Samsung Electronics Co., Ltd.

S-Printing Solution Co., Ltd.

Hewlett-Packard Development Company, L.p.

Jae-hyeuk Jeong

Hae-ree Joo

Kyeong Pang

Jung-ik Choi

Kyung-yol Yon

Soon-cheol Jeong

Min-Young Cheong

Dong-jin Seol

Duck-hee Lee

Hong-chul Shin

Yo-Da Shin

Cheong-jin Jang

Min-chan Kim

Ae-kyung Choi

Kwang-ho Kang

Deuck-woo Jang

A semiconductive roller to stably generate high-quality images for a long period of time by efficiently inhibiting migration of free epichlorohydrin (ECH) component to a surface of the semiconductive roller includes an elastic layer formed of a semiconductive rubber composition including about 50 to about 70 parts by weight of a base rubber and about 30 to about 50 parts by weight of a hydrin rubber. An extracted amount of the ECH component from the elastic layer is about 2% by volume or less, wherein the extracted amount is determined based on a reduced amount of chlorine (Cl) intensity measured using X-ray fluorescence (XRF) analysis performed before and after extraction of the ECH component from the elastic layer using tetrahydrofuran (THF).

Semiconductive roller of an image-forming apparatus

A pickup roller includes a supporting layer and a pickup layer, which includes a base surrounding the outer perimeter of the supporting layer and a plurality of particles which are distributed throughout the base and have a different hardness than a hardness of the base.

Pickup roller and image forming apparatus having the same

Disclosed are an electrophotographic toner and a method of preparing the same. The electrophotographic toner includes latex; a colorant; and a releasing agent. The absolute value of a differential value of complex viscosity with respect to temperature, of the electrophotographic toner in a temperature range of 100&#xb0; C.-160&#xb0; C. is in a range of about 0.03 to about 0.06, and complex viscosity (&#x3b7;) of the electrophotographic toner at 140&#xb0; C. is in a range of about 1.0&#xd7;10Pa&#xb7;s to about 6.0&#xd7;10Pa&#xb7;s.

Electrophotographic toner and method of preparing the same

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

The disclosure provides electrophotographic toner and a method of preparing the same. The toner includes a latex, a colorant, and a releasing agent, wherein the toner has a weight-average molecular weight of about 50,000 to about 80,000; a complex viscosity of about 1&#xd7;10to about 5&#xd7;10(Pa&#xb7;s) at a temperature ranging from about 100&#xb0; C. to about 140&#xb0; C.; and a storage modulus Pa (dG') to a loss modulus Pa (dG&#x2033;) (dG&#x2032;/dG&#x2033;) ratio of about 1.10 to about 1.25.

A toner for electrophotography is provided including a binder resin, a coloring agent, a charge controlling agent, and a releasing agent, wherein when the temperature of the toner is in the range from a temperature 40&#xb0; C. lower than a fixing temperature of the toner to a temperature 10&#xb0; C. lower than the fixing temperature of the toner, the D Log &#x3b7;*/DT absolute value is 0.02 or more, when the temperature of the toner is in the range from a temperature 10&#xb0; C. lower than the fixing temperature of the toner to a temperature 10&#xb0; C. higher than the fixing temperature of the toner, the D Log &#x3b7;*/DT absolute value is 0.005 or less, and the complex viscosity (&#x3b7;*) of the toner at a fixing temperature and an angular velocity of a fixing heat roller is in the range from about 5.0&#xd7;10Pa&#xb7;s to 1.0&#xd7;10Pa&#xb7;s. The toner has excellent fixing properties so that the quality of an image can be stabilized, and cause less contamination.

A toner for electrophotography is provided including a binder resin, a colorant, a charge control agent, and a release agent, wherein a glass transition temperature (Tg) is over 55&#xb0; C., a molecular weight distribution (MWD) is in the range of about 4.5 to 5.5 when a weight average molecular weight is in the range of about 45,000 to 55,000, and a compression elastic modulus is about 750 MPa or higher at room temperature. Mechanical properties of toner can be obtained at room temperature by controlling rheological properties of toner. The developing properties and fixing properties of toner for electrophotography can be improved by lowering viscosity at a high temperature, and thus image quality can be stabilized.

A toner for electrophotography is provided that includes a binder resin, a colorant, a charge control agent, and a releasing agent, wherein the toner has a complex viscosity (&#x3b7;) of about 4.0&#xd7;10Pa&#xb7;s to about 1.6&#xd7;10Pa&#xb7;s at a temperature ranging from about 40&#xb0; C. lower than a toner fixing temperature to about 10&#xb0; C. higher than the toner fixing temperature and has a specified activation energy of 15 to 85 KJ/mol. By defining viscosity dependency in a linear modulus region of a toner and comprehensively defining thermal and rheological properties with respect to fixing conditions, a fixing phenomenon can be generalized and the quality of a toner can be evaluated.

A variable tension type belt fusing unit includes a main roller, a pair of belt driving rollers which is disposed near the outer circumferential surface of the main roller and is pressurized towards the main roller, and a fusing belt having a nip portion and a non-tension portion. At least one of the pair of belt driving rollers is independently and temporarily driven to apply or release a tension to the nip portion. In a driving method of the variable tension type belt fusing unit, the tension is applied to the nip portion of the fusing belt when the variable tension type belt fusing unit is prepared for an operation, the fusing belt travels while maintaining the tension during the operation of the variable tension type belt fusing unit, and the tension is released when the operation is completed.

Variable tension belt type fusing unit usable with image forming apparatus and driving method thereof

A fixing device for fixing a toner image onto a recording medium, and an image forming apparatus having the same are provided. The fixing device includes a fixing roller heated by a heating source, and a pressing unit disposed opposite the fixing roller to bias a recording medium towards the fixing roller so that the recording medium contacts the fixing roller. The pressing unit has a movable support member, a pressing member mounted at the support member to face the fixing roller, a pressing belt rotatably disposed around the support member and the pressing member and biased by the pressing member to form a nip with the fixing roller, a driving roller for rotating the pressing belt, and a resilience applying member for biasing at least one of the support member and the driving roller toward the fixing roller. Accordingly, the pressing unit basically expands the width of the fixing nip to improve the image fixing capability.

Growing community of inventors

Suwon-si, South Korea

Jae-hyeuk Jeong