Electrophotographic apparatus, image forming method, and process cartridge for developing an image with toner containing an external additive

An image forming method, comprising a cycle of:

• a charging step of charging an electrophotographic photosensitive member by a charging means disposed in contact with the electrophotographic photosensitive member,
• an exposure step of exposing the charged electrophotographic photosensitive member to image light to form an electrostatic image on the electrophotographic photosensitive member,
• a developing step of developing the electrostatic image with a toner supplied from a developing means to form a toner image on the electrophotographic photosensitive member, and
• a transfer step of transferring the toner image on the electrophotographic photosensitive member onto a transfer-receiving material;
• wherein
• said charging means includes a charging member comprising magnetic particles disposed in contact with the electrophotographic photosensitive member so as to charge the electrophotographic photosensitive member based on a voltage received thereby,
• said magnetic particles are surface-coated with a coupling agent having a linear alkyl group having at least 6 carbon atoms, and
• residual toner remaining on the electrophotographic photosensitive member after the transfer step is processed by the charging member and recovered by the developing means in the charging step after the developing step, respectively, in a subsequent cycle,
• wherein in the developing step a toner containing an external additive is used, the toner has a weight-average particle size of 1-9 μm, and the external additive has a weight-average particle size of 0.012-0.4 μm.

A process cartridge, comprising:

• an electrophotographic photosensitive member;
• and
• charging means forming an integral unit with said electrophotographic photosensitive member, which is detachably mountable to a main assembly to form an electrophotographic photosensitive apparatus;
• said electrophotographic apparatus including the electrophotographic photosensitive member, and (i) said charging means for charging said electrophotographic photosensitive member, (ii) imagewise exposure means for exposing said electrophotographic photosensitive member to light, (iii) developing means for developing an image formed on said electrophotographic photosensitive member, and (iv) transfer means for transferring the developed image onto a transfer material, disposed in this order opposite to the photosensitive member, wherein
• said charging means includes a charging member comprising magnetic particles disposed in contact with the electrophotographic photosensitive member so as to charge the electrophotographic photosensitive member based on a voltage received thereby,
• said magnetic particles are surface-coated with a coupling agent having a linear alkyl group having at least 6 carbon atoms, and
• said developing means also functions to recover residual toner remaining on the electrophotographic photosensitive member after processing by the transfer means and the charging means,
• wherein the developing means supplies a toner containing an external additive, the toner has a weight-average particle size of 1-9 μm, and the external additive has a weight-average particle size of 0.012-0.4 μm.