Kyocera Document Solutions Inc.

Kohei Yamauchi

Hiroki Uemura

Toshiki Takemori

Toner includes, as toner particles, first particles and second particles. The first particles each include a first core and a first shell layer covering a surface of the first core. The first core contains a first binder resin and is free from metal stearates. The second particles each include a second core and a second shell layer covering a surface of the second core. The second core contains a metal stearate. The first shell layer and the second shell layer are formed of resins of the same type, respectively. The content of the metal stearate in the second core is 50% by mass or more with respect to the mass of the second core as a whole. The number ratio of the second particles is 5% or more but 25% or less of the total number of the first particles and the second particles.

Toner

Toner particles of a toner contain a non-crystalline polyester resin, a crystalline polyester resin, a styrene-acrylic acid-based resin, and an ester wax. The crystalline polyester resin has a repeating unit derived from an acrylic acid-based monomer and a repeating unit derived from a styrene-based monomer. The styrene-acrylic acid-based resin has a repeating unit derived from an acrylic acid-based monomer having an amino group and a repeating unit derived from a styrene-based monomer. An amino group ratio in the styrene-acrylic acid-based resin is at least 40% and no greater than 60%. The toner has a storage elastic modulus of at least 1.00&#xd7;10Pa and no greater than 5.00&#xd7;10Pa at 90&#xb0; C. The ester wax has a melting point of at least 60&#xb0; C. and no higher than 80&#xb0; C. A dispersion diameter of the ester wax in the toner particles is at least 500 nm and no greater than 1,000 nm.

Electrostatic latent image developing toner

An electrostatic latent image developing toner includes a plurality of toner particles containing a non-crystalline polyester resin and a crystalline polyester resin. The toner particles contain as the crystalline polyester resin a dispersoid of crystallized crystalline polyester resin (CPES) domains. The CPES domains of the CPES dispersoid have an aspect ratio of at least 3.40 and no greater than 10.0 in terms of number average value. The toner particles have a roundness of at least 0.950 and no greater than 0.970 in terms of number average value. In a cross-sectional image of each of the toner particles, a ratio of a total area occupied by the CPES dispersoid to a cross-sectional area of the toner particle is at least 10.0% and no greater than 30.0%. The non-crystalline polyester resin includes a repeating unit derived from alkenyl succinic anhydride. The crystalline polyester resin includes a repeating unit derived from n-butyl methacrylate.

Toner particles contain a non-crystalline polyester resin. The toner particles further contain 10 parts by mass to 30 parts by mass of a crystalline polyester resin, 30 parts by mass to 50 parts by mass of a styrene-acrylic acid-based resin, and 8 parts by mass to 15 parts by mass of an ester wax relative to 100 parts by mass of the non-crystalline polyester resin. The crystalline polyester resin includes a repeating unit derived from an acrylic acid-based monomer and a repeating unit derived from a styrene-based monomer. The styrene-acrylic acid-based resin includes a repeating unit derived from an acrylic acid-based monomer having an amino group and has an amino group ratio of 40% to 60%. The ester wax in the toner particles has a dispersion diameter of 500 nm to 1,000 nm.

An electrostatic latent image developing toner includes a plurality of toner particles each including a composite core and a shell layer covering a surface of the composite core. The composite core is a composite of a toner core and a plurality of organic particles each adhering to a surface of the toner core. The shell layer contains a first resin having a glass transition point of at least 50&#xb0; C. and no greater than 90&#xb0; C. The organic particles each contain a releasing agent and a second resin having a glass transition point of at least 90&#xb0; C. and no greater than 110&#xb0; C.

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Osaka, Japan

Kohei Yamauchi