JPH103773A - Tape cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make detection light emitted from a light emitting portion of a photo sensor for detecting a tape end provided in a recording / reproducing device to be reflected by a reflection surface of a photo-derivative and to be accurately directed to a light receiving portion. . SOLUTION: The tape cartridge 1 is an optical derivative of a plastic molded article having a reflecting surface 13a for reflecting a detection light 201c emitted from a light emitting portion 201a of a photo sensor 201 provided in a recording / reproducing device toward a magnetic tape 4. 13 is provided. The light derivative 13 is formed in a convex shape immediately after molding so that the reflecting surface 13a becomes a flat surface due to contraction after molding, and before contraction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cartridge in which a magnetic tape is run by a driving belt or the like.

[0002]

2. Description of the Related Art As a tape cartridge in which a magnetic tape is run using a drive belt, an external storage medium of a computer, for example, a tape cartridge used for backup of a personal computer or an office computer is known. . The tape cartridge is generally called a data cartridge, and is used by being loaded into a recording / reproducing device such as a data backup device connected to the device main body of the computer, and uses the data signal stored in the memory of the device main body. It records or supplies the recorded data signal to the memory of the device main body.

As the above-mentioned tape cartridge (hereinafter, referred to as a data cartridge), a large type and a mini type are known. The data cartridge has a light derivative (end sense mirror) that reflects the detection light emitted from the light emitting unit of the photo sensor for tape position detection provided in the recording / reproducing device toward the light receiving unit. The detection light reflected by the reflecting surface of the light derivative is applied to the magnetic tape, and the detection light transmitted through the detection light transmitting portion provided at the start end or the end of the magnetic tape is received by the light receiving portion. Is detected at the beginning, end or type.

FIG. 9 is a sectional view of a main part of a large type data cartridge (hereinafter referred to as DC).
The detection light 202 emitted from the first light emitting unit 201a is D
The light enters the DC 301 from the detection light transmitting portion 303 provided on the cover 302 of the C 301, is refracted at substantially a right angle by the reflection surface 305 a of the light guide 305 attached to the base plate 304, and hits the magnetic tape 306. Then, the magnetic tape 306 runs, and the magnetic tape 3
06, the detection light transmitting part 307 is provided with the light derivative 305.
Comes to the position of the optical axis of the detection light 202 reflected by the reflection surface 305a of the magnetic tape 306.
, And through the detection light transmission portion 308 provided on the cover 302, and is received by the light receiving portion 201b of the photosensor 201.

FIG. 10 is a sectional view of a main part of a mini-type data cartridge (hereinafter, referred to as MDC).
01 is emitted from the light emitting unit 201a of MDC
Detecting light transmitting portion 3 provided on base plate 304 of 301
03 to the MDC 301 and the base plate 30
The light guide 305 is refracted at a substantially right angle by the reflection surface 305 a of the light guide 305 and hits the magnetic tape 306. When the magnetic tape 306 travels and the detection light transmitting portion 307 provided on the magnetic tape 306 comes to the position of the optical axis of the detection light 202 reflected by the reflection surface 305a of the light guide 305, the detection light 202 transmits through the detection light transmission portion 307 of the magnetic tape 306 and transmits through the detection light transmission portion 308 provided on the cover 302, and is received by the light reception portion 201 b of the photosensor 201. I have.

[0006] The derivative 305 is formed by injection molding a transparent plastic, and has a reflecting surface 305.
In a, a reflective film layer (not shown) is provided by a method such as hot stamping of an aluminum foil.

[0007]

By the way, as shown in FIG. 11, the reflection surface 305a of the light derivative 305 is often concave due to thermal contraction after injection molding or so-called sink mark. A shift occurs in the direction of the detection light 202 reflected by the reflection surface 305a, and
The tape position cannot be detected because it cannot be accurately reflected toward b, or the detection light 202 is irregularly reflected on the reflection surface 305a, so-called insufficient light quantity, so that accurate detection cannot be performed. In some cases, the product yield is low and the product cost is high. The present invention has been made to solve the above-mentioned conventional problems.

[0008]

SUMMARY OF THE INVENTION The present invention provides an optical derivative of a plastic molded article having a reflecting surface for reflecting a detection light emitted from a light emitting portion of a photo sensor provided in a recording / reproducing apparatus toward a magnetic tape. In the tape cartridge provided, the light derivative was formed such that the reflection surface became flat by shrinkage after molding.

[0009]

FIG. 1 is a perspective view of an MDC 1. FIG. The MDC 1 is formed by mounting a synthetic resin cover 3 on an aluminum base plate 2.

FIG. 2 is an exploded perspective view of the MDC 1. The base plate 2 includes a first reel 5 and a second reel 6 for winding the magnetic tape 4, and a first tape guide 7 for guiding the winding of the magnetic tape 4 to the first reel 5. A second tape guide 8 for guiding the winding of the magnetic tape 4 onto the second reel 6;
A drive roller 9 disposed between the tape guide 7 and the second tape guide 8, a drive belt 10 in a loop shape driven by the drive roller 9, and the drive belt 10 A first corner roller 11 in pressure contact with the peripheral surface, a second corner roller 12 in pressure contact of the drive belt 10 with the peripheral surface of the second reel 6, and detection light to be described later. And a light derivative 13 for guiding.

The cover 3 includes the first and second reels 5 and 6, the first and second tape guides 7 and 8, the drive roller 9, the drive belt 10, the first and second corner rollers 11, 12, and mounted on the base plate 2 with screws 14... So as to cover the light derivative 13 and the like.

A head insertion portion 21 is provided at one side of the front side of the cover 3 and at a position corresponding to the notch 2a for inserting the head of the base plate 2, and the drive roller 9 is provided at a center portion. A cutout window 22 for exposing is provided, and a detection light transmitting portion (window) 23 and an erroneous recording prevention member 24 are attached to the other end. A lid 25 is rotatably attached to the head insertion section 21, and the lid 25 is urged by a torsion coil spring 26 in a direction to close the head insertion section 21. As shown in FIG. 3, the light guide 13 has the detection light transmitting portion (window) 23 sandwiched between the magnetic tape 4 and the detection light transmitting portion (window) 23 provided on the cover 3. The detection light transmission portion (notch portion) 2b provided on the base plate 2 is opposed to the detection light transmission portion (notch portion) 2b. The detection light transmission portion (notch portion) 2b is mounted on the base plate 2 in a closed state.

As shown in FIG.
Consists of a tapered portion 13b provided with a reflection surface 13a and a base portion 13c connected to the lower end of the tapered portion 13b. Positioning recesses 13d... 13d are provided at both ends of the base portion 13c. The projections 13e... 13e and the recesses 13d... 13d and the projections 13e.

The light derivative 13 is formed by injection molding a highly transparent plastic, for example, a polycarbonate resin. Reflection surface 1 of light derivative 13
FIG.
As shown in FIG. 5A, the reflective surface 13a has a convex shape and shrinks due to heat radiation. Then, as shown in FIG. 5B, the reflective surface 13a becomes a flat surface (flat surface). ing. After the reflecting surface 13a has become a flat surface, a reflecting film layer (not shown) is provided on the reflecting surface 13a by hot stamping an aluminum foil or the like.

FIG. 6 is a cross-sectional view of a mold structure for forming the photo-derivative 13. The mold structure 101 is
The lower molds 102 and 103 and the upper and lower molds 10
A pair of left and right slide dies 1 arranged between the two
04 and 105.

The pair of left and right slide dies 10
The inner surface 105a of the mold (cavity) that forms the reflection surface 13a of the light derivative 13 of one of the slide molds 105 of the slide mold 105 is formed in a concave shape. The reflecting surface 13a of the derivative 13 is formed in a convex shape.

The concave amount of the concave mold inner surface 105a is determined by considering the material of the light guide 13, the thickness of the tapered portion 13b, the size of the reflective surface 13a, and the like. It is set to a value that results in a flat surface when contracted. In the case of the embodiment, the light derivative 13 is formed of a polycarbonate resin. The thickness T of the tapered portion 13b is 0.7 mm, and the size of the reflection surface 13a is about 9.86 mm in vertical width W2 and about 4.0 mm in horizontal width W2 (see FIG. 4). . The dimensions and shape of the concave mold inner surface 105a in the case of the embodiment are as shown in FIG. 7 when a virtual plane connecting the four sides constituting the reflection surface 13a is set to 0 (zero). The peak value H of the unevenness is set to be a spherical R shape (spherical shape) of 1/500 to 1/100 mm. As shown in FIG. 3, the light emitting section 20 of the photo sensor 201 provided in the recording / reproducing apparatus (not shown) for detecting the tape start and end or the type of the magnetic tape 4 is shown.
1a is located below the detection light transmitting portion (notch portion) 2b provided on the base plate 2 of the MDC 1, and the light receiving portion 201
b is located in front of the detection light transmitting portion (window) 23 provided on the cover 3 of the MDC 1.

The MDC 1 of the embodiment has the above-described structure, and the shrinkage after molding the light derivative 13 causes the reflection surface 13a
In consideration of the above shrinkage, it was formed so as to have a convex surface before shrinking so that the reflecting surface was prevented from becoming concave due to shrinkage after molding as in the conventional light derivative 13. I do. Then, as shown in FIG. 3, the detection light 201c emitted from the light emitting portion 201a of the photo sensor 201 of the recording / reproducing apparatus is reflected by the reflection surface 13a
At a right angle, is reflected toward the magnetic tape 4, passes through a detection light transmitting portion (hole) 41 provided on the magnetic tape 4, is received by the light receiving portion 201 b, and is The start and end or the type of tape are detected.

In the above embodiment, the MD having a V-shaped cross section is used.
Although the light derivative 13 of C1 has been described, as shown in FIG. 8, a so-called prism type light derivative 1 having a triangular cross section used for DC (large type data cartridge).
The present invention is also applied to 3 and the like.

[0020]

As described above, in the tape cartridge of the present invention, when the light derivative is molded from plastic, the reflection surface of the light derivative is formed so as to be convex immediately after molding. The convex reflective surface is recessed and flattened when contracted by heat radiation, so when using an optical derivative, the reflective surface is flat and emits from the light emitting part of the photo sensor. The reflected detection light can be accurately reflected toward the light-receiving part without irregular reflection, and the detection performance of the tape end and the like can be improved, and the workability such as hot stamping of the aluminum foil on the reflection surface is improved. As a result, there is an effect that an inexpensive and high-performance product can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view.

FIG. 2 is an exploded perspective view.

FIG. 3 is a sectional view of a main part.

4 (A) is a plan view of a photo-derivative, FIG. 4 (B) is a side view thereof, and FIG. 4 (C) is a front view thereof.

5A is a cross-sectional view of a photo-derivative before contraction, and FIG. 5B is a cross-sectional view after contraction.

FIG. 6 is a sectional view of a mold structure.

FIG. 7 is a sectional view of a main part of a mold.

8A is a cross-sectional view of another embodiment before contraction, and FIG. 8B is a cross-sectional view after contraction.

FIG. 9 is a sectional view of a main part of a conventional example.

FIG. 10 is a sectional view of a main part of a conventional example.

FIG. 11 is a sectional view showing a problem of the conventional example.

[Explanation of symbols]

1 ... tape cartridge (data cartridge), 4 ...
Magnetic tape, 13: optical derivative, 13a: reflective surface, 201
... Photosensor, 201a ... Light-emitting unit, 201b ... Light-receiving unit, 201c ... Detection light.

Claims (1)

[Claims] 1. A tape cartridge provided with a light guide of a plastic molded article having a reflecting surface for reflecting a detection light emitted from a light emitting portion of a photo sensor provided in a recording / reproducing device toward a magnetic tape, A tape cartridge, wherein the derivative is injection-formed so that the reflective surface becomes flat by shrinkage after molding.