JPS60171665A - Surface treatment of drum for video tape recorder - Google Patents

Abstract

PURPOSE:To improve the durability of a drum for video tape recorder, by etching the outer peripheral surface layer of the drum with an alkaline aqueous solution while the drum is rotated and projecting silicon particles. CONSTITUTION:An upper drum 1 is fitted to a rotary shaft 8 united with a drum fixing table 7 in one body and fixed to the fixing table 7. The rotary shaft 8 united with the drum fixing table 7 is freely rotated by means of driving force transmitted from a motor 10 through a connecting section 9. A sliding table 11 can be moved in the vertical direction along a strut 12 below the upper drum 1 fixed to the rotary shaft 8. A tank 14, in which an alkaline aqueous solution 13 is preserved, is provided on the sliding table 11 and it is arranged that the surface of the solution 13 is contacted with or separated from the outer peripheral surface of the drum 1 by moving the sliding table 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for treating the surface of a drum for a video tape recorder, which contacts the surface of a magnetic recording medium while rotating at high speed.

Conventional configuration and its problems In recent years, with the high density recording of magnetic recording media, iron has become increasingly popular.

Recently, a lot of research has been done on non-binder metal thin film magnetic tapes, in which thin films of cobalt, nickel, or alloys containing these as main components are formed on a substrate film by vacuum evaporation, electroplating, etc. Compared to ordinary coated magnetic tape made of oxidized magnetic powder bound with a resin binder, the surface roughness is 1/3 to 1/4, and the magnetic film thickness is extremely thin at 1/3. Since the phase is composed of approximately 100% metal, when the magnetic tape is actually run on a video tape recorder, the surface of the magnetic tape may be scratched or the magnetic film may be completely peeled off. These surface damages on magnetic tapes lead to fatal defects that make recording and nailing completely impossible in practice.

As a result of various studies on the above issues,
The mechanism of damage to the magnetic tape surface is that the magnetic head is removed and adhesive wear occurs with the upper drum material that slides on the magnetic tape surface while rotating at high speed together with the magnetic head, causing l-IJ damage. It turned out that

The relative relationship between the conventional magnetic tape and the upper drum will be explained below.

FIG. 1 shows a schematic diagram of a drum for a video tape recorder. In FIG. 1, 1 is an upper drum to which a magnetic head 2 is attached and rotates together with the magnetic head 2 at a speed of 1 h in the direction of arrow A; 3 is a fixed lower drum attached coaxially with the upper drum 1; 4 is a fixed lower drum attached coaxially with the upper drum 1; is traveling in the direction of arrow B while moving soil drum 1.
and a magnetic tape that comes into sliding contact with the lower drum 3. For the quality of the upper drum 1 in Fig. 1, an aluminum-silicon alloy casting containing 1 to 13 wt% of total silicon is generally used from the viewpoint of workability and productivity. 1 is a partially enlarged schematic cross-sectional view of an upper drum for a videotape recorder made of a material such as . In FIG. 2, the surface portion 11L of the upper drum 1, which is in contact with the surface portion 4a of the metal thin film type magnetic tape 4, is cut by a cutting process such as a cutting tool, so that the surface layer 6a of most of the silicon particles 6 is removed. It is ranked. There is a state where the surface layer of the recon particle is slightly exposed as shown in 6b. Therefore, the surface 4a of the magnetic material of the magnetic tape 4 of -C1 magnetic material %, I', < I@ type has a large adhesion force with other metals (easily adhesion). There was a problem in that the surface portion 4a of the magnetic tape 40 was damaged due to contact with the aluminum material, which has certain properties.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for treating the surface of a drum for a video tape recorder, which can improve surface durability against magnetic tape.

Structure of the Invention The present invention is a surface treatment method in which an upper drum having an outer circumferential surface that contacts the magnetic tape surface is immersed in an alkaline aqueous solution while rotating to perform an etching treatment. It is possible to improve the copper durability of the magnetic tape by eluating and making the silicon particles, which are almost uniformly scattered in the aluminum fabric, protrude from the surface of the entire aluminum fabric.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to drawing 1g.

FIG. 3 is an enlarged schematic cross-sectional view of the surface portion of the upper drum obtained by the surface treatment method of the present invention.

From FIG. 3, the surface layer 62L of the aluminum material 5 is eluted by etching, and the surface layer 6& of the silicon particles 6 is uniformly protruded, so that the metal thin film type magnetic tape 4
The actual contact area between the magnetic material surface 4& and the surface portion 6a of the aluminum fabric 5 becomes smaller, and the friction coefficient 1(r) decreases.

In addition, the protrusion of the particles 6 prevents direct contact between the magnetic material surface 4a and the surface portion 6a of the aluminum fabric 5, prevents adhesion occurring at the interface between the two, and improves the durability of the metal thin film type magnetic tape 4, especially , surface damage, i.e. +nfJ jM 2
(: It is something that will further improve your sexual ability.

Here, the coder drum system for videotape applied to the present invention is 6. () Aluminum-silicon alloy containing t percent or more of silicon, which is uniformly dispersed at a rate of about 100 to 200 pieces per 9100 micrometer square meter of aluminum fabric, and whose diameter is about 0.1 to 0.3 micrometers. This is desirable.

The surface treatment method of the present invention for obtaining a drum for a videotape recorder having the above-mentioned configuration includes, for example, rotating an upper drum fixed to an H-rotation shaft in a fixed direction, and disposing the outer peripheral surface of the drum in a prepared alkaline aqueous solution. By fully immersing only the upper drum, the silicon particles on the surface of the upper drum are made to protrude.

The time that the outer peripheral surface of the rotating upper drum is immersed in the alkaline aqueous solution is im
5 seconds to 30 seconds since J Alkali 1st graders are extremely slow.
The rotation speed of the upper drum should be approximately 10 to 180 rpm, considering the scattering of the etching solution and uniform etching. , m are preferable, and 3-Or, p, m is more preferable.

Next, an etching device applied to the method for surface treatment of a videotape precoder drum of the present invention will be described with reference to FIG. Upper drum 1 kl - Fitted into a rotating shaft 8 integrated with the drum fixing base 7 and fixed to the drum fixing base 7. The rotating shaft 8, which is integrated with the drum fixing base 7, is rotatable according to the driving force from the motor 10 through the connecting portion 9.

Reference numeral 11 denotes a slide table, which is located below the upper drum 1 fixed to the rotary shaft 1-8 and is movable up and down by a column 12.

A tank 14 in which an alkaline aqueous solution 13 is stored is installed on the slide stand 11, and as the slide stand 11 moves, the liquid level of the alkaline aqueous solution 13 changes between a position where the entire outer peripheral surface of the upper drum 1 is immersed and a position where it is separated. It is possible.

A more specific embodiment of the present invention will be described below. Using the etching device shown in Figure 4, the size of the silicon particles scattered in the aluminum fabric was determined by the upper drum.
~3.0 micron aluminum-silicon alloy (
JIS A4302FD), and while rotating the upper drum at 3 Qr, p, m, prepare an alkaline aqueous solution with a liquid concentration of 0.1, 0.6, 1.0, 6.0, 10.
．． 0, 15. o, 20. Using an aqueous sodium hydroxide solution of 0 wt %, the outer peripheral surface was immersed in the solution for 10 seconds to perform an etching process. The amount of silicon protrusion on the surface of the upper drum obtained by the etching process, that is, the extent to which the silicon particles protrude from the surface of the aluminum fabric was measured using a surface roughness meter. Furthermore, the etched upper drum was fixed in a video table recorder and rotated at high speed (18 o'r, p, m), and a metal thin film type magnetic tape surface was brought into contact with the surface of the drum at a pressure of about 20 mm to create a magnetic field. A tape length of 6 m was repeatedly run for 10 passes, some for 60 passes, at a speed of 14 mm/s. After running, the surface of the magnetic tube 2 was inspected visually and with an optical microscope, and the degree of damage was compared with that of an untreated drum.

The results are shown in Table 1.

From Table 1, the drum surface is etched to make silicon particles protrude by at least 0.01 microns from the surface of the aluminum fabric, that is, the liquid concentration is 0.6 W'.
r, above, hydroxide) When a metal thin film type magnetic tape was run on an upper drum etched with a +7um aqueous solution, the surface of the magnetic tape was less likely to be damaged than when an untreated drum was used. In particular, those etched in a 10 wt % sodium hydroxide aqueous solution, that is, those with a surface protrusion of silicon particles of 0.1 to 0.5 microns, show that even after running the magnetic tape repeatedly for 60 passes, the surface There is little damage and the effect is great. However, 20
Etched in wt% sodium hydroxide aqueous solution, that is, the surface protrusion amount of silicon particles is 0.9
When the magnetic tape was 1.5 microns in diameter, damage occurred on the magnetic tape surface as in the case where the liquid concentration was 0.5 wt% or less.

This is because the size of silicon particles scattered in the aluminum fabric is 1.0 to 3.0 microns.
When etching with a 0wt% thorium hydroxide aqueous solution, the amount of elution from the aluminum fabric is large, and the silicon particles on the surface layer are easily peeled off or peeled off + ML, and silicon particle powder is generated by repeated running of the magnetic tape. This is thought to have caused scratches on the surface of the magnetic tape.

Therefore, the liquid a degree (wt%) of the sodium hydroxide aqueous solution
) is from 0.5 to 16. It was found that the range of owt was born out of wedlock. As an etching method, the entire upper drum was ffl in a 10 wt% sulfur/lium hydroxide aqueous solution.
1. and those treated by immersion in
I compared it with many things. As a result, the song title was 1, and uneven etching had occurred on the entire outer peripheral surface of the ram. Furthermore, when measuring the amount of protrusion of silicon particles, it is found that from 0.01 to 0.
．． There is a large variation of 8 microns, and scratches were observed on the tape surface even in the evaluation of repeated running of magnetic tape, and the rotation method is effective as a method to uniformly protrude silicon particles only on the outer peripheral surface of the ten drums. Met.

It has been found that by making the silicon particles protrude, not only damage to the tape surface but also stick-slip (tape squeal) caused by tape running can be improved, and the effect of the present invention is extremely large.

Effects of the Invention As described above, the present invention rotates the upper tram for a videotape recorder and immerses it in an alkaline aqueous solution, thereby eluting the aluminum component, which is the main component of the drum material, and dissolving it almost uniformly into the aluminum fabric. This makes it possible to make the silicon particles that have already been dispersed in the magnetic tape stick out, thereby improving the durability of the magnetic tape.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a drum for a videotape recorder, Figure 2
The figure is an enlarged cross-sectional schematic diagram of a conventional tram for a videotape recorder, and FIG. 3 is an enlarged schematic diagram showing the state of protrusion of silicon particles on the surface of the tram obtained by the present invention and the contact state of the magnetic tape with magnetic surface blood. FIG. 4 is a schematic diagram of an etching apparatus applied to the method of surface treatment of a drum for a videotape recorder according to the present invention. 5... Aluminum fabric strip, 6a - Aluminum fabric surface, 6...-Silicon material, 6a--. Silicon particle surface layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] While rotating a drum for a videotape recorder, the drum outer circumferential surface layer in contact with the magnetic tape is covered with aluminum or is made of aluminum-recon alloy casting and has exposed silicon particles. A method for surface treatment of a drum for a videotape recorder, comprising etching the layer in an alkaline aqueous solution to cause the silicon particles to protrude.