JPH05166253A - Tape deck - Google Patents

Abstract

PURPOSE:To enable the surer detection of the beginning and terminal ends of a tape by mounting a central prism for delivering the light of a light emitting body to both sides and both-side prisms for introducing this light to a light receiving body by turning the light emitting surfaces of the central prism at a prescribed angle. CONSTITUTION:The central prism 27 for delivering the light from the light emitting body to both sides and the both-side prisms 31, 32 for guiding this light to the light receiving body are provided. The light emitting surfaces 27a, 27b of the prism 27 and the prisms 31, 32 are formed by having 7 deg. angle with the X-axis passing the central part of the prism 27. The prism 27 is mounted by turning the prism 27 at the prescribed angle to the prisms 31, 32 side. Consequently, the light from the light emitting body progresses along the light emitting surfaces 27a, 27b of the prism 27 and, therefore, the light is received near the centers of the prisms 31, 32. As a result, the beginning and terminal ends of the tape are surely detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape deck incorporated in a video tape recorder for recording or reproducing data by mounting a video cassette, an audio cassette, a digital recording cassette or the like.

[0002]

2. Description of the Related Art Conventionally, there is a technique in which a transparent tape is continuously provided at the beginning and end of a magnetic tape, and light from a light emitter passing through the transparent tape is incident on a light receiver to detect the beginning and end of the magnetic tape.

In this case, a holder is erected on the wiring board,
A light-emitting body is attached to the holder so that the holder is arranged at substantially the same height as the tape, and a light-receiving body is provided on the deck chassis.

[0004]

In the prior art as described above, since the holder is erected on the wiring board and the light emitting body is attached to the holder and is arranged at substantially the same height position as the tape, the wiring board At the time of processing and assembling, there is a problem in structure and assembling work in that the holder protruding from the board is easily damaged and wiring for connecting the light receiving body provided on the deck chassis to the wiring board is required.

Further, in order to solve the above-mentioned problems, as in Japanese Patent Application No. 3-79492 "Tape Deck", which was previously filed by the present applicant, a light-emitting body and a light-receiving body which simply detect the beginning and end of the tape. In a tape deck equipped with a central prism for sending light from a light emitter to both sides and a double-sided prism for guiding light from the central prism to a light receiver, the central prism in the double-sided prism is adopted. There is a problem that the light received from the tape is not accurate, and in some cases the amount of received light is too small to detect the beginning and end of the tape.

The present invention has been made in view of the above circumstances, and it is possible to easily solve the problems of the structure and the assembling work and simplify the working and assembling work of the wiring board and the wiring. It is an object of the present invention to provide a tape deck that can easily reduce the occurrence of defective products and manufacturing costs and can reliably detect the beginning and end of the tape.

[0007]

In order to achieve the above object, the present invention provides a taper deck having a light-emitting body and a light-receiving body for detecting the start and end of the tape, and a central prism for sending light from the light-emitting body to both sides. And both side prisms that guide the light from the central prism to the photoreceptor,
It is characterized in that each light emitting surface of the central prism is attached to the corresponding prisms on both sides by rotating by a predetermined angle.

[0008]

With the above structure, by providing the central prism and the prisms on both sides on the deck chassis side, the light emitting body and the light receiving body can be directly attached and fixed to the wiring board. The work can be simplified and the wiring can be simplified, and the occurrence of defective products and the manufacturing cost can be easily reduced.

Further, in the double-sided prism, the light received from the central prism becomes accurate, the amount of light received increases, and it becomes possible to reliably detect the beginning and end of the tape.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a front view of a main part, FIG. 2 is a plan view of a VHS video tape recorder, FIG. 3 is a bottom view of a VHS video tape recorder, FIG. 4 is a plan view showing cassette mounting, and FIG. 5 is cassette mounting. It is a front explanatory view.

In the figure, 1 is a rectangular deck chassis in plan view, 2 is a rotatable head cylinder for mounting a recording / playback head, and 3 and 4 are slide bodies 7 and 8 which slide and guide via rails 5 and 6. Tape loading pins 10 and 11 for vertically mounting the magnetic tape 9a of the VHS video cassette 9 on the cylinder 2 and supplying and winding reel shafts for supporting the tape reel of the cassette 9 as an engaging shaft.
Reference numeral 2 is a head for inputting and outputting audio signals, 13 is an erasing head, 14 is a capstan, and 15 is a pinch roller.

Further, in the figure, 16 is a cassette holder for supporting the cassette 9, 17 and 18 are erected on the upper surface of the chassis 1 and left and right for movably mounting the cassette holder 16 at an insertion / removal position of the cassette 9 or a recording / reproducing position. Guide plate,
Reference numeral 19 is a tape running motor for rotating the capstan 14, 20 is a loading motor for driving the tape loading lever 21, the cassette loading gears 22, 22, and the like. The loading motor 20 slides the loading lever 21 to load the loading pin. The reciprocating motion of 3 and 4 and loading motor 2
The loading gears 22 and 22 are rotated forward and backward by 0 to reciprocate the cassette holder 16.

Further, as shown in FIGS. 1, 4 and 5,
A wiring board 23 for forming a recording / reproducing circuit and a motor control circuit is provided, and the board 23 is fixed to the lower surface of the chassis 1 with screws 24, and a light emitting diode 25 as a light emitting body and phototransistors 26, 26 as light receiving bodies are provided.
Are directly attached and fixed to the substrate 23.

A central prism 27 made of acrylic resin in the shape of a quadrangular prism is provided, and the central prism 27 is locked and fixed to the chassis 1 by a hook 28 provided by insert molding, and the lower end surface of the central prism 27 is the light emitting diode. 25 and the central prism 27
Left and right reflecting surfaces 29 and 30 are formed on the upper end of the light emitting diode 25 through the reflecting surfaces 29 and 30 of the central prism 27.
It is configured to send the light from the both sides.

Further, both side prisms 3 made of acrylic resin
1, 32, and both side prisms 31, 32 are locked and fixed to the outer surface of each guide plate 17, 18 through hooks 33, 33 integrally formed on the left and right guide plates 17, 18, respectively. Phototransistors 26, 2 on the end face
The cassette 9 at the recording / playback position is arranged to face 6
The light of the light emitting diode 25 is sent from the central prism 27 to the both-side prisms 31, 32 through the inspection holes 33a, 33a, 34, 34 of and the transparent tapes 35, 36 at the beginning and end of the cassette tape 9a, and the phototransistor 26. , 2
6 is made incident, and the end and the start of the tape 9a are detected.

Further, as shown in FIG. 1, each reflecting surface 29, 30 at the upper end of the central prism 27 is formed by intersecting in an X shape in a front view, and the inspection holes 3 on both sides of the cassette 9 are formed in a vertically long oval.
The upper and lower widths of the reflecting surfaces 29, 30 can be easily formed to be large by facing the upper and lower widths of 4, 34.
It is also possible to bend it into a crank shape like the prism 32 on the right side and extend it so as to bypass other parts.

By the way, the positional relationship between the central prism 27 and the two-sided prisms 31, 32 is the standard state as shown in FIG. 6 when seen in a plan view. That is, when the vertical axis is the Y axis and the horizontal axis is the X axis of the orthogonal axes passing through the center point O of the central prism 27, the two-sided prisms 31, 32 are inclined at an angle of 7 degrees (according to the JIS standard) with respect to the X axis. Installed.

Therefore, in the central prism 27, the light emitting surfaces 27a and 27b are also formed with an angle of 7 degrees with respect to the X axis (see FIG. 7). However, in this state, the light from the lower light emitting diode 25 shifts from the central point O of the central prism 27 and travels along the light emitting surfaces 27a and 27b, as indicated by the arrows A and B in the arrow. Will be condensed below the center thereof, and in the right prism 32, will be condensed above the center thereof.

That is, in this arrangement, the prisms 3 on both sides are
In the cases of 1 and 32, the light received from the central prism 27 is not accurate, and in some cases the amount of received light is so small that the beginning and end of the tape 9a cannot be detected.

Therefore, as shown by an arrow D in FIG. 8 from the state of FIG. 6, the central prism 27 is rotated clockwise by a predetermined angle (0.8 degrees in this embodiment) and attached (see FIG. 8). In this case, in the central prism 27, the light emitting surfaces 27a and 27b are respectively 7.8 degrees with respect to the X axis,
It becomes 6.2 degrees (see FIG. 9).

In this way, the light from the lower light emitting diode 25 travels along the light emitting surfaces 27a and 27b as shown by arrows E and F through the reflecting surfaces 29 and 30 of the central prism 27. In the case of 32, the light can be received exactly in the vicinity of the center thereof, and the tape start and end can be surely detected.

[0022]

As described above, according to the present invention, in a tape deck provided with a light emitting body and a light receiving body for detecting the end and beginning of the tape, a central prism for sending light from the light emitting body to both sides and a central prism. A prism on both sides that guides the light from the to the light receiver is provided, and each light emitting surface of the central prism is attached by rotating it to the corresponding prism on both sides by a predetermined angle, so that the central prism and the prisms on both sides are provided on the deck chassis side. As a result, the light emitting body and the light receiving body can be directly fixed to the wiring board, and the work of assembling and assembling the wiring board and the wiring can be easily performed, resulting in defective products and manufacturing cost. Can be easily reduced. Further, in the both-side prism, the amount of light received from the central prism can be increased, and the tape start and end can be reliably detected.

[Brief description of drawings]

FIG. 1 is a front explanatory view of a main part according to the present invention.

FIG. 2 is a plan view of a video tape recorder according to the present invention.

FIG. 3 is a bottom view of the video tape recorder according to the present invention.

FIG. 4 is a plan view showing mounting of the cassette according to the present invention.

FIG. 5 is a front view showing the mounting of the cassette according to the present invention.

FIG. 6 is an explanatory plan view of a main part in a comparison state according to the present invention.

FIG. 7 is an enlarged plan view of the central prism shown in FIG.

FIG. 8 is an explanatory plan view of a main part of an embodiment according to the present invention.

9 is an enlarged plan view of the central prism of FIG.

[Explanation of symbols]

 9a tape 25 light emitting diode (light emitting body) 26 phototransistor (light receiving body) 27 central prism 27a, 27b light emitting surface 31, 32 both-sided prism

Claims (1)

[Claims] 1. A tape deck comprising a light-emitting body and a light-receiving body for detecting the beginning and end of a tape, a central prism for sending light from the light-emitting body to both sides, and a double-sided prism for guiding light from the central prism to the light-receiving body. And with
A tape deck in which each light emitting surface of the central prism is attached to the corresponding prisms on both sides by rotating by a predetermined angle.