JPH10162455A - Magnetic recording and reproducing device and production of drum for magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease friction between a magnetic tape and a drum and to improve travelling property of a magnetic tape by adding an additive to a plastic base material, injection molding to obtain at least one of a fixing drum and rotating drum, and then subjecting the formed body to chemical etching. SOLUTION: A lead guide part 3 is formed around a fixed drum 1. The forming material for the drum is a plastic material such as polyetherimide and polyphenylene sulfide. The plastic material for injection molding to produce the fixed drum is, for example, polyetherimide(PEI), and additives such as carbon fiber by 5 to 65wt.% and conductive whisker by 65 to 5wt.% are added to the polyetherimide matrix, and if necessary, other additives are added by 0 to 60wt.%. The mixture is injection molded to produce a drum master of the fixed drum 1. Then the drum master is swollen in an etching process and then subjected to chemical treatment, washed and sufficiently dried.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a fixed drum and a rotating drum which rotates with respect to the fixed drum. The rotating drum has a magnetic head, and a signal is supplied to a magnetic tape by rotating the rotating drum. And a method for manufacturing a drum of the magnetic recording and reproducing apparatus.

[0002]

2. Description of the Related Art This type of magnetic recording / reproducing apparatus is used in, for example, a video tape recorder and an audio tape recorder. FIG. 5 shows this type of magnetic recording / reproducing device (also referred to as a magnetic drum device or a magnetic head device) which is generally used. The magnetic recording / reproducing apparatus has a fixed drum 1 and a rotating drum 2, and the rotating drum 2 operates in a rotation direction R by operating a motor M on the fixed drum 1.
It is possible to rotate continuously along. The rotating drum 2 is provided with a magnetic head H for recording a signal on the magnetic tape T or reproducing a signal recorded on the magnetic tape T. One or more magnetic heads H are provided for the rotary drum 2. The fixed drum 1 has a lead guide 3 for guiding the side of the magnetic tape T. The lead guide portion 3 is formed obliquely along the peripheral surface of the fixed drum 1. Thus, the magnetic tape T is guided along the tape guide direction E from the entrance side IN to the exit side OUT along the tape running direction E. At this time, since the rotating drum 2 rotates in the rotation direction R, the magnetic head H can record a signal on the magnetic tape T by the helical scan method or reproduce a signal by the helical scan method.

As described above, the magnetic tape T runs along the lead guide portion 3 of the fixed drum 1. At this time, the magnetic tape T floats at the entrance IN due to the air generated by the rotary drum 2. . This layer of air is called an air film. However, as the magnetic tape T runs obliquely and approaches the outlet side OUT, the thickness of the air film decreases, and the magnetic tape T comes into contact with the peripheral surface of the fixed drum 1 and the rotating drum 2. In such a tape running situation, for example, when a video tape recorder is used under high temperature and high humidity conditions such as the rainy season, the following problems occur.

[0004]

That is, as the magnetic tape T is fed and travels, the magnetic tape T comes into close contact with, for example, the peripheral surface of the fixed drum 1 and the frictional force between the two increases. As a result, the magnetic tape T sticks to the fixed drum 1, and finally the running of the magnetic tape T stops. This phenomenon is called a tape sticking phenomenon. It is considered that the main causes of the tape sticking phenomenon are the hygroscopicity of the surface of the magnetic tape T and the softening of the surface of the magnetic tape T due to frictional heat. In order to prevent this sticking phenomenon, when an aluminum fixed drum, which is currently used most in video tape recorders, is used, the surface roughness of the fixed drum is set to 4 to 5 μm by cutting, and the fixed drum 1 An air film (air layer) is easily formed between the peripheral surface and the magnetic tape T.

On the other hand, even in such video tape recorders and the like, cost reduction is strictly required. Therefore, when the fixed drum and the rotating drum are not made of expensive aluminum but made of plastic, they are required. When a fixed drum or a rotating drum made of plastic is used, the adhesion between the fixed drum and the magnetic tape T is particularly good, so that the surface of the fixed drum 1 needs to be actively roughened by post-processing. Methods for roughening the surface of the fixed drum 1 include cutting,
Sand blasting, gyro finishing, buffing, tape wrapping, and the like.

However, such post-processing causes the following problems. When forming a drum made of plastic, mold injection molding is used. However, since the above-mentioned mechanical post-processing is performed on the molded plastic, the dimensional change of the drum is large, and precision is required. There is no point in performing a simple mold injection molding, and the cost is rather increased. That is, the dimensional accuracy of the molded product of the drum deteriorates. In addition, such post-processing naturally increases costs.

Therefore, the present invention solves the above-mentioned problems, and reduces the friction with the magnetic tape and reduces the running of the magnetic tape even when at least one of the fixed drum and the rotating drum is made of a plastic base material. Quality can be improved,
Further, it is an object of the present invention to provide a magnetic recording / reproducing apparatus and a method for manufacturing a drum of the magnetic recording / reproducing apparatus which can reduce the cost.

[0008]

According to the present invention, there is provided a stationary drum and a rotating drum which rotates with respect to the stationary drum. The rotating drum includes a magnetic head.
In a magnetic recording / reproducing apparatus that records a signal on a magnetic tape by rotating a rotating drum or reproduces a signal from a magnetic tape, at least one of a fixed drum and a rotating drum is an additive to a plastic base material. This is achieved by a magnetic recording / reproducing apparatus which is formed by performing a chemical etching process after injection molding with addition of a magnetic recording / reproducing device. In the present invention, at least one of the rotating drum and the fixed drum is
It is formed by adding an additive to a plastic base material, performing injection molding, and then performing an etching process. Thereby, the friction between the magnetic tape and the drum is reduced without greatly changing the dimensions of the drum, thereby reducing the adhesion and improving the running property of the magnetic tape.

The object of the present invention is to provide, in the present invention, a fixed drum and a rotating drum rotating with respect to the fixed drum, the rotating drum having a magnetic head, and rotating the rotating drum to form a magnetic tape. A method for manufacturing at least one of a fixed drum and a rotating drum of a magnetic recording / reproducing apparatus which is configured to record a signal or reproduce a signal from a magnetic tape. Injection molding the drum prototype, removing the dirt components on the surface of the drum prototype, swelling the drum prototype, and chemically etching the drum prototype, magnetic tape of at least one of the fixed drum and the rotating drum This is achieved by a method for manufacturing a drum of a magnetic recording / reproducing apparatus in which minute irregularities are formed on a running surface. In the present invention, an additive is added to a plastic base material to injection mold a drum prototype. Adding an additive to a plastic substrate in this way provides conductivity for antistatic,
This is to increase rigidity and reduce frictional resistance. Then, the dirt component on the surface of the drum prototype is removed, and the drum prototype is swollen. The reason for removing the dirt component on the surface of the drum prototype is to facilitate chemical etching in the post-processing. The reason for swelling the drum model is that the resin surface is hard and hard to be etched as it is, so that the surface is somewhat softened to facilitate immersion.

Thereafter, the drum prototype is subjected to chemical etching to form minute irregularities on the tape running surface of the drum. By forming the unevenness on the magnetic tape running surface in this way, the friction between the magnetic tape and the drum is reduced, the adhesion is reduced, and the running property of the magnetic tape can be improved.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIG. 1 is a perspective view showing the appearance of the magnetic recording / reproducing apparatus of the present invention, and FIG. 2 is a sectional view showing an example of the structure of the magnetic recording / reproducing apparatus of FIG. This magnetic recording / reproducing device
Also called a rotating magnetic head device or a rotating magnetic drum device, the magnetic head H records a signal on the magnetic tape T by rotating the rotating drum 2 while sending the magnetic tape T in the tape running direction E, Alternatively, the signal of the magnetic tape T is reproduced. This magnetic recording / reproducing apparatus is, for example, a recording / reproducing type video tape recorder (VT).
R), and has a fixed drum 1, a rotating drum 2, and a motor M. The rotating drum 2 is also called an upper drum, and the fixed drum 1 is also called a lower drum.

FIG. 2 shows a structural example of the magnetic recording / reproducing apparatus shown in FIG. 1. In this structural example, the upper end portion 14 of a drum shaft (also referred to as a rotating shaft) 14 is attached to a flange 2a of the rotating drum 2.
a is fixed by press-fitting or bonding. For example, a magnetic head H for recording / reproducing is screwed to the rotating drum 2 in FIG. One or more magnetic heads H are set according to the type. The rotor core 3 a of the rotary transformer 3 is fixed to the rotating drum 2. The fixed drum 1 includes a cylindrical portion 17 and a stator core 3b of the rotary transformer 3. Between the rotor core 3a and the stator core 3b of the rotary transformer 3, for example, the magnetic head H transmits a reproduction signal obtained when reproducing the signal of the magnetic tape T in a non-contact manner, or the magnetic head H transmits the magnetic tape T to the magnetic tape T. When recording a signal, the signal is used to transmit a recording signal from the stator core 3b to the rotor core 3a in a non-contact manner.

A lead guide 3 for guiding the magnetic tape T is formed on the outer peripheral surface of the fixed drum 1 as shown in FIG. The motor M is, for example, a brushless motor, and the rotor yoke 33 of the motor M is
Is fixed to the lower end portion 14b of the main body. By driving the motor M, the rotor yoke 33, the drum shaft 14, the flange 2a, and the rotating drum 2 can be rotated with respect to the fixed drum 1. The bearings 60, 60
The drum shaft 14 is rotatably supported with respect to the cylindrical portion 17.

The fixed drum 1 and the rotating drum 2
In particular, when the fixed drum 1 is manufactured, the fixed drum 1 is formed by adding an additive to a plastic base material, performing injection molding, and then performing an etching process. For details,
The fixed drum 1 and the rotating drum 2 are manufactured through the steps shown in FIG. Referring to FIG. 3, for example, the fixed drum 1 is molded into a predetermined shape by an injection molding process using a mold. That is, the lead guide portion 3 is formed on the peripheral surface of the fixed drum 1. At this time, plastic is used as a molding material, and for example, polyetherimide (PEI), polyphenylene sulfide (PPS), or the like can be used. As an example of an embodiment of the present invention, a plastic for injection molding of a fixed drum uses polyetherimide (PEI), and a polyetherimide matrix contains 5-65 Wt% of an additive, for example, carbon fiber and a conductive material. 65 whiskers
To 5 Wt%, and if necessary, other additives (for example, polytetrafluoroethylene resin powder: PTF
E) is added to 0 to 60 Wt% and injection molded to form a fixed drum 1
To form a drum prototype.

The drum model of the molded fixed drum 1 is as follows.
In the degreasing step of FIG. 3, dirt on the surface of the drum prototype, for example, mainly oil dirt, is removed. In this degreasing step, in order to remove oil stains and the like, washing is performed at room temperature for 10 minutes using alcohol or diflon (fluorochlorinated hydrocarbon). Thereafter, in the swelling step, the washed drum master is immersed in dimethylformalamide (DMF) at room temperature for 10 minutes to swell. As described above, the reason for the swelling of the drum prototype is that the resin surface is hard and hard to be etched as it is, so that the surface is somewhat softened to facilitate immersion. Thereafter, in the etching step, the swollen drum master is immersed at 75 ° C. for 20 minutes to perform a chemical etching process by using a sulfuric acid / chromic acid etching solution to promote the reaction, and the drum master is minutely etched around the drum master. Add irregularities. Thereafter, the drum prototype subjected to the chemical etching as described above is sufficiently dried through a water washing step.

In this manner, the fixed drum 1 is obtained by the action of chemical etching.
In the above, fine irregularities are formed on the magnetic tape running surface, that is, the surface on which the magnetic tape runs. When the dimensions of the fixed drum 1 after chemical etching were measured, the diameter was 30.
mm fixed drum outer diameter, roundness and cylindricity are all 1μ
m or less.

Incidentally, in the above-described example, the fixed drum is taken as an example, but the rotary drum 2 can of course be made in the same manner as the fixed drum 1. In any case, besides polyetherimide,
As polyphenylene sulfide or other materials, it is also possible to use selected from polycarbonate, polyether sulfone, polyarylate, polyether ether ketone, polyether ketone, and liquid crystal polymer. Examples of the additive include carbon fibers, whiskers, inorganic fillers, spherical fillers and the like.
Or a combination thereof.

FIG. 4 shows the frictional characteristics of the fixed drum 1 obtained in the embodiment of the present invention and the magnetic tape T caused by repeated running. Among these, the fixing drum made of an aluminum alloy (A4032), which is currently most frequently used, has the lowest friction coefficient, but the fixing drum according to the embodiment of the present invention in which polyetherimide (PEI) is chemically etched. The drum and the cut product of polyphenylene sulfide (PPS) outside the scope of the present invention show almost the same characteristics. In addition, since the fixed drums of the molded articles of polyetherimide (PEI) and the molded articles of polyphenylene sulfide (PPS), which are outside the scope of the present invention, are not subjected to chemical etching, friction with the magnetic tape is reduced. Large sticking of the magnetic tape has occurred.

As described above, the running characteristics of a magnetic tape on a drum can be improved by using a plastic material as a base material for a drum cylinder such as a fixed drum or a rotating drum and subjecting the surface to chemical etching. Was. Furthermore, since the method of forming minute irregularities on the magnetic tape running surface by chemical etching is used,
A large number of drums can be manufactured at one time, and can be manufactured at a very low cost as compared with other processing methods.

When the magnetic drum is used as a molded product of a plastic material, the magnetic tape running surface is chemically etched to reduce friction with the magnetic tape and improve the running property of the magnetic tape. Hunting and sticking can be prevented. The hunting means that when the magnetic tape is running, the tape is softened between the drum and the air film is cut due to abrasion of the drum surface.
(Tick-Slip) and intermittent running. Since the chemical etching method is used, a large number of drums can be processed at one time, and the cost can be reduced.
Since the chemical etching method is used, the change in the dimensions of the drum is extremely small as compared with the case of machining, and the use of a mold is significant even when using a mold at the time of molding.

From the above, by applying the magnetic recording / reproducing apparatus of the present invention to audio equipment such as a home video tape recorder, data recorder, digital audio tape recorder (DAT), etc. It is possible to provide an inexpensive device capable of realizing a simple recording / reproducing operation and reducing costs.

[0023]

As described above, according to the present invention,
Even when at least one of the fixed drum and the rotating drum is made of a plastic base material, friction with the magnetic tape can be reduced, the running property of the magnetic tape can be improved, and the cost can be reduced. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a preferred embodiment of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a sectional view showing a structural example of the magnetic recording / reproducing apparatus of FIG. 1;

FIG. 3 is a diagram showing an example of a drum manufacturing method of the magnetic recording / reproducing apparatus of the present invention.

FIG. 4 shows a drum obtained by the drum manufacturing method of the present invention;
The figure which shows the tape running characteristic of the drum obtained by other methods.

FIG. 5 is a perspective view showing a commonly used magnetic recording / reproducing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed drum, 2 ... Rotary drum, 4 ... Lead guide part, T ... Magnetic tape, M ... Motor

Claims (4)

[Claims] 1. A fixed drum and a rotating drum that rotates with respect to the fixed drum. The rotating drum has a magnetic head. By rotating the rotating drum, a signal is recorded on a magnetic tape. In a magnetic recording / reproducing apparatus for reproducing a signal from a tape, at least one of the fixed drum and the rotating drum is formed by performing a chemical etching process after injection-molding a plastic base material with an additive. Characteristic magnetic recording / reproducing device. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the plastic substrate is selected from polyphenylene sulfide and polyetherimide. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the additive is selected from carbon fibers, whiskers, inorganic fillers, and spherical fillers. 4. A fixed drum and a rotating drum rotating with respect to the fixed drum, the rotating drum having a magnetic head, and recording a signal on a magnetic tape by rotating the rotating drum; This is a manufacturing method for manufacturing at least one of a fixed drum and a rotating drum of a magnetic recording / reproducing apparatus which is configured to reproduce a signal from a tape. By removing the dirt components on the surface of the drum prototype, swelling the drum prototype, and chemically etching the drum prototype, minute irregularities are formed on the magnetic tape running surface of at least one of the fixed drum and the rotating drum. A method for manufacturing a drum of a magnetic recording / reproducing apparatus, comprising: