Non-Abrasive Magnetic Head Cleaning System

1. Field of the Invention

This invention relates to systems for cleaning the magnetic heads and pressure pads 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 and pressure pads on flexible disk drives are extremely difficult to access without partially disassembling the drive system. Due to this difficulty, head cleaning is 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 heads and 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 mircrons or aluminum oxide (Al.sub.2 O.sub.3) of the same diameter. The assembly is used to initially lap the magnetic heads of disk drive machines and subsequently remove contaminant build-up on the heads.

A third system for cleaning magnetic heads is disclosed in U.S. Pat. No. 4,065,798 issued to Sugisaki, et al., on Dec. 27, 1977. This system includes a cleaning 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 heads and pressure pads 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.

These and other objects are achieved by providing a head cleaning system which incudes 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 and pressure pad of a flexible disk system (or both sets of 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 insuring that the head(s) are dry and clean. The porous nature of the cleaning disk facilitates the collection of foreign particles.

In the drawings, wherein like numerals refer to corresponding components in the several Figures:

FIG. 1 is a top plan view of the cleaning system of the present invention; and

FIG. 2 is a side view, in section, of the cleaning system of the present invention shown in position to clean the magnetic head and pressure pad of a disk drive system.

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 is not critical and may conveniently be the standard black vinyl-like or paper-like material which is utilized for normal magnetic floppy disk jackets. 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 fibrous material having a white or other light color material 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 frequent replacement is not necessary. Materials which may be used for the cleaning disc 12 include spunbonded polyester (e.g., Dupont Reemay) or spunbonded olefin (e.g., Dupont Tyvek).

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 radial opening 16 which exposes a sector of the cleaning disk 12 in the range of approximately 45.degree.-180.degree. (i.e., 1/8-1/2 of the cleaning area of the cleaning disk) and preferably approximately 120.degree.. The opposite side of the jacket 10 contains a normal thin radial slit opening 18. The openings 16 and 18 serve to expose the surface of the cleaning disk to a magnetic head and pressure pad 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 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 120.degree. 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 (i.e., the opening 16 covers a 90.degree. sector). 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 normally used 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 such as one employing freon and isprophyl alcohol there is the problem of the solution quickly evaporating before cleaning commences. Since the material used for the disk 12 is absorbent, the 120.degree. opening 16 permits quick saturation in one application while still allowing the jacket 10 to support the disk 12.

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 jacket 10 with the cleaning disk 12 is shown in engagement with a drive system 20. After a portion of the cleaning disk is saturated with cleaning solution via opening 16 a magnetic head 22 contacts one side of the cleaning disk 12 via opening 16 and a pressure pad 24 contacts the other side of the disk 12. In the case of a dual sided magnetic disk system, a second magnetic head would replace the pressure pad 24. The drive system 20 rotates the cleaning disk 12. Debris which has accumulated on the magnetic head 22 and the pressure pad 24 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(s). This wet-dry cycle facilitates drying and cleaning of the heads. 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.

In summary, the present invention provides a system which permits convenient one-step cleaning of the magnetic heads and pressure pads on magnetic disk drive systems. This is facilitated by using a jacket having an enlarged opening and carrying a cleaning disk of fibrous and porous absorbent material. A cleaning solution is applied to the cleaning disk through the enlarged 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 heads and pressure pads of the system.