JPH01248381A - Tape guide for video cassette - Google Patents

Abstract

PURPOSE: To obtain an inexpensive tape guide which does not damage a tape or give bad influence on travelling of a tape or on the picture quality by using a glass having specified hardness. CONSTITUTION: Tape guides 8, 9 for a videocassette 1 are made of a tubular glass having 6.0 to 7.5Mohs' hardness scale. After a tubular glass is cut into specified length, the glass is subjected to hydrofluoric acid treatment to remove fins on the glass surface, namely the surface is made more smooth and the whole glass is made opaque. Thereby, the obtd. smooth glass does not damage a tape or give bad influences on the travelling property of a tape, which suppresses the production rate of dropout.

Description

[Detailed description of the invention] “Industrial Application Area The present invention relates to a tape guide for a video cassette.

[Prior Art] Generally, a video cassette has a feed reel and a take-up reel rotatably housed in a case, and a magnetic tape is guided between these reels by pins or tape guides protruding from the inner surface of the case. The vehicle travels along a predetermined travel trajectory at a constant speed.

[Problems to be Solved by the Invention] Conventionally, such tape guides have been manufactured using austenitic stainless steel or plastic. However, in the former case, the manufacturing cost is high and static electricity is easily generated, which causes deterioration of image quality.On the other hand, in the latter case, the surface is rough, which can damage the tape or disrupt the running of the tape. was there.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive tape guide for a video cassette that has a smooth surface and does not damage the tape or adversely affect tape running or image quality.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a bidet power setting tape guide with a hardness of 6.0 to 7 on the Mohs hardness scale.
．． Constructed of tubular glass with a hardness of 5. As a glass with such hardness, borosilicate glass is preferable, but
It is not limited to glass as long as it has a similar hardness.

During manufacturing, tubular glass is cut to a predetermined length and then treated with hydrofluoric acid (hydrogen fluoride) to remove the cast/edges on the glass surface, making the surface flatter and making the entire glass opaque. Color it.

[Function] The smooth glass used does not damage the tape and does not adversely affect the running properties of the tape, so the incidence of dropouts can be kept low. In addition to the above,
Since glass generates static electricity at a lower rate than other materials, such as stainless steel, there is less deterioration in image quality caused by it.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the plastic acid video cassette 1 is box-shaped, consisting of a cassette case 2 and a case cover (not shown) that covers the opening surface of the case 2.
Two glue bars 3 and 4 are rotatably housed in the case 2. One of the reels is a feeding reel 3 that feeds out the magnetic tape 5, and the other is a feeding reel 3 that feeds out the magnetic tape 5.
It is a take-up reel 4 for winding up.

A guide pin 6 is provided on the inner surface of the case 2.
The tape 5 that comes into contact with the guide pin 6 is unwound from the unwinding tape 3 while being lightly pressed by the flap 7.

The tape 5 is passed over two tape guides 8 and 9 which are erected on one edge of the case 2 and spaced apart from each other in the longitudinal direction of the case 2, and is guided by the guides. After that, the magnetic tape 5
The tape is wound onto the take-up reel 4 while in contact with a roller 10 rotatably provided near the tape guide 9.

The tape guide according to the present invention uses borosilicate glass, which has a hardness of 7 on the Mohs hardness scale, as its material. Then, the tubular glass is cut into a predetermined length using an appropriate cutting device, and its surface is processed. Then,
Finish the inner or outer surface of the tubular glass by treating it with hydrofluoric acid.

Figure 2 shows the roughness of the glass surface after hydrofluoric acid treatment.
As the surface roughness measuring device, a measuring device manufactured by Rank Teira Hovun was used. As a result, the surface roughness of the borosilicate glass tape guide was found to be less than 0.017zm.
This surface roughness is similar to that of previously used earthenitic stainless steels (for example, SUS 31 according to JIS standards).
No. 6 stainless steel) Acid tape guide surface roughness 0.5
~1.0Ij,m (see Figure 3) and surface roughness of a tape guide made of plastic (acetal copolymer) 0.5
~1.6 l11 (see Figure 4).

Furthermore, when the number of occurrences of dropouts was measured using video tapes using the above three types of tape guides, the results shown in Table 1 below were obtained. The values in the table are 5 μSe when the signal level is 20 dB or more lower than the reference value.
This is the total number of dropouts that occur in one minute, assuming that one dropout occurs during continuous time c. For the measurement, 50 video tapes were prepared, and the middle portion of the tape was measured, avoiding the ends of the tape that were directly connected to the reel.

Tue ↓ The videotape using the tape guide according to the present invention is
It can be seen from Table I that the incidence of dropouts is lower than when using other tape guides. This means that the tape guide has a smoother surface than other tape guides, so the tape runs more stably.

In addition to the above comparative tests, the repeated running time of the tape during fast forwarding and rewinding was measured. The measurement results are shown in Table II.

Table II From the table, it can be seen that the material of the tape guide itself does not affect the running of the tape.

[Effects of the Invention] In the present invention, glass with a hardness of 6°0 to 7°5 is used for the tape guide, so it is inferior in durability when compared to tape guides made using other materials. On the other hand, the unit price of the product can be kept low, and since static electricity is not generated, deterioration of image quality can be prevented. Furthermore, since the surface is smoothed by hydrofluoric acid treatment, the tape will not be damaged and stable tape running can be provided.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the inside of a video cassette using the tape guide according to the present invention, Figure 2 is a graph showing the surface roughness y of the glass tape guide, and Figure 3 is the surface roughness of the stainless steel tape guide. FIG. 4 is a graph showing the surface roughness of a plastic tape guide. DESCRIPTION OF SYMBOLS 1... Video cassette, 2... Case, 3... Feeding reel, 4... Take-up reel, 5... Tape,
8.9... Tape guide patent applicant Niska Co., Ltd. Agent
Patent Attorney 2 1) Yong Some Ohashi Kunihiko Koyama Yu

Claims (3)

[Claims] (1) In a video cassette equipped with a tape guide that guides a magnetic tape running between two reels, the tape guide has a hardness of 6.0 to 7 on the Mohs hardness scale.
A tape guide for a video cassette, characterized in that it is formed of glass having a hardness in the range of 5. (2) The video cassette tape guide according to claim 1, wherein the glass is borosilicate glass. (3) The video cassette tape guide according to claim 2 or 3, wherein the glass is tubular and has an inner or outer surface treated with hydrofluoric acid.