JPH08315453A - Detector for transfer position of recording medium tape - Google Patents

Abstract

PURPOSE: To obtain a transfer position detector for a recording medium tape capable of obtaining a highly reliable detection signal and also reducing the number of components. CONSTITUTION: A white colored disk 30a is integrally provided on a rotary shaft 30, and plural through holes 31 successively arranged along the circumferential direction are formed on this disk 30a, and further a black fiber member 32 such as a felt, etc., provided at the upper surface side of the disk 30a so as to cover each hole 31, and a light emitting/receiving device 26 having a part for emitting the light toward the lower surface of the disk 30a and a part for receiving the reflected light of the disk 30a are furnished in the detector. And, the constitution is made so that the tape transfer position is detected by an output signal of the light emitting/receiving device 26 corresponded to the rotation of the disk 30a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium tape transfer position detecting device provided in a recording / reproducing apparatus using a magnetic tape as a recording medium.

[0002]

2. Description of the Related Art FIG. 8 shows a tape transfer portion of a recording / reproducing apparatus using a magnetic tape as a recording medium.
A tape supply reel is attached to the reel shaft 11 protruding from 0,
Tape reels are mounted on the reel shafts 12, respectively.

The magnetic tape delivered from the tape supply reel is transferred at a constant speed by the capstan 13 and the pinch roller 14, and in this case, the magnetic tape guided by the guide pin 15 is used. After being brought into contact with the magnetic head 16 to be magnetically recorded, it is guided by a guide pin 17 and wound by a tape winding reel. When the recorded magnetic tape is to be reproduced, the magnetic tape is rewound once and is sent out to the tape winding reel side at a constant speed as in recording.

Such a recording / reproducing apparatus detects where on the magnetic tape the information to be reproduced is recorded, and when the additional recording is performed, the recordable magnetic tape is used.
A detecting device is provided on a rotary shaft that rotationally drives the reel shaft 11 or 12 to detect the position of the reel.

That is, the tape amount (tape length) sent from the tape supply reel or the tape take-up reel is used to wind the tape from the number of rotations of the rotary shaft. By detecting the tape amount thus obtained, the transfer position of the magnetic tape required for recording or reproduction is searched.

FIG. 9 is a sectional view showing a rotary shaft portion for rotationally driving the tape winding reel. As shown in the figure, a columnar shaft rod 19 is fixed to a support plate 18 fixed to the device substrate 10, and a cylindrical rotary shaft 20 is rotatably provided on the shaft rod 19.

The rotary shaft 20 has the reel shaft 12 fixedly attached to an upper portion of the rotary shaft 20 projecting from the apparatus substrate 10 so as to rotate the reel shaft 12 integrally. As shown in FIG. 10, a disc 20a is integrally formed, and further, a Jemmenster-21 is fixed to the lower surface of the disc 20a.

The J-Menster-21 has a circular reflecting plate made of an aluminum plate or the like, and black portions 21a are radially provided on the circular reflecting plate. The black portions 21a are colored at equal intervals by printing means or the like.

The rotating shaft 20 is a disk 20a.
A friction plate (felt) 22 is provided on the upper surface of the
It is connected to the interlocking gear 23 via 2. That is, in the interlocking gear 23, the bearing portion 23b formed to project from the central convex portion 23a is rotatably supported by the rotating shaft 20, and the friction plate 22 is in contact with the inner surface of the convex portion 23a.

The interlocking gear 23 is formed as a gear on the outer circumference, and this gear meshes with the output gear 25 of the motor 24 and is interlockingly driven.

Further, a light emitting / receiving device 26 having a light emitting element and a light receiving element is arranged opposite to the above-mentioned Ge-Menster-21, and the light-receiving / emitting unit 26 outputs a pulse in accordance with the rotation of the Ge-Menster-21. . The light receiver / receiver 26 is fixed to a part of the device, and the light receiver / receiver 26 and the dimester 21 constitute a detector.

In this rotary shaft mechanism, the interlocking gear 23 is rotated by the rotational driving of the motor 24, and the disk 20a is interlockedly rotated by the rotation of the interlocking gear 23 through the friction plate 22, so that the rotary shaft 20 is rotated. The reel shaft 12 is rotated to drive the reel shaft 12, and the tape winding reel winds the magnetic tape.

In this case, the interlocking gear 23 rotates at a constant angular velocity by the motor 24, while the angular velocity of the rotary shaft 20 changes depending on the winding amount of the magnetic tape transported at a constant velocity. This difference in angular velocity is corrected by the rotational deviation caused by the friction plate 22.

From this, the transfer amount of the magnetic tape is quantified by the number of rotations of the rotary shaft 20 from the start of winding, so that the magnetic tape can be detected by detecting the number of rotations of the rotary shaft 20. It is possible to search the transfer position of the.

In the detection device, the light emitting element of the light receiving and emitting device 26 projects the light toward the memester 21 and the light reflected by the reflecting portion of the memester 21 is the light receiving element of the light receiving and emitting portion 26. Is received by.

As a result, since the pulse signal corresponding to the rotation of the rotary shaft 20 is output from the light receiver / receiver 26, the transfer position of the magnetic tape can be detected by knowing the number of pulses of this pulse signal. .

[0017]

SUMMARY OF THE INVENTION In the above-described conventional detection device, the Gemenster-21 is prepared as a separate component,
This had to be attached to the disk 20a of the rotary shaft 20 using an adhesive or the like, and it was necessary to improve the number of parts and the assembly work.

Further, the above-mentioned detecting device is a Gemenster
There is a problem that it is not possible to increase the signal ratio of the pulse signal output according to the reflecting portion and the non-reflecting portion 21.

In other words, when the 26 light emitting elements of the light receiver / receiver are considered as point light sources, the reflected light reflected when the light is projected from the point light source to the Jimenster-21 spreads at a constant angle. Therefore, the light receiving element receives the reflected light with a predetermined light receiving area, which causes the signal ratio of the pulse signal not to increase.

In view of the above situation, it is an object of the present invention to provide a transfer position detecting device for a recording medium tape which can obtain a highly accurate detection signal and can reduce the number of parts. And

[0021]

In order to achieve the above-mentioned object, the present invention detects and records the number of rotations of a rotary shaft for rotating a tape supply reel or a tape winding reel. In the detection device for detecting the transfer position of the medium tape, a disk member having at least one surface as a light reflecting surface is concentrically and integrally provided on the rotation shaft, and the disk member has a circular shape. A plurality of through holes sequentially arranged along the circumferential direction are formed, and a light non-reflecting member provided on the other surface side of the disc member so as to cover each through hole and one surface of the disc member. The tape transfer position is detected by the output signal of the light receiving and emitting means corresponding to the rotation of the disc member. A detection device having the above-mentioned configuration is proposed.

Further, in the above-mentioned detecting device, there is proposed a detecting device having a structure in which a bay-shaped groove along the circumferential direction is formed between each through hole of the disc member.

[0023]

The light emitted from the light emitting portion of the light receiving and emitting means is reflected by the plate surface between the through holes of the disc member and is not reflected by the through hole portion of the disc member.

Therefore, since the light receiving portion receives only the reflected light from the reflecting surface portion of the disc member, the light emitting and receiving means outputs a highly accurate detection signal according to the rotation of the disc member.

Further, if the non-reflective member provided on the other surface side of the disc member is made of a black fiber member such as felt, the non-reflective member acts as a Jim Menster and a friction plate. There is no need to provide a separate Menster as in the example.

By providing bay-shaped grooves along the circumferential direction between the through holes of the disc member, the light emitted from the light emitting portion of the light receiving and emitting means to the disc member with a certain angle spreads out in a bay shape. Since the light is condensed by being reflected by the groove and is incident on the light receiving portion, it is advantageous in increasing the signal ratio of the detection signal output by the light receiving and emitting means and improving the reliability.

[0027]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a first embodiment and is a sectional view showing a rotary shaft portion of a tape winding reel. Since this drawing is a sectional view similar to FIG. 8 shown as a conventional example,
The same members are designated by the same reference numerals and the description thereof is omitted.

In this embodiment, the rotary shaft 30 having the structure shown in FIG.
It is characterized by having. That is, the rotary shaft 30 colors the disc (disc member) 30a white, and the disc 30a is formed with a plurality of through holes 31 radially formed at equal intervals.

In this embodiment, a black colored fiber member 32 made of felt or the like is provided as a friction plate. The fibrous member 32 is incorporated so as to be sandwiched between the disk 30a of the rotary shaft 30 and the inner surface of the convex portion 23a of the interlocking gear 23 so as to correct the deviation between the angular velocity of the rotary shaft 30 and the angular velocity of the interlocking gear 23. .

Black fiber member 3 incorporated as described above
Since 2 covers each through hole 31 of the disk 30a, in the disk 30a of the rotating shaft 30, the white portion serving as the inter-hole surface is the reflection area and the through hole portion is the non-reflection area.

Therefore, the reflected light is received by the light-receiving element of the light-receiving device 26 as the surface between the through holes of the disk 30a sequentially turns to the light-projecting path of the light-emitting element of the light-receiving device 26, and the light-emitting element of the light-receiving device 26 is also received. When the through-hole 31 sequentially turns on the light projecting path of, there is no reflection.

As is widely known, since the black fiber member 32 such as felt has a high light absorbing effect, the light radiated to the fiber member 32 through the through hole 31 is hardly reflected.

From this fact, the reflection and non-reflection of the light generated by the rotation of the disk 30a are discriminated as much as possible, so that the pulse signal of the light receiving and emitting device 26 which receives and outputs the reflected light is a distinct pulse. Become. As a result, the signal ratio of the pulse signal output by the light receiver / receiver 26 is large, and the pulse tape signal can be counted to detect the transfer position of the magnetic tape.

In the case of carrying out as described above, even if the disk 30a of the rotary shaft 30 is colored in black and the fiber member 32 is colored in white, the rotation of the disk 30a causes reflection and non-reflection of light. Can be carried out. Further, each through hole 31 of the disk 30a may be closed by a transparent plate material.

FIG. 3 shows a rotary shaft 40 shown as a second embodiment.
It is a perspective view of. The rotary shaft 40 is equipped with a disk 40a similar to the rotary shaft 30 of the first embodiment, and is characterized in that a bay-shaped groove 42 is formed on the surface between the through holes 41. The rotary shaft 40 is also assembled in the same manner as the rotary shaft 30 shown in FIG. 1 with the fiber member 32 interposed between the rotary shaft 40 and the interlocking gear 23.

As is apparent from FIGS. 4 to 7, the bay-shaped groove 42 is formed on the lower surface of the disk 40a along the circumferential direction, and cuts are formed between the through holes 41. It is a concave groove.

When the light emitting element 26a and the light receiving element 26b of the light receiving and emitting device 26 are arranged as shown in FIG. 4, that is, the light emitting element 26a and the light receiving element 26b are arranged in the diameter direction of the disk 40a. When they are arranged side by side at right angles, as shown in FIG. 5, they are formed as bay-shaped grooves 42 which are arc-shaped cut-out grooves centered on the light receiving portion of the light receiving element 26b.

When the light emitting element 26a and the light receiving element 26b of the light receiving and emitting device 26 are arranged side by side in the diameter direction of the disk 40a as shown in FIG. 6, as shown in FIG. And the light receiving portion of the light receiving element 26b as two focal points, the bay-shaped groove 42 formed of an oval cut groove.
To form as.

When such a bay-shaped groove 42 is provided on the disk 40a, the light projected from the light emitting element 26a with a certain angle spread is reflected by the bay-shaped groove 42 to be condensed and received. It is incident on 26b. As a result, the photoelectric conversion current of the light receiving element 26b increases, and the signal ratio of the detection signal output by the light receiving and emitting device 26 can be increased to improve the reliability.

Although each embodiment of the present invention has been described above, the fiber member covering the disk and the through hole is not limited to white or black, and one of them is a reflection surface and the other is a non-reflection surface. Other colors may be applied, and the disk may be colored on only one side thereof without coloring the entire surface. In the above embodiment, the table
Although the detection device provided on the rotary shaft of the tape winding reel has been described, the same can be applied to the rotary shaft of the tape supply reel.

[0041]

As described above, in the detecting device of the present invention, the disc member of the rotating shaft is configured to repeat reflection and non-reflection due to the surface between the through holes and each of the through holes. The accuracy of separating the reflected light and the non-reflected light of the projected light is high, and it is possible to detect the tape position with high accuracy by a simple signal processing means.

Further, since the bay-shaped groove is provided on the surface between the through holes provided in the disk member of the rotating shaft, the light emitted from the light emitting portion is condensed and received by the reflection of the bay-shaped groove. Thus, the detection signal level is increased to provide a highly reliable detection device with a large signal ratio.

Further, since the detecting device of the present invention does not require the Jimmenster which has been used conventionally, it is advantageous in terms of the number of parts and the assembling work.

[Brief description of drawings]

FIG. 1 is a sectional view showing a rotary shaft portion of a tape winding reel shown as a first embodiment.

FIG. 2 is a perspective view showing a rotary shaft of the first embodiment.

FIG. 3 is a perspective view showing a rotary shaft of a second embodiment.

FIG. 4 is a plan view showing a rotation shaft of a second embodiment.

5 is a partial cross-sectional view taken along the line AA in FIG.

FIG. 6 is a plan view showing a rotation shaft of another second embodiment.

7 is a partial cross-sectional view taken along the line BB in FIG.

FIG. 8 is a perspective view showing a magnetic tape transfer portion of the recording / reproducing apparatus.

FIG. 9 is a sectional view showing a rotary shaft portion of a tape winding reel shown as a conventional example.

FIG. 10 is a perspective view of a rotating shaft shown as a conventional example.

[Explanation of symbols]

 12 reel shaft 19 shaft rod 23 interlocking gear 26 light receiving and emitting device 30 rotating shaft 30a disk 31 through hole 32 fiber member 40 rotating shaft 40a disk 41 through hole 42 bay groove

Claims (3)

[Claims] 1. A detection device for detecting the number of rotations of a rotating shaft for rotating a tape supply reel or a tape winding reel to detect a transfer position of a recording medium tape, wherein the rotation is performed. The shaft is provided with a disk member having at least one surface having a light-reflecting surface so as to rotate concentrically and integrally, and a plurality of through holes sequentially arranged along the circumferential direction are formed in the disk member, Further, a non-reflecting member for light provided on the other surface side of the disk member so as to cover each through hole, a light emitting portion emitting light toward one surface of the disk member, and receiving reflected light on the one surface. And a light receiving and emitting means having a light receiving portion, wherein the tape transfer position is detected by an output signal of the light receiving and emitting means corresponding to the rotation of the disc member. 2. A structure in which at least one surface of the above-mentioned disc member is a non-reflecting surface of light, a member covering each through hole is a reflecting member of light, and the light emitting / receiving means receives the reflected light of the reflecting member. The detection device according to claim 1, wherein the detection device is provided. 3. The detection device according to claim 1, wherein bay-shaped grooves are formed along the circumferential direction between the through holes of the disc member.