Abstract: When a magnetic disc is fabricated by forming on a rigid substrate a film of a magnetic coating material containing magnetic fine particles and a binder, and orienting and curing the film, the film is formed while a magnetic field is applied thereto, said magnetic field being larger in the strength on the inner side than on the outer side of said rigid substrate, thereby making it possible to form a magnetic layer that is uniform in thickness, or is thicker on the inner side and thinner on the outer side. This makes it possible to provide a coated type of magnetic disc in which there is a limited difference in the reproduction output and overwriting properties between the inner and outer sites.

Abstract: A magnetic disk suitable for high density recording and reproduction of information wherein said disk is a coating type disk comprising a rigid substrate having a magnetic layer coated thereon from a magnetic coating composition of ferromagnetic submicron particles in a binder, wherein the substrate has a surface roughness Ra of up to 0.007 .mu.m, the magnetic layer has a thickness of up to 0.5 .mu.m, a surface roughness Ra of up to 0.005 .mu.m, and a porosity of 4 to 45%.

Abstract: Information is magnetically recorded in and reproduced from a magnetic disk using a flying magnetic head. The disk is a coating type disk comprising a rigid substrate having a magnetic layer coated thereont from a magnetic coating composition of ferromagnetic submicron particles in a binder. High density recording is possible when the substrate has a surface roughness Ra of up to 0.007 .mu.m, the magnetic layer has a thickness of up to 0.5 .mu.m, a surface roughness Ra of up to 0.005 .mu.m, and a porosity of 4 to 45%.

Abstract: Information is magnetically recorded in and reproduced from a magnetic disk using a flying magnetic head. The disk is a coating type disk comprising a rigid substrate having a magnetic layer coated thereon from a magnetic coating composition of ferromagnetic submicron particles in a binder. High density recording is possible when the magnetic layer having a coercive force of at least 1100 Oe and a thickness of up to 0.5 .mu.m is combined with the flying magnetic head whose gap adjoining portion is made of a soft magnetic material having a saturation magnetic flux density of at least 0.7 T.

Abstract: A method of inspecting surface defects in a magnetic disk. First, a predetermined inspection signal is recorded on a randomly selected track of the magnetic disk during a first rotation of the disk. Second, during a second rotation of the disk, the inspection signal is read and a read signal is produced. Then, during a third rotation of the disk, the value of the read signal is compared with a reference value to determine whether any surface defect exists, and a seek operation is performed to move to the next track of the magnetic disk which is inspected. During one of the second and third rotations of the disk, the read signal is used to set a new reference value to be used in a surface defect inspection of a new track to be inspected.

Abstract: A grommet is disclosed, which grommet comprises a female member of a U-shaped end face containing a U groove for accommodating a stretched cord and provided at one extremity of said U groove with an elevated wall rising from the bottom of said groove and at the other extremity with a projecting wall extending inwardly from one side wall and a male member adapted to fit the U groove of the female member for fast engagement therewith, whereby the engagement of the male and female members gives rise to a laterally elongate opening on the side incorporating said elevated wall and a longitudinally elongate opening on the side incorporating the projecting wall. When the male and female members are brought into mutual engagement with a cord interposed therebetween, the cord is fastened in position in its twisted state within the grommet.