Abstract: A silica particle has a compression and aggregation degree of from 60% to 95% and a particle compression ratio of from 0.20 to 0.40.

Abstract: A titanium oxide aerogel particle has absorption at wavelengths of 450 nm and 750 nm in a visible absorption spectrum, a surface to which a metal compound containing a metal atom and a hydrocarbon group is bonded via an oxygen atom, a BET specific surface area in a range of 120 m2/g to 1,000 m2/g, and a value A is in the range of 0.03 to 0.3. The value A is calculated by formula: A={(peak intensity of C—O bond+peak intensity of C?O bond)/(peak intensity of C—C bond+peak intensity of C?C bond)}. In the formula, the peak intensity is a value determined from a C 1s XPS spectrum.

Abstract: A titanium oxide aerogel particle includes a metallic compound that has a metal atom and a hydrocarbon group, the metallic compound being bonded to a surface of the aerogel particle via an oxygen atom. The titanium oxide aerogel particle has a BET specific surface area of 120 m2/g to 1000 m2/g, and has absorption at wavelengths of 450 nm and 750 nm.

Abstract: An electrostatic charge image developing toner includes a styrene-acrylic resin and exhibits a z average molecular weight Mz of 80,000 to 400,000 and a molecular weight distribution curve satisfying Expression (1): 1.3?b/a?2.0, and an electrostatic charge image developing toner includes a styrene-acrylic resin, and exhibits a z average molecular weight Mz of 100,000 to 400,000 and a molecular weight distribution curve satisfying Expression (A): 0.75?(c+d)/(2×d)?0.95, wherein a, b, c and d are defined in the specification.

Abstract: An electrostatic charge image developing toner has a surface property index value represented by Formula S of 2.0 to 2.8, an electrostatic charge image developing toner has a surface property index value represented by Formula S of more than 2.8 and 3.5 or less, and an electrostatic charge image developing toner has a surface property index value represented by Formula S of more than 1.0 and less than 2.0 and a calculated value of a specific surface area in Formula S of 0.70 to 1.3: (Surface property index value)=(Measured value of specific surface area)/(Calculated value of specific surface area)??Formula S wherein (Calculated value of specific surface area)=(Sum of surface areas calculated from equivalent circle diameters of 4,500 toner particles in flow type particle image analysis)/{((Specific gravity of toner)×(Sum of volumes calculated from equivalent circle diameters of 4,500 toner particles in flow type particle image analysis)}.

Abstract: An electrostatic charge image developing toner includes a styrene-acrylic resin and exhibits a z average molecular weight Mz of 80,000 to 400,000 and a molecular weight distribution curve satisfying Expression (1): 1.3?b/a?2.0, and an electrostatic charge image developing toner includes a styrene-acrylic resin, and exhibits a z average molecular weight Mz of 100,000 to 400,000 and a molecular weight distribution curve satisfying Expression (A): 0.75?(c+d)/(2×d)?0.95, wherein a, b, c and d are defined in the specification.

Abstract: Provided is a toner including toner particles. The toner particles has a volume particle diameter distribution index on a side of the largest diameter (GSDv (90/50)) of 1.26 or less; a number particle diameter distribution index on a side of the smallest diameter (GSDp (50/10)) of 1.28 or less; GSDv (90/50)/GSDp (50/10) of from 0.96 to 1.01; and an average circularity of 0.95 or more and 1.00 or less.

Abstract: A titanium oxide aerogel particle includes a metallic compound that has a metal atom and a hydrocarbon group, the metallic compound being bonded to a surface of the aerogel particle via an oxygen atom. The titanium oxide aerogel particle has a BET specific surface area of 120 m2/g to 1000 m2/g, and has absorption at wavelengths of 450 nm and 750 nm.

Abstract: A titanium oxide aerogel particle has absorption at wavelengths of 450 nm and 750 nm in a visible absorption spectrum, a surface to which a metal compound containing a metal atom and a hydrocarbon group is bonded via an oxygen atom, a BET specific surface area in a range of 120 m2/g to 1,000 m2/g, and a value A is in the range of 0.03 to 0.3. The value A is calculated by formula: A={(peak intensity of C—O bond+peak intensity of C?O bond)/(peak intensity of C—C bond+peak intensity of C?C bond)}. In the formula, the peak intensity is a value determined from a C 1s XPS spectrum.

Abstract: Provided is a silica titania composite aerogel particle including a base particle in which an element ratio Si/Ti of silicon to titanium is greater than 0 and equal to or lower than 6. A BET specific surface area of the silica titania composite particle is within a range of 200 m2/g to 1200 m2/g, and the silica titania composite particle has absorption at wavelengths of 450 nm and 750 nm.

Abstract: A silica-titania composite aerogel particle includes: a base particle including silicon and titanium whose element ratio Si/Ti is more than 0 and 6 or less; and a surface layer present on the base particle and including a metal compound having a metal atom and a hydrocarbon group. The silica-titania composite aerogel particle has absorption at wavelengths of 450 nm and 750 nm in a visible absorption spectrum, has a BET specific surface area in the range of 200 m2/g to 1,200 m2/g, and has a value A in the range of 0.03 to 0.3. The value A is calculated by formula: A=(peak intensity of C—O bond+peak intensity of C?O bond)/(peak intensity of C—C bond+peak intensity of C?C bond). The peak intensity is obtained from a C is XPS spectrum.

Abstract: An electrostatic charge image developing toner includes toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement by differential scanning calorimetry (DSC) before and after being stored at a temperature of 50° C. and a humidity of 90% RH for 24 hours, a relationship between an onset temperature T1 (° C.) of an endothermic peak having the lowest peak temperature in a first heating step with respect to the toner particles before being stored and an onset temperature T2 (° C.) of an endothermic peak having the lowest peak temperature in a first heating step with respect to the toner particles after being stored satisfies Expression (1): 2<T2?T1<10.

Abstract: A resin particle composition includes resin particles, inorganic particles surface-treated with oil, and silica particles having a compression aggregation degree of 60% to 95% and a particle compression ratio of 0.20 to 0.40.

Abstract: A resin particle composition includes resin particles, polishing agent particles having an average circle-equivalent diameter of 0.1 ?m to 3.0 ?m, and silica particles having a compression aggregation degree of 60% to 95% and a particle compression ratio of 0.20 to 0.40.

Abstract: An electrostatic charge image developing toner includes toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement by differential scanning calorimetry before and after being heated at a temperature of 50° C. and a humidity of 50% RH for a week, a relationship between an endothermic amount S1 (J/g) derived from the crystalline resin in a first heating process with respect to the toner particles before being heated and an endothermic amount Sh (J/g) derived from the crystalline resin in a first heating process with respect to the toner particles after being heated satisfies Expression (1): 0.50?S1/Sh?0.90.

Abstract: An electrostatic image developing toner contains: toner particles, first silica particles having an average equivalent circle diameter of 10 nm to 120 nm and second silica particles having a compressive agglomeration degree of 60% to 95%, a particle compression ratio of 0.20 to 0.40 and an average equivalent circle diameter being greater than the average equivalent circle diameter of the first silica particles.

Abstract: An electrostatic charge image developing toner includes toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement by differential scanning calorimetry before and after being heated at a temperature of 50° C. and a humidity of 50% RH for a week, a relationship between an endothermic amount x (J/g) derived from the crystalline resin with respect to the toner particles before being heated and an endothermic amount y (J/g) derived from the crystalline resin with respect to the toner particles after being heated satisfies Expression (1): x/y<0.3.

Abstract: An electrostatic charge image developing toner includes toner particles including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement to determine an area ratio of the crystalline resin present on a surface of the toner particle before and after being heated at a temperature of 50° C. and a humidity of 50% RH for a week, a relationship between an area ratio a (%) of the crystalline resin present on a surface of the toner particles before being heated and an area ratio b (%) of the crystalline resin present on a surface of the toner particles after being heated satisfies Expression (1): 0.05?(b?a)/b?0.50.

Abstract: An electrostatic charge image developing toner includes toner particles each including an amorphous resin and a crystalline resin, wherein, when the toner particles are subjected to a measurement to determine an area ratio of the crystalline resin on a cross section of the toner particle before and after being heated at a temperature of 50° C. and a humidity of 50% RH for three days, a relationship between an area ratio a (%) of the crystalline resin on a cross section with respect to the toner particles before being heated, and an area ratio b (%) of the crystalline resin on the cross section with respect to the toner particles after being heated satisfies Expression (1): 0.9?a/b?1.0.

Abstract: A toner for electrostatic image development includes toner particles; and an external additive containing silica particles and polytetrafluorethylene particles, the silica particles having a compression-aggregation degree of 60% or more and 95% or less and a particle compression ratio of 0.20 or more and 0.40 or less.