PURPOSE: To provide the titled means capable of preventing a copying paper from being bent at the time of printing and capable of preventing such troubles as jamming from occuring, by a method wherein a member for preventing the copying paper from jamping-up is provided on either one or both sides of a printing part.

CONSTITUTION: A stand is mounted on a upport shaft parallel with an oscillatable shaft 3 for the main body part of the data type which shaft 3 has a central part rectangular in cross sectional shape and is directed in a direction perpendicular to the feed direction of the copying paper. Support side plates 5 are suspended from both side ends of the stand, and horizontal plates 6 for preventing the paper from jumping-up is integrally fitted to the lowe ends of the plates 5 on the outside of the latter. Guide edge parts 7 of the plates 6 closer to a fixing device of the copying machine are bent skewly upwards. Both ends of the paper can be prevented from bending by a local pressing-down action of the main body part 9, a general pressing-up action of a stamper roller 63 and an elastic deformation of the roller 63.