The excellent fusing toner by controlling polyester crystallinity

摘要

In recent years, it is required that the toner can be fused at lower energy from the viewpoint of saving energy. It has already been reported by Shirai et al; good fusing ability is achieved by using amorphous polyester including crystalline polyester. It is supposed that the good fusing ability is due to drastic change of viscoelasticity of crystalline polyester around melting temperature. On the other hand, the storage stability of the toner including crystalline polyester is not good compared with that of the toner without crystalline polyester. The thermal property of the toner including crystalline polyester is focused. As a result, glass transition temperature (Tg) of the toner is dramatically decreased compared with that of the toner without crystalline polyester. It is known that Tg of the toner including crystalline polyester is affected by the crystallinity of this toner itself. It means that crystal can't be kept in the toner by kneading process in case that crystalline polyester and amorphous polyester are miscible each other well. It is essential to improve crystallinity of the toner in order to improve the storage stability. In this study, one method was investigated in order to improve the storage stability of the toner including crystalline polyester. The method is annealing treatment. The crystallinity of this toner was increased by treating at a temperature 50℃ to 90℃. This temperature means more than Tg of the toner and less than melting temperature of crystalline polyester. It is found that Tg of the toner is also increased by annealing treatment. In addition, it is found that the fusing ability of this toner with the annealing treatment can be kept the lowest.