Magnetic particle-containing member for use in copying machine

An image forming apparatus comprising:

• a photosensitive member having an amorphous carbon layer on an outer surface thereof;
• and
• a developing device accommodating a toner and a carrier for use of developing an electrostatic latent image formed on the surface of the photosensitive member, said carrier comprising minute particles each of which has a size of 200 .mu.m or less and at least one of an octahedron shape and an irregular shape, having a ratio of 1/R exceeding 10 in less than 80% of the particles on the basis of the total number of minute particles wherein 1 is the maximum length of a particle and R is a diameter of a column having the longest portion of the particle as a central axis, and having a shape coefficient SF1 smaller than 120 and a shape coefficient SF2 smaller than 110 in less than 80% of the particles on the basis of the total number of minute particles wherein SF1={(the maximum length).sup.2 /(an area)}.times.(.pi./4).times.100 wherein the maximum length is a mean value of maximum lengths in projected images of particles and an area is a mean value of projected areas of particles and wherein SF2={(a circumferential length).sup.2 /(an area)}.times.{100/(4.pi.)} wherein a circumferential length is a mean value of circumferential lengths in projected images of particles and an area is a mean value of projected areas of particles, which minute particles have a multi-point contact with the surface of the photosensitive member sufficient to scrape off said surface thereof.

A method for treating a photosensitive member having an amorphous carbon layer on an outer surface thereof and provided in an image forming apparatus comprising the steps of:

• supplying a member including minute particles;
• and
• rubbing the surface of the photosensitive member by means of said member comprising minute particles each of which has a size of 200 .mu.m or less and at least either an octahedron shape and an irregular shape, having a ratio of 1/R exceeding 10 in less than 80% of the particles on the basis of the total number of minute particles wherein 1 is the maximum length of a particle and R is a diameter of a column having the longest portion of the particle as a central axis, and having a shape coefficient SF1 smaller than 120 and a shape coefficient SF2 smaller than 110 in less than 80% of the particles on the basis of the total number of minute particles wherein SF1={(the maximum length).sup.2 /(an area)}.times.(.pi./4).times.100 wherein the maximum length is a mean value of maximum lengths in projected images of particles and an area is a mean value of projected areas of particles and wherein SF2={(a circumferential length).sup.2 /(an area)}.times.{100/(4.pi.)} wherein a circumferential length is a mean value of circumferential lengths in projected images of particles and an area is a mean value of projected areas of particles, which minute particles have a multi-point contact with the surface of the photosensitive member sufficient to scrape off said surface thereof.

An image forming apparatus comprising:

• a photosensitive member having an amorphous carbon layer on a surface thereof;
• a developing device accommodating a toner for developing an electrostatic latent image formed on the surface of the photosensitive member;
• and
• a cleaner for cleaning a residual toner on the surface of the photosensitive member, said cleaner including minute particles each of which has a size of 1.0 .mu.m or less and at least one of an octahedron shape and an irregular shape having a ratio of 1/R exceeding 10 in less than 80% of the particles on the basis of the total number of minute particles wherein 1 is the maximum length of a particle and R is a diameter of a column having the longest portion of the particle as a central axis, and having a shape coefficient SF1 smaller than 120 and a shape coefficient SF2 smaller than 110 in less than 80% of the particles on the basis of the total number of minute particles wherein SF1={(the maximum length).sup.2 /(an area)}.times.(.pi./4) 100 wherein the maximum length is a mean value of maximum lengths in projected images of particles and an area is a mean value of projected areas of particles and wherein SF2={(a circumferential length).sup.2 /(an area)}.times.(100/(4.pi.)} wherein a circumferential length is a mean value of circumferential lengths in projected images of particles and an area is a mean value of projected areas of particles, which minute particles have a multi-point contact with the surface of the photosensitive member sufficient to scrape off said surface thereof.