| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem that when a measured electrostatic image graduation is not erased, it overlaps with the next graduation after one cycle of rotation of a roller, thereby reducing SN ratio.SOLUTION: An electrostatic image transfer roller 47a applies DC voltage different in voltage from a primary transfer voltage to an electrostatic image transfer layer 26, to transfer an electrostatic image graduation 32 to the electrostatic image transfer layer 26. A secondary transfer unit 44 applies DC voltage different in voltage from a secondary transfer voltage to the electrostatic image transfer layer 26, to reduce a potential difference between a high-potential section and a low-potential section of the electrostatic image graduation 32. The secondary transfer unit 44 includes a secondary transfer outer roller 39 formed by arranging an elastic layer around a conductive central axis. Volume resistivity of the elastic layer in contact with the electrostatic image transfer layer 26 is larger than that of the elastic layer in contact with a recording material. |
