TONER SUPPLY ROLLER, DEVELOPING DEVICE, AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To prevent toner from aggregating and fusing in a developing device when a low-temperature fixing toner is used for an image forming apparatus with a high-speed process. SOLUTION: A toner supply roller 52 is used in a developing device 34, which is equipped with: a developing roller 48 depositing toner 68 on an electrostatic latent image formed on the outer circumference surface of an electrostatic latent image carrier 12 to visualize the electrostatic latent image; and a toner supply roller 52 supplying and collecting the toner 68 to and from the developing roller 48. A ratio R (VS/VD) of a circumferential velocity VSof the supply roller 52 to a circumferential velocity VDof the developing roller 48 ranges from 0.2 to 0.8 and the contact pressure of the supply roller 52 to the developing roller 48 ranges from 5 to 30 N/m. The toner supply roller 52 has a polyurethane foam layer 56, in which the number of cells per inch ranges from 30 to 80 and the opening ratio of cell wall faces ranges from 3 to 50%. COPYRIGHT: (C)2010,JPO&INPIT