Mitsui Toatsu Chemicals, Incorporated

Masaaki Shin

Akira Misawa

Kazuo Hisamatsu

Keiichi Ishikawa

Kazuo Hagiwara

Akio Fujiwara

Kenji Uchiyama

Takashi Yamamoto

Nobuhiro Hirayama

Shoji Kawasaki

Hisatomo Sato

Hiroshi Taniwaki

Hiroshi Ozawa

Kazuo Sugazaki

Nobuki Kobayashi

Yasuo Okada

Ichiro Otsuka

Mitsuyoshi Nakamura

Akio Fuziwara

Hironori Aizawa

Shoji Kawaski

Atsuo Okubo

Yoku Shiraishi

The present invention provides a toner composition mainly comprising a binder resin (D) which contains at least 20% by weight of an urethane-modified polyester resin (C) obtained by reacting a polyester resin (A) with an isocyanate compound (B) and whose gel fraction ranges from 2 to 75% by weight. The toner composition exhibits good melting properties upon heating suitable for fast reproduction such as a low lower limit of the fixing temperature and a wide range for permitted fixing temperature and is further excellent in resistance to blocking, resistance to carrier contamination and image-forming properties. The binder resin as the main component of the toner composition can be prepared according to a method comprising the step of continuously adding an isocyanate compound (B) to a polyester resin (A) in an equivalent ratio, NCO/OH, of the amount of the NCO groups of the isocyanate compound (B) to that of OH groups of the polyester resin (A) ranging from 0.3 to 1.00 with kneading to react them, in a kneading means having a built-in screw.

Toner composition for electrophotography

An object of the present invention is to provide an electrophotographic toner for high-speed copying machines having a high hot-roll speed and capable of fixing a toner at lower temperatures. The toner according to the present invention comprises a vinyl resin which has a wide molecular-weight distribution (Mn:1,000-20,000, Mw: 50,000-2,000,000), a glass transition temperature (Tg) of 40.degree.-75.degree. C. and a low acid value (AV:1-10); and a glycidyl compound in an amount sufficient to provide 0.05-1.0 equivalent of glycidyl groups per equivalent of COOH groups in the vinyl resin. It assures well-balanced fixing property, offset resistance and blocking resistance. In particular, it exhibits a remarkable effect in improving offset resistance and also in grindability during the production of the toner.

Electrophotographic toner and production process thereof

This invention discloses electrophotographic toners and the methods for their preparation. The electrophotographic toners contain resin and coloring agents as primary components. The resin is a non-crosslinked polymer of vinyl monomers or its mixtures, and has a number average molecular weight (Mn) of 2,000-15,000, a Z average molecular weight (Mz) of not less than 400,000 and Mz/Mn of 50-600. The electrophotographic toners exert an excellent fixing ability at high duplication speed or at lower temperatures.

Electrophotographic toner production process

A continuous method of treating a polymer reaction mixture for continuously separating a styrene polymer and volatile ingredient by flowing down, for example, a mixture of low molecular weight styrene polisher and high molecular weight styrene polymer through a circular-ring-shaped space formed between a jacketed double pipe and a concentrically located inner pipe of a heat-exchanger, and flashing into a vacuum chamber connected with said heat-exchanger, is provided. The polymer is useful for the preparation of electrophotographic toner.

Continuous method of treating polymer reaction mixture

Disclosed is a toner composition for electrophotography which comprises, as a principal component, a urethane-modified polyester resin whose loss tangent (tan .delta.) has a maximum and a minimum both falling within the range of from 0.7 to 2.5, the loss tangent being determined at 150.degree. C. and a frequency ranging from 10.sup.-2 to 10 Hz. The toner composition has excellent low temperature fixing ability and offset resistance as well as a wide range of permitted fixing temperature.

A toner composition for electrophotography comprises, as a principal component, a reaction product of a mixture which comprises 20 to 80% by weight of a polyester resin (A) whose number average molecular weight ranges from 1,000 to 5,000, whose glass transition point ranges from 0.degree. to 50.degree. C. , whose OH value ranges from 20 to 60 KOHmg/g and which is prepared by using at least one trifunctional alcohol in an amount of from 2 to 10 mole % on the basis of the total amount of starting raw alcohols consisting of at least one diol and at least one trifunctional alcohol; and 80 to 20% by weight of a polyester resin (B) whose number average molecular weight ranges from 1,000 to 5,000, whose glass transition point ranges from 50.degree. to 90.degree. C. and whose OH value is not more than 5 KOH mg/g, with a diisocyanate. The toner composition has hot-melt properties suitable for rapid copying, for instance, the lower limit of fixing temperature thereof is low and the temperature range within which the toner can be fixed is very wide. Moreover, the toner composition is excellent in resistance to offset, antiblocking properties, resistance to ADF contamination, pulverization properties and quality of images. Thus, the toner composition shows practically excellent quality as a toner composition for electrophotography.

Electrophotographic toner

Resin for toner and toner containing same

A resin for toner of electrophotography comprises a urethane-modified polyester resin (D) having a glass transition temperature ranging from 40.degree. to 75.degree. C., which is obtained by reacting a resin mixture composed of a polyester resin (A) having a number-averaging molecular weight of 1,000 to 15,000 and a hydroxyl value of 10 to 100 and a polyester resin (B) having a number-average molecular weight ranging from 1,000 to 5,000 and a sum of acid value and hydroxyl value of less than 10, in a weight ratio of (A)/(B) ranging from 20:80 to 60:40, with 0.3 to 0.99 molar equivalent of an isocyanate compound (C) per one molar equivalent of hydroxyl group of the polyester resin (A). The resin for toner is excellent in grindability and storage stability and it provides toners for electrophotography having good anti-blocking properties and good fixing properties whereby good images free of fogging can be obtained.

Resins for toner of electrophotography and method for manufacturing the

Electrophotographic toner comprising a color agent and a mixture of

A resin for toner of electrophotography comprises a urethane-modified polyester resin (D) having a glass transition temperature ranging from 40.degree. to 75.degree. C., which is obtained by reacting a resin mixture composed of a polyester resin (A) having a number-average molecular weight of 1,000 to 15,000 and a hydroxyl value of 10 to 100 and a polyester resin (B) having a number-average molecular weight ranging from 1,000 to 5,000 and a sum of acid value and hydroxyl value of less than 10, in a weight ratio of (A)/(B) ranging from 20:80 to 60:40, with 0.3 to 0.99 molar equivalent of an isocyanate compound (C) per one molar equivalent of hydroxyl group of the polyester resin (A). The resin for toner is excellent in grindability and storage stability and it provides toners for electrophotography having good anti-blocking properties and good fixing properties whereby good images free of fogging can be obtained.

An electrophotographic toner, which can exhibit good fixation in high-speed copying and is not affected by an environment such as high humidity, is provided by containing, as a principal component thereof, a resin blend composed of (a) 40-90 wt. % of a vinyl copolymer (I) formed of 70-97 wt. % of an aromatic vinyl monomer, 3-30 wt. % of an alkyl fumarate which is an C.sub.1-8 monoalkyl or dialkyl ester and 0-5 wt. % of an acid monomer and having a number average molecular weight of 2,000-15,000 and (b) 10-60 wt. % of a vinyl polymer (II) having a number average molecular weight of 20,000-500,000.

Electrophotographic toner for high speed electrophotography

Resin composition containing vinyl polymer and olefin polymer for use in electrophotography, electrostatic recording and electrostatic printing and the like, more particularly the resin composition obtained by uniformly dispersing the olefin polymer in the vinyl polymer, and the toner containing this resin composition are disclosed.

Growing community of inventors

Fujisawa, Japan

Masaaki Shin