JPS6271077A - Cartridge for storing recording medium - Google Patents

Abstract

PURPOSE:To detect optically various information with high precision by setting the surface roughness of each of entrance and exit transmission faces and the reflecting face of a prism provided in a main body case to <=0.1mum in terms of Ra value. CONSTITUTION:When a magnetic tape cartridge is loaded to a player, the detecting light emitted from a light emitting element 36 is made incident on the entrance transmission face 33a of a prism 33 through a through hole 35. This incident light 36a has the optical path changed at 90 deg. by each of the first and second reflecting faces 33b and 33c and is emitted to the side from an exit transmission face 33d in parallel with the incident light 36a. A through hole 38 is formed in a position facing the exit transmission face 33d on a case side wall 12, and an exit light 36b is transmitted through a tape 2 and is exposed to the outside of the case through the through hole 38 and is detected by a photodetecting element 37 in the player side. In this case, the surface roughness of each of the entrance transmission face 33a, the first and second reflecting faces 33b and 33c, and the exit transmission face 33d is set to <=0.1mum in terms of center line average roughness Ra value.

Description

[Detailed Description of the Invention] [Industrial Application Fields] 1. The second invention is to provide an optical path changing means (prism) for optically detecting the edge of a magnetic tape, for example in a magnetic tape cartridge, within the main body case. It relates to a cartridge containing a recording medium.

Information detection here is not limited to detecting the edge of a magnetic tape;
It broadly includes detection of the presence or absence of a detection hole opened in the main body case of a magnetic tape cartridge and/or magnetic disk cartridge to prevent accidental erasure, and various detections such as the quality of the magnetic tape or magnetic disk.

[Conventional technology]

Magnetic tape cartridge or magnetic disk cartridge 2.
Some cartridges that house recording media such as DVDs have already been proposed that are equipped with optical path changing means such as prisms inside the main body case in order to optically detect various information about the built-in recording media on the player side. ing. For example, Japanese Utility Model Application No. 53-99122, No. 58-724
Publication No. 0.

This is recognized in Publication No. 59-135580.

For example, as a method for detecting the tape end of a magnetic tape cartridge as shown in FIG. 1, optical path changing means (hereinafter referred to as prisms) 33 made of a transparent material are installed on the left and right of the front end inside the main body case 1, as shown in FIGS. 1 and 2. Equip. When the two-body case l is loaded into the player, detection light is incident on the prism 33 from the light emitting element (external light source) 36 provided on the player side through the transparent through hole 35 in the side wall 12 of the main body case l. Make it. In FIG. 2, after the incident light 36a passes through the entrance transmission surface 331 of the prism 33, the optical path is changed by 90 degrees at the first and second reflection surfaces 33b and 33C, and from the exit transmission surface 33d to the input The light is emitted toward the outside of the main body case 1 in parallel with the emitted light 36a. Next, the emitted light 36b is directed to the front side of the exit transmission surface 33d of the prism 33? After passing through the tape located here (the magnetic tape and the transparent leader tape connected to its terminal), it is exposed to the outside through the through hole 38 formed in the side wall 12 of the case, and is transmitted to the light receiving element 37 of the player 1. It has been detected as an error.

The light receiving element 37 receives the emitted light 36b after passing through the magnetic tape and the 1.1-dar tape, which have different transparency, that is, light transmittance.
By detecting the difference in the amount of light, the magnetic tape and the leader tape can be distinguished, that is, the end of the magnetic tape can be detected.

[Problem that the invention seeks to solve]

In detecting the tape end as described above, in order to ensure detection accuracy, it is desirable to maintain a large difference between the amount of detection light after passing through the leader tape and that after passing through the magnetic tape. Therefore, it is necessary to set the light transmittance of the prism 33 to be high.

However, when the light transmittance is low, the attenuation rate of the transmitted light is large and the difference in the amount of detected light becomes relatively small, leading to erroneous detection.

However, conventionally, attention has been paid only to the material of the prism 33, and no attention has been paid to other factors that influence the light transmittance of the eye. Therefore, there is a problem in that highly accurate detection cannot be performed in some cases. A similar problem was observed in the conventional prism when detecting light in the above-mentioned erroneous erasure prevention means.

Therefore, the inventors of the present invention have repeatedly conducted various experiments and research on setting the light transmittance of the prism 33 to be high, and have found that the biggest factor affecting the light transmittance of the prism 33 is its transmission surface. I learned that it depends on the surface roughness of the opposite side. Incidentally, the influence of other factors 1, for example, the tilt angle of the reflective surface with respect to the optical axis of the incident light, on the molding accuracy is ±10
It only shows a relatively low value of around %.

Furthermore, the inventors of the present invention conducted the following experiment to determine the surface roughness of the transmitting surface and reflective surface that is desirable for setting the light transmittance of the prism 33 to be high.

That is, a transparent synthetic resin prism A-B-ct having the same shape as the prism 33 shown in FIGS. 1 and 2 is made,
Magnetic tape cartridge? Detection of magnetic tape steel was carried out.

Here, the transmission surfaces ad of prisms A and B-C.

The reflective surfaces b-c are the entrance and exit transmission surfaces 33a and 33d of the prism 33, and the first and second reflective surfaces 33b and 33, respectively.
c, and these surface roughnesses were set to the values shown in Table 1 below. However, the display is based on the center line average roughness value Ra
(μm). The optical transmittance of the magnetic tape and leader tape used as samples were set to about 60% and about 5%, respectively, which are the lowest values in the standards related to magnetic tape edge detection, and the experiment was conducted under the worst conditions. Light transmittance is based on a glass prism (1
00%).

The light transmittance of the prism according to the tape end detection related standards mentioned above is 50% or more, which is satisfactory according to the specifications of prism B and prism C.

Table 2 below shows the false detection rate (%) when magnetic tape ends are experimentally detected by loading a magnetic tape cartridge incorporating prism A-B-C with the above specifications into a player.
shows.

According to Table 2, Prism B caused false detection even though it satisfied the standard light transmittance. This is due to other factors that affect the light transmittance of the prism, such as the above-mentioned error in the forming accuracy of the reflecting surface, or the accuracy of the assembly of the prism 33 to the main body case 1.

From the above experimental results, the entrance and exit transmission surfaces 33a and 33d of the prism 33 and the first and second reflection surfaces 33b and 33C
The individual surface roughness at Ra value is 0.1 μm.
It can be seen that if the following conditions are used, the light transmittance of the prism can be set high and detection can be performed with high accuracy.

〔the purpose〕

The present invention was proposed based on such knowledge, and
By focusing on the surface roughness of the transmitting surface and reflective surface of the prism and setting the light transmittance of the prism to be high, various types of information can be optically detected with high precision. The purpose is to provide a cartridge containing a recording medium.

[Means for solving problems]

That is, one aspect of the present invention is, for example, as shown in FIG.
3a and 33d and the first and second reflective surfaces 33b and 33c are characterized in that each surface roughness is set to an Ra value of 0.171 m or less. however.

It goes without saying that the present invention envisages that the entrance transmission surface 3Sa and the exit transmission surface 33d are formed on the same plane, as seen in the so-called triangular prism l.

The material of the prism 2 may be one with high light transmittance, such as transparent glass or transparent synthetic resin, but in reality, it is preferable to mold it integrally with the material inside the main body case l to save time and effort when assembling it. Therefore, in that respect, it is particularly meaningful to use synthetic resin.

〔effect〕

According to the present invention, the light transmittance of the prism 33, which is the optical path changing means, can be set high, so that the difference in the amount of light between the incident light 36a and the output light 36b described above can be increased, thereby reducing the risk of false detection. This means that various types of information can be detected with high precision.

[Embodiment 1] FIGS. 1 to 5 illustrate a digital recording/playback type audio magnetic tape cartridge as a first embodiment of the present invention.

In FIGS. 2 and 3, reference numeral 1 denotes a main body case formed by screwing together upper and lower plastic cases 1d and 1b in a lid-like manner. There are tapes 2 on the left and right inside of the main body case 1.
It has hubs 3,3 around which it is wound. These hubs 3, 3 are inserted into the left and right drive shaft insertion holes (
(not shown) and can rotate.

Chive guide members 5 are installed on the front left and right sides of the main body case 1. The tape 2 is led out from one hub 3 to the front of the case via these guide members 5, 5, and is wound around the other hub 3. The upper wall 6 of the main body case 1 has a transparent window 7 extending approximately between the left and right sides of the rear half. The amount of tape wrapped around each hub 3 can be visually confirmed through the transparent window 7.

As shown in FIG. 2, a tape loading pocket 8 is recessed in the front surface of the main body case 1. The front and lower portions of this pocket 8 are open.

The main body/case 1 has a front cover 9 on the front side. The front cover 9 is pivotally attached to the main body case 1 so that the front side thereof can be rotated between a closed position (when not in use) and an upward open position (when in use). That is, the left and right pieces 10.1 of the front lid 9
As shown in FIG. 4, the drive shaft 11 is rotatably supported at the front ends of the left and right side walls 12 of the main body case 1.

A shutter 13 is attached to the lower surface of the main body case 1 so as to be slidable back and forth. When the shutter 13 is not in use, it moves forward from the position in use shown in FIG. 4 and closes the lower surface of the opening of the pocket 8 and the drive shaft insertion hole. Note that through holes (not shown) are provided on the left and right sides of the lower surface 14 of the shutter 13, and these through holes are located directly below the drive shaft insertion hole during use.

The main body case 1 is provided with a plate 15 which also serves as a component of the transparent window 7 and a brake member 16 as means for preventing the left and right knobs 3 and 3 from rotating when not in use.

In FIG. 5, the plate 15 is composed of a main body plate part 17 and a transparent window plate part 18 integrally connected to the rear thereof,
2 For example, AS, which has a light acceptance rate almost equivalent to that of transparent glass.
Made of transparent synthetic resin such as resin or acrylic. The main body plate portion 17 has a slit-shaped opening 1 extending from left to right in the front-back direction.
9 and 19 are formed, and the main body plate portion 17 is divided into three division pieces 17a, 17b, and 17c at these openings 19 and 19.

The plate 15 is fixed to the inner surface of the case upper wall 6 by, for example, ultrasonic welding, such that the window plate portion 18 tightly fits into a window 20 provided through the plate.

To this end, the window plate portion 18 has a welded portion 21 on its periphery that is butted against the periphery of the window 20 . Also.

Welded parts 22 and 23 having the same height as the welded part 21 are formed at the front and rear ends of the upper surfaces of the left and right divided pieces 17a and i7c, respectively, and these welded parts 22 and 23 are connected to the case upper wall 6.
It is welded while it is in contact with the inner surface of the Center split piece 1
The front end of 7b is fitted into a wall member 21 projecting from the upper case la, as shown in FIG. The wall member 24 similarly protrudes from the T case 1, and its front end is clamped and fixed between both wall members.

The brake member 16 has a horizontal plate portion 25 that is horizontally elongated on the left and right as a main body, and has a concave shape with legs 26 integrally hanging from the left and right end surfaces of the main body. A certain amount of Smiloaf is inserted into the gap formed in between so that it can be slid back and forth. The lower ends of the legs 26, 26 are supported on the inner bottom surface of the main body case, and come into contact with the inner surfaces of the left and right side walls 12, 12 of the main body case 1, thereby preventing the brake member 16 from rattling in the vertical and horizontal directions. are doing. At the lower ends of the legs 26, 26 are guides 27 that are long in the front and back direction.
- 27 is integrally formed, and brake release winds 28, 28 are formed at the front end thereof.

The brake member 16 is made of polysecure resin or the like.

Recesses 2 are provided on the left and right rear ends of the horizontal plate portion 25 of the brake member 16.
9 and 29 are provided, and the engaging piece 3 is inserted from the concave formation of each concave portion 29 and 29.
0.30 backwards in succession. A spring member 31 is hooked between the upper wall 6 of the case and the horizontal plate portion 25, and the entire brake member 16 is moved to a braking position on the rear side of the case by the spring member 31.

Always energized to slide. When the brake member 16 is not in use, it is in the braking position shown in FIG. The hubs 3, 3 are engaged with each other, thereby preventing the hubs 3, 3 from idling when not in use.

When the tape cartridge is inserted into the player's holder G in a horizontal position, for example, a member on the player side first slides and displaces the shank 13 toward the rear of the case as shown in FIG.
Now the bottom of pocket 8 has an opening T. From this state 4;
When the player is pushed down to the load position, a member on the player's side comes into contact with the front lid 9 and rotates it to open upward. Then, the tape loading pin on the player side enters the pocket 8, and the drive shaft enters the conversion hubs 3, 3 from below.

As the front cover 9 is rotated to open upward, the brake release molds 28, 28 of the brake member 16 are pulled out forward. Therefore, the engagement between the engagement pieces 3θ, 30 and the engagement portion 32 is released, and each hub 3, 3 becomes in a free rotation state.

Now, the left and right divided pieces 17a and 17c of the plate 15
A prism, z 33-.33, is integrally molded at the front end of the .

In FIG. 1, each prism 33 has a front end protrusion 34a.
It has an L-shape with a hanging portion 34b extending downward from the inner end surface of the protruding portion 34a. The outer end surface of each front end protrusion 34a facing the case side wall 12 is the inlet transmission surface 3.
3a, and the case side wall 12 has the inlet permeable surface 33.
A through hole 35 is provided in a portion facing a. Projection part 3
The inner end surface of 4a and the inner end surface of the hanging portion 34b are first and second reflecting surfaces 33b and 33b, respectively, each having an inclination of 45 degrees.
33C, and the outer end surface of each hanging portion 34b is set as an exit transmission surface, 33d.

A light emitting element 36 and a light receiving element 37 are provided on the left and right sides of the player. Now, when the player is equipped with a magnetic tape cartridge, the detection light emitted from one light emitting element 36 passes through the through hole 35 and reaches the entrance transmission surface 33 of the prism 33.
incident on a. This incident light 36a is transmitted to the first reversal surface 33b.
, the optical path is changed by 90 degrees at the second reflecting surface 33C, and the light is emitted laterally outward from the exit transmission surface 33d parallel to the incident light 36a. A through hole 38 is formed in the case side wall 12 at a portion facing the exit transmission surface 33d, and the emitted light 36b passes through the tape 2+ and is exposed to the outside of the case through the through hole 38, where it is received by the player. It is detected by element 37. As a result, the end of the magnetic tape is detected as described above.

In such a magnetic tape cartridge.

Entrance transmission surface 33a First and second reflection surfaces 33b and 33c
! 3J and the exit transmission surface 33d are subjected to a canopy processing.

The surface roughness of each surface is set to an Ra value of 0.1 μm or less. Specifically, the prism molding surface portion of the mold is polished using diamond powders with different particle sizes (for example, particle sizes of 30, 10, and 6 (109 μm), starting from the largest particle size).1. A plate 15 with mirror-finished prisms was obtained using a mold.

In addition, the upper through hole when not in use:! 5 is closed by the side piece 10 of the front cover 9 in the closed position, and the lower passage hole 38 is closed by the forward movement of the shutter 13, and when not in use, dust and the like pass through these passage holes 35 and 38 to the case. This prevents the particles from entering the interior of the prism 33 and from adhering to the prism 33.

In this first embodiment, the prism 33 is molded integrally with the play 115 made of transparent synthetic resin in order to obtain the transparent window plate portion 18, so the number of parts can be reduced by nine.

The ease of assembly was improved and production costs were significantly reduced.

It should be noted that the prism 33 is not limited to that of the above-mentioned embodiment, and a single prism may be installed inside the main body case 1, its material may be transparent glass, and its shape may vary. The present invention can also be applied to a configuration in which the light emitting element 36 and the light receiving element 37 on the player side are located above or below the main body case l, which may be other than L-shaped, for example, a triangular prism.

[Embodiment 2] FIGS. 6 and 7 show a second embodiment of the present invention, in which a magnetic disk cartridge in which a magnetic disk 41 is rotatably housed inside a main body case 1 is provided.

There, a plurality of detection holes 40a and 40b are provided in the bottom wall 4 at the rear left corner of the main body case L to provide a function to prevent accidental erasure.
・40c and a through hole 35 in the left side wall 12 of the main body case 1
It is transparent. Then, the prism 33 is housed in the left rear corner of the main body case 1.

In such a case, when the magnetic disk drive or trifuji is loaded into the player, the light emitting element 36 provided on the player side is opposed to the outer side of the nine through holes 35 as shown in FIG. A light receiving element 37 faces directly below 40c. The detection light emitted from the light emitting element 26 passes through the through hole 35.
The incident light 36a enters the entrance transmission surface 33a of the prism 33 through the prism 33, and after the optical path is changed by 90 degrees at the first and second reflection surfaces 33b and 33c, it exits from the exit transmission surface 33d. be done. The emitted light 36b is transmitted through the detection hole 40a.
40b and 4Qc are used to expose the outside of the case to the light receiving element 37.
are detected respectively. that time.

By covering, for example, one of the plurality of detection holes 40a, 40b, and 40c, the magnetic disk 4
1 is in an erasable or non-erasable state. Selective viewing of these detection holes may be performed at the manufacturing stage of the main body case 1.

Some devices allow switching operations to be performed by the user.

Also in this case, the inlet transmission surface 33 of the prism 33
a, first and second reflective surfaces 33 b and 33 c.

The surface roughness of the protrusion surface 33d is Ra as in Example 1.
When the value was set to 0.1 μm or less, highly accurate detection was possible as in Example 1.

[Brief explanation of drawings]

1 to 5 show a first embodiment in which the present invention is applied to a magnetic tape cartridge. FIG. 1 is a sectional view taken along the line ■-■ in FIG. 2, and FIG. The plan view and FIG. 3 are external perspective views. FIG. 4 is a side view, and FIG. 5 is an exploded perspective view. 6 and 7 show a second embodiment in which the present invention is applied to a magnetic disk cartridge. FIG. 6 is a partially cutaway plan view, and FIG. 7 is a longitudinal sectional side view of the main part. 1... Main body case. 2...Tape. 3...Hub. 7...Transparent window. 15...Plate. 16...Brake member. 17... Body plate part of the plate. 18...Transparent window plate part of the plate. 33...Prism. 33a... Prism entrance transmission surface. 33b...first reflective surface of the prism. 33c...Second reflective surface of the prism. 33d...Exit transmission surface of the prism. 36... Light emitting element. 36a...Incoming light. 36b... Emitted light. 37... Light receiving element. Inventor Sumi B Takashi Thinking
Fuji b Japanese Butsuma Sei Sasaki Yudo Ke Toritake patent
Applicant Hitachi Maxell Co., Ltd. Agent Patent Attorney
Oriyose Samurai Figure 3 IQ M Figure 1 Figure 4

Claims (1)

[Claims] The optical path changing means 33 provided in the main body case 1 changes the optical path of the incident light 36a that enters the main body case 1 from an external light source and outputs the incident light 36a to the outside of the main body case 1.
In the cartridge containing a recording medium, the optical path changing means 33 includes an entrance transmission surface 33a that transmits the incident light 36a, and an entrance transmission surface 33a that allows various information detection to be performed by detecting the incident light 36b. The first and second reflecting surfaces 33b each change the optical path of the light after passing through by 90 degrees.
33c and an exit transmission surface 33d that transmits the emitted light 36b, and these entrance transmission surfaces 33a, first and second
A cartridge containing a recording medium, characterized in that the surface roughness of each of the reflective surfaces 33b and 33c and the exit transmitting surface 33d is set to a centerline average roughness Ra value of 0.1 μm or less.