1. In the multi-layer structure, soft (foamed elastomer) and solid (solid polymer elastomer) are used to realize the soft and dense elastomer. Such elastic roller (secondary transfer roller) can meet the requirements of the close fitting of transfer paper and developing tape in the operation of roller shaft；

2. The relationship between series and parallel connection is used to set the resistance range of each layer to achieve stable and accurate volume resistance, so as to ensure the uniform and stable electrostatic field strength of the secondary transfer roller and solve the constant transfer rate;

3. The composite polymer elastic semiconductor combined with electronic conductivity and ionic conductivity is used to improve the weatherability of the secondary transfer roller. It can work well under the climate conditions of North and South and four seasons.