JPH04298841A - Rotary head assembly - Google Patents

Abstract

PURPOSE:To absorb away a moisture film in order to prevent the attraction of a magnetic tape by the moisture film formed between the sliding surface of a stationary drum and a magnetic tape and the generation of vibration and stick slip of the magnetic tape. CONSTITUTION:An insulated 1st metallic plating electrode 12 is provided on the surface of the stationary drum 3 on which the magnetic tape slides and an insulated 2nd metallic plating electrode 13 is provided on the surface on which the magnetic tape does not slide. The surfaces of the two electrodes 12, 13 are coated with a solid electrolyte layer 14, by which a dehumidifying element is constituted. A DC voltage to turn the 1st electrode 12 to a positive electrode is impressed between the two electrodes. The formed moisture passes the solid electrolyte layer 14 and is decomposed to oxygen and hydrogen ions by the 1st electrode 12. The hydrogen ions pass the solid electrolyte and are again turned into water by the 2nd electrode 13. This water is released into the atm. air.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head assembly that improves the recording and reproducing characteristics of a magnetic recording device and the running characteristics of a magnetic tape.

0002

2. Description of the Related Art FIG. 7 is a perspective view showing the structure of a conventional rotary head assembly for a VTR. In the figure, 1 is a rotating drum, 2 is a head mounting window provided on the rotating drum 1, 3 is a fixed drum that rotatably supports the rotating drum 1, 4 is a magnetic head attached to the head mounting window 2, and 5 is a magnetic head. 6 is a guide pin, 7 is a guide roller, and 8 is a lead groove for guiding the magnetic tape 5 wound around the fixed drum 3.

Next, the operation will be explained. The magnetic tape 5 is wound diagonally around the rotating drum 1 and the fixed drum 3 and runs. The rotating drum 1 rotates at 1800 rpm, and a magnetic head 4 attached to the rotating drum 1 scans the magnetic tape 5 obliquely. The magnetic head 4 protrudes from the head mounting window 2, and records and reproduces signals on the magnetic tape 5 by bringing it into contact with the magnetic tape 5.

When the magnetic tape 5 runs in the direction of arrow A, the magnetic tape 5 is guided by the guide pin 6, guide roller 7, and lead groove 8 so that the relative positions of the magnetic head 4 and the magnetic tape 5 coincide. be done. At this time, the state of contact between the magnetic tape 5 and the head 4, the rotating drum 1, and the fixed drum 3 is such that an air film 9 is formed between the rotating drum 1 and the magnetic tape 5, as shown in FIG. The magnetic tape 5 does not come into direct contact. This air film 9 has a relative speed of 5.8 m between the rotating drum 1 and the magnetic tape 5.
It is formed because of its high speed of /s.

Since the fixed drum 3 is fixed, the relative speed with the magnetic tape 5 is as low as 0.3 m/s, so there is an air film 9 between the fixed drum 3 and the magnetic tape 5. is not formed and comes into direct contact. The surface roughness of the magnetic tape 5 is 1 μm or less and it is very smooth. Therefore, when the magnetic tape 5 runs while contacting the fixed drum 3, stick-slip occurs and the magnetic tape 5 vibrates, causing the magnetic tape 5 to vibrate. Due to the vibration of the magnetic tape 5, the relative position between the head 4 and the magnetic tape 5 shifts, and the reproduction output of the head 4 decreases.

Such stick-slip of the magnetic tape 5 occurs when a minute moisture film 10 is formed between the magnetic tape 5 and the fixed drum 3, and the fixed drum 3 and the magnetic tape 5 are attracted to each other. arise due to When the relative humidity of the surrounding environment increases, a moisture film 10 is uniformly formed on the contact interface between the fixed drum 3 and the magnetic tape 5, and the adsorption force increases. As a result, the magnetic tape 5 vibrates more intensely, and the reproduction output of the magnetic head 4 significantly decreases. .

Furthermore, due to the adsorption by the moisture film 10, the driving torque of the capstan motor for running the magnetic tape 5 increases, causing problems such as a change in the running speed of the magnetic tape 5 or a stoppage of the running of the magnetic tape 5. A problem arises.

[0008] As described above, the conventional rotating head assembly is difficult to operate as the relative humidity of the surrounding environment increases.
If a moisture film is formed between the magnetic tape 5 and the magnetic tape 5, there will be problems such as stick-slip of the magnetic tape 5 and a decrease in the playback output.Furthermore, the driving torque of the capstan motor will increase. , there were problems such as the magnetic tape 5 stopping running.

[0009]

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to prevent contact between the fixed drum 3 and the magnetic tape 5 even if the relative humidity of the surrounding environment increases. It is an object of the present invention to provide a rotary head assembly capable of preventing the formation of a moisture film 10 on the interface and preventing adhesion between a fixed drum 3 and a magnetic tape 5.

0010

[Means for Solving the Problems] The rotary head assembly according to the present invention has an insulating layer on the surface of the fixed drum that slides on the magnetic tape, which is insulated from the fixed drum, and a slit that allows the magnetic tape to be removed. first and second metal plated electrodes separated into a sliding surface side and a non-sliding surface side, and a hygroscopic solid electrolyte layer formed to cover these metal plated electrodes; or A solid electrolyte layer whose surface is covered with a breathable insulating film is provided, and a DC voltage is applied between the first and second metal plated electrodes.

[0011]

[Operation] The solid electrolyte layer allows moisture generated between the magnetic tape and the sliding surface of the fixed drum to pass through the first and second
Supplied to metal plated electrodes. The metal-plated electrode on the positive side electrolyzes this water, and the hydrogen ions move within the solid electrolyte layer along with the flow of current, combine with oxygen at the metal-plated electrode on the negative side, and become water, which is released into the atmosphere. is released.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the stationary drum of this embodiment, FIG. 2 is a plan view thereof, and FIG. 3 is a longitudinal cross-sectional view thereof, in which a hygroscopic solid electrolyte is used. In the figure, 11 is an insulating layer, 12 is a first metal plating electrode, 13 is a second metal plating electrode, 14 is a hydrogen ion conductive solid electrolyte layer,
15 is a slit, and 16 is a humidity sensor provided on the fixed drum 3.

The fixed drum 3 of this embodiment is manufactured as follows. First, the insulating layer 11 is formed on the outer peripheral surface of the fixed drum 3. Next, on this insulating layer 11, a first metal plating electrode 12 is placed on the side that slides in contact with the magnetic tape 5, and a second metal plating electrode 13 is placed on the side that does not come into contact with the magnetic tape 5. Form. At this time, the first and second
The metal plated electrodes 12 and 13 are separated by a slit 15 formed in the axial direction of the fixed drum 3.

Next, a hygroscopic solid electrolyte layer 14 is formed to cover the surfaces of the first and second metal plated electrodes 12 and 13. This solid electrolyte layer 14 is made of a material with high friction resistance in order to selectively transmit ions and prevent wear due to friction with the magnetic tape 5.
For example, it is made of a ceramic material such as β-alumina substitute.

The first and second metal plating electrodes 12 and 13 are made of a metal such as palladium, and are arranged such that the first metal plating electrode 12 is a positive electrode and the second metal plating electrode 13 is a negative electrode. , a DC voltage is applied from a power supply 18.

Next, the operation of this embodiment will be explained. The relative humidity of the surrounding environment is measured by the humidity sensor 16 attached to the fixed drum 3, and when the relative humidity exceeds about 50 to 60%, a DC voltage is applied between the first and second metal plating electrodes 12 and 13. do. first and second metal plating electrodes 12,
When a DC voltage is applied between the fixed drum 3 and the magnetic tape 5, the moisture film 10 formed at the contact interface between the fixed drum 3 and the magnetic tape 5 passes through the solid electrolyte layer 14 and forms the first metal plated electrode 1, which is the positive electrode.
2, the hydrogen ions move through the solid electrolyte 14 along the flow of current, and combine with oxygen again at the second metal plating electrode 13, which is the negative electrode, to become water, which is released into the atmosphere. be done.

FIG. 4 is a perspective view of a fixed drum according to a second embodiment of the present invention, and FIG. 5 is a plan view thereof, showing the solid electrolyte layer 14.
It can be used regardless of whether it is hygroscopic or non-hygroscopic. In the figure, reference numeral 17 denotes an insulating thin film having air permeability, and is made of, for example, fluorocarbon resin deposited on the surface of the solid electrolyte layer 14 to a thickness of 500 to 2000 Å.

Next, the operation of this embodiment will be explained. The air-permeable insulating thin film 17 allows moisture generated between the magnetic tape 5 and the magnetic tape 5 to pass therethrough and supplies it to the solid electrolyte layer 14, and thereafter, the moisture is discharged in the same manner as in the first embodiment.

FIG. 6 is a partially enlarged vertical sectional view of another embodiment of the present invention, in which a slit 15 is provided in an annular manner below the lead groove 8, and a second metal plating electrode 13 is attached to the fixed drum 3.
It is formed in an annular shape at the lower end of the .

In the above embodiment, a rotary head assembly of a VTR is shown, but the present invention can be similarly applied to a rotary drum of a digital audio tape recorder (DAT). Further, in addition to the fixed drum, the same effect can be obtained even when applied to the guide pin 6 or other pins provided in a magnetic tape running system.

[0021]

According to the present invention, the first and second metal plated electrodes 12, 13 and the solid electrolyte layer 14 constitute a dehumidifying element, so that the magnetic tape slides between the magnetic tape and the fixed drum. The moisture generated between the surface and the surface is decomposed into oxygen and hydrogen ions at the first metal plated electrode, which is the positive electrode, and these hydrogen ions pass through the solid electrolyte layer to the second electrode, which is the positive electrode.
Since the metal plated electrode becomes moisture and is released into the outside air, the formation of a moisture film is prevented. Therefore, it is possible to obtain a rotating drum assembly that can prevent the fixed drum from adhering to the magnetic tape, and from causing vibration and stick-slip of the magnetic tape.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the invention.

FIG. 2 is a plan view of this embodiment.

FIG. 3 is a longitudinal sectional view of this embodiment.

FIG. 4 is a perspective view of a second embodiment of the invention.

FIG. 5 is a plan view of this embodiment.

FIG. 6 is a partially enlarged vertical sectional view of a third embodiment of the present invention.

FIG. 7 is a perspective view showing a conventional rotating drum assembly and its peripheral configuration.

FIG. 8 is a partially enlarged cross-sectional view showing the state of contact between the conventional magnetic tape and a rotating drum and a fixed drum.

[Explanation of symbols]

3 Fixed drum 11 Insulating layer 12 First metal plating electrode 13 Second metal plated electrode 14 Solid electrolyte layer 15 Slit 17 Breathable insulation film 18 DC power supply

Claims (2)

[Claims] [Claim 1] A slit is formed on an insulating layer formed on a magnetic tape sliding surface of a fixed drum so that the magnetic tape is separated into a surface on which it slides and a surface on which it does not slide. Applying a DC voltage between the first and second metal plating electrodes, a hygroscopic solid electrolyte layer formed to cover the surfaces of these metal plating electrodes, and the first and second plating electrodes. Rotating head assembly with power supply. 2. The rotary head assembly according to claim 1, wherein the solid electrolyte layer is hygroscopic or non-hygroscopic and further comprises a gas permeable insulating film covering the surface of the solid electrolyte layer.