JPS60187985A - Guide roller - Google Patents

Abstract

PURPOSE:To reduce the load torque of a magnetic tape by using a synthetic resin containing a conductive powder to form a guide roller in a tape cassette. CONSTITUTION:A magnetic tape 7 is brought into contact with guide rollers 1a and 1b and guide pins 6a-6d when it is run in a certain speed. Rollers 1a and 1b are supported by pins 4a and 4b as supporting shafts and are rotated. In such a case, electrification on the inside peripheral surface of, for example, the roller 1a due to friction between this inside peripheral surface and the pin 4a is attenuated immediately because migration of electric charge is made eary by reduction of the surface resistance due to the roller 1a formed with the synthetic resin containing the conductive powder.

Description

TECHNICAL FIELD This invention relates to a guide roller rotatably supported within a tape cassette.

Conventional technology Traditionally, guide rollers were made of synthetic resin, so when the guide rollers were rotated for a long time, the friction between them and the support shaft that supported them rotatably caused the guide rollers to become electrically charged, and as a result, the guide rollers stopped running. There are disadvantages such as an extra load being placed on the magnetic tape being moved, and the magnetic tape sticking to the surface of the guide roller, making the tape running unstable.

A tape cassette in which a conductive guide roller is rotatably supported is known from Japanese Patent Publication No. 50-10484. However, since this device is intended to automatically stop the tape and uses the kite roller as an electrical contact, the resistance value must be kept quite low. That is, the guide rollers are made of metal because current must flow through them. However, when the guide roller is made of metal, it is necessary to reduce the weight in order to reduce the rotational load on the guide roller, and one possible means of achieving this is to make the wall thickness as thin as possible by using wall relief etc. However, reducing the wall thickness makes it difficult to achieve dimensional accuracy, and if you try to ensure accuracy, it takes a lot of man-hours for cutting, resulting in high costs.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a conductive guide roller that is light in weight and easy to achieve dimensional accuracy.

Approximate number of inventions This invention includes a guide roller rotatably supported by a spindle in a tape cassette, which is made of synthetic resin containing conductive powder, and the guide roller is charged by friction between the guide roller and the spindle. This prevents

1"Double 11 FIG. 1 is a view showing a guide roller according to an embodiment of the present invention and a part of a tape cassette in which this guide roller is rotatably supported.

The guide rollers 1a and 1b have a hollow cylindrical shape,
It is formed by injection molding of a synthetic resin mixed with conductive powder such as carbon, metal powder, or metal filler, such as carbon-containing polyacetal, metal powder-containing ABS (acrylonitrile butadiene styrene), or metal filler ABS. These guide rollers 1a.

Reference numeral 1b denotes a guide roller support bin 4 protruding from the vicinity of both left and right ends of the lower cassette half 2 constituting the tape cassette, on the side where the magnetic head insertion windows 3a, 3b, etc. are located.
a and 4b, each of which is rotatably supported.

Further, in the lower cassette half 2, there is a magnetic head insertion window 3a on a line connecting the guide roller support bins 4a and 4b.
, 3b, etc., supporting columns 5a, 5b, 5c.

Guide bins 6a and 6b correspond to 5d, respectively.

5c and 5d are provided. The magnetic tape 7 is arranged so as to contact the guide rollers 1a, 1b and the guide bins 6a, 6b, 6c, 6d during constant speed running.

Next, the action of the idle roller of the present invention based on the above configuration will be explained.

When running at a constant speed, the magnetic tape 7 is moved from a tape feed-out hub (not shown) to a guide roller 1a in the direction of the arrow shown in FIG.
, guide bin 6a, (3b.

5c, 6d, and guide rollers 1b in this order, and is wound up on the tape winding side (not shown). At this time, the guide rollers 1a and II3 are supported by guide roller support pins 4a and 4b, which are support shafts, respectively, and rotate.

At that time, for example, the inner circumferential surface of the guide roller is charged due to friction between the inner circumferential surface of the guide roller 1a and the guide roller support bin 4a, but this is because the guide roller is made of synthetic resin containing conductive powder. The surface resistance is low and charges can easily move. Therefore, even if the magnetic tape is charged, it is immediately attenuated, and unstable running of the magnetic tape due to an increase in load torque can be prevented. Note that since the guide roller of the present invention is not made of metal, the mixing ratio of the conductive material can be freely changed depending on moldability, tensile conductivity, and cost.

FIG. 2 shows a guide roller showing an embodiment of the pond of the present invention. The difference from the above-mentioned embodiment is that the weight of the guide roller is reduced by the relief, and the other points are the same, so a description thereof will be omitted.

In the one shown in FIG. 2, the outer ring and inner ring of the guide roller 8 are connected by ribs 9 during injection molding.

Therefore, the weight is lighter than that of the above embodiment, and the load torque on the magnetic tape can be reduced.

Note that the shape of the ribs 9 is arbitrary, and adjacent ribs may have different shapes in order to prevent meat from shrinking.

Effects of the Invention In the present invention, since the idle roller, which is rotatably supported by a spindle within the tape cassette, is formed of a synthetic resin containing conductive powder, the load torque on the magnetic tape can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the invention, and FIG. 2 is a diagram showing another embodiment of the invention. 1a, 1b... Guide roller, 2... Lower cassette half, 4a, 4b... Support shaft, 8... Guide roller.

Claims (1)

[Claims] A guide roller rotatably supported within a tape cassette by a support shaft, and characterized in that an idle roller is formed of a synthetic resin containing conductive powder.