by the invention]

The above-mentioned conventional technique has a problem that since the roller needs to be thick, it is apt to be deformed by shrinkage, and in order to prevent it, a complicated mold design and process are unavoidable.

The object of the present invention is to eliminate many steps such as raw material kneading, cast vulcanization curing, and grinding after releasing from the prior art, and further,
Not only is it seamless and lightweight compared to conventional technology,
The non-charging layer is as thin as 1 to 3 mm, and the inner foam layer can be arbitrarily set and molded from 5 to 70 mm, so that the roller diameter can be freely selected and the practical range can be expanded to meet the needs of various rollers. Another object of the present invention is to provide a seamless non-charging roller and a manufacturing method thereof.

[Means for solving problems]

The inner layer has a mandrel as the shaft core, and the periphery of the inner layer is in front of the foamed structure by using the chemical foaming curing reaction by the reaction injection molding method, and the outer peripheral part is formed by extrusion molding using the conductive composite material. A method for manufacturing a lightweight, seamless non-charging roller in which a cylindrical tubular body is molded and the heat-shrinkability of the tubular body is used to firmly adhere to the inner layer portion will be described.

FIG. 1 shows a process for manufacturing a lightweight seamless non-charging roller according to the present invention.

The mold is composed of a cylindrical main body 6, an upper mold 7 and a lower mold 8.
By setting the core metal in the mold and injecting the chemically active composition stock solution containing the foaming agent from the gate 10 by the reaction injection molding method, the curing reaction accompanied by foaming is promoted in the mold,
A foam layer is formed around the core metal as a central axis. Separately from this, a pipe-shaped tubular body obtained by an ordinary extrusion molding method is coated with a conductive material, and heated in a heating tank to firmly fix by utilizing heat shrinkability, and is lightweight and seamless. A charging roller can be molded.

[Action]

In the present invention, a core metal is used as a central axis, a low-density foam layer is provided around the core, and the outer peripheral portion is firmly fixed by utilizing the heat shrinkability of a plastic or rubber pipe-shaped tubular body obtained by separate extrusion molding. It is a method for obtaining a lightweight and seamless non-charging roller which manufactures the above-mentioned multi-layer structure by a simple process. By this process, conventional steps such as kneading, casting, vulcanization curing, and grinding after release can be eliminated at once. As a result, capital investment and energy consumption can be greatly reduced.

FIG. 2 is a partial cross-sectional view of a lightweight seamless non-charging roller according to the present invention, in which the non-charging layer 3, the low-density foam layer 5 and the non-foaming layer 4 forming the skin portion thereof are firmly fixed. .

FIG. 3 shows the density distribution of the lightweight seamless non-charging roller according to the present invention, which is the basis of weight reduction as a whole. The roller according to the present invention is seamless and lightweight (corresponding to 30 to 50% of the weight of the conventional product), and the thickness of the foam layer can be freely changed to 5 to 70 mm, which makes it practical for various printers of computer terminals. It can meet various needs from large size to small size. Because of its light weight, it not only contributes to weight reduction of printers and conveyors, but also contributes greatly to streamlining product structure design, such as simplifying bearing structure design and reducing drive energy.

The friction coefficient (μ) can be varied by selecting the material of the non-charged layer on the outer peripheral portion. That is, in the case of resin, μ =
It can be changed from 0.1 to 0.3, and in the case of rubber, μ = 0.5 to 0.9. Since these values can be freely selected depending on the application, it can meet a wide range of product needs.

〔Example〕

In carrying out the present invention, the outer peripheral portion will be described as a pipe-shaped cylindrical body obtained by extruding conductive carbon composite polypropylene.

Fig. 4 shows the wall thickness and surface resistance value of a pipe-shaped tubular body obtained by extrusion molding of a conductive carbon composite material obtained by kneading and blending polypropylene and nitrile rubber used as a matrix to impart conductivity. Show.

The surface resistance of these cylinders is as small as 10 ⁶ Ω or less, which is sufficient to form the non-charged layer on the outer circumference of the roller.

Next, the pipe-shaped cylindrical body obtained as described above and the inner layer foam obtained according to the above-mentioned steps were fixed by heat shrinkage. That is, a polyurethane material was used as the material for forming the foam layer. The first undiluted solution contains a polyol as a main component, a polyether polyol obtained by adding an alkylene oxide to an aromatic or aliphatic alcohol or amine, a reaction accelerator (catalyst), an alkyl halide having a low boiling point, etc. And a foam stabilizer such as alkylene oxide-modified polydimethylsiloxane.

The second stock solution used 4-4 ′ diphenylmethane diisocyanate as the isocyanate.

The molding machine used was SF15F / 15 manufactured by Battenfeld of West Germany, which has a mixing head capable of collision-mixing the first and second stock solutions. Stock solution mixing pressure 180-200kgf / cm ² , injection pressure 3-10kg
It was set to f / cm ² .

Set the mold temperature to any temperature within the range of 50 to 70 ° C, ± 1
Controlled at ° C.

The injection time is 1 to 3 seconds, and the time to cure and release is 1 to
3 minutes. This is 1/1 of the molding time of a conventional rubber roller
It is about 10.

The non-chargeable roller obtained by molding is a partial cross-sectional view No. 2
The structure is as shown in the figure, and its density distribution is as shown in FIG. The foam layer of the inner layer portion is a high-density layer as compared with the foam portion because it forms a skin layer at the interface portion in contact with the core metal portion and the outer layer portion because it is compressed by the foaming pressure in the mold.

Using this as an inner layer, a roller having a multi-layer structure in which the inner layer portion was firmly fixed to the outer peripheral portion by heat shrinkage was obtained. The surface resistance value is as small as 10 ⁶ Ω or less as shown in FIG. 4, and it has a sufficient non-charging function.

The friction coefficient (μ) with paper is 0 for resin polypropylene.
Small as 1 ≦ μ ≦ 0.3, 0.5 for nitrile rubber composite material
It was as large as ≦ μ ≦ 0.9, and it was found that there was no problem at all in terms of the paper feeding function of various printers with excellent sliding characteristics.

EFFECTS OF THE INVENTION The present invention uses a separately molded non-chargeable pipe-shaped tubular body as an outer peripheral layer, forms a foamed layer by reaction injection molding on the inside, and utilizes the heat shrinkability of the outer layer to firmly bond with the inner layer. The present invention provides a new production technique for manufacturing a fixed multi-layered roller by a simple molding process. This manufacturing method is not only a rationalization process that eliminates the conventional raw material kneading, vulcanization, and grinding steps, but the resulting molded product has an antistatic function and has a foam layer, which allows for a wide range of artificial thickness. It is possible to change the temperature and the weight is excellent, and the coefficient of friction (μ) with paper can be selected from 0.1 to 0.3 by using resin for the outer peripheral part, and μ can be selected from 0.5 to 0.9 by using rubber. It has the feature of adding flexibility.

The lightweight, non-chargeable roller obtained by the present invention can be used in printers and electronic component transporters of various product shapes and has a great degree of freedom in selection of diameter and frictional characteristics, and also has a problem of electrostatic damage. Is gone.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a non-charging roller according to the present invention, and FIG. 2 is a partial cross-sectional view showing a seamless non-charging roller partial cross section according to the present invention, showing a multilayer structure having a density distribution, FIG. 3 is an explanatory view showing the density distribution of the cross section of the seamless non-charging roller according to the present invention, and FIG. 4 is a graph showing the surface resistance value of the outer peripheral non-charging layer. 1 ... Seamless non-charging platen roller 2 ... Core metal 3 ... Non-charging pipe cylinder 4 ... Foam skin layer, 5 ... Foam layer 6 ... Mold body, 7 ... Upper mold 8 ... … Lower mold, 10 …… Mixing head 11 …… Injection port, 12 …… Roller support 13 …… Heating furnace

Claims (2)

[Claims] 1. A seamless non-charging roller comprising an organic polymer foam layer integrally formed between a cored bar and a seamless conductive polypropylene cylinder concentrically formed outside the cored bar. . 2. A core metal is previously installed inside a mold cavity, and in this state, a chemically active composition stock solution containing a foaming agent is injected by a reaction injection molding method to cure with foaming in the mold. A pipe-shaped tubular body obtained by extrusion-molding conductive polypropylene into a cored foam with a foam layer formed on the periphery with this core as the central axis is made strong by utilizing heat shrinkability. A method for producing a seamless non-charging roller, which is characterized in that it is adhered to a sheet to form a laminated structure.