JPS5912880A - Platen roller - Google Patents

Abstract

PURPOSE:To reduce the amount of noise caused by impaction in the printing operation as well as reduce the weight of a platen roller by integrally molding a cylindrical core metal having a shaft on its both ends with a lowly foamable resin. CONSTITUTION:The central portion 8 of a cylindrical periphery 9 having shafts 7' on its both ends 10, formed of a solid non-expanded material having a high ridigity, is molded integrally with a lowly foamable resin to make up a core metal portion, which is covered with a vulcanized rubber layer 4'. A platen roller can thus be simply manufactured at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a platen roller, and particularly to a planitin roller used in a paper feeding mechanism of a printing device such as a typewriter.

Generally, the structure of this type of platen roller is such that the outer circumferential surface of a cylindrical core metal part with details on both end faces is covered with a rubber part. The center is hollow to prevent it from getting too big.

That is, as shown in FIG. 1, the core part is a cylindrical steel pipe 1.
Disc-shaped metal boss portions 2.2 are fitted to both ends of the steel pipe 1, and a shaft portion 7 is formed in the center of the boss portion, and the outer diameter is approximately equal to the outer diameter of the steel pipe 1. A step is formed to fit into the steel pipe 1, and the boss portion is welded and fixed to the steel pipe 1 at this step 3.3.

A rubber layer 4, which is a coating layer, is formed on the outer circumferential surface of the core metal part by heating the rubber, and then the outer circumference of the rubber and the shaft part 1 are polished to obtain a platen roller.

The reason for polishing the shaft portion 7 is that it is necessary to make the shaft portion 7 and the rubber layer 4 concentric with high precision. For the same reason, if the shaft part 7 becomes rusty, the shaft part 7 and the rubber part 4 will become misaligned, so the boss part 2 including the shaft part 7 is made of expensive stainless steel that does not rust. It is common that

However, since the conventional platen thus obtained has a hollow portion 5 at its center, when an impact occurs during a printing operation, the impact reverberates in the hollow portion 5, increasing the noise caused by the impact.

In order to prevent this loud noise, conventionally, as shown in Fig. 2, the steel pipe 117 has a soundproof material 6 inside it, such as a paper tube or foam material.
A structure with i people is adopted.

In short, the conventional platen roller has a core metal structure of steel pipe 1. Boss part 2. Three parts of the soundproofing material 6 are required, and its manufacture requires a step of enclosing the soundproofing material 6, a step of welding the boss portion 2, and a step of polishing the shaft portion 1. Further, the boss portion 2 is made of an expensive material such as stainless steel.

Therefore, the conventional platen roller has a large number of core metal parts, a large number of manufacturing steps, and uses expensive materials, resulting in high costs.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a platen roller that is lightweight, has low impact noise during printing operations, has a simple structure, and is inexpensive.

In order to achieve this object, in the present invention, the core part of the platen roller is formed by integral molding of low-foaming resin, and the center part of the core part is made of a foamed part of low-foaming resin, and the outer peripheral part and both ends A structure is adopted in which the part and the shaft part are made of non-foamed parts.

The present invention will be described in detail below based on embodiments of the present invention shown in the drawings.

In the platen roller according to the present invention shown in FIG. 3, the outer appearance of the core metal part is a cylindrical shape with shaft parts 7', 7' formed on both end faces, similar to the conventional metal core part. , is formed by integral molding of low foam resin.

Numerous small circles in the figure indicate bubbles in the low foaming resin. That is, the inner central portion 8 of the core metal portion is formed of a foamed portion of a low foaming resin.

On the other hand, the shaded area in the figure shows the non-foamed area of the low-foamed resin, ie, the Norirad skin area. As shown in the figure, the outer periphery 99 and both ends 10 of the core metal part
．． 10. The shaft portions 7', 7' are formed of non-foamed parts.

The center part 8 is made of a foamed part of a low-foam resin, so it has a sound-dampening property, and the shaft part 7/1r, the outer peripheral part 8, and both ends 10 and 10 are made of non-foamed parts of NoriRad. Therefore, it has the strength to withstand the mechanical stress applied to the core metal part when the platen roller is used. In addition, the weight of the entire core metal group is small because it is made of low-foam resin.

The rubber layer 4' that covers the outer circumferential surface of the core metal part formed in this way is formed by heating the rubber separately from the core metal part to form a rubber tube, and then press-fitting it onto the core metal part. A platen roller is obtained.

Note that the rubber is heated at a high temperature (approximately 150°C), but since the process is performed separately from the core metal, the resin forming the core metal is not exposed to high temperatures, and the resin is not exposed to high temperatures. There is no fear of any impact.

As is clear from the above description, in the platen roller according to the present invention, the core part is formed by integral molding of low foam resin, and the structure of the low core part in the center of the core part is simple. The number of parts is only one, and the manufacturing process is only an integral molding process. In addition, the material is a low-expansion resin that is inexpensive and lightweight.

For the above reasons, the platen roller according to the present invention can be manufactured easily and inexpensively, is lightweight, and has the excellent effect of reducing noise caused by impact during printing operations because it has a sound-deadening part. can get.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views explaining the structure of a conventional platen roller, and FIG. 3 is a cross-sectional view explaining the structure of a platen roller according to the present invention.44'...Rubber layer
1'...Shaft part 8...Center part 9...
・Outer peripheral part 10...end part

Claims (1)

[Claims] 1. A platen roller comprising a cylindrical metal core having shaft portions on both end faces, the outer peripheral surface of which is covered with a surface layer, the platen roller being characterized in that the core metal is integrally molded from a low-foaming resin.