Apparatus for producing a substrate having a surface with a plurality of spherical dimples for photoconductive members

An apparatus for producing a substrate having a surface with a plurality of spherical dimples, said substrate being suitable for a light receiving member, said apparatus comprising:

• a substrate supporting means for supporting a cylindrical substrate in a rotatable state;
• a cylindrical rotating vessel having a circumferential wall with external and inner wall faces said cylindrical rotating vessel containing said substrate supporting means coaxially placed therein such that said cylindrical rotating vessel encloses said substrate supporting means while establishing a desired space between said cylindrical substrate supported on said substrate supporting means and said inner wall face of said cylindrical rotating vessel, said cylindrical rotating vessel containing a plurality of freely movable rigid spheres formed of a material selected from the group consisting of steel, aluminum, nickel, brass, ceramic and plastic, said cylindrical rotating vessel being rotatable so as to allow said rigid spheres to move in the rotation direction of said cylindrical rotating vessel as said cylindrical rotating vessel rotates, said circumferential wall of said cylindrical rotating vessel being provided with a plurality of perforations capable of retaining said rigid spheres on the inner wall face of the cylindrical rotating vessel, said plurality of perforations being of a size which is smaller than that of the rigid spheres and which allows a surface coating liquid to pass therethrough under pressure so as to propel the rigid spheres retained on the inner wall face into collisions with the surface of the cylindrical substrate supported on said substrate supporting means;
• a cylindrical external wall member coaxially surrounding the cylindrical rotating vessel, said external wall member having a space or storing the surface coating liquid at a lower portion thereof;
• a supplying means for supplying the surface coating liquid under pressure toward the cylindrical rotating vessel such that the surface coating liquid is ejected through said plurality of perforations into the cylindrical rotating vessel, said supplying means terminating in a plurality of nozzles arranged at intervals from about 5 mm to about 50 mm, said supplying means having a means for generating an injection force to said surface coating liquid which provides a kinetic energy to the rigid spheres corresponding to the potential energy obtained when the rigid spheres are dropped from a height of from 0.05 to 2.0 meters;
• and said plurality of nozzles oriented at an angle of .+-.45.degree. with respect to a horizontal plane to the central axis of the cylindrical rotating vessel to supply the surface coating liquid toward said cylindrical rotating vessel at said angle of .+-.45.degree. with respect to the horizontal plane to the central axis of the cylindrical rotating vessel;
• a storing tank for storing the surface coating liquid;
• and
• circulating means for circulating the surface coating liquid to the supplying means.