A toner including a toner particle including a binder resin, wherein fine particles A and B are present on a surface of the toner particle; the fine particles A are a fatty acid metal salt; the fine particles B have a specific volume resistivity; an average theoretical surface area of the toner particle, an amount of the fine particles A, and a coverage ratio of the toner particle surface by the fine particles A satisfy a specific relationship; the amount of the fine particles B is in a specific range; and a proportion F of an area occupied by a part of the fine particles B embedded in a surface vicinity region of the toner in a total area occupied by the fine particles B present in a cross section of one particle of the toner is 50% by area or more.

A toner includes a toner particle including a surface layer containing an organosilicon polymer. The toner particle contains a styrene acrylic resin and a block polymer that has i) a polyester segment C and a vinyl polymer segment A, the mass ratio C/A of the polyester segment C to the vinyl polymer segment A being 40/60 to 80/20, and ii) a melting point Tm of 55° C. to 90° C. The organosilicon polymer has a partial structure represented by Rf—SiO.sub.3/2.

An image forming apparatus includes an image holding member including a conductive substrate, a photosensitive layer, and a protection layer; a charging unit; an electrostatic image forming unit; a developing unit that includes an electrostatic image developer having a toner and develops the electrostatic image to form a toner image; a transfer unit that transfers the toner image onto a surface of a recording medium; a fixing unit that fixes the toner image; and a cleaning unit that includes a cleaning blade. The toner includes toner particles and silica particles having a number average particle size of 110 nm to 130 nm, a large-diameter-side number particle size distribution index (upper GSDp) of less than 1.080, and an average circularity of 0.94 to 0.98, wherein 80 number % or more of the silica particles have a circularity of 0.92 or more.

A toner according to an embodiment includes toner base particles and an external additive. The external additive contains silica particles having a D.sub.50 of 70 to 120 nm. The joining degree of the silica particles is 80% or more. The toner base particles contain a crystalline polyester resin and an ester wax. The ester wax is a condensation polymer of three or more types of carboxylic acids and two or more types of alcohols. The proportion of a carboxylic acid, the content of which is highest, is between 70 and 95 mass %. The proportion of a carboxylic acid with a carbon number of 18 or less is 5 mass % or less. The proportion of an alcohol, the content of which is highest, is between 70 and 90 mass %. The proportion of an alcohol with a carbon number of 18 or less is 20 mass % or less.

A developer includes a toner including toner particles and a carrier including carrier particles. The carrier particles each include a carrier core and a carrier coating layer covering the carrier core. The carrier coating layer contains a fluorine-containing resin. The toner particles each include a toner mother particle and resin particles located on a surface of the toner mother particle. The resin particles have a number average primary particle diameter of at least 70 nm and no greater than 200 nm. A dispersion obtained by dispersing 0.1 g of the resin particles in 100 mL of distilled water has an electrical conductivity of at least 2.5 μS/m and no greater than 6.0 μS/m. A degree of aggregation Y.sub.160 of the resin particles represented by expression (1) “Y.sub.160=100×M.sub.160A/M.sub.160B” is at least 15% by mass and no greater than 40% by mass.

There is provided a resin composition containing an infrared absorber as an inner salt, at least either a carboxylic acid ester or a phosphoric acid ester, and a resin; and an image forming material containing an infrared absorber as an inner salt, at least either a carboxylic acid ester or a phosphoric acid ester, and a thermoplastic resin.

An external additive for toner comprising a particle of a silicon polymer having a siloxane bond and a Si—O—C bond, wherein in an FT-IR spectrum of the external additive obtained by an ATR method, a maximum peak is present in a range of from 1030 cm.sup.−1 to 1070 cm.sup.−1, where an average intensity in a range of from 1015 cm.sup.−1 to 1025 cm.sup.−1 of the spectrum is denoted by A and an average intensity in a range of from 1085 cm.sup.−1 to 1095 cm.sup.−1 is denoted by B, the A and the B satisfy a following formula (1):

[00001]$\begin{array}{cc}0.55\le A/B\le 1.5.& \left(1\right)\end{array}$

An external additive for toner comprising a particle of a silicon polymer having a siloxane bond and a Si—R.sup.1 bond, wherein the R.sup.1 represents an alkyl group having from 1 to 6 carbon atoms, in a chart obtained by .sup.29Si—NMR measurement of the external additive, where a total peak area attributed to the external additive is denoted by A, and a peak area attributed to the Si—R.sup.1 bond is denoted by B, a following formula (1) is satisfied, and in the chart obtained by .sup.29Si—NMR measurement of the external additive, where a total peak area attributed to the silicon polymer is denoted by SA, and a peak area attributed to a T unit structure is denoted by S3, a following formula (2) is satisfied;

[00001]$\begin{array}{cc}0.260\le B/A\le 0\mathrm{.450}& \left(1\right)\\ 0.00\le S3/\mathrm{SA}\le 0\mathrm{.50}.& \left(2\right)\end{array}$

A toner that is excellent in low-temperature fixability at the time of high-speed printing, achieves both hot offset resistance and winding resistance, and has such satisfactory durability as not to be liable to cause an image failure even at the time of long-term endurance. The toner includes a toner particle containing a binder resin including a first resin and a second resin, wherein the first resin is a crystalline resin, wherein the second resin is an amorphous resin, wherein, the toner has a domain-matrix structure formed of: a matrix containing the first resin; and domains each containing the second resin, wherein, an endothermic quantity ΔH (J/g) derived from the first resin satisfies a relationship of ΔH≥3, and wherein, in flow tester measurement of the toner, the following relationships are satisfied: T10≥65; T1−T10≤10.

A fine particle of a silicon polymer having a siloxane group and a silanol group, wherein a moisture adsorption amount of the fine particle at a temperature of 30° C. and a humidity of 80% RH is from 1.0 mg/g to 22.0 mg/g, an amount of the silanol group of the fine particle measured by a titration method using KOH is from 0.012 mmol/g to 0.120 mmol/g, and a number average particle diameter of primary particle of the fine particle is from 0.05 μm to 0.30 μm.