Samsung Electronics Co., Ltd.

Duck-hee Lee

Jong-moon Eun

Sang-deok Kim

Seok-hoon Choi

Ki-won Seok

Hae-ree Joo

Jae-hyeuk Jeong

Soon-cheol Jeong

Jung-ik Choi

Deuck-woo Jang

An electrophotographic toner includes a binder resin, a colorant, and a releasing agent, wherein the electrophotographic toner has a complex viscosity (&#x3b7;) of 4e2 Pa&#xb7;s to 8e3 Pa&#xb7;s at a temperature range of 120 to 160&#xb0; C. and an angular velocity range of 1.6 to 10 rad/s, a rate of change of the complex viscosity of 165 to 185 Pa&#xb7;s/&#xb0; C. at 1.6 rad/s, and 70 to 80 Pa&#xb7;s/&#xb0; C. at 10 rad/s within the temperature range, a stress relaxation of 1.0 e3 to 4.5 e4 Pa at a relaxation time of 0.05 to 0.3 seconds under a temperature range of 120 to 160&#xb0; C., and a rate of change of the stress relaxation (&#x394;G/&#x394;T) of 785 to 1000 Pa/&#xb0; C. at 0.05 seconds and 190 to 215 Pa/&#xb0; C. at 0.3 seconds within the temperature range above.

Toner for electrophotography

An electrophotographic developing agent is provided that includes a binder resin, a releasing agent, a colorant, and a charge control agent. By using a binder resin having a high acid value and a mixture of two waxes having different melting points as a releasing agent, a electrophotographic developing agent is obtained, which has excellent fusing property and durability and does not result in hot offset and wrap jamming.

Electrophotographic developing agent

A non-magnetic one-component electrophotographic developing agent is provided having improved properties. The electrophotographic developing agent includes parent toner particles comprising a binder resin, a releasing agent, a colorant, and a charge control agent, and an external additive which is added to a surface of the parent toner particles, wherein the binder resin comprises a high viscosity polyester resin having a weight average molecular weight of about 90,000-140,000 and a gel content of less than about 5% and a low viscosity polyester resin having a weight average molecular weight of about 52,000-65,000 and a gel content of less than about 2%. According to an embodiment of the present invention, an electrophotographic developing agent having improved image gloss and fusing property, while ensuring durability may be prepared by using a blended combination of a high viscosity polyester resin and a low viscosity polyester resin.

A toner composition for an electrophotography image forming apparatus includes toner particles and external additives. The toner particles include a colorant, a charge control agent and a release agent with binder resins. The external additives include a first silica having an opposite polarity to the toner particles, a second silica having the same polarity as the toner particles, a sodium titanate having the same polarity as the toner particles, and an aluminum oxide having the same polarity as the toner particles.

Toner composition for electrophotography image forming apparatus

A non-magnetic one-constituent developing agent is an electro-photographic developing agent that provides high quality images without fogging, scattering of toners and ineffective development by maintaining stable charges and a uniform distribution of toners over an extended lifetime in a developing apparatus of an electro-photographic image processing device. In addition, the developing agent has deodorizing, anti-bacterial and sterilizing functions.

Electro-photographic developing agent

A nonmagentic one-component toner for an electrophotographic image forming apparatus includes a toner with toner particles, a binder resin having a coloring agent, a charging control agent, and a release agent, and an external additive added to the toner particles. The external additive includes approximately 0.1 to 3.0 wt % of silica having a charge opposite to the toner particles, approximately 0.1 to 3.0 wt % of silica having a same charge as the toner particles, and approximately 0.1 to 4.0 wt % of titanium dioxide.

Nonmagnetic one-component toner for electrophotographic image forming apparatus

A toner having toner particles containing a binder resin and a colorant; and a first external additive having 0.1 to 3.0 wt % of large silica particles with an average particle size of 20 to 200 nm; a second external additive having 0.1 to 3.0 wt % of small silica particles with an average particle size of 5 to 20 nm; a third external additive having 0.1 to 2.0 wt % of hydrophobic titanium dioxide microparticles with a resistance of 105 to 1012 &#x3a9;cm; and a fourth external additive having at least one of 0.1 to 2.0 wt % of conductive titanium dioxide particles with a resistance of 1 to 105 &#x3a9;cm and 0.1 to 2.0 wt % of positively chargeable aluminum oxide particles. Therefore, a thin toner layer with a uniform toner amount is formed on a toner carrier and stable charge distribution and toner flowability are maintained for a long time, thereby resulting in prevention of fog and toner scattering, and improvements in developing efficiency and toner durability.

Toner used with electrophotography

A developing device used with an electrophotographic image forming apparatus and developing method thereof includes a power supplying unit which applies a first electric field to a toner transfer body and a supplying member so that the toner is supplied to the toner transfer body when a development operation is performed, and applies a second electric field to the toner transfer body and the supplying member so that the toner is removed from the toner transfer body when the development operation is not performed, by varying a developing bias and a supplying bias.

Developing device having variable bias voltages applied thereto used with electrophotographic image forming apparatus and developing method thereof

A method of forming an image in a developing apparatus of an image forming apparatus and an image forming apparatus including a retrieving/auxiliary developing roller being in contact with the circumference of the photosensitive drum to retrieve or collect toner remaining on a region other than an image region of the circumference of the photosensitive drum and to first develop the latent electrostatic image, a first toner layer control member uniformly re-distributing the remnant toner and electrifying toner on the circumference of the retrieving/auxiliary developing roller and a developing roller having a gap with the circumference of the photosensitive drum to secondly develop the firstly developed latent electrostatic image so as to completely visualize the latent electrostatic image, a supply roller supplying toner to the developing roller, and a second toner layer control member for regularly coating the toner, which is supplied by the supply roller, throughout the circumference of the developing roller and controlling the amount of the electrification of the toner of the developing roller.

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Seoul, South Korea

Duck-hee Lee