JPH05210897A - Recording and reproducing device and revolving guide - Google Patents

Abstract

PURPOSE:To obtain a good jitter performance at a low cost by forming the roller of the revolving guide of a plastic resin and coating the outer peripheral surface of the roller with a metallic film. CONSTITUTION:This revolving guide 1 is constituted of the roller 3 which can rotate around a guide shaft 2 and an upper flange 4 and a lower flange 5 which hold this roller 3. The roller 3 is formed of a material having a small sp. gr. The metallic film, for example, chrome plating 12, is applied on the outer peripheral surface of the roller 3. The coefft. of friction of a tape and the roller 3 is made smaller than the coefft. of friction of the roller 3 consisting of polyacetal by the chrome plating 12. The flawing of the tape by the flanges 4, 5 is, therefore, decreased. The weight increase of the roller 3 by the chrome plating 12 is slight and the inertia force of rotation hardly changes. Then, the influence on the jitter is hardly generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape guide for a recording / reproducing apparatus such as a VTR or DAT, and more particularly to a rotary guide suitable for cost reduction and high image quality.

[0002]

2. Description of the Related Art In a recording / reproducing apparatus such as a VTR or DAT using a tape as a medium, a rotary guide having a flange is arranged near the inlet side and the outlet side of a drum device having a recording / reproducing head. As a material for the rollers of these rotary guides, a resin such as plastic is generally used for cost reduction. However, if you use resin rollers,
The coefficient of friction between the tape and the tape sliding surface of the roller increases, and the slidability deteriorates. Normally, the tape enters from the direction orthogonal to the guide axis of the rotation guide, but if the tape enters with a wrapping lead angle with respect to the guide axis due to an error or the like, the tape is separated from the tape by the rotation of the roller and the roller. The frictional force of the rotary guide causes the axial movement of the rotary guide. When the friction coefficient between the tape and the roller is high, the upper end surface or the lower end surface of the tape is strongly pressed against the flange, and the tape is easily damaged. In recent years, tapes have tended to become thinner due to longer recording time, and have become about 10 μm thick. For this reason, prevention of this damage has become an even more important issue. For such problems,
The conventional technique is to reduce the friction coefficient between the tape and the roller by using a material such as metal or ceramic having a good slidability with the tape, as described in JP-A-63-292448. Was there.

[0003]

The above-mentioned conventional example is based on the VT.
No consideration is given to the image quality performance and cost of R. V
In a tape traveling system in a magnetic recording / reproducing apparatus such as a TR, a tape corresponds to a spring, and a rotary inertia force such as a reel, a rotation guide, and a tension post in a tape cassette forms a vibration system corresponding to a mass. Therefore, when the tape runs, longitudinal vibration occurs in the running direction. Further, vibrations caused by the rotation of the drum motor, the capstan motor, and the mechanical elements add to the tape as a disturbance. When the frequency of these disturbances and the resonance frequency of the tape running system match, the longitudinal vibration of the tape becomes large, and the time-axis fluctuation of the reproduction screen, that is, the so-called jitter becomes very large.

The resonance frequency of the tape running system is usually in a high band with respect to the frequency of mechanical disturbance. However, if a metal roller having good slidability with the tape is used in the rotation guide in order to suppress the above-mentioned tape damage, the weight is large and the rotational inertia force is large as compared with the resin roller. The resonance frequency between the spring and the mass of the roller is lowered. For this reason, the resonance point of the tape running system becomes close to a relatively low frequency that matches the mechanical disturbance due to the drum motor, the capstan motor, etc., and the longitudinal vibration of the tape becomes large. Therefore, the jitter is significantly increased, and the screen is likely to be deteriorated. Further, the metal roller requires a cutting process due to its accuracy, which increases the cost. It is conceivable to use ceramics or the like for the roller as a material which is excellent in slidability with the tape and is lightweight, but the cost becomes higher than that of the metallic roller. Therefore, the present invention provides a rotation guide that can obtain good jitter performance at low cost while preventing the tape from being damaged at the flange.

[0005]

In order to achieve the above object, the present invention forms a roller of a rotation guide with a plastic resin and forms a metallic coating on the outer surface of the roller. Further, the bearing portion in contact with the guide shaft of the roller is formed of the first plastic resin having good slidability with the guide shaft, and the outer periphery of the bearing portion is made of the second plastic resin having good fixing property to the metallic film. Stack the rollers,
The outer surface of this roller is covered with a metallic coating.

[0006]

The tape sliding surface of the plastic resin roller is formed of a metallic film having a low coefficient of friction with the tape. Since the tape sliding surface is metallic, the transfer force that the tape receives in the axial direction of the rotation guide is small, and the upper and lower end surfaces of the tape are not damaged by the flange and the running state is not unstable. Since the metal film is thinly formed, the rotational inertial force of the roller is lower than that of the metal roller, so that the frequency of longitudinal vibration of the magnetic tape is high. For this reason, the influence on the jitter is reduced, and the screen shake is less noticeable. Furthermore, for the formation of the metal coating, for example, by performing a coating process such as plating or vapor deposition, it is cheaper than cutting a metal roller, and since the main body is plastic, for example, a molding process is possible, The cost can be kept low. Further, by forming the bearing portion in contact with the guide shaft of the roller with the first plastic resin having good slidability with the guide shaft, the roller rotates stably. Further, by stacking a second plastic resin roller having a good fixing property of the metallic film on the outer periphery of the bearing portion, it is possible to more reliably prevent the metallic film covering the outer surface of the roller from falling off. Can be prevented.

[0007]

Embodiments of the present invention will be described below with reference to FIGS. The present embodiment shows the case where the present invention is applied to an 8 mm VTR. FIG. 2 is an overall configuration diagram of a main part of a recording / reproducing apparatus using the present invention. In FIG. 1, 101 is a drum, 102 is a tape cassette having an opening 103, 104 and 105 are input side reels and output side reels, 106 and 107 are input side guide bases and output side guide bases, and 108 and 109 are Input side inclined pin, output side inclined pin, 1'1, respectively are input side rotation guide, output side rotation guide, 110 is capstan,
111 is a capstan motor, 112 is a pinch roller,
Reference numeral 113 is a chassis, 114 is an entrance side catcher, 115 is an exit side catcher, 116 is a tension pin, 117 is a tape pull-out guide, 118 is an impedance roller, 1
Reference numeral 19 is a head mounted on the drum 101, and 6 is a tape. At the time of loading, the inlet side guide base 104 and the outlet side guide base 105 move from the inside of the opening 103 of the tape cassette 102 toward the inlet side catcher 114 and the outlet side catcher 115, respectively. Along with this, the tape 6 in the tape cassette 102 is rotated by the rotation guide 1,
1'and the tilt guides 108, 109,
It is wound around the drum 101 at a predetermined angle. Further, the tension post 116 and the pull-out guide 117 also pull out the tape 6 from the tape cassette 102. Pinch roller 112
Holds the tape 6 and press-bonds it to the capstan 110 with a predetermined pressure. When the capstan 110 is driven by the capstan motor 111 to rotate, the tape 6 runs in the direction of arrow A during normal recording / reproduction, for example. The drum 101 rotates in the direction of arrow B, and the head 119 mounted on the drum 101 obliquely scans the tape 6 to record a signal on the tape 6 and reproduce the signal on the tape 6.

In the tape running system shown in FIG. 2, the tape 6 corresponds to a spring, and the reel 104 in the tape cassette 102,
105, the rotation guides 1 ′, 1, the capstan 110, the pinch roller 112, the tension post 116, the pull-out guide 117, and the impedance roller 118 form a vibration system in which the rotational inertial force corresponds to the mass. Therefore, when the tape 6 runs, longitudinal vibration occurs in the running direction.
Further, the vibration accompanying the rotation of the drum 101 and the capstan motor 111 is applied to the tape 6 as a disturbance. Longitudinal vibration of the tape 6 due to these causes becomes a time-axis fluctuation of the reproduction screen, so-called jitter. FIG. 3 is a view of the rotation guide 1 which is the object of the present invention as seen from the direction of arrow B in FIG. The rotation guide 1 is composed of a roller 3 rotatable around a guide shaft 2 and flanges 4 and 5 which are press-fitted and fixed above and below the guide shaft 2 with the roller 3 interposed therebetween. 4 is called an upper flange and 5 is called a lower flange. The gap between the upper and lower flanges 4 and 5 has a gap with respect to the width of the roller 3. Further, the above-mentioned interval has a constant gap with respect to the tape width. A case where the tape 6 enters the rotation guide 1 from a direction orthogonal to the guide axis 2 is shown by a dotted line 7 in the drawing. In this case, since the tape moving direction 8 and the roller rotating direction 9 coincide with each other, the tape and the roller run in close contact with each other, and the relative position does not shift.

Now, as a basic rule of tape regulation, it is the principle that the upper and lower ends of the tape are regulated alternately in the tape running system. Considering the rotation guide 1 on the output side in FIG. 2, the upper end surface of the tape 6 is restricted by the upper flange 4 in the width direction. In this case, as shown in the figure, the tape 6 must be inserted from the upper side by the angle θ as shown by the solid line of 10. The reason for this will be described below. Now, consider a point on the surface of the tape 6 at the position of the point a where the tape 6 is incident on the roller 3 of the rotation guide 1 and a point on the surface of the roller 3. It is assumed that, after a certain time, the point on the surface of the tape 6 at the position of the point a advances to the position of the point b along the traveling direction 8 ′ of the tape 6. At this time, the point on the surface of the roller 3 which was at the position of the point a advances along the rotation direction 9 of the roller and thus reaches the position of the point b ′. That is, the point on the surface of the tape 6 and the point on the surface of the roller 3 which overlap at the position of the point a are displaced by bb ′ in the axial direction of the rotation guide 1 after a certain time. Therefore, the tape 6 and the roller 3 generate a dynamic friction in the axial direction of the rotation guide 1, and the tape 6 receives a frictional force from the roller 3 in the direction of arrow A. This becomes the axial force of the rotation guide 1 applied to the tape 6 from the roller 3,
Further, the pressing force acts on the upper flange 4 of the tape 6. As a result, the upper end surface of the tape 6 contacts the upper flange 4 and its position is regulated. If the tape 6 enters the roller 3 from below as indicated by the alternate long and short dash line 11 the frictional force received by the tape 6 will act in the direction of the lower flange in the figure. Therefore, when the tape is to be regulated by the upper flange 4 in the rotation guide 1 as described above, the regulation force is reduced, and problems such as unstable running occur. Therefore, in order to secure the regulation force to the upper flange 4, a proper amount of this frictional force A is indispensable. However, if the friction coefficient between the tape 6 and the roller 3 becomes excessive,
The frictional force A also becomes excessive, and the upper end surface of the tape 6 is strongly pressed against the upper flange 4 and the tape is damaged.

FIG. 1 shows a sectional view of a rotary guide 1 according to an embodiment of the present invention. The rotation guide 1 is composed of a roller 3 rotatable around a guide shaft 2, and an upper flange 4 and a lower flange 5 which are press-fitted and fixed above and below the guide shaft 2 with the roller 3 interposed therebetween. In order to eliminate rattling in the thrust direction of the roller 3, the upper and lower surfaces of the roller 3, that is, the flanges 4, 5,
A protrusion 3'is provided on the surface facing the. here,
The roller 3 is formed of a material having a small specific gravity, such as polyacetal resin. A metal film, for example, chrome plating 12 is applied to the outer peripheral surface of the polyacetal resin roller. Due to the chrome plating 12, the friction coefficient between the tape 6 and the roller 3 becomes smaller than that of the polyacetal roller. Therefore, the damage of the tape by the flange is
It can be reduced to the same level as conventional metal rollers. The weight increase of the roller 3 due to the chrome plating 12 is negligible, and the rotary inertia force hardly changes. Therefore, the resonance frequency between the spring of the tape 6 and the mass of the roller 3 remains high, and the resonance point of the tape running system shown in FIG. 2 is at the frequency of mechanical disturbance due to the drum motor, the capstan motor 111, or the like. do not get closer. Therefore, the effect on jitter is
It hardly happens. FIG. 4 is a jitter spectrum when the rotation guide of the present invention using a roller made of polyacetal resin and plated with chrome is mounted. Further, FIG. 5 is a jitter spectrum when a stainless steel rotation guide is attached. In FIG. 5, resonance of the tape running system occurs due to the increase in the weight of the roller, and
The jitter component of 080 Hz is outstandingly outstanding. On the other hand, in FIG. 3, no remarkable protrusion of the jitter component is seen. Further, the chrome plating treatment is less expensive than cutting a metallic roller, and the cost can be kept low.

As described above, according to this embodiment, good jitter performance can be obtained at low cost while preventing the tape from being damaged at the flange. In this embodiment, the rotation guide of the present invention is applied to the output side rotation guide 1 in FIG. 2, but it may be applied to the input side rotation guide 1 ′. Although the roller is made of polyacetal resin in this embodiment, it may be made of ABS, SAN, styrene, polycarbonate, polyethylene, polysulfone, nylon, polypropylene, PPS, phenol, fluorine, polyimide, or other various resin materials. .. In addition, although the material of the metal coating is carbon in this embodiment, nickel, silicon, boron, vanadium, zirconium, aluminum, or other metal plating can be used instead. Further, in the present embodiment, only the outer peripheral surface of the roller is plated, but plating the upper and lower surfaces of the roller and the surface in contact with the guide shaft also have the effect of allowing electricity charged in the roller to escape through the flange and the guide shaft. ..

Next, a second embodiment of the present invention for improving the slidability between the roller and the guide shaft to stably rotate the roller and improving the fixing property of the metallic film will be described. FIG. 6 shows a sectional view of a rotary guide 1 according to a second embodiment of the present invention. Similar to the first embodiment, the rotation guide 1 includes a roller 3 rotatable about a guide shaft 2, and an upper flange 4 and a lower flange 5 which are press-fitted and fixed above and below the guide shaft 2 with the roller 3 interposed therebetween. Composed of. here,
The bearing portion 3b in contact with the guide shaft 2 of the roller 3 is made of polyacetal resin as a material having a small specific gravity and excellent slidability. On the outer peripheral surface of the bearing portion 3b made of polyacetal resin, a roller 3a formed of a material having a small specific gravity and easily fixing a metallic film, for example, ABS resin, is concentrically laminated. Chrome plating 12 is applied to the outer surface of the roller 3a as a metallic film. Here, in order to eliminate the rattling of the roller 3 in the thrust direction, the dimension of the bearing portion 3b in the height direction is made substantially equal to the interval between the upper and lower flanges 4, 5. On the outer peripheral surface of the bearing portion 3b, the dimension in the height direction is set to the bearing portion 3b.
A slightly smaller roller 3a is laminated. That is,
The outer diameter of the protrusion 3 ′ of the roller 3 and the outer diameter of the bearing 3b in the first embodiment shown in FIG. 1 are the same. Since the friction coefficient between the bearing portion 3b made of polyacetal resin and the guide shaft 2 is low, the roller 3 rotates stably and the running load of the tape 6 does not increase. In addition, the roller 3a
Since it is made of ABS resin, which has better fixability for chrome plating 12 than polyacetal resin, chrome plating 12
Is more stably fixed on the surface of the roller 3.

Due to the chrome plating 12, the coefficient of friction between the tape 6 and the roller 3 is made of polyacetate resin or A
It is smaller than the roller made of BS resin. Therefore, the damage of the tape due to the flange can be reduced to the same level as that of the conventional metallic roller. Since both the polyacetal resin and the ABS resin have small specific gravity, the weight of the roller 3 is small. The weight increase of the roller 3 due to the chrome plating 12 is negligible, and the rotary inertia force hardly changes. For this reason,
The resonance frequency between the spring of the tape 6 and the mass of the roller 3 remains high, and the resonance point of the tape running system shown in FIG. 2 does not approach the frequency of mechanical disturbance caused by the drum motor, the capstan motor 111, or the like. Therefore, with respect to the jitter, the same effects as those of the first embodiment shown in FIGS. 4 and 5 can be obtained. In addition, the chrome plating treatment is less expensive than cutting a metal roller, and the cost can be kept low as in the first embodiment.

As described above, according to this embodiment, the metallic coating can be stably fixed while the sliding friction between the roller and the guide shaft is kept low. In this embodiment, the rotation guide of the present invention is applied to the output side rotation guide 1 in FIG. 2, but it may be applied to the input side rotation guide 1 ′. Further, in the present embodiment, the bearing portion 3b has a cylindrical shape, but the outer shape of the bearing portion 3b has another shape, for example, a shape having a protrusion, and the shape of the joint portion of the roller 3a with the bearing portion 3b is This bearing part 3
You may fit the bearing part 3b and the roller 3a according to the outer shape of b. Further, in this embodiment, the material of the roller is Duracon resin for the portion in contact with the guide shaft,
Although the chrome-plated portion is ABS, other resin materials having respective characteristics may be used. Further, in the present embodiment, the material of the metal film is chrome, but other metal plating can be replaced.

[0015]

According to the present invention, since the roller of the rotary guide is formed of plastic resin and the tape sliding surface is formed of a metal film having a low coefficient of friction with the tape, scratches of the tape on the rotary guide are prevented. Good jitter performance can be obtained at low cost, while preventing to the same extent as a metallic rotation guide.
In addition, by forming the bearing portion in contact with the guide shaft of the roller with a plastic resin having good slidability with the guide shaft,
Since the roller rotates stably, it does not affect the jitter and the tape running load does not increase. Further, by laminating a plastic resin roller having a good fixing property of the metallic film on the outer periphery of the bearing portion, it becomes possible to stably fix the metallic film covering the outer surface of the roller.

[Brief description of drawings]

FIG. 1 is a front view of a rotation guide.

FIG. 2 is a plan view of a tape running system.

FIG. 3 is a sectional view of a rotation guide.

FIG. 4 is a jitter spectrum when a rotation guide using a carbon-plated roller is attached to a polyacetal roller.

FIG. 5 is a jitter spectrum when a rotation guide using a stainless steel roller is attached.

FIG. 6 is a sectional view of a rotation guide.

[Explanation of symbols]

 1 ... Rotating drum 2 ... Guide shaft 3 ... Roller 4 ... Upper flange 5 ... Lower flange 6 ... Tape 12 ... Carbon plating

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyasu Sawano, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock Company, Hitachi Media Visual Media Research Institute (72) Hirofumi Taguchi 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Inside Hitachi Media Media Research Laboratories

Claims (3)

[Claims] 1. A tape (6) stretched between two reels (104, 105) and a head (119) for recording information on the tape (6) or reproducing information from the tape (6).
And a tape guide means for forming a running path of the tape (6) so that recording and reproduction can be performed by the head (119), and the tape guide means is formed of a plastic resin. A recording / reproducing apparatus characterized by further comprising a rotation guide (1) having a roller (3) whose outer surface is covered with a metallic film (12). 2. A guide for guiding the running of a tape (6), the guide shaft (2) and a roller (3) rotatably supported by the guide shaft (2).
And a flange (4) fixedly supported on the guide shaft (2) at at least one of the upper and lower ends of the roller (3).
(5), the roller (3) is made of plastic resin, and
A rotation guide characterized in that the outer surface of the roller (3) is covered with a metallic coating (12). 3. A guide for guiding the running of a tape (6), the guide shaft (2) and a roller (3) rotatably supported by the guide shaft (2).
And a flange (4) fixedly supported on the guide shaft (2) at at least one of the upper and lower ends of the roller (3).
(5) and a bearing portion (3b) which is in contact with the guide shaft (2) of the roller (3)
Is formed of a first plastic resin, and a second plastic resin roller (3a) having an outer surface covered with a metallic coating (12) is laminated on the outer periphery of the bearing portion (3b). A rotating guide.