An electrostatically charged image developing toner includes a particulate toner matrix containing an external additive on the surface of the particulate toner matrix. The external additive includes silica particles A and silica particles B. The silica particles A have a number average primary-particle diameter in the range of 40 to 100 nm and an average circularity in the range of 0.50 to 0.90, and are surface-modified with silicone oil. The silica particles B have a number average primary-particle diameter of 25 nm or more and smaller than the number average primary-particle diameter of the silica particles A, and are surface-modified with alkylalkoxysilane having a specific structure or silazane.

Provided is a toner containing a toner particle including a binder resin, a wax, and a colorant. The softening point of the toner is at least 80 C. and not more than 140 C. The average circularity of the toner is at least 0.940. The integrated value of stress in the toner at 150 C. which is measured by using a tackiness tester is at least 78 g.Math.m/sec.

A toner including a toner particle having a core-shell structure that has a core formed from a resin 1 and a shell formed from a resin 2 on the surface of the core, wherein the resin 1 contains more than 50 mass % of an ester group-containing olefin-based copolymer, the ester group-containing olefin-based copolymer has a monomer unit Y1 represented by formula (1) below, and at least one type of monomer unit Y2 selected from the group consisting of monomer units represented by formula (2) and formula (3) below, the ester group concentration in the ester group-containing olefin-based copolymer is from 2 mass % to 18 mass %, and the resin 2 is an amorphous resin having a Tg value of from 50 C. to 70 C.

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There is provided a magnetic substance containing substituted -iron oxide particles applicable as a magnetic toner of one-component development system, and a technique related thereto, which is the magnetic substance containing substituted -iron oxide particles in which a part of -iron oxide is substituted with a metal element other than iron, and satisfying at least one of the following conditions: (Condition 1) A molar extinction coefficient of a magnetic substance dispersion liquid at a wavelength of 450 nm is less than 770 dm.sup.3 mol.sup.1 cm.sup.1. (Condition 2) A molar extinction coefficient of the magnetic substance dispersion liquid at a wavelength of 500 nm is less than 430 dm.sup.3 mol.sup.1 cm.sup.1.

An electrostatic charge image developing toner includes: a toner particle and a strontium titanate particle that is externally added to the toner particle, in which an average primary particle diameter of the strontium titanate particle that is present on a surface of the toner particle is 30 nm or more and 100 nm or less, and average primary particle circularity is 0.82 or more and 0.94 or less, and in which circularity that becomes 84% of accumulation of the primary particle is greater than 0.92.

A magnetic toner includes toner particles. The toner particles each include a toner core and a shell layer covering a surface of the toner core. The toner cores contain a polyester resin and a magnetic powder. The magnetic powder includes specific magnetic particles. The shell layers contain a specific vinyl resin.

A magnetic toner is provided, which has a magnetic toner particle containing a binder resin, a wax, and a magnetic body, wherein, when Dn is a number-average particle diameter of the toner, CV1 is coefficient of variation of a brightness variance value of the toner in a particle diameter range of Dn0.500 to +0.500, and CV2 is coefficient of variation of a brightness variance value of the toner in a particle diameter range of Dn1.500 to 0.500, a relationship CV2/CV1 1.00 is satisfied; an average brightness of the toner in the range of Dn0.500 to +0.500 is 30.0 to 60.0; and when, in a cross section of the toner observed using a transmission electron microscope, which is divided with a square grid having a side of 0.8 m, coefficient of variation CV3 of an occupied area percentage for the magnetic body is 40.0 to 80.0%.

An electrostatic latent image developing toner includes toner particles each including a toner mother particle and an external additive. The toner mother particle includes a composite core and a shell layer. The composite core is a composite of a toner core, organic particles, and polyhedral magnetic particles. The organic particles each contain a releasing agent and adhere to a surface of the toner core. The magnetic particles include magnetic particles adhering to the surface of the toner core and magnetic particles adhering to surfaces of the organic particles. An amount of the magnetic particles is 0.5 parts by mass to 2.0 parts by mass relative to 100 parts by mass of the toner cores. In a cross-sectional image of each toner particle, an area of protruding portions of the magnetic particles, which protrude from the shell layer, accounts for 10% to 75% of an overall area of the magnetic particles.

A toner comprising: a toner particle containing a binder resin and a colorant; and an external additive, wherein the external additive is a composite particle having an organic substance and an organosilicon polymer coating layer on the surface of the organic substance, and when a curve for the variation (dE/dT) in the storage elastic modulus E of the toner with respect to temperature T [ C.] is obtained on the basis of a curve of the temperature Tthe storage elastic modulus E [Pa] of the toner, as determined by powder dynamic viscoelasticity measurements of the toner, the relative minimum value on the lowest temperature side between the onset temperature and 90 C. is 1.3510.sup.8 or less.

A toner comprising a toner particle that contains a binder resin and a release agent, wherein the toner particle has a surface layer that contains an organosilicon polymer and the luminance histogram of a backscattered electron image of the toner particle has two peak values P1 and P2 and a minimum value V between P1 and P2, P2 originates from the organosilicon polymer, and the luminance giving P1 and P2 are in specific ranges, percentages for P1 and P2 are each at least 0.50%, and using the luminance Bl at V as a reference point, specific relationships are satisfied by A1, AV, and A2, where A1 is the total number of pixels at luminance from 0 to (Bl30), AV is the total number of pixels at luminance from (Bl29) to (Bl+29), and A2 is the total number of pixels at luminance from (Bl+30) to 255.