JPH05314584A - Reel base for detecting rotation - Google Patents

Abstract

PURPOSE:To make a rotation detecting mechanism of an optical reel base thin structive by disposing a reflecting plate on the remote side of the reel base against a photocoupler. CONSTITUTION:The reflecting plate 6 is disposed integrally with an upper part of a reel base main body 1, and the reel base main body 1 is made to be a nonreflecting part, and then the reel base main body is bored in a part required for reflecting, and the photocoupler 5 is arranged to pass its optical path through the reel base main body. By this method, the reel base rotation detecting mechanism can be reduced in thickness corresponding to an effective distance of the photocoupler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a rotation detecting mechanism for a reel that winds a tape.

[0002]

2. Description of the Related Art As shown in Japanese Patent Laid-Open No. 3-44851, a conventional device has a reflector plate on which a pattern of a reflection surface for rotation detection is printed, which is arranged at the bottom of a reel stand, that is, on the side close to a photocoupler. Also, the photocoupler was installed by ensuring the reaction distance of the photocoupler from the reflector.

[0003]

In consideration of the thin mechanism, it is indispensable to make the reel stand thin. However, in the conventional method, the reel stand rotation detecting mechanism has a reel stand thickness +
A space is required that is the sum of the thickness of the reflector + the reaction distance of the photocoupler and the thickness of the photocoupler. In particular, the photocoupler consists of a light emitting element and a light receiving element, so it is difficult to shorten the reaction distance of the photocoupler, and the mechanism is made thinner. Has become a harmful effect of.

An object of the present invention is to reduce the thickness of a rotation detecting mechanism including a photo coupler.

[0005]

[Means for Solving the Problems] A reflector is arranged on the upper part of the reel stand, that is, on the side far from the photocoupler, and a hole corresponding to the optical path of the photocoupler is formed in the reel stand body.
The structure is such that the light from the photocoupler passes through the reel stand body.

Further, the reflection plate has only a reflection surface, the reel body is used as a non-reflection surface, and the reel base rotation detection mechanism is made thin by forming a hole in the reel base body only as a reflection surface. Try to.

[0007]

[Function] Since the reflecting surface of the photocoupler is on the upper surface side of the reel stand main body, if the reaction distance of the photocoupler is set by adding the gap between the thickness of the reel main body and the upper surface of the photocoupler at the time of rotation, it is almost the same as the photocoupler. It is possible to reduce the thickness of the coupler by the reaction distance.

[0008]

Embodiments of the present invention will be described with reference to the drawings.

The reel stand main body 1 has a gear portion 1-1 for engaging with the reel driving means on the outer periphery thereof, and a claw 2 as a claw for engaging the hub of the cassette and driving the reel on the cassette side. There is.

The crown 2 can be moved up and down by a spring 3 in order to prevent interference with the cassette hub when the cassette is mounted, and it is stopped by a cap 4 which also serves as a rotation axis of the reel stand so as not to come off from the reel stand body 1. ing.

The reel base is engaged with a reel shaft 9 which stands upright on the chassis 8, and the polyslider washer 7 is attached.
It is rotatably fixed by. In order to control the rotation speed of the reel stand, the photo coupler 5 is attached to the chassis 8 below the reel.
Is placed to monitor the bottom surface of the reel.

On the cassette side of the reel stand main body 1, a reflector plate 6 having a glossy surface for reflecting the light of the photocoupler is integrated with the reel stand main body 1.

To improve the accuracy of reel rotation speed detection, 1
Since a repeating pattern of a reflective surface and a non-reflective surface is required so that a signal is generated several times per rotation, the reel stand main body 1
Is molded with black resin to be used as a non-reflective surface, and the reflective surface portion is configured such that holes 1-2 are formed in the reel stand main body 1 so that the reflective surface can be seen. (A configuration in which a reflection plate 6 is printed with a reflective / non-reflective pattern and the reel base body 1 is insert-molded so that the gear portion and the shaft portion are integrated with the reflection plate is also conceivable.) The light emitted from the reel passes through the hole of the reel body 1 and is reflected by the glossy surface of the reflection plate 6 at the top of the reel and can enter the light receiving element of the photocoupler. The signal is output several times, and the rotation speed can be detected.

[0014]

1) Since the optical path of the photocoupler can be secured by utilizing the thickness of the reel unit, the reel rotation detecting mechanism corresponding to the reaction distance of the photocoupler can be thinned.

2) Polyacetal resin is often used in the reel body in order to prevent noise during rotation of the reel and wear of the shaft gear portion. However, if the periphery of the gear portion is thinned to reduce the thickness, the strength becomes insufficient. Strengthening can be achieved by integrally molding (metal).

[Brief description of drawings]

FIG. 1A is a plan view of an embodiment of the present invention, and B is a sectional side view thereof.

[Explanation of symbols]

 1 ... Reel stand main body, 2 ... Crow, 3 ... Spring, 4 ... Cap, 5 ... Photocoupler, 6 ... Reflector plate, 7 ... Polyslider washer, 8 ... Chassis, 9 ... Reel shaft, 1-1 ... Reel body Gear part, 1-2 ... Hole in reel body.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuhiko Izumi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Ltd.

Claims (2)

[Claims] 1. In an optical reel rotation detection having a photocoupler, a reel stand and a reflector, a reel stand main body is arranged between the reflector and the photocoupler, and a hole passing through the reel stand main body is provided. Characteristic rotation detection reel stand. 2. The rotation detecting reel stand according to claim 1, wherein a part of the reel stand is used as a non-reflective surface.