Dynamic magnetic information storage or retrieval – General recording or reproducing – Signal switching
Reexamination Certificate
1999-05-10
2003-04-01
Miller, Brian E. (Department: 2652)
Dynamic magnetic information storage or retrieval
General recording or reproducing
Signal switching
C360S053000, C360S271100
Reexamination Certificate
active
06542322
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotary head apparatus and, more particularly, to a rotary head apparatus having a function to verify recorded data.
2. Description of Related Art
FIG. 5
is a sectional view of a prior art rotary head apparatus.
FIG. 6
is an explanatory view of the prior art rotary head apparatus. And
FIG. 7
is a timing chart showing a recording signal and a reproducing signal of the prior art rotary head apparatus which are plotted on angle axes.
The magnetic recording-reproducing device mounted with this type of rotary head apparatus is used in backing up data in a computer, and has a verifying function to perform a read-after-write operation. The prior art rotary head apparatus, as shown in
FIG. 5
, has a stationary drum K mounted in a lower position, a rotary drum D mounted above the stationary drum K, and a motor M mounted above the rotary drum D. The stationary drum K has a cylindrical stationary shaft
51
fixed at center thereof. The rotary drum D is rotatable on the center of the stationary shaft
51
and fitted with four magnetic heads
52
.
These four magnetic heads
52
are each comprised of a recording magnetic head W including a couple of magnetic head elements and a reproducing magnetic head R including a couple of magnetic head elements. For the recording magnetic head W a magnetic head called a combination head disposed adjacently to the couple of magnetic head elements Wa and Wb is used. Similarly, for the reproducing magnetic head R there is used a combination head comprising a couple of magnetic head elements Ra and Rb. The two magnetic heads W and R are symmetrically arranged on both sides of the stationary shaft
51
at center.
A rotary transformer
53
supplies a recording signal at the time of recording to the four magnetic heads
52
and takes out a reproducing signal at the time of reproduction. The rotary transformer
53
is comprised of a transformer
53
a
on the stationary side and a transformer
53
b
on the rotary side. These rotary transformers
53
are disposed between the stationary drum K and the rotary drum D. The transformer on the stationary side
53
a
is mounted on the stationary drum K. The transformer on the rotary side
53
b
is mounted on the rotary drum D and turns together with the rotating drum D.
Two ball bearings
55
,
55
are mounted on both sides of a center hole
56
of the rotary drum D, so that the rotary drum D will be rotatable.
The motor M is comprised of a stator section S supported on the stationary shaft
51
and a rotor section L mounted on the rotary drum D. The rotor section L is mounted on the top of the rotary drum D and the stator section S is secured on the stationary shaft
51
so as to be above the rotary section L.
The stator section S is comprised of a cylindrical stationary member
57
inserted on the stationary shaft
51
, a motor control circuit board
58
mounted with a motor control circuit, and a core
60
of a magnetic metal fitted with a coil
59
.
The rotor section L is formed in a shape of cup and has a rotor motor yoke
61
attached on the rotary drum D and a cylindrical magnet
62
fixedly bonded to the inside of the side wall of the rotor motor yoke
61
. The core
60
is disposed inside the cylindrical magnet
62
; the core
60
and the magnet
62
are oppositely arranged with the same amount of clearance provided all around.
The above-described prior art rotary head apparatus is of such a design that the rotary drum D is turned by power from the motor M; with the rotation of the rotary drum D the four magnetic heads
52
also are turned to move a magnetic tape T pressed with a predetermined pressure in contact with these magnetic heads
52
, thereby performing recording or reproduction.
As shown in
FIG. 6
, the prior art rotary head apparatus is driven to perform read-after-write operation. At this time the rotary drum apparatus turns through an effective wrap angle P of about 180 degrees, that is, through the angle for signal recording into, or reproducing from, the magnetic tape T. Furthermore, information, when recorded on the magnetic tape T by the recording magnetic head W, is recorded by the magnetic head W during a turn from 0° (the reference position in which the recording magnetic head W of the rotary drum D faces the magnetic tape T as shown in the timing chart in
FIG. 7
) to 180 ° of the rotary drum D; that is, magnetic head elements Wa and Wb operate to record nearly simultaneously the recording magnetic head W of the rotary drum D. The magnetic head elements Wa and Wb are arranged a little apart from each other, and therefore there is an about 1° to 2° delay on the angle axis. Consequently the magnetic head element Wb follows the magnetic head element Wa in the direction of rotation (i.e., direction of recording).
Reproduction using the reproducing magnetic head R is a read-after-write operation to check to see whether or not signal recording on the magnetic tape T is done properly in accordance with a reproducing signal. The reproducing magnetic head R and the recording magnetic head W are arranged at a spacing of 180° on the outer peripheral surface of the rotary drum D; the reproducing angle, therefore, will not overlap the recording angle at which the recording signal is recorded. That is, while the rotary drum D is turning from 180° to 360° (i.e., 0°) within which angle no recording is done by the recording magnetic head W, the reproducing magnetic head R reproduces the signal recorded by the recording magnetic head W. The recording signal to be reproduced by the magnetic head element Ra at this time is a signal recorded by the magnetic head element Wa, and the signal to be reproduced by the magnetic head element Rb is a signal recorded by the magnetic head element Wb. In this manner the read-after-write operation is repeated.
In this type of rotary head apparatus, however, recording is done by the recording magnetic head W only within the range of 180° during a 360° turn (one turn) of the rotary drum D as shown in FIG.
7
. Furthermore, reproduction for the read-after-write operation that can be done by the reproducing magnetic head R is similarly 180°. In a rotary head apparatus having the magnetic head
52
including a couple of combination heads, the effective wrap angle P is about 180°, and therefore the speed of rotation, that is, the time for data recording and reproducing for read-after-write operation can not be decreased as far as the same constitution as mentioned above is employed. Consequently the rate of data transfer also can not be improved.
Various kinds of means have been proposed in an attempt to improve the rate of data transfer; of these means there has been known a means for improving the rate of data transfer by a rotary head apparatus using eight magnetic head elements including two combination heads of the first and second recording magnetic heads W
1
and W
2
and two combination heads of the first and second reproducing magnetic heads R
1
and R
2
. The recording magnetic head W
1
is comprised of a combination head with a couple of magnetic head elements W
1
a
and W
1
b
adjacently arranged. Similarly the recording magnetic head W
2
is comprised of a couple of magnetic head elements W
2
a
and W
2
b
; the reproducing magnetic head R
1
is comprised of a couple of magnetic head elements R
1
a
and R
1
b
; and the reproducing magnetic head R
2
is comprised of a couple of magnetic head elements R
2
a
and R
2
b.
The couple of recording magnetic heads W
1
and W
2
are arranged symmetrically with the stationary shaft
51
placed at center. In a similar manner the couple of reproducing magnetic heads R
1
and R
2
are also symmetrically positioned with the stationary shaft
51
at center. The four magnetic heads
52
are arranged at an equal spacing of 90° on the outer peripheral surface of the cylindrical rotary drum D in the order of W
1
, R
1
, W
2
and R
2
when viewed clockwise.
According to the rotary head apparatus thus constituted, the recording magnetic head
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Chen Tianjie
Miller Brian E.
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