Abstract: The external additive for toner includes an external additive particle containing: a fine particle A; and a plurality of fine particles B that are each present so as to partially protrude from a surface of the fine particle A, wherein the fine particle A (i) is a particle of an organosilicon compound having a siloxane bond, (ii) has a number-average particle diameter of 0.03 ?m or more and 0.30 ?m or less, and (iii) has an average circularity of 0.90 or more, wherein, when the number-average particle diameter of the fine particle A is represented by DA, and a number-average particle diameter of the plurality of fine particles B is represented by DB, DB/DA is 0.10 or more and 0.63 or less.

Abstract: An external additive for toner comprising: a fine particle A containing, as a binder component, an organosilicon compound having a siloxane bond; and a fine particle B that is present on a surface of the fine particle A in a state of being at least partially embedded in the surface of the fine particle A, wherein the external additive for toner (i) has a number-average particle diameter of a primary particle of 0.03 ?m or more and 0.30 ?m or less, and (ii) has a Young's modulus of 10 GPa or more and 30 GPa or less, wherein content ratios, on a number basis, of the following unit (a), unit (b), and unit (c) in the fine particle A based on all silicon atoms present in the fine particle A satisfy the following expressions (1) and (2). (a)+(b)+(c)?0.80??(1) (b)+(c)?0.

Abstract: The external additive for toner includes an external additive particle containing: a base particle A; and a plurality of convex forming particles B each configured to form a convex portion on a surface of the base particle A. The base particle A and the convex forming particles B are particles each containing a silicon compound having a siloxane bond, and a chemical bond is formed between the base particle A and each of the convex forming particles B. The base particle A and the convex forming particles B each have a total content of the following unit (a), unit (b), and unit (c) of 80 mass % or more and 100 mass % or less: where R1 and R2 each represent an alkyl group having 1 or more and 6 or less carbon atoms.

Abstract: There is provided a photocatalyst coating composition that is capable of forming a smooth and even photocatalyst coated film without the formation of aggregated particles. The photocatalyst coating composition according to the present invention includes photocatalyst particles, inorganic oxide particles other than the photocatalyst particles, a dispersion medium composed mainly of water, and a thickening agent, wherein the composition has a viscosity of 0 mPa·s or more to 10 mPa·s or less and, when the concentration of the composition is condensed tenfold, has a viscosity of not less than 40 mPa·s as determined under conditions of a shear rate of 1.0 s?1 and a temperature of 25° C. with a rheometer.