In the full color laser printers and copiers, the performance features of high print speed, fine image quality and environmental friendliness are required. Therefore the special toner also has been required for high speed printing and fine image quality. Recently many chemically prepared toners (CPTs) have been proposed, and these toners are suitable to achieve small and narrow particle size distribution. But most of these toners use styrene acrylic resin, and only a few toners use polyester which is superior to styrene acrylic resin in low-energy fusing. But due to the use of organic solvents in the manufacturing process, environmental friendliness remains a matter for improvement in polyester CPTs.We reported a novel PES CPT without using any solvent in the manufacturing process at NIP27 and NIP28.In this study, three technologies for advanced PES CPT were described.1) To develop polyester chemically prepared toner which has larger fusing latitudes for full color printers, we developed a technology to cross-link polyester with oxazoline polymer.2) To develop eco-friendly polyester chemically prepared toner for low-energy fusing, we tried to introduce crystalline polyester by emulsification in aqueous phase. It was found that crystalline polyester could be emulsified successfully in the presence of amorphous polyester which makes crystalline part soluble with amorphous part.3) We have found it is possible to make a toner having coreshell structure in which the core contains crystalline polyester for low-temperature fusing and the shell uses seed polymerization of styrene for storage stability. In this seed polymerization process, styrene monomer was reacted and cross-linked with the polyester of surface of the toner particles. The shell made by seed polymerization is suitable to be insoluble with polyester core.From this study, we could obtain a toner having core-shell structure in which the core contained crystalline polyester and the shell contained amorphous polyester cross-linked by styrene. Furthermore, the toner provided improved performance in storage stability and low-temperature fusing.