Magnetic disk drive with a filter assembly capable of removing dust and toxic gases

#The present invention relates to a filter assembly capable of selectively removing toxic gases and dust floating in and entering a magnetic disk drive, and a magnetic disk drive having such a filter assembly.

#It is a common practice with a personal computer or a word processor to use storage implemented as a magnetic disk drive accommodating magnetic disks therein. To meet the increasing demand for greater storage capacity and higher recording density, the spacing between a head and the associated disk must be reduced. However, a reduced spacing between the head and the disk brings about a problem that when dust and toxic gases, i.e., sulfur oxides, nitrogen oxides and chlorides enter the disk drive and deposit on the disks, they erode the disks and cause head crash to occur. To eliminate this problem, it has been customary to provide the disk drive with a filter device made up of a dust filter and a gas filter. For example, a filter device taught in Japanese Utility Model Publication No. 3-37696 consists of a dust filter in the form of filter paper folded in a corrugated configuration, and a gas filter received in a casing and constituted by activated charcoal.

#However, the above-described filter device is not satisfactory since the ability thereof to remove dust and toxic gases is not sufficient in relation to materials constituting the individual filters. Particularly, since the ability of the conventional device to remove erosive gases is insufficient, the disks are locally eroded and suffer from microscopic undulations on the surfaces thereof. This results in head crash and, therefore, prevents recording and reproducing characteristics from being effectively maintained, thereby degrading the reliability of a magnetic disk drive.

#The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken with the accompanying drawings in which:

#FIG. 1 is a section of a magnetic disk drive incorporating a conventional filter assembly;

#FIG. 2A is a projection view of a filter assembly embodying the present invention;

#To better understand the present invention, a brief reference will be made to a prior art magnetic disk drive capable of removing dust and toxic gases, shown in FIG. 1. As shown, the disk drive 10 has a hermetically sealed casing 12 including a base 12a. A drive mechanism, not shown, for driving magnetic disks 16 is mounted on the base plate 12a. The disks 16 are mounted on a spindle 14 which is directly connected to the drive mechanism. Magnetic heads 20 are respectively fitted on the free ends of arms 18, and each faces the surface of one of the disks 16. The arms 18 are retained by a positioning mechanism 22.

#A breathing filter 24 is provided in a part of the casing 12 so as to implement communication of air inside and outside of the disk drive 10. The filter 24, therefore, obviates a pressure difference between the inside and the outside of the apparatus 10 while preventing dust from entering the apparatus 10. A filter assembly 26 is also disposed in the casing 12 and implemented by activated charcoal capable of removing toxic gases and dust. When the disks 16 are rotated, air streams generated on the surfaces of the disks 16 are caused to flow into the filter assembly 26. As a result, dust floating within the apparatus 10 and toxic gases are collected by the filter assembly 26.

#However, the conventional filter assembly 26 cannot remove dust and toxic gases satisfactorily, as stated earlier. Therefore, it is likely that erosive gases erode the disks 16 and form microscopic undulations on the surfaces thereof.