Abstract: In a printing apparatus for performing a printing operation on both obverse and reverse surfaces of a continuous web paper with an ink jet printing machine, there is a construction having a first printing unit for printing on one surface of the continuous web paper and a second printing unit for printing on the other surface of the continuous web paper, in which the first printing unit and the second printing unit are arranged at an identical position in respective paths of travel of a first portion and a second portion of the continuous web paper as oriented in parallel to each other, as facing downwards and as shifted to each other in the direction perpendicular to directions in which the first portion and the second portion of the continuous web paper are traveling, and the path of travel of the first portion of the continuous web paper which is printed by the first printing unit and the path of travel of the second portion of the continuous web paper which is printed by the second printing unit are made c

Abstract: A paper folding apparatus for a form printing machine includes an automatic paper cutting device having a cutting cylinder, which is disposed on an upstream side of an oscillatory shooter assembly, and which is adapted to form a cross line of cuts interposed by at least one small uncut portion in a continuous web of paper. The cutting cylinder is synchronously rotated with the paper for forming the cross line of cuts in response to a signal detected according to a predetermined length of travel of the continuous web of paper.