Toner and production method thereof, image forming apparatus and image forming method, and process cartridge

A developer for developing a latent electrostatic image formed on a latent image carrier,

• wherein the developer is a two-component developer which comprises a toner and carrier;
• and the toner comprises at least a binder resin, toner-base particles containing an inorganic filler, and inorganic fine particles;
• wherein the toner is obtained by adding, into an aqueous medium, a toner material liquid in which at least the binder resin and the inorganic filler are dispersed and/or dissolved in an organic solvent, so that the toner material liquid is emulsified, and removing the organic solvent therefrom,
• wherein the filler is contained in a filler-layer in the vicinity of a surface of the toner-base particles, a number average particle diameter of the primary particles of the inorganic fine particles is 90 nm to 300 nm, and the average circularity of the toner is 0.94 or more;
• and
• wherein a filler-existence ratio Xsurf of the filler which exists in a region from the surface to a depth of 200 nm from the surface of the toner base particles and an average filler-existence ratio Xtotal of the filler present in a total content of the toner base particles satisfy an inequality of Xsurf>Xtotal.

A process cartridge comprising:

• a latent image carrier, and
• a developing unit,
• wherein the latent image carrier is configured to carry a latent image, the developing unit is configured to develop the latent electrostatic image formed on the surface of the latent image carrier into a visible image by supplying a toner to the latent electrostatic image, and the latent image carrier and the developing unit are formed in a singled body and detachably mounted to the main body of an image-forming apparatus, and
• wherein the toner comprises at least a binder resin, toner-base particles containing an inorganic filler, and inorganic fine particles;
• wherein the toner is obtained by adding, into an aqueous medium, a toner material liquid in which at least the binder resin and the inorganic filler are dispersed and/or dissolved in an organic solvent, so that the toner material liquid is emulsified, and removing the organic solvent therefrom,
• wherein the filler is contained in a filler-layer in the vicinity of a surface of the toner-base particles, a number average particle diameter of the primary particles of the inorganic fine particles is 90 nm to 300 nm, and the average circularity of the toner is 0.94 or more;
• and
• wherein a filler-existence ratio Xsurf of the filler which exists in a region from the surface to a depth of 200 nm from the surface of the toner base particles and an average filler-existence ratio Xtotal of the filler present in a total content of the toner base particles satisfy an inequality of Xsurf>Xtotal.

An image-forming apparatus comprising:

• a latent image carrier configured to carry a latent image,
• a charging unit configured to uniformly charge a surface of the latent image carrier,
• an exposing unit configured to expose the charged surface of the latent image carrier based on image data to form a latent electrostatic image on the latent image carrier,
• a developing unit configured to develop the latent electrostatic image formed on the surface of the latent image carrier into a visible image by supplying a toner to the latent electrostatic image,
• a transferring unit configured to transfer the visible image on the surface of the latent image carrier to a recording medium, and
• a fixing unit configured to fix the visible image on the recording medium,
• wherein the toner comprises at least a binder resin, toner-base particles containing an inorganic filler, and inorganic fine particles;
• wherein the toner is obtained by adding, into an aqueous medium, a toner material liquid in which at least the binder resin and the inorganic filler are dispersed and/or dissolved in an organic solvent, so that the toner material liquid is emulsified, and removing the organic solvent therefrom,
• wherein the filler is contained in a filler-layer in the vicinity of a surface of the toner-base particles, a number average particle diameter of the primary particles of the inorganic fine particles is 90 nm to 300 nm, and the average circularity of the toner is 0.94 or more;
• and
• wherein a filler-existence ratio Xsurf of the filler which exists in a region from the surface to a depth of 200 nm from the surface of the toner base particles and an average filler-existence ratio Xtotal of the filler present in a total content of the toner base particles satisfy an inequality of Xsurf>Xtotal.

An image-forming method comprising:

• charging a surface of a latent image carrier uniformly,
• exposing the charged surface of the latent image carrier based on image data to form a latent electrostatic image on the latent image carrier,
• developing the latent electrostatic image formed on the surface of the latent image carrier into a visible image by supplying a toner to the latent electrostatic image,
• transferring the visible image on the surface of the latent image carrier to a recording medium, and
• fixing the visible image on the recording medium,
• wherein the toner comprises at least a binder resin, toner-base particles containing an inorganic filler, and inorganic fine particles;
• wherein the toner is obtained by adding, into an aqueous medium, a toner material liquid in which at least the binder resin and the inorganic filler are dispersed and/or dissolved in an organic solvent, so that the toner material liquid is emulsified, and removing the organic solvent therefrom,
• wherein the filler is contained in a filler-layer in the vicinity of a surface of the toner-base particles, a number average particle diameter of the primary particles of the inorganic fine particles is 90 nm to 300 nm, and the average circularity of the toner is 0.94 or more;
• and
• wherein a filler-existence ratio Xsurf of the filler which exists in a region from the surface to a depth of 200 nm from the surface of the toner base particles and an average filler-existence ratio Xtotal of the filler present in a total content of the toner base particles satisfy an inequality of Xsurf>Xtotal.