Abstract: To improve the positioning accuracy which has been limited so far due to a vibration mode of an actuator for positioning a head and increase the capacity of an apparatus by raising the density of tracks for recording or reproducing information.

Abstract: A magnetic disk apparatus has: a head (2) that performs data recording and playback while moving relative to a magnetic disk (26) rotating at the prescribed speed; an actuator (3) that positions said head relative to said magnetic disk (26); and a controller (4) that detects the position of said head by means of servo sector that have positioning information recorded magnetically on said magnetic disk (1) and performs control to position said actuator (3) by means of this detection signal, wherein said magnetic disk (1) has at least a part in which the arrangement of tracks is spiral. The magnetic patterns on the disk include a servo sector and a data sector both formed on the same spiral track. The servo sector includes burst patterns for servo control.

Abstract: An automatic disk changer has a recording/reproducing device capable of operating a reproducing-only disk and a recording/reproducing possible disk, disk trays that can be placed on the recording/reproducing device, and each of which has a disk-type discriminating means able to discriminate as to whether the disk could be a reproducing-only disk or a recording/reproducing possible disk, a tray storage holding the disk trays, and a tray carrier able to pullout/insert the disk trays from/into the tray storage and able to transport the disk tray to/from the recording/reproducing device.

Abstract: The stepping motor controller of the present invention includes: a stepping motor including a rotor and an excitation coil; a drive section for supplying multiple-stage drive current to the excitation coil in response to an input command value, thereby enabling a micro step drive; a control section for controlling the stepping motor by varying the command value to be provided for the drive section; and a position detection control section for generating a detection signal in accordance with a rotation position of the rotor.

Abstract: In an automatic medium changing apparatus capable of storing a multiplicity of optical disks, the control parameters required for the drive control system of a drive unit for recording-reproducing are automatically regulated for all the combinations of the existing drive units and all the media held. The resulting values of the control parameters are stored in a control unit of the automatic medium changing apparatus and the apparatus is controlled by the corresponding control parameters transferred from the control unit at the time of processing the medium.

Abstract: A charging device for charging a movable object to be charged. A charging member contacts the object to be charged. A power source applies a voltage to the charging member, wherein the power spectrum PS satisfies the following relation when the space frequency of the profile of the surface of the charging member is analyzed.In the section of 10.ltoreq.f.ltoreq.100 (cycles/mm):PS.ltoreq.-2.5.times.log(f/2)(.mu.m.sup.2)In this way, the charging device prevents charge unevenness due to undulations on the surface of the charging member and charges uniformly while generating very little ozone.

Abstract: A charging device for charging a moving photoconductor. The charging device includes a charging member, an electric power supply for applying a voltage to the charging member, and a light exposing device, such as a LED for exposing surfaces of the charging member and the photoconductor in a closing region where the surfaces of the charging member and the photoconductor move closer to each other. The charging member is a blade having a transparent layer for guiding a light beam from the LED to the closing region and a shading layer for shading the light beam to a contacting region and a separating region. The contacting region is where the surfaces of the charging member and the photoconductor contact, and the separating region is where the surfaces of the charging member and the photoconductor gradually separate from each other.

Abstract: A charging device for charging a movable object to be charged. A charging member contacts the object to be charged. A power source applies a voltage to the charging member, wherein the power spectrum PS satisfies the following relation when the space frequency of the profile of the surface of the charging member is analyzed.In the section of 10.ltoreq.f.ltoreq.100 (cycles/mm):PS.ltoreq.-2.5.times.log (f/2)(.mu.m.sup.2)In this way, the charging device prevents charge unevenness due to undulations on the surface of the charging member and charges uniformly while generating very little ozone.

Abstract: A cutting tool comprising a supporting base and an outside and an inside abrasive grain layer projecting concentrically from the supporting base in a radially spaced relationship, and a method for its production. The outside and inside abrasive grain layers are formed by electrodepositing abrasive grains on the supporting base and then dissolving part of the supporting base. The inner circumferential surface of the projecting portion of the outside abrasive grain layer and the outer circumferential surface of the projecting portion of the inside abrasive grain layer are smooth surfaces.

Abstract: A cutting tool comprising a supporting base and an outside and an inside abrasive grain layer projecting concentrically from the supporting base in a radially spaced relationship, and a method for its production. The outside and inside abrasive grain layers are formed by electrodepositing abrasive grains on the supporting base and then dissolving part of the supporting base. The inner circumferential surface of the projecting portion of the outside abrasive grain layer and the outer circumferential surface of the projecting portion of the inside abrasive grain layer are smooth surfaces.