1. Field of the Invention:
The present invention relates to a recording and reproducing device. In particular, the present invention relates to a recording and reproducing device having a recording medium, or a recording and/or reproducing head with excellent lubricity and durability.
2. Description of the Prior Art:
Recording and reproducing devices comprise a recording medium, a recording and/or reproducing head giving and receiving recording signals to or from the recording medium, and a mechanism section and a circuit section giving and receiving the recording signals. The recording media include for example magnetic tapes, magnetic discs, magnetic cards, optical magnetic discs, and the like. The recording and/or reproducing heads include for example VTR heads which record analog signals, magnetic recording heads for magnetic discs which record and erase digital signals, optical magnetic recording heads, optical heads, and the like.
Among these recording media described above, the magnetic recording medium is mainly classified into a coated type, and a vacuum evaporation type, depending on its preparation procedure.
The coating type-magnetic recording medium is generally prepared by mixing a magnetic powder such as Fe.sub.2 O.sub.3, or a mixture of .gamma.-Fe.sub.2 O.sub.3 and Co, etc., with a mixture of poly (vinyl butyral), toluene, and methylisobutylketone, and the like, and dispersing it therein to form a paint; and coating the paint on the surface of the base plate of the recording medium at a 4-5 .mu.m thickness. Although this coated type-magnetic recording medium is easy to make, it has unsatisfactory performances for a high density recording process because the particles of the magnetic powder are present in a dispersed state in a resin such as poly (vinyl butyral), and the particles of the magnetic powder cannot be made in a smaller size beyond a certain level.
The vacuum evaporation type-recording medium is prepared by vacuum-evaporating magnetic metals such as Fe--Ni, Ni--Co, etc., or oxidized magnetic metals on the surface of the base plate by the electron beam method, or the sputtering method in such a manner that the thickness of the vacuum-evaporation film will be 1,000-2,000 angstroms. Because the vacuum evaporation type-recording medium has magnetic metals or oxidized magnetic metals on the top surface, it has higher recording density compared to the coating type-recording medium. This advantage is offset in that the surface lacks lubricity and durability.
Therefore, the vacuum-evaporated surface of the recording medium described above is coated with silicon glass, or water glass, etc., and baked to form an overcoat layer followed by coating a lubricant which provides lubricity to the surface. However, the resulting magnetic recording medium still does not have sufficient durability. Moreover, the overcoat layer and the lubricant cannot be coated thinly and uniformly. Therefore, the distance between the head and the recording layer becomes large, thus the recording medium cannot utilize its own recording ability of high density. It provides only a recording density of 20 mega bits when a 5.25 inch-disc used.
Recording and/or reproducing heads are prepared, for example, by the following procedure. First, two or more magnetic films are formed in a prescribed form by vacuum evaporation on the surface of a ceramic base plate in the direction of its length. Next, another ceramic base plate is adhered to the vacuum-evaporated surface. Then, after the surface containing the interface line of the combined ceramic plates is polished until at least part of the magnetic films is exposed, the combined ceramic plate is cut into several pieces so that each piece has one magnetic film.
The polished surface of the head is the surface which comes into contact with a recording medium. The lubricity and anti-wear property of the head depends on the kind of the ceramics used, and the degree of polishing. No treatment has been made to improve its lubricity and anti-wear property. Therefore, conventional heads are not only susceptible to damaging the recording medium, but undergo significant wear, which provides poor reliability.
USPTO Backgrounds
USPTO Backgrounds