To achieve the low energy fusing, the application of the crystalline polyester is studied. To compare with usual polyester, the crystalline polyester melts very quickly when it comes to the melting point. To compare with wax, crystalline polyester is very hard. So the toner that contains crystalline polyester can be fused in low energy but has enough durability.It is not popular yet because of some problems (One of the problems is poor storage stability because this resin is plasticizated for mixing usual resin, the other one is low anti-offset property because of low elasticity.) though.This report shows the properties of the toner that contains crystalline polyester, or how well that toner works for low energy fusing. In this study, the way to overcome problems of toner that contains crystalline polyester, or the better way to use crystalline polyester for toner is reported. e.g.1) Which melting point's crystalline polyester is better for toner. 2) How to control the dispersion size of the crystalline polyester. 3) Which dispersion size of the crystalline polyester is better for low energy fusing and storage ability.