ROTARY PRINTING CYLINDER

Rotary printing cylinders usually have the form of a steel cylinder, the surface of which is covered with a copper layer into which in transferring elements are engraved. Such printing cylinders are heavy, expensive to manufacture and can only be used for one printing pattern. According to this invention it is suggested to avoid the above drawbacks by using a separate printing sleeve (I) with a cylindrical outer printing surface and a conical inner surface, which sleeve can be firmly applied onto a basic cylinder (7) the outer surface of which has a corresponding conical shape. To make the sleeve changing easier the basic cylinder is provided with ducts (10) emerging into the conical surface, through which ducts compressed air can be discharged into the space between the sleeve and the cylinder when the sleeve is mounted or dismounted.