JPH0438646A - Rotary head device - Google Patents

Abstract

PURPOSE:To obtain stable contact between a magnetic head and a magnetic tape over the whole range around a cylinder by changing the position of a tape guide member over against the outer circumferential surface of the rotary cylinder in accordance with a signal of a position detecting means. CONSTITUTION:A position detecting sensor is composed of a magnet 12 and an MR element 13, and the magnet 12 if fitted to the rotary cylinder 1, while the MR element 13 is fitted opposite to the magnet 12 to a stationary cylinder 16. The stationary cylinder 16 is provided with a tape guide for guiding the magnetic tape 11. An output obtained from the MR element 13 is changed when the magnet 12 approaches the MR element 13, so that the rotary position of the rotary cylinder at that time can be detected. Then, the tape guide member is controlled to be changed in its position over against the outer circumferential surface of the rotary cylinder in accordance with an output signal of the position detecting sensor. By this method, the magnetic tape on its inlet side where the magnetic tape floating amt. is large is pulled to a magnetic head window part, so that the stable contact between the magnetic head and the magnetic tape can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotating gutter device in a magnetic recording/reproducing device.

2. Description of the Related Art Conventional rotary head devices generally have a configuration as shown in Japanese Patent Application Laid-Open No. 60-46968. The configuration will now be explained with reference to FIGS. 6 and 7.

FIG. 6 is a plan view of a conventional rotary head device viewed from the head mounting side. In the figure, 1 is a rotating cylinder, 2 is a head chip, 14 is a head mounting base, 15 is a head chip base, and 11 is a magnetic tape. The head chip 2 is fixed to a hent chip stand 15, and the head chip stand 15 is fixed to a head mounting stand 14, respectively. and,
Henod 3/\-7 The mounting base 14 is attached to the rotary cylinder 1 so that the tip of the helad tip 2 protrudes a certain amount from the outer peripheral side of the rotary cylinder 1.
It is attached to.

FIG. 7 is a side sectional view of a conventional rotary head device, with 16
17 is a fixed cylinder, 17 is a bearing, and 18 is a rotating shaft. The rotating cylinder 1 rotates integrally with the rotating shaft 18 in the direction of arrow B in FIG. 6 with respect to a bearing 17 provided at the center of the fixed cylinder 16.

The magnetic tape 11 runs along a tape guide (not shown) provided on a fixed cylinder in the direction of the arrow as shown in FIG. , leaves the cylinder at the position marked exit on the right side of the figure.

Problems to be Solved by the Invention The configuration of such a conventional rotary head device has the disadvantage that the contact between the magnetic tape and the magnetic head is incomplete, as described below.

FIG. 8 is a diagram showing the contact state (head touch state) between the magnetic tape and the magnetic head on the entrance side and the exit side in a conventional rotary head device.

In a magnetic recording/reproducing apparatus such as a VTR, the head contact state between the magnetic tape and the magnetic head is an important factor in order to perform good magnetic recording/reproducing.

When the cylinder rotates at high speed, an air film is formed between the cylinder and the magnetic tape, and the air film layer becomes thicker, especially on the inlet side.The flying height of the magnetic tape relative to the cylinder surface is large, and the contact with the magnetic head is on the exit side. It is easy to be incomplete in comparison. Particularly in high-density recording magnetic recording devices, the quality of this head touch significantly affects the recording and reproducing characteristics.

This deterioration in head touch due to increased magnetic tape floating can be improved by increasing the amount of head protrusion. As a result, the head touch becomes worse and, in addition, the head wear increases.

The present invention solves the above-mentioned problems. Even when the rotary cylinder rotates at high speed and the tape floats significantly on the input side, the magnetic tape sticks to the cylinder and contacts the magnetic head throughout the entire range. It is an object of the present invention to provide a rotating head device that can provide good head touch over the entire range.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides an electro-mechanical conversion member that is attached to the head mounting window on the rotary cylinder near the magnetic head via an electro-mechanical conversion member that is displaceable in the normal direction of the rotary cylinder. a tape guide member, a position detection means for detecting the rotational position of the rotary cylinder, and a guide member control means for controlling the position of the tape guide member with respect to the outer peripheral surface of the rotary cylinder in accordance with an output signal of the position detection means. It is characterized by comprising:

According to the above-described structure, the present invention pulls the magnetic tape into the magnetic head window on the entry side where the magnetic tape has a large flying height, thereby achieving a stable contact state between the magnetic head and the magnetic tape.

Example Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

I will explain.

FIG. 1 is a plan view of the rotary cylinder of the rotary head device of the present invention, seen from the head mounting side. In the figure, 1 is a rotary cylinder, 2 is a blade tip, 3 is a guide plate, 4 is a head substrate, and 5 is an actuator. The head chip 2 is fixed to a head substrate 4. Head board 4
The tip of the helad tip 2 is attached to the rotary cylinder 1 so that the tip thereof protrudes a certain amount from the outer circumferential surface of the rotary cylinder 1. The guide plate 3 and the actuator 5 are connected to the head substrate 4
It is installed on top.

FIG. 2 is a diagram showing the configuration of the actuator.

In the figure, 3 is a guide plate, and 6 is a support substrate.

The guide plate 3 is fixed to a support substrate 6, and the support substrate 6 is fixed to a moving coil bobbin 7.

A moving coil 19 is wound around the moving coil bobbin 7. 8 is a permanent magnet, 9 is a leaf spring, 10 is an actuator base, and 11 is a magnetic tape.

When the excitation current is not flowing through the moving coil 19, the moving coil bobbin 7, the support board 6, and the guide plate 3 are in the position shown in FIG. 2 by the leaf spring 9.

FIG. 3 is a schematic diagram of a position detection sensor of a rotary cylinder in a rotary head device of the present invention.

The position detection sensor is composed of a magnet 12 and an MR element 13. The magnet 12 is attached to the rotating cylinder 1, and the MR element 13 is attached to the fixed cylinder so as to face the magnet 12. The fixed cylinder 16 is provided with a tape guide (not shown) that guides the magnetic tape 11. Since the output obtained from the MR element 13 changes when the magnet 12 approaches the MR element 13, the rotational position of the rotating cylinder at that time can be detected.

The moving coil bobbin 7 is in the second
At the position shown in the figure, the actuator control circuit (not shown) is operated by the signal from the position detection sensor (output signal of the MR element 13), and the cylinder rotation angle is approximately 3.
When the temperature exceeds 0 degrees, an exciting current begins to flow through the moving coil 19. This excitation current reaches its maximum at a cylinder rotation angle of approximately 90 degrees, and remains at this level until the magnetic head separates from the magnetic tape. After separating, the excitation current for the coil 19 from the actuator control circuit decreases, and the moving coil bobbin 7 and therefore the guide plate 3 return to the position shown in FIG. 2.

FIG. 4 is a diagram showing the state when the moving coil 19 is energized with excitation current. By energizing the moving coil 19, the moving coil bobbin 7 moves in the outer circumferential direction of the cylinder, so the guide plate 3 also moves in the outer circumferential direction, and as described above, the guide plate 3 moves in the radial direction of the cylinder at a position where the cylinder rotation angle is about 90 degrees. The amount of protrusion is the maximum. At this time, the position of the front surface of the guide plate 3 is approximately equal to the outer peripheral surface of the rotating cylinder.

FIG. 5 is an external view of the vicinity including the window from which the magnetic head protrudes when the moving coil excitation current is energized and when it is not energized.

As described as a problem with the prior art, tape floating from the cylinder is large on the tape inlet side of the cylinder G-7, but since the guide plate 3 is retracted from the outer peripheral surface of the cylinder when not energized, As shown in FIG. 2, the area of the magnetic head window becomes narrower and the magnetic tape is drawn into the magnetic head window, improving the contact between the magnetic head and the magnetic tape. Since tape floating is not large at the center and exit side of the cylinder, the contact pressure between the head and tape becomes too strong at the actuator position shown in Figure 2, leading to significant head wear and the risk of damaging the magnetic tape. Therefore, by driving the actuator and moving the guide plate 3 closer to the outer circumferential surface of the cylinder, the area of the magnetic head window can be reduced as shown in Figure 4 to reduce the amount of tape sucked into the window and to create a proper magnetic head. Ensure magnetic tape contact.

Effects of the Invention As described above, in the present invention, a tape guide is attached near the magnetic head in the head mounting window on the rotary cylinder via an electro-mechanical conversion member that can be displaced in the normal direction of the rotary cylinder. 10＼-7 A member, a position detection means for detecting the rotational position of the rotary cylinder, and a guide member control means for controlling the tape guide member to change its position with respect to the outer peripheral surface of the rotary cylinder according to a signal from the position detection means. With this configuration, the magnetic tape is drawn into the head window at a position on the cylinder where the tape has a large floating height, and the drawing into the head window is reduced at a normal position where the air film layer is thin, so that the magnetic tape is pulled into the cylinder. Stable contact between the magnetic head and the magnetic tape can be obtained throughout the entire winding range.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a rotary cylinder in a rotary head device according to an embodiment of the present invention as seen from the head mounting side, FIG. 2 is a sectional view of an actuator, and FIG. 3 is a position of the rotary cylinder in a rotary head device of the present invention. A schematic diagram of the detection sensor. Figure 4 is a cross-sectional view showing the state when the moving coil excitation current is energized. Figures 5 and 5B show the window from which the magnetic head protrudes when the moving coil excitation current is energized and when it is not energized. FIG. 6 is a perspective view of the vicinity including 11 of the conventional rotating head device.
, ＞A plan view as seen from the head mounting side, FIG. 7 is a side sectional view of a conventional rotary head device, and FIGS. 8A and B are diagrams of the magnetic tape and magnetic head at the entrance and exit sides of a conventional rotary head device. It is a sectional view showing a contact state. 1... Rotating cylinder, 2... Head chip, 3... Guide plate, 6... River actuator,
7...Moving coil bobbin, 8...Permanent magnet, 11...Magnetic tape, 12...Magnet, 13...MR element, 16...・Fixed cylinder, 19...Moving coil. Name of agent: Patent attorney Shigetaka Awano and one other person (B)

Claims (2)

[Claims] (1) A fixed cylinder provided with a tape guide that guides a magnetic tape, a rotating cylinder that rotates coaxially with the fixed cylinder, a head mounting window provided at an end of the outer peripheral surface of the rotating cylinder, and the head A magnetic head that protrudes a certain amount from the mounting window and is attached to the rotating cylinder, and the magnetic head of the head mounting window on the rotating cylinder via an electro-mechanical conversion member that is displaceable in the normal direction of the rotating cylinder. a tape guide member attached nearby, a position detecting means for detecting the rotational position of the rotary cylinder, and a guide member that changes the position of the tape guide member with respect to the outer circumferential surface of the rotary cylinder in response to a signal from the position detecting means. A rotary head device comprising: a control means. (2) A guide member control means for changing the position of the tape guide member relative to the outer circumferential surface of the rotating cylinder at the starting end of contact between the tape and the cylinder in response to a signal from the position detection means. The rotating head device according to item 1.