n.
油墨辊

Ductor \Duc"tor\, n. [L., fr. ducere to lead.]
1. One who leads. [Obs.] --Sir T. Browne.

2. (Mach.) A contrivance for removing superfluous ink or
coloring matter from a roller. See {Doctor}, 4. --Knight.

{Ductor roller} (Printing), the roller which conveys or
supplies ink to another roller. --Knight.