Ricoh Company, Ltd.

Tomoegawa Co., Ltd.

Tohru Moriya

Tomomi Suzuki

Kohtaroh Ogino

Natsuko Matsushita

Yoshihito Suwa

Tatsuya Dan

Yousuke Suzuki

Kazuyoshi Hattori

Atsushi Sasai

Hitoshi Onoda

Kohei Hayasaka

Kazuki Washizu

A toner comprising a binder resin and a release agent is provided. When the toner is subjected to a FTIR-ATR mapping within a measurement range in a 50 &#x3bc;m square, divided in 1,024 pixels each in a 1.56 &#x3bc;m square, an average value of an intensity ratio of an absorption spectrum peak at a wavenumber of 2850 cmto an absorption spectrum peak at a wavenumber of 828 cmin each of the pixels is from 0.10 to 0.19, and a proportion of pixels in which the intensity ratio is 0.20 or higher to all the pixels is from 5% to 10%.

Toner and developer

Provided is a toner including at least a binder resin, and having peak ratio W/R of from 0.20 to 0.70 when measured with FT-IR according to ATR method, W/R being a ratio of height W of maximum spectral peak attributed to bisphenol A skeleton of the toner and observed at from 1,480 cmto 1,520 cmto height R of maximum spectral peak attributed to carbonyl group of the toner and observed at from 1,700 cmto 1,750 cm, wherein molecular weight distribution of the toner obtained by GPC of THF-soluble component of the toner has main peak in a range of from 1,000 to 10,000, half value width of the molecular weight distribution is a molecular weight of 20,000 or less, and content of a THF-insoluble component in the toner is from 5% by mass to 40% by mass.

Toner, image forming apparatus, image forming method, and toner stored unit

A toner, containing: a binder resin; and kaolinite, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by gel permeation chromatography (GPC) of THF soluble matter of the toner, and wherein the toner contains the kaolinite in an amount of 5% by mass to 35% by mass.

Toner, image forming apparatus, image forming method, and process cartridge

A toner, including: a binder resin; and calcium carbonate, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by GPC (gel permeation chromatography) of THF soluble matter of the toner, and wherein the toner contains the calcium carbonate in an amount of 5% by mass to 35% by mass.

A toner for electrophotography includes toner particles containing at least a binder resin and a colorant, to which strontium titanate and hydrophobic silica as external additives are admixed, wherein the strontium titanate has a BET specific surface area of 20-50 m/g and contains particles in a rectangular parallelepiped shape and wherein the hydrophobic silica contains hydrophobic silica A that has at least a BET specific surface area of 150-300 m/g and the surface of which has been treated with an aminosilane and hexamethyldisilazane and hydrophobic silica B that has at least a BET specific surface area of 90-150 m/g and the surface of which has been treated with hexamethyldisilazane.

Toner for electrophotography and process for producing the same

A toner for developing electrostatic charge images in which offset phenomenon and winding phenomenon do not occur in a wide temperature range, even if the binding resin contains the alicyclic olefinic resin, that is, a toner for developing electrostatic charge images which is superior in fixability in a high temperature range, and which is superior in melt contamination resistance, is provided. In the toner for developing electrostatic charge images comprises at least binder resin and colorant, the binding resin containing alicyclic olefinic resin (A) and thermoplastic elastomer (B). It is preferable that the alicyclic olefinic resin (A) be a copolymer comprising cyclic olefin (A1) and an acyclic unsaturated monomer (A2) as an element. Additionally, it is preferable that the melting point of the thermoplastic elastomer (B) be 60 to 190&#xb0; C.

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Shizuoka, Japan

Tohru Moriya