Toner used in electrophotography having toner particles and silica powder
A toner is provided which can stably provide a favorable density stability, line reproducibility and dot reproducibility even in high-speed copying machines, printers and the like which form high resolution latent images over a long period regardless of environmental conditions, and can provide the image quality adaptable to embedded pattern printing, QR code printing and the like. The present invention is characterized in that the toner which includes toner particles including at least a binder resin and a colorant, and a fine silica powder, has a volume median diameter (D 50 ) of not less than 0.70 μm and not more than 3.00 μm, and a total pore volume of not more than 0.200 cm 3 /g, measured in the range of the pore diameter from not less than 1.7 nm and not more than 300.0 nm.
1. A toner, comprising: toner particles comprising at least a binder resin and a colorant, and a fine silica powder, wherein the fine silica powder has a volume median diameter (D 50 ) of 0.70 μm or more and 3.00 μm or less, a total pore volume of 0.200 cm 3 /g or less, as measured in the range of the pore diameters 1.7 nm or more and 300.0 nm or less, and a specific surface area of not less than 1.0 m 2 /g and not more than 20.0 m 2 /g.
2. The toner according to claim 1 , wherein the fine silica powder has an average pore diameter of 50.0 nm or less.
3. The toner according to claim 1 , which further comprises a hydrophobic fine inorganic powder having a BET specific surface area of 50 m 2 /g or more and 300 m 2 /g or less.
4. The toner according to claim 1 , wherein the fine silica powder has an adsorbed moisture amount, in the adsorption process at the relative humidity of 80% RH in the moisture adsorption-desorption isotherm at 30° C. of the fine silica powder, of 0.01 mass % or more and 1.00 mass % or less.
5. The toner according to claim 1 , wherein the fine silica powder is manufactured by a vapor-phase method.
6. The toner according to claim 5 , wherein the vapor-phase method is a vapor-phase oxidation method.