Toner for use in electrophotography and its manufacturing process comprising a charge control additive of an oxide coated with a mixture of tin oxide and antimony

A toner for use in electrophotography comprising:

• toner particles which comprise blinder resin and a magnetic material;
• and
• an external additive which comprises coated particles wherein said particles are selected from the group consisting of silica, aluminum oxide and cerium oxide, and wherein said coating on said particles comprises a mixture of homogeneously distributed tin oxide and antimony, wherein said external additive is attached on the surface of said toner particles, and
• wherein said magnetic material imparts magnetism to said toner, and the amount of said magnetic material is equal to 25 parts by weight to 50 parts by weight with respect to 100 parts by weight of said binder resin.

A method for manufacturing a toner for use in electrophotography comprising the steps of:

• melting and kneading binder resin, colorant, electrostatic charge control agent and wax in a kneader to form kneaded matter;
• producing toner particles by grinding and classifying the kneaded matter after said kneaded matter has been cooled;
• and
• producing a toner having a positive electrostatic charge by mixing and adding to said toner particles an external additive;
• said additive comprising particles selected from the group consisting of silica, aluminum oxide, and cerium oxide, which are coated with a coating mixture of tin oxide and antimony.

A method for manufacturing a toner for use in electrophotography comprising the steps of:

• melting and kneading binder resin and a magnetic material in a kneader to produce kneaded matter;
• producing magnetic toner particles by grinding and classifying the kneaded matter after said kneaded matter has been cooled;
• and
• producing a single component magnetic toner by mixing and adding to said toner particles an external additive, wherein said additive comprises particles selected from the group consisting of silica, aluminum oxide, and cerium oxide, which are coated with a coating mixture of tin oxide and antimony.