Ricoh Company, Ltd.

Kiwako Hirohara

Osamu Uchinokura

Satoshi Ogawa

Daisuke Ito

Daisuke Inoue

Satoshi Kojima

Junichi Awamura

Takahiro Honda

Tsuneyasu Nagatomo

Teruki Kusahara

Tomoyuki Satoh

Syouko Satoh

Masaki Watanabe

Tsuyoshi Sugimoto

Naohiro Watanabe

Shinya Hanatani

Mamoru Hozumi

An image forming apparatus including: image bearing member; latent image forming unit; developing unit; transfer unit; fixing unit, wherein toner in the developing unit contains amorphous polymer, crystalline resin and releasing agent, when the toner is measured for G' at 40&#xb0; C. to 210&#xb0; C. with rheometer at 1 Hz and 1 deg, G&#x2032;(100) is &#x2266;20,000 and G&#x2032;(150) is &#x2267;500 Pa, and straight line drawn by connecting points of the G&#x2032;(100) and G&#x2032;(110) on curve of the G&#x2032; has gradient of &#x2266;0.035, the gradient being 'a' expressed by: a=|logG&#x2032;(100)&#x2212;logG&#x2032;(110)|/10, and the fixing unit includes: heating member containing flexible endless belt; heat source fixed within the flexible endless belt; and press member in contact with the belt to form nip portion, and the fixing unit is configured to heat/press the medium passing through the nip portion to fix the image on the medium.

Image forming apparatus

A toner including: toner base particles; and an external additive, the toner base particles each comprising a binder resin and a colorant, wherein the external additive comprises non-spherical particles and spherical particles, wherein the non-spherical particles are each a secondary particle in which spherical primary particles are coalesced together, and wherein the non-spherical particles and the spherical particles in the external additive satisfy a relationship expressed by the following formula (1):3(%)&#x3c;(%)&#x2003;&#x2003;Formula (1) where Ca is greater than 10% but smaller than 20% and Cb is greater than 40% but smaller than 70%, and Ca and Cb are values given by: 

Toner, two-component developer and image forming apparatus

A toner for developing an electrostatic image, including: toner base particles each including a binder resin and a releasing agent; and inorganic fine particles, wherein the toner includes the inorganic fine particles as an external additive on a surface of the toner base particle, wherein the toner base particles have a BET specific surface area of 2.5 m/g to 5.0 m/g, and wherein the inorganic fine particles comprise inorganic fine particles (A) which are each a secondary particle where a plurality of primary particles are coalesced together.

Toner for developing electrostatic image, two-component developer and image forming apparatus

A toner containing toner particles, each toner particle containing: a releasing agent; a colorant; and a binder resin containing at least a crystalline polyester resin and a non-crystalline polyester resin, wherein in the case where a volume average particle diameter of the toner is defined as Dv, the toner contains a group of the toner particles having 4/5 Dv, and a group of the toner particles having 6/5 Dv, and wherein an endothermic value A of the crystalline polyester resin at a first temperature increase in DSC of the toner, an endothermic value B of the crystalline polyester resin at a first temperature increase in DSC of the group of the toner particle having 4/5 Dv, and an endothermic value C of the crystalline polyester resin at a first temperature increase in DSC of the group of the toner particles having 6/5 Dv satisfy the relation represented by the following formulas:50&#x3c;()&#xd7;100&#x3c;90, and110&#x3c;()&#xd7;100&#x3c;150.

Toner, developer, image forming method and image forming apparatus

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Miyagi, Japan

Kiwako Hirohara