Magnetic disc device including device for controlling humidity in a disc enclosure

Claim 1

A magnetic disc device comprising: (a) at least one magnetic disc (1); (b) a base (2); (c) an enclosure (3) covering said base and containing said at least one magnetic disc; (d) a breathing filter (6) for regulating a pressure difference between the inside and outside of said enclosure under a dust-proof condition; and (e) a moisture removing mechanism placed in said enclosure and including: a container (14); a filter (10) within said container; and a reversible desiccating agent (13) contained in said container, said reversible desiccating agent performing a moisture absorbing action and a moisture discharging action in accordance with an increase and decrease in relative humidity within said enclosure respectively, substantially all moisture absorbed during said moisture absorbing action being discharged by said moisture discharging action, said moisture removing mechanism removing the moisture intruding into said enclosure through said breathing filter, wherein said reversible desiccating agent is selected from the group consisting of a first compound consisting essentially of SiO 2 , Al 2 O 3 , CaO, FeO 3 , Ne 2 O, K 2 O, and P 2 O 5 , and a second compound consisting essentially of CaCl 2 ·2H 2 O, SiO 2 , MgO, Al 2 O 3 , Fe 2 O 3 , and FeO.