PURPOSE: To reduce running cost even with a throw-away system by layering a buffer layer consisting of base to be detachably wound on a periphery of a blanket cylinder made of a flexible sheet material and blowing material and a transfer layer consisting of flexible sheet made of rubber or synthetic resin and to be contacted with a master.

CONSTITUTION: A blanket sheet 33 is made by sequentially layering a base 33a, a buffer layer 33b, and a transfer layer 33c and fixing the layers. The base 33a is made of a flexible sheet material having a prescribed nerve. The buffer layer 33b is made of foamed material with a predetermined thickness having a large number of foames. The transfer layer 33c is made of flexible sheet material made of rubber or synthetic resin. Although the transfer layer 33c will be compressed by a master and a paper for transferring an image, collapse of the transferring image will be avoided by the elastic deformation of the buffer layer 33b. The buffer layer 33b also prevents the base 33a for absorbing damping water from swelling up at an early stage with the damping water. As the buffer layer 33b has flexibility, the blanket sheet can be wound on a blanket cylinder easily.