Kawamata, Toshio; Hayakawa, Satoru; Endo, Yasushi;

Magnetic recording disk

A magnetic recording disk having a good overwriting characteristic and an excellent electromagnetic characteristic, as well as superior running durability. The magnetic recording disk comprises a non-magnetic support having coated thereon, in the order, a non-magnetic layer comprising mainly a non-magnetic powder and a binder resin and a magnetic layer comprising mainly a ferromagnetic powder and a binder resin, wherein the magnetic layer is formed by applying a magnetic layer coating solution onto the coated non-magnetic layer while the non-magnetic layer remains in a wet condition, the average thickness of the magnetic layer is 0.5 .mu.m or less, and the maximum thickness and the minimum thickness thereof fall within the range of .+-.15% of the average thickness of the magnetic layer.

• Linear positioning apparatus Rotary dobbies for weaving looms
• Phosphor manufacturing process Window lift mechanism
• Variable coupler for optical fibers Plasma processing apparatus
• Composition of synthetic detergents Multi-channel DMA with scheduled ports
• Cushioned valve seat Polyimide waveguides as optical sensors
• Facade wall assembly Method for treating pulp
• Vehicle navigation system and method Weighted exercise and therapeutic suit
• Aminoacyllabdanes Paint box and easel combination
• Corynebacterial stress proteins Letter feeder
• Natural lighting apparatus Solar array system
• Digital signal receiver Record storage apparatus
• Animal feeding nipple Emergency locating transmitter
• Ear cover and method Chisel plow landside
• Micronized alkaline earth metal carbonate Rock anchor
• Tamp assembly Computation optimizer
• Composite video apparatus Food handling implement
• Force and torque converter Hinged detent
• Hub conditioning and alignment tool 2,4-disubstituted triazine derivatives
• Radio frequency automatic identification system Brushless rotary machine
• Cold water ozone disinfection Side port - RC engine
• Fuel nozzle with water injection Programmable power supply
• Non-contact type IC card Linearity corrected horizontal deflection circuit
• Watercraft engine control Masonry cutter
• Multizone catalytic reforming process Lipopeptide derivatives

What is claimed is:

1. A magnetic recording disk comprising a non-magnetic support having coated thereon, in the following order, a non-magnetic layer comprising mainly a non-magnetic powder and a binder resin and a magnetic layer comprising mainly a ferromagnetic powder and a binder resin, wherein the non-magnetic layer is formed by applying a non-magnetic coating solution containing a first solvent onto the non-magnetic support, the magnetic layer is formed by applying a magnetic layer coating solution containing a second solvent onto the coated non-magnetic layer while the non-magnetic layer remains in a wet condition, the first solvent for the non-magnetic coating solution has a boiling point higher than that of the second solvent for the magnetic layer is 0.01 to 0.5 .mu.m, and the maximum thickness and the minimum thickness of the magnetic layer fall within the range of .+-.15% of the average thickness of the magnetic layer.

2. The magnetic recording disk as in claim 1, wherein at least a part of the non-magnetic powder is an electroconductive powder.

3. The magnetic recording disk as in claim 1, wherein the ferromagnetic powder is a ferromagnetic metal powder or a hexagonal series ferrite powder.

4. The magnetic recording disk as in claim 1, wherein the magnetic recording disk has a surface electric resistance of 5.times.10.sup.9 .OMEGA./sq or less.

5. The magnetic recording disk as in claim 1, wherein the first solvent has a boiling point of 90.degree. C. or more, the second solvent has a boiling point 100.degree. C. or less, and the difference in boiling point between the first solvent and the second solvent is 40.degree. C. or more.

6. The magnetic recording disk as in claim 2, wherein the electroconductive powder is carbon black.