Ricoh Printing Systems, Ltd.

Ricoh Company, Ltd.

Hirobumi Ouchi

Shigenori Yaguchi

Junji Kobayashi

Tomonari Hokkyo

Tsuneaki Kawanishi

Ryuuichi Shimizu

A toner for electrophotography containing at least a fixing resin, a coloring agent and a wax is a toner containing rice wax and carnauba wax as the wax constitutional component thereof. A cleaning unit employs the blade cleaning mode; and for the purposes of keeping the performance of the cleaning unit and preventing the generation of printing failure. The toner has a relationship between a charge amount X (i.e., an absolute value of charge amount of the toner, &#x3bc;C/g) and a deposition amount Y (mg/cm) satisfied with the following expression (1) or (2):X&#x2266;21 &#x2003;&#x2003;(1)&#x3e;21 and&#x2266;&#x2212;0.0329+1.6223 &#x2003;&#x2003;(2)

Developing toner for electrophotography and electro-photographic device

In the image forming apparatus by: visualizing an electrostatic latent image formed on an electrostatic charge carrying member; transferring a toner image, which is thus visualized, to a recording medium, or to a recording medium through an intermediate transfer material; and fixing the toner image, which is thus transferred to the recording medium, to obtain a recorded image, the toner includes at least a fixing resin, a colorant, a releasing agent, and an external additive, the toner has an average particle diameter in a range of from 4 to 12 &#x3bc;m and including no particle having a diameter of 45 &#x3bc;m or more, a ratio of a toner adhesion amount in a character part to a toner adhesion amount in a solid image part upon printing is more than 0.5 and less than 4, and the toner adhesion amount in a character part is 1.6 mg/cmor less.

Image forming apparatus

An electrophotographic toner comprising at least a fixing resin, a coloring agent, a release agent and a charge control agent, wherein the release agent is carnauba wax, the charge control agent is a boron complex of a salicylic acid derivative, and the fixing resin contains two kinds of polyester resins in ratio represented by the following equation (1); wherein in the above equation, A(T)&#x2212;A(T)&#x3c;B(T)&#x2212;B(T), A(T) represents a softening point (&#xb0; C.) of the polyester A, A(T) a flow-out start point (&#xb0; C.) of the polyester A, B(T) a softening point (&#xb0; C.) of the polyester B, B(T) a flow-out start point (&#xb0; C.) of the polyester B, C a weight rate of the polyester A in the fixing resin, and D a weight rate of the polyester B in the fixing resin.

Electrophotographic toner and image forming apparatus

The invention provides an electrostatic charge image developing toner containing a fixing resin and a wax, characterized in that in a DSC curve measured by a differential scanning calorimeter for the wax, a maximum endothermic peak of endothermic peaks at temperature up is less than 70&#xb0; C., on-set temperature attributable to the maximum endothermic peak is above 50&#xb0; C., and lowest on-set temperature of on-set temperatures attributable to endothermic peaks except the maximum endothermic peak is in a range of from 30&#xb0; C. to 40&#xb0; C.

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Ibaraki, Japan

Hirobumi Ouchi