Abstract: A detection mechanism is provided with a sealing member made of elastic material for preventing toner leakage between (a) a pierced wall surface of a toner tank through which a rotating shaft is inserted and (b) a second side plate provided on the rotating shaft. With this structure, a flat splicing surface of the sealing member is made to closely contact a second side plate that can be coated with a high lubricant member whose frictional forces is small. When a sealing force of the sealing member is strongly compressed, the sealing member prevents toner from coming into the sliding surface.

Abstract: In the present detection mechanism, a sealing member made of elastic material for preventing toner leakage is provided between (a) a pierced wall surface of a toner tank through which a second rotating shaft is inserted and (b) a second side plate provided on the second rotating shaft. In this manner, a flat sliding surface of the sealing member is made to closely contact the second side plate, so that it is possible to easily coat the sliding surface with a high lubricant member whose frictional forces is small. Thus, even when a sealing force of the sealing member is enhanced by strongly compressing the sealing member by means of the pierced wall surface and the second side plate so as to prevent the toner from coming into the sliding surface, it is possible to easily suppress unwanted resistance to rotation of the second rotating shaft.

Abstract: The tester and the test method for testing an eccentricity of a head turnout zone of a magnetic disk determine a turnout zone as acceptable or unacceptable by spirally scanning a turnout zone of a magnetic disk with a laser spot by rotating the magnetic disk and continuously moving either the laser spot radially of the magnetic disk or the magnetic disk radially thereof, obtaining a detection signal having amplitude corresponding to an intensity of a scattering light from the magnetic disk irradiated with the laser spot, extracting a first waveform of the detection signal corresponding to an intermediate region between an inside variation region in which an inside boarder line of the turnout zone radially of the magnetic disk by radial movement of the turnout zone caused by an ecentricity of the turnout zone and an outside variation region in which an outside boarder line of the turnout zone radially of the magnetic disk by the radial movement of the turnout zone caused by the eccentricity of the magnetic dis

Abstract: A developing apparatus which is equipped with a developer control member for controlling the developer on a developer supporter to a prescribed thickness, and which uses a one-component developer, characterized in that recessed sections are formed at the surface of the developer supporter to receive the developer, and the density .alpha. of particles of the developer which enter the recessed sections and the nip width L1 between the developer control member and the developer supporter satisfy the relationship: 3<.alpha..multidot.L1<10.

Abstract: A developer cartridge for image forming apparatuses which performs development to form images with non-magnetic, one-component type developer. The cartridge includes a developing roller for supplying developer to a photoconductor drum, a developer feed roller in non-contact with the developing roller for supply developer to the developing roller, and a developer-layer thickness control member for controlling the thickness of the developer layer on the developing roller. The developer feed roller is shaped as a regular polygonal prism. Since no recesses are formed in the surface of the regular polygonal prism, driving torque does not increase when developer is scrubbed from the prism, thus ensuring consistent operation and improved image quality. Non-magnetic, one-component type developer is compressed onto the developing roller by supplying the developer via the developer feed roller into a bottleneck between the developing roller and a developer applying member.