JP2004126575A5 - - Google Patents

Claims (14)

In a developer having at least toner particles containing a binder resin and a colorant, an inorganic fine powder, and a conductive fine powder,
When the wettability of the developer to a methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, the methanol concentration when the transmittance is 80% is in the range of 35 to 80% by volume,
The inorganic fine powder contains at least silica treated with silicone oil,
The volume average particle diameter Da of the conductive fine powder and the number average particle diameter Db of the primary particles of the inorganic fine powder satisfy the following formula (1):
Da ≧ 10 Db (1)
A developer, wherein the release rate a of the conductive fine powder is 50 % to 95%, and the release rate b of the inorganic fine powder is 0.1% to 3 %. When the wettability of the developer to a methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, the methanol concentration when the transmittance is 10% is in the range of 40 to 85% by volume. The developer according to claim 1 . When the wettability of the developer to a methanol / water mixed solvent is measured by the transmittance of light having a wavelength of 780 nm, the methanol concentration when the transmittance is 80% is C80, and the methanol concentration when the transmittance is 10%. when was the C10, developer according to claim 1 or 2, characterized by satisfying the following formula (2).
0 <C10-C80 ≦ 10 (2) The developer according to any one of claims 1 to 3 , wherein the conductive fine powder exists as an aggregate and has a volume average particle diameter Da of 0.1 to 4 µm. The surface of the conductive fine powder is hydrophobized with at least one hydrophobizing agent selected from silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane compounds, and silane coupling agents. The developer according to any one of claims 1 to 4 , wherein Developer according to any one of claims 1 to 5 content of the conductive fine powder is characterized in that from 0.1 to 5.0% by weight of the total developer. Developer according to any one of claims 1 to 6 wherein the electrically conductive powder, the resistance is equal to or less than 10 ⁹ Ω · cm. Developer according to any one of claims 1 to 6 wherein the electrically conductive powder, the resistance is equal to or less than 10 ⁶ Ω · cm. The conductive fine powder, zinc oxide, developer according to any one of claims 1 to 8, characterized by containing tin oxide, an oxide of at least one selected from titanium oxide. The developer according to any one of claims 1 to 9 , wherein the content of the inorganic fine powder is 0.1 to 3.0% by mass of the whole developer. The silica developer according to any one of claims 1 to 10, characterized in that treated with at least a silane compound and silicone oil. The developer according to any one of claims 1 to 11 , wherein the number average particle diameter Db of primary particles of the inorganic fine powder is 4 to 80 nm. Developer according to any one of claims 1 to 12 weight average particle diameter of the developer is equal to or is 3μm or 12μm or less. Developer, after adding and mixing inorganic fine powder, the developer according to any one of claims 1 to 13, characterized in that it is manufactured by adding a conductive fine powder.