JPS61202865A - Platen roller - Google Patents

Abstract

PURPOSE:To reduce the weight of a shaft core and increase rigidity by providing a cylindrically formed hard foamed urethane resin layer, a non-foamed hard urethane resin skin layer and a shaft core with more than three pieces of reinforcing rib arranged toward a circumferential direction at an equal interval. CONSTITUTION:A hard foamed urethane resin layer 2 is formed in a cylindrical form on the external circumference of a metal shaft 1, and a hard urethane resin skin layer 3 is coated on the external circumference and edge of the hard foamed urethane resin layer 2. At least three pieces of reinforcing rib 4 fixed in an external circumferential shaft direction of a solid metal shaft 1 with a prearranged width in a fixed radial direction should be fitted in a circumferential direction at an equal interval. In this way, the diameter of the metal shaft 1 can be narrowed by forming the reinforcing rib 4. Its weight can be reduced and at the same time, its rigidity is increased. Thus the application of the hard foamed resin layer 2 and the resin skin layer 3 as a roller base enables a light-weight platen to be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background and Objects of the Invention] The present invention relates to a platen roller, and particularly to a platen roller with an improved lightweight structure.

The platen roller is used in impact printing type printers such as typewriters. As shown in FIG. 4, in the conventional platen roller, the axis of a solid metal shaft 1 passes through the center of the roller 6 in the axial direction.
A roller 6 is formed on the outer periphery of a metal shaft 1 by vulcanizing hard ebonite rubber 5 into a cylindrical shape. Since both the metal shaft 1 and the hard ebonite 5 have a high density, the weight of the platen roller becomes large, and therefore the platen roller consumes a large amount of energy, leading to an increase in the size of the drive motor and equipment, an increase in electric power consumption, an increase in noise, etc. It turns out.

In addition, the metal shaft 1 has a relatively large diameter in order to obtain rigidity that can withstand impact during printing. For this reason, various measures are being considered to reduce the weight of the platen roller. For example, adopting a hollow shaft with a larger diameter may be considered to make the platen roller lighter. There's something to be said. In addition, in relation to this kind of 0-ra,
1102, Japanese Patent Publication No. 59-34316, etc. are known.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a platen roller that can reduce the weight of a solid shaft core and increase rigidity.

[Summary of the Invention] The platen roller of the present invention includes a hard foamed urethane resin layer formed into a cylindrical shape around the outer periphery of a solid shaft that passes through the center of the roller in the axial direction, and a coating on the outer periphery of the hard foamed urethane resin layer. A non-foamed hard urethane resin skin layer formed by the above-mentioned method, and the above-mentioned shaft core, which is formed with at least three reinforcing ribs arranged at equal intervals in the circumferential direction toward the axial direction of the outer peripheral surface. It was established.

[Example] Hereinafter, an example of the platen roller of the present invention will be used, and the same parts as in the conventional one will be indicated by n symbol and will be explained with reference to FIGS. 1 to 3.
do. Figure 1 is the front view, Figures 2 and 3 are the front view, respectively.
It is a sectional view taken along arrows II-I and III-III in the figure. In the figure, reference numeral 2 denotes a hard foamed urethane resin layer formed into a cylindrical shape around the outer periphery of the metal shaft 1.

3 is a hard urethane resin skin layer that covers the outer periphery and end surface of the hard urethane foam resin [12].

Reference numeral 4 denotes a reinforcing rib, which is fixed in the axial direction of the outer circumference of the solid metal shaft 1 and has a predetermined width in the radial direction. Although this embodiment shows a case in which four reinforcing ribs 4 are provided, at least three reinforcing ribs 4 are installed at equal intervals in the circumferential direction. By forming the reinforcing ribs 4, the metal shaft 1 can be made smaller in diameter, reducing its weight and increasing its rigidity. By using the hard urethane foam resin WJ2 and the hard urethane resin skin layer 3 as the roller base, it is possible to form a platen roller that is even lighter than conventional hard ebonite rubber, and therefore lightweight.

The hard foamed urethane resin layer 2 includes, for example,
When reacting a polyol and a polyisocyanate to obtain a polymer having a so-called urethane bond, R-1
By mixing a fluorocarbon solution such as 1 and a very small amount of water as necessary, it is formulated so that the carbon gas generated by the gasification of the fluorocarbon solution or the reaction between water and isocyanate creates an almost independent cell structure. It is something that can be obtained by doing.

Either polyester urethane resin or polyether urethane resin can be used. here,
Rigid urethane foam resin has a low density, so it can be lightweight as mentioned above, and when it is made into a foam layer with a closed cell structure, it can reduce sound propagation and increase sound absorption, reducing noise. It is something that contributes. Further, the hard urethane resin skin 113 is used to obtain a tough and smooth outer layer that can withstand the impact of the print head, and to enable clear printing. The appropriate thickness of the hard urethane resin skin layer is 0.15jIII or more; if it is less than 0.151m1, it will not be able to sufficiently withstand the impact during printing, and there is also a high risk of pinholes occurring. It is.

In this way, the platen roller of this embodiment has four reinforcing ribs formed in the axial direction on the outer circumferential surface of the solid metal shaft at equal intervals in the circumferential direction, making it possible to reduce the weight of the shaft core and to increase the rigidity. can be made larger.

Furthermore, since the roller body is formed of a hard foamed urethane resin layer and covered with a hard urethane resin skin layer, the weight can be significantly reduced compared to the case of conventional hard ebonite rubber. In the above embodiments, the case where the shaft core is a metal shaft has been described, but similar effects can be obtained with materials other than metal.

[Effects of the Invention] As described above, the platen roller of the present invention has the effect of being able to reduce the weight of the solid shaft core and to increase the composition.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the platen roller of the present invention, and FIGS. 2 and 3 are II-II in FIG. 1, respectively. A sectional view taken along arrows 1--2, and FIG. 4 is a longitudinal sectional view of a conventional platen roller. 1...Metal shaft. 2...Hard foamed urethane resin layer. 3...Hard urethane resin skin layer. 4... Reinforcement rib. 6... Laura.

Claims (1)

[Claims] (1) A hard foamed urethane resin layer formed into a cylindrical shape around the outer periphery of a solid shaft that passes through the center of the roller in the axial direction, and a non-foamed hard urethane resin layer coated on the outer periphery of the hard foamed urethane resin layer. A platen roller comprising: a resin skin layer; and the shaft core having at least three reinforcing ribs arranged circumferentially at equal intervals in the axial direction of the outer peripheral surface.