Patent Number: 7,613,419

Title: Image forming apparatus and image forming method characterized by a particular nip time

Abstract: An image forming apparatus equipped with an image bearing member, a latent electrostatic image forming unit which forms a latent electrostatic image on the image bearing member, a developing unit which develops the latent electrostatic image by using a toner to form a toner image, a transfer fixing member which is roll shaped or belt shaped and bears the toner image , a heating unit which heats the toner image on the transfer fixing member; and a pressurizing member which is roll shaped and forms a transfer fixing nip with the transfer fixing member. The toner image on the transfer fixing member is transferred and fixed simultaneously to a recording medium which passes through the transfer fixing nip to record an image on the recording medium. At this time, the nip time, the time it takes for the recording medium to pass through the transfer fixing nip is set at 30 ms or less, the toner contains at least a binder, the binder has a main peak in an area of 5,000 to 15,000 molecular weight in a molecular weight distribution measured by GPC, the component of 30,000 or more molecular weight is 0.05% or less and a value of weight-average molecular weight (Mw) / number average molecular weight (Mn), Mw/Mn is 2 to 6.

Inventors: Suzuki; Kazumi (Shizuoka, JP), Fujita; Takashi (Yokohama, JP), Kosugi; Hideki (Sagamihara, JP), Kadota; Ichiro (Tokyo, JP), Nakafuji; Atsushi (Tokyo, JP), Takagaki; Hiromitsu (Yokohama, JP)

Assignee: Ricoh Company, Ltd.

International Classification: G03G 15/16 (20060101)

Expiration Date: 1/03/02017