Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
1998-11-25
2001-06-26
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S075000, C360S246100
Reexamination Certificate
active
06252737
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a contact magnetic disk apparatus and, more particularly, to a contact magnetic disk apparatus for recording/reproducing information by bringing the contact pads of a magnetic head into contact with a magnetic disk surface coated with a lubricant.
2. Description of the Prior Art
FIGS. 1A and 1B
, and
2
show a conventional example. Referring to
FIGS. 1A and 1B
, a magnetic head
53
is held on the surface of a magnetic disk
50
, rotated in the direction of an arrow D
1
, through a suspension
51
and an arm
52
. A recording/reproducing element
54
and contact pads
55
are fixed to the magnetic head
53
. The contact pads
55
are urged against the magnetic disk surface by the suspension
51
. Along with the operation of an actuator
56
, the magnetic head
53
is moved in substantially the radial direction of the magnetic disk
50
. The section of each contact pad
55
which is parallel to a slider surface
53
a
of the magnetic head
53
is formed into an elliptic shape having a minor axis in the radial direction of the magnetic disk
50
. The two contact pads
55
are arranged in the radial direction of the magnetic disk
50
. In the magnetic disk
50
, a substrate
61
at the center is sandwiched by magnetic films
62
, protection films
63
, and lubricant films
64
in the order named, as shown in FIG.
2
. Hence, the contact pads
55
of the magnetic disk
50
are kept in contact with the lubricant film
64
of the magnetic disk
50
. Wear of the magnetic disk surface is prevented while realizing a high recording density.
In general, the substrate
61
is made of glass or an aluminum alloy coated with a nickel-phosphorus plating film. The magnetic films
62
are made of a cobalt alloy, e.g., CoPtCr or CoCtTa. The protection films
63
are made of carbon. The lubricant films
64
contain perfluoropolyether and the like.
In the above conventional example, rotation of the magnetic disk generates a centrifugal force to move and scatter the lubricant, leading to a decrease or nonuniformity in thickness of the lubricant films. In this case, the lubricant may become insufficient and the contact portions may accordingly be worn, leading to a recording/reproducing error or erroneous erasure of the recorded information.
The present invention is made on the basis of the following situation. Namely, the present inventors experimentally found that a constant relationship was present between the operation of a contact magnetic head driven by an actuator and the thickness decreasing tendency of the lubricant.
SUMMARY OF THE INVENTION
The present invention has been made in order to solve the inconveniences of the prior art, and has as its object to provide a contact magnetic disk apparatus in which a decrease in thickness of a lubricant applied to the outermost surface of a magnetic disk medium is prevented, so that wear of a contact magnetic head and a magnetic disk medium can be effectively suppressed.
In order to achieve the above object, according to the major aspect of the present invention, there is provided a contact magnetic disk apparatus comprising a magnetic disk having a surface coated with a lubricant, a magnetic head for recording and reproducing information on and from the magnetic disk, a contact pad fixed to a slider surface of the magnetic disk, a suspension for urging the contact pad against the surface of the magnetic disk through the lubricant, an arm connected to the suspension, an actuator for operating the arm to move the magnetic head in a substantially radial direction of the magnetic disk, and a control section for controlling an operation of the actuator, wherein the control section has a lubricant uniforming function of increasing a speed with which the magnetic head is moved toward an outer periphery of the magnetic disk to be higher than a speed with which the magnetic head is moved toward an inner periphery of the magnetic disk.
With the arrangement described in the major aspect, when the magnetic head is moved toward the inner periphery, the lubricant is effectively guided toward the inner periphery. When the magnetic head is moved toward the outer periphery, it does not comparatively influence movement of the lubricant in the centrifugal direction (in the outer peripheral direction of the magnetic disk).
In connection with the above major aspect, the present invention has auxiliary aspects as follows.
According to the first auxiliary aspect, the lubricant uniforming function described in the major aspect moves the magnetic head toward the inner periphery of the magnetic disk at a speed not higher than V
0
=R×n where R is a radius of the contact pad and n is a rotation speed of the magnetic disk and toward the outer periphery of the magnetic disk at a speed higher than V
0
.
According to the second auxiliary aspect, the contact pad described in the above major aspect has a section parallel to the slider surface of the magnetic head, which is formed into a circle.
According to the third auxiliary aspect, the contact pad described in the above major aspect has a section parallel to the slider surface of the magnetic head, which is formed into a C shape open toward the inner periphery of the magnetic disk.
According to the fourth auxiliary aspect, the contact pad described in the above major aspect has a section parallel to the slider surface of the magnetic head, which is formed into a semicircle having an arc toward the inner periphery of the magnetic disk.
According to the fifth auxiliary aspect, the surface of the magnetic disk described in the above major aspect has an average square roughness of 0.1 nm to 0.5 nm.
According to the sixth auxiliary aspect, the magnetic pad described in the above major aspect is urged against the surface of the magnetic disk with a load of not more than 0.5 gf.
According to the first to sixth auxiliary aspects described above, it is experimentally confirmed that movement of the lubricant in the centrifugal direction is suppressed comparatively effectively even when the magnetic head is moved toward the outer periphery of the magnetic disk.
The present invention has the arrangement and function as described above. Therefore, the present invention can provide an excellent magnetic disk apparatus that is not conventionally available, in which a decrease in thickness of the lubricant applied to the surface of the magnetic disk can be effectively suppressed by optimizing the shape of the contact pad provided to the magnetic head, the seek moving speed of the magnetic head, the urging load of the magnetic head, and the surface roughness of the magnetic disk, and the mechanical reliability of the apparatus can be improved through wear prevention of the magnetic disk and magnetic head.
The above and many other objects, features and advantages of the present invention will become manifest to those skilled in the art upon making reference to the following detailed description and accompanying drawings in which preferred embodiments incorporating the principles of the present invention are shown by way of illustrative examples.
REFERENCES:
patent: 5309301 (1994-05-01), Gregory et al.
patent: 5541789 (1996-07-01), Fukuoka et al.
patent: 5850321 (1998-12-01), McNeil et al.
patent: 5889635 (1999-03-01), Sato
patent: 7-211045 (1995-08-01), None
patent: 8-83421 (1996-03-01), None
McGinn & Gibb PLLC
NEC Corporation
Sniezek Andrew L.
Wong Kin
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