Toner for electrostatic latent image development, electrostatic latent image developer, process for preparing toner for electrostatic latent image development, and image forming method

A process for preparing a toner for electrostatic latent image development, which comprises:

• mixing a resin minute particle dispersion, a colorant dispersion and a release agent dispersion, and aggregating the resin minute particles, the colorant particles and the release agent particles to form aggregated particles;
• and heating the aggregated particles to a temperature not lower than a glass transition temperature of the resin minute particles to fuse and coalesce the particles;
• combining the coalesced particles with external additives;
• wherein a variation in a number average particle diameter of the coloring particles is 25 or in, an average circularity of the coloring particles is 0.975 or more, and a variation in a clrcularity of the coloring particles is 2.5 or less;
• and wherein as the external additive, at least monodisperse spherical particle having a true specific gravity in a range of 1.0 to 1.9 are used, and a ratio of a number average particle diameter DTN of the coloring particles and a number average particle diameter Dadd of the monodisperse spherical particles (DTN/Dadd) is in a range of 25≦DTN/Dadd80.

An electrostatic latent image developer comprising a toner for electrostatic latent image development and a carrier, the toner for electrostatic latent image development comprising:

• coloring particles containing at least a binding resin, a colorant and a release agent;
• and
• an external additive,
• wherein a variation in a number average particle diameter of the coloring particles is 25 or less, an average circularity of the coloring particles is 0.975 or more, and a variation in a circularity of the coloring particles is 2.5 or less;
• and
• wherein as the external additive, at least monodisperse spherical particle having a true specific gravity in a range of 1.0 to 1.9 are used, and a ratio of a number average particle diameter DTN of the coloring particles and a number average particle diameter Dadd of the monodisperse spherical particles (DTN/Dadd) is in a range of 25≦DTN/Dadd≦80.

An image forming method comprising a charging step of charging a surface of an electrostatic latent image supporting member, an electrostatic latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image supporting member, a developing step of developing the electrostatic latent image using an electrostatic latent image developer to form a toner image, a transferring step of transferring the toner image formed on the surface of the electrostatic latent image supporting member onto a surface of a transfer receiving material, and a cleaning step of removing toner remaining on the surface of the electrostatic latent image supporting member,

• wherein:
• the cleaning step is a step of removing remaining toner using an electrostatic brush;
• the electrostatic latent image developer comprises a toner for electrostatic latent image development and a carrier;
• the toner for electrostatic latent image development has coloring particles containing at least a binding resin, a colorant and a release agent, and an external additive;
• a variation in a number average particle diameter of the coloring particles is 25 or less;
• an average circularity of the coloring particles is 0.975 or more;
• and a variation in a circularity of the coloring particles is 2.5 or less;
• and
• wherein as the external additive, at least monodisperse spherical particle having a true specific gravity in a range of 1.0 to 1.9 are used, and a ratio of a number average particle diameter DTN of the coloring particles and a number average particle diameter Dadd of the monodisperse spherical particles (DTN/Dadd) is in a range of 25≦DTN/Dadd≦80.