Non-abrasive magnetic head cleaning system

A cleaning system for flexible disk equipment or the like. The system includes a cleaning disk made of an absorbent and porous fibrous material which has an area substantially saturated with a liquid cleaning solution. The cleaning disk is rotatably supported within a flat jacket. The jacket includes opposed openings on either side so as to expose a portion of the cleaning disk to enable the disk to come into contact with a magnetic head or heads. At least one of the openings is enlarged to expose a relatively large portion of the surface of the cleaning disk, so as to facilitate complete saturation of an area of the cleaning disk with a liquid cleaning solution while leaving a portion of the cleaning disk dry. The jacket containing the disk is placed within a flexible disk system which rotates the saturated disk, thus causing the magnetic head(s) to be cleaned in a non-abrasive fashion with a wet, dry, wet action. An improved jacket for use with a thickened cleaning disk is also disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to systems for cleaning the magnetic head(s) in 
flexible disk systems. With flexible disk drives, as with other pieces of 
data processing equipment, preventive care and periodic maintenance are 
necessary to insure efficient, smooth and error free operation. Unlike 
other peripheral devices, the magnetic heads on flexible disk drives are 
extremely difficult to access without partially disassembling the drive 
system. Due to this difficulty, head cleaning is generally done only when 
read/write problems are being experienced. 
2. Prior Art 
Several systems have been developed in an attempt to provide a convenient 
means of cleaning the head(s) on flexible disk systems. One such system 
utilizes two flexible disk jackets. One of the jackets contains an 
abrasive lapping material, and the other contains a cleaning cloth 
material. The first jacket is inserted into the flexible disk system and 
run through the machine for a predetermined amount of time (generally no 
longer than ten seconds in order to avoid damage to the magnetic head from 
the abrasive material) so as to loosen debris from the head. The second 
jacket is then run through the machine so as to pick up the loosened 
debris. The flexible disk jackets which are used contain standard size 
openings (i.e. thin radial slots) in order to allow the heads and pressure 
pad to contact the cleaning material. 
A second system, described in IBM Technical Disclosure Bulletin Vol. 20, 
No. 8, January 1978, utilizes a standard flexible disk jacket and 
substitutes an abrasive disk for the normal magnetic disk. The abrasive 
disk is coated with either chromic oxide (CR.sub.2 O.sub.3 having a 
diameter of less than 0.7 microns or aluminum oxide (Al.sub.2 O.sub.3 of 
the same diameter. The assembly is used to initially lap the magnetic 
heads of flexible disk drives and subsequently remove contaminant build-up 
on the head(s). 
A third system for cleaning magnetic heads is diclosed in U.S. Pat. No. 
4,065,798 issued to Sugisaki et al., on Dec. 27, 1977. This system 
includes a laminated disk which has a flexible non-magnetic support (e.g., 
polyvinyl chloride) coated with a magnetic layer on one side and a fibrous 
cleaning material on the other side. The cleaning disk is located within a 
cartridge which contains a lubricating layer facing the magnetic layer of 
the cleaning disk, and includes a normal radial slit which allows the 
magnetic head to contact the fibrous cleaning material. 
It is therefore an object of this invention to provide a system for 
cleaning the magnetic head(s) of flexible disk drive machines without the 
need for any disassembly of the machine. 
It is another object of the present invention to provide a head cleaning 
system which is substantially non-abrasive and will therefore not harm the 
magnetic heads in any way. 
It is another object of the invention to provide a head cleaning system 
which permits the use of a liquid cleaning solution. 
It is a further object of the invention to provide a head cleaning system 
which may be left engaged in a disk drive machine for long periods of time 
without damage to the magnetic heads. 
SUMMARY OF THE INVENTION 
These and other objects are achieved by providing a head cleaning system 
which includes a cleaning disk made of an absorbent lint free and porous 
material which has an area substantially saturated with a liquid cleaning 
solution and a dry area. The cleaning disk is rotatably supported within a 
jacket that includes opposed radial openings on its upper and lower 
surfaces for exposing the cleaning disk to the magnetic head of a flexible 
disk system (or both magnetic heads if the drive system is equipped for 
dual sided flexible disks). At least one of the openings exposes enough of 
the surface of the cleaning disk so as to facilitate saturation of 
approximately 1/8 to 1/2 of the cleaning disk area with the cleaning 
solution without requiring removal of the disk from the jacket. As the 
disk rotates a wet/dry/wet/dry surface is presented to the head(s) which 
provides an effective non-abrasive cleaning. Also, the formulation of the 
solution is such that it evaporates during the predetermined cleaning 
cycle (generally less than three minutes) insuring that the head(s) are 
dry and clean. The porous nature of the cleaning disk facilitates the 
collection of foreign particles. 
The saturation opening exists on only one side of the jacket while the 
other side of the jacket has a perforated oblong section. This perforated 
section remains intact as to single head disk drives and dual head disk 
drives where the heads are not in direct opposition to one another. The 
oblong perforated section is removed to form an opening for cleaning a 
head when the jacket is employed in dual head disk drives where the heads 
are in direct opposition to one another. More specifically, the saturation 
opening in the jacket which exposes the cleaning disk should have a 
configuration that provides adequate support for the cleaning disk, 
thereby avoiding any substantial sagging of the cleaning disk which would 
interfere with the disk drive and hamper removal of the cleaning system. 
This support should be provided while exposing an adequate area of the 
cleaning disk for saturation. One means for accomplishing such support is 
the forming of an opening in the jacket which inherently provides support 
to the cleaning disk. Such openings in general have at least one major 
boundary which is more generally chordal as distinguished from radial or 
concentric. The other major boundary generally tends to be more 
curvilinear although not necessarily circular.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now to FIG. 1, the present invention includes a jacket 10 which 
rotatably supports a cleaning disk 12. The material used for the jacket 10 
may conveniently be the standard vinyl-like material which is utilized for 
normal magnetic floppy disk jackets. Other materials are also within the 
scope of the present invention. The cleaning disk 12 is made of a 
lint-free, absorbent material of a porous nature so that contaminants and 
debris picked up from the head(s) are trapped and held by the cleaning 
disk surface. Preferably, the disk 12 is made from a lint free fibrous 
porous material having a white or other light color so that an operator 
may easily tell when the disk 12 needs replacement by checking it for 
discoloration. The cleaning disk 12 should be relatively resistant to wear 
so that several cleanings can be accomplished with the same disk. 
Materials which may be used for the cleaning disk 12 include, but are not 
limited to, spunbonded polyester (e.g., Dupont Reemay) or spunbonded 
olefin. 
Referring further to FIG. 1, the jacket 10 includes a center opening 14 for 
accommodating a drive shaft of a disk drive system. Similarly, the 
cleaning disk 12 includes a center opening 15 through which a drive shaft 
passes. The jacket 10 includes an enlarged opening 16 which exposes a 
portion of the disk 12 of approximately 1/8-1/2 of its cleaning area and 
preferably approximately 1/4. The opposite side of the jacket 10 contains 
a perforated thin radial section 18a which is left in place when the 
invention is used to clean single head drives. If the disk drive has two 
heads, the perforated radial section 18a is removed, exposing opening 18, 
so that both heads can be cleaned at the same time. When cleaning single 
head drives, the perforated radial section 18a is not removed because the 
solution and cleaning material could damage the pressure pad of certain 
models of disk drives. It is, of course, possible to devise a pressure pad 
construction that would not be so damaged. 
The openings 16 and 18 serve to expose the surface of the cleaning disk to 
the magnetic head of a disk drive system, or to two magnetic heads in the 
case of a dual-sided disk drive system. The enlarged opening 16 is 
provided to facilitate saturation of a suitable portion of the cleaning 
disk 12 with a cleaning fluid in one application without requiring the 
removal of the cleaning disk 12 from the jacket 10 or rotation of the disk 
12. Depending upon the absorbency and wetting action of the material of 
the cleaning disk 12, the size of the opening 16 may be either smaller or 
larger than the size shown. Generally, with the aforementioned materials 
the opening will be sufficient if it exposes approximately one quarter of 
the surface of the cleaning disk 12. The basic purpose is to permit the 
application of cleaning fluid through the opening 16 which will then be 
absorbed by the cleaning disk 12 over the appropriate portion of its 
surface. If the jacket 10 contained thin radial slots which are typically 
for magnetic disk jackets (i.e., approximately the size of the opening 
18), it would be difficult, if not impossible, to properly saturate the 
cleaning disk 12 in one application. Rather, a small portion of the disk 
12 would have to be saturated and then the disk 12 would have to be 
rotated so as to expose another unsaturated portion. This process would 
have to be continued until the appropriate portion of the cleaning disk 12 
were saturated with cleaning fluid. When a volatile cleaning solution is 
employed there is the problem of the solution quickly evaporating before 
cleaning commences. Since the material used for the disk 12 is absorbent, 
the size of the opening 16 facilitates quick saturation in one application 
while still allowing the jacket 10 to support the disk 12. 
In addition to the size of the opening 16, it has been determined that the 
configuration of the opening is also of significance. It is preferred that 
opening 16 have a configuration such as shown in FIG. 1. The configuration 
of opening 16 has a generally straight or chordal portion 19 and an 
adjacent area that provides support for the cleaning disk 12. The portion 
19 of opening 16 is connected to a curved portion 21 that is generally 
separated from the portion 19 by a decreasing dimension or width W. The 
maximum dimension should be at least large enough to enable the entire 
head of the disk drive to be cleaned by the cleaning disk. In the 
preferred embodiment this occurs at the diametrical width 23, which 
includes a radiused or circular portion 25 continuous with curved portion 
21. 
Alternate configurations of opening 16 may be employed provided saturation 
of the disk is facilitated, while the support of the disk and jacket is 
maintained so as to minimize planar distortions (sagging, etc.) that may 
interfere with the insertion and removal of the cleaning system. For 
example, the opening 16 may be generally triangular, elliptical or 
rectangular. The rectangular configuration involves some disadvantageous 
compromises which may be tolerated or which may be overcome by the 
addition of a second saturation opening. 
In a single head disk drive the side of the cleaning disk not in contact 
with the head is completely supported by the pressure pad. In a dual-head 
disk drive with the heads in direct opposition to one another, the 
perforated portion 18a is removed and the second head projects through the 
opening 18 formed by the removal of the perforated portion 18a. This 
opening may conveniently be the same size and configuration utilized on 
standard floppy disk jackets. Any other configuration which enables the 
entire head to be cleaned would also be acceptable. 
In certain dual-head disk drives, the heads on opposite sides of the disk 
are offset with respect to one another, with a pressure pad being located 
in opposition to each head. In order to clean disk drives with such head 
arrangements without engagement of the pressure pads, the same jacket may 
be employed with a thicker cleaning disk, which would enable both of the 
heads to contact the cleaning disk without the pressure pads engaging the 
disk. In this manner, cleaning of both heads simultaneously without 
interference from the pressure pads is facilitated. 
Referring further to FIG. 1, a plurality of holes 27 in the jacket are 
employed to enable the cleaning device of this invention to simulate a 
magnetic disk and thereby enable the disk drive to be rotated and 
controlled in the same manner as if a magnetic disk were positioned in the 
system. The different holes are for different types of disk drives. For 
example, the hole 33 is employed in a single-sided single-head drive while 
the hole 35 is employed in double-sided disk drives such as those 
employing opposed heads. A compatible hole or holes are formed in the 
cleaning disk. Of course, other hole configurations for use with different 
types of drives are within the scope of the invention. 
Many types of cleaning solutions may be used to saturate the disk 12. For 
example, a typical isopropyl alcohol or a mixture of isopropyl alcohol and 
a flourocarbon (e.g., freon) could be utilized. Any solution may be 
employed that: has solvent properties such that it dissolves common 
contaminants found on heads, does not leave a residue on the heads, and 
evaporates during the predetermined cleaning cycle (e.g., less than three 
minutes). In the preferred embodiment the cleaning solution evaporates in 
less than 90 seconds when rotated by a commercially available floppy disk 
drive. 
Referring now to FIG. 2, the cleaning system is shown in engagement with a 
single head drive system 20. After a portion of the cleaning disk 12 is 
saturated with cleaning solution via opening 16 the cleaning system is 
inserted in drive 20, where a magnetic head 22 contacts one side of the 
cleaning disk 12 via opening 16 and a pressure pad 24 (schematically 
shown) applies pressure to the outside of the jacket 10 and therefore the 
disk 12, but is prevented from contacting the cleaning disk 12. The drive 
system 20 rotates the cleaning disk 12 and includes a clutch (not shown) 
which grasps the cleaning disk 12. Debris which has accumulated on the 
magnetic head 22 is dissolved by the cleaning solution and carried away by 
the cleaning disk 12. The dry portion of the cleaning disk contacts the 
head after the wet portion of the cleaning disk contacts the head. This 
wet-dry cycle facilitates cleaning and drying of the beads. Since the 
fibrous material of the disk 12 is substantially non-abrasive, the drive 
system 20 may be left engaged for a long period of time without any damage 
to the magnetic head 22. 
FIGS. 3 and 4 show an alternate embodiment of the invention. In these 
figures the same numerals employed in FIGS. 1 and 2 are employed to 
designate similar parts. The primary difference between the embodiments 
shown in FIGS. 3 and 4 and that of FIGS. 1 and 2 is the addition of two 
isolation means in the form of bridge members 36 and 38 which extend 
across the opening 16 from portion 19 to portion 21. As shown in FIG. 4, 
when the jacket 10 is inserted into the disk drive, the bridge members 36 
and 38 contact a pair of pressure pads 24A and 24B and prevent the 
pressure pads from contacting the cleaning disk 12. It should be noted 
that the disk drive employed in FIG. 4 is an arrangement different from 
that shown or mentioned in connection with FIG. 2. The disk drive of FIG. 
4 in addition to employing a pair of pressure pads 24A and 24B utilize a 
magnetic head 22 located between the pressure pads. On the opposite side 
of the jacket in an opposed relationship to the pressure pads are 
structural members 40 and 42 which support the jacket 10 and facilitate 
operation of the pressure pads 24A and 24B. In this type of disk drive it 
is common to employ a pair of magnetic heads 22 in direct opposed 
relationship. In such a disk drive employing two magnetic heads the 
perforation 18 would be removed and both magnetic heads would be in direct 
contact with the cleaning disk 12 to enable simultaneous cleaning of both 
heads. The addition of the bridge members 36 and 38 enables the subject 
invention to be employed not only in connection with the disk drives as 
described in connection with FIGS. 1 and 2 but also disk drives such as 
shown in FIG. 4. The bridge members 36 and 38 permit the cleaning disk 21 
to be rotated at approximately the same speed as if a magnetic disk were 
employed in the jacket 10; thus enabling the floppy disk drive to operate 
in the same manner in the cleaning mode as it would operate in a magnetic 
storage mode. 
FIGS. 5 and 6 illustrate how the cleaning system of the present invention 
engages drives with dual headed configurations. In the system shown in 
FIG. 5, the perforated portion 18a has been removed so that two opposing 
heads 22a and 22b contact opposite sides of the cleaning disk 12 so as to 
facilitate their simultaneous cleaning. In the system shown in FIG. 6, 
offset heads 22a and 22b both engage the cleaning disk 12, while the 
pressure pads 24a and 24b are left disengaged so that they do not retard 
the motion of the cleaning disk. As stated previously, the use of a 
thicker cleaning disk enables the heads in an offset arrangement to come 
into sufficient contact with the disk to achieve proper cleaning action 
despite the non-engagement of the pressure pads. 
Although the use of a relatively thick cleaning disk is advantageous when 
cleaning disk drives having an offset head arrangement, the extra 
thickness presents some problems with respect to the jacket. Since a 
typical floppy disk and cleaning disk are relatively thin, most jackets 
have previously been made simply by providing two flat sheets of material 
and securing them together at their edges, such as by folding one edge 
over another as shown in FIG. 1. When a thick cleaning disk is employed 
with this type of jacket, pressure from the sides of the jacket results in 
the cleaning disk having a tendency to drag and stick as it is being 
rotated. This problem may be overcome by utilizing a modified jacket 50, 
as is shown in FIGS. 7 and 8. The jacket 40 is formed with two panels or 
sheets 52 and 54. One or both of the panels includes an embossed section 
52a and/or 54a which is slightly larger in diameter than that of the 
cleaning disk 12. When the panels 52 and 54 are fastened together, the 
embossments form a cavity within which the cleaning disk 12 is held. The 
additional space provided by the cavity permits the thick cleaning disk 12 
to rotate freely within the jacket 50. The panels 52 and 54 may be sealed 
by one of a number of different methods, including but not limited to 
ultrasonic welding, heat sealing and the use of adhesives. It should be 
noted that the additional thickness of the jacket 50 caused by the 
embossments will not interfere with the operation of the disk drive 
system. Furthermore, the embossed jacket 50 is not limited to use with a 
cleaning disk, but could also be employed with regular magnetic floppy 
disks. 
Referring to FIG. 9, yet another alternate embodiment of the invention 
employs a jacket 60 which has standard narrow slit openings 62. In 
addition, separate openings 64 are included in the top side of the jacket 
60 to facilitate saturation of the cleaning disk 12. The openings 62 are 
such that the disk 12 will have little or no tendency to sag through them. 
Of course, many variations in the size, number and configuration of 
openings can be devised. The basic consideration is to provide a jacket 
which facilitates saturation of the cleaning disk while still providing 
adequate support for the cleaning disk. 
In summary, the present invention provides a system which permits 
convenient cleaning of the magnetic heads in a magnetic disk drive system. 
This is facilitated by using a jacket having an enlarged saturation 
opening and carrying a cleaning disk of fibrous and porous absorbent 
material. The saturation opening or openings must be of a configuration 
that enables the disk to be supported so as to minimize planar 
distortions. A cleaning solution is applied to the cleaning disk through 
the saturation opening until a portion of the cleaning disk is saturated. 
The jacket containing the disk is then placed within a disk drive system 
which is then turned on for a period of time so as to clean the magnetic 
head(s).