Canon Kabushiki Kaisha

Hiroshi Yusa

Koichi Tomiyama

Tsutomu Kukimoto

Takashige Kasuya

Tsuyoshi Takiguchi

Eiichi Imai

Hiroyuki Suematsu

Yoshihiro Ogawa

Takakuni Kobori

Masayoshi Kato

Hisayuki Ochi

Tetsuhito Kuwashima

Yuki Karaki

Tetsuya Kuribayashi

Manabu Ohno

Masaichiro Katada

Kiyoko Tsuchiya

Syuhei Moribe

Kazuo Maruyama

Hirohide Tanikawa

Katsuhisa Yamazaki

Satoshi Yoshida

Shuhei Moribe

Motoo Urawa

Keita Nozawa

Masao Takano

Yasutaka Akashi

Masanori Ito

Satoshi Handa

Takaaki Kohtaki

Masuo Yamazaki

Osamu Tamura

Hideto Iida

Tsuyoshi Takuguchi

Kohichi Tomiyama

A toner of the present invention comprises at least a binder resin comprising as a main component a polyester resin, a wax, and a colorant, in which in case of measuring a wettability of the toner with respect to a mixed solvent of methanol and water in terms of an optical transimittance at an optical wavelength of 780 nm, a methanol concentration of the mixed solvent is in a range of 45 to 65% by volume when an optical transmittance is 80% and 10%, respectively; a melt index (MI) is of 0.1 to 10 g/10 min at a temperature of 125&#xb0; C. and a load of 5 kg; the toner comparises a resin component insoluble to tetrahydrofuran (THF insoluble component) in an amount of 5 to 40% by mass based on a mass of the binder resin; and the toner comprises a THF soluble component having a main peak in a molecular weight region of 3,000 to 20,000, and has a proportion of a component having a molecular weight of 10,000 or less in the THF soluble component is 50% by mass or more, according to a chromatogram of the THF soluble component measured by gel permeation chromatography. According to the toner of the present invention, it is possible to control lowering of an image density after leaving under a high temperature and high humidity environment, and a decline in the image density due to a charge-rise phenomenon upon low rate printing. Further, the toner has excellent fixing property and high temperature offset characteristic, and occurring of the end-offset is controlled.

Toner

In a toner having a polyester resin as a binder resin component, and a colorant, the toner contains (a) in the binder resin component, from 20.0% by weight to 65.0% by weight of a tetrahydrofuran-insoluble matter A1 in 6-hour extraction and from 35.0% by weight to 80.0% by weight of a tetrahydrofuran-soluble matter A2 in 6-hour extraction, (b) in the binder resin component, from 10.0% by weight to 30.0% by weight of a tetrahydrofuran-insoluble matter B1 in 16-hour extraction and from 70.0% by weight to 90.0% by weight of a tetrahydrofuran-soluble matter B2 in 16-hour extraction, and (c) in the binder resin component, from 0.5% by weight to 3.0% by weight of an orthodichloro-benzene-insoluble matter C1 in 6-hour extraction at 185&#xb0; C. and from 97.0% by weight to 99.5% by weight of an orthodichlorobenzene-soluble matter C2 in 6-hour extraction at 185&#xb0; C. The proportion of C1 to B1, C1/B1, is from 0.06 to 0.15, and the A1, B1 and C1 satisfy the following expression (1):A1&#x3e;B1&#x3e;C1.&#x2003;&#x2003;Expression (1)A process cartridge makes use of this toner.

Toner, and process cartridge

A toner showing a high transferability and suitable for use in cleanerless image forming system is formed of toner particles comprising at least a binder resin and magnetic iron oxide. The toner is characterized by a specific circularity distribution relative to its weight-average particle size and a controlled degree of surface-exposed magnetic iron oxide providing an extract solution with hydrochloric acid showing an absorbance of 1.0-2.5 at a wavelength of 340 nm. The toner is suitably produced by a production system including a rotary mechanical pulverizer and a one-pass surface treatment apparatus for continuously applying a mechanical impact force to pulverized toner particles therein.

Dry toner, toner production process, image forming method and process cartridge

A toner is constituted by at least a binder resin, a colorant and a wax. The binder resin has been formed from monomers including a vinyl monomer and polyester-forming monomers containing at least a polybasic carboxylic acid having three or more carboxyl groups or its anhydride, and comprises at least a hybrid resin comprising a vinyl polymer unit and a polyester unit.

Toner and resin composition for the toner

A toner is principally constituted by a binder resin, a colorant and a wax. The toner has a maximum heat-absorption peak of 60-135&deg; C. as measured by differential scanning calorimetry (DSC). The toner further has a viscoelastic characteristic measured at an angular frequency of the toner of 6.28 rad/sec including: a temperature giving a loss molecules G&Prime; of 3&times;10,Pa of 90-115&deg; C., a temperature giving a loss modulus G&Prime; of 2&times;10,Pa of 95-120&deg; C., a temperature giving a loss modulus G&Prime; of 1&times;10,Pa of 105-135&deg; C., a tan &dgr; (loss modulus G&Prime;/storage modulus G&prime;) when G&Prime;&equals;1&times;10,-3&times;10,Pa of 0.6-2.0, a storage modulus at 170&deg; C. (G&prime; (170&deg; C.)) of 1&times;10,-1&times;10,Pa, a loss modulus at 170&deg; C. (G&Prime; (170&deg; C.)) of 1&times;10,-1&times;10,Pa, and a ratio of a tan &dgr; at 170&deg; C. (tan &dgr;,) to a tan &dgr; at 150&deg; C. (tan &dgr;,) (tan &dgr;,/tan &dgr;,) of 1.05-1.6. The toner contains a tetrahydrofuran (THF)-soluble content exhibiting a molecular weight distribution according to gel permeation chromatography (GPC) chromatogram providing a main peak in a molecular weight region of 2,000-30,000 and a ratio (Mw/Mn) of above 100 between weight-average molecular weight (Mw) and number-average molecular weight (Mn). The resultant toner is effective in improving a low-temperature fixability and a high-temperature anti-offset characteristic while retaining an appropriate gloss of a fixed image in a broader temperature range.

Toner, two-component type developer, heat fixing method, image forming method and apparatus unit

Toner and image forming method

A toner for developing an electrostatic image is disclosed which has at least one endothermic peak in the temperature region of 120.degree. C. or below in differential thermal analysis and contains, in its particles having particle diameters of 3 .mu.m or larger, not less than 93% by number of particles having a circularity of at least 0.90 and less than 30% by number of particles having a circularity of at least 0.98. The toner does not cause the re-transfer under high transfer current conditions and can realize the formation of good images with high image density. Also, an image forming method using the toner is disclosed.

Toner for developing electrostatic image and image forming method

A toner is comprised of a composition containing at least a polymer component and a charge control agent. The polymer component contains substantially no tetrahydrofuran (THF)-insoluble matter. The polymer component THF-soluble has a major peak and a minor peak in the specific molecular weight regions in gel permeation chromatography (GPC). The low molecular weight component and high molecular weight component of the polymer component, each of which shows the specific molecular weight region in GPC, have the specific acid values, respectively. The difference between the acid values is in the specific range.

Process cartridge

A toner for forming an image has toner particles containing at least a colorant, a binder resin and a wax. The toner has (i) a circularity distribution in which the toner has an average circularity of 0.900 to less than 0.965, contains 20 to 60% by number of particles with a circularity of less than 0.95 and has a mode circularity of 0.90 or more; and (ii) a particle size distribution in which the toner has a circle-equivalent average diameter of 2.0 to 10.0 .mu.m and has at least one peak of frequency by number in the region of a circle-equivalent diameter of 0.6 to 3.0 .mu.m and at least one peak of frequency by number in the region of a circle-equivalent diameter of from more than 3.0 .mu.m to 10.0 .mu.m. The wax has an endothermic main peak as measured by DSC of 60 to 120.degree. C. The binder resin contains THF soluble matter and 0 to 5.0% by weight of THF insoluble matter. The THF soluble matter having a molecular-weight distribution as measured by GPC in which the THF soluble matter has a content (M1) of 5% or less of a component with a molecular weight of less than 50,000, a content (M2) of 20 to 45% of a component with a molecular weight of 50,000 to 500,000, and a content (M3) of 2 to 25% of a component with a molecular weight exceeding 500,000 and the following condition (1) is satisfied:

Toner for forming an image, image forming method and heat-fixing method

A magnetic black toner for electrophotography, includes: (a) magnetic black toner particles containing a binder resin, a magnetic material in 30-200 wt. parts per 100 wt. parts of the binder resin, and a first solid wax, and (b) first inorganic fine powder. The first solid wax (ii) provides a DSC heat-absorption main peak in a range of 60.degree.-120.degree. C., and (iii) shows a molecular weight distribution factor Mw/Mn of 1.0-2.0. The binder resin (iv) has a THF (tetrahydrofuran)-insoluble content of at most 5 wt. %, and (v) contains a THF-soluble content showing a GPC molecular weight distribution including a content (M1) of 40-70% in molecular weights of below 5.times.10.sup.4, a content (M2.ltoreq.M1) of 20-45% in molecular weights of 5.times.10.sup.4 -5.times.10.sup.5, and a content (M3&lt;M2) of 2-25% in molecular weights exceeding 5.times.10.sup.5. (vi) The magnetic black toner exhibits a tan .delta. of 0.5-3.0 in a range of 150.degree.-190.degree. C. and a tan .delta. at 150.degree. C. that is equal to or larger than a tan .delta. at 100.degree. C. The magnetic black toner shows a good fixability in an oil-less fixation system to provide a fixed image having a gloss comparable to one obtained by a non-magnetic color toner.

Magnetic black toner and multi-color or full-color image forming method

An image forming apparatus includes a member to be charged for carrying an electrostatic latent image; a contact charging means for contact charging the member to be charged and a developing means for developing the latent image. The developing means includes a developer having a magnetic toner and fine powder treated with a silicone oil or varnish-treating agent, wherein the magnetic toner particles include a binder resin and contain from 10-70 wt. % of magnetic fine powder. An image forming method includes the steps of contact charging, latent image forming and developing with a developer having the binder resin, 10 to 70 wt. % magnetic fine powder and fine powder treated with a silicone oil or varnish-treating agent.

Images forming apparatus and developer for developing electrostatic

Toner for developing electrostatic images, process cartridge, and image

A developer for developing an electrostatic image has a toner which contains a particulate toner, a particulate silica A and a particulate silica B. The toner has a weight-average particle size of not larger than 12.0 .mu.m and a particle-number distribution showing not more than 50% of toner particles not larger than 4.0 .mu.m in particle size and not more than 10% of toner particles not smaller than 10.08 .mu.m in particle size, each of the toner particles having a toner composition containing at least a polymer component and a charge controlling agent. The particulate silica A is composed of silicone oil-treated silica particles and has an average particle size of not larger than 0.1 .mu.m, while the particulate silica B is composed of silicone oil-treated silica particles and has an average particle size of 0.5 to 50 .mu.m. The particulate silica B also has a particle-number distribution showing not more than 50% of silica particles not larger than 1.0 .mu.m in particle size and not more than 10% of silica particles not smaller than 100 .mu.m in particle size. Also disclosed is an image forming method which uses this developer.

Developer for developing an electrostatic image and image forming method

Growing community of inventors

Yokohama, Japan

Hiroshi Yusa