Mounting-proofing machine for flexographic plates

Claim 1

A flexographic mounting-proofing machine comprising: A. an impression cylinder rotatable on a first shaft about a fixed horizontal axis; B. an impression cylinder gear having the same diameter as the impression cylinder and rotatable on a second shaft and a swingable arm for supporting said second shaft about a horizontal axis which as the arm swings is displaced with respect to the fixed axis of the impression cylinder from an initial position in which the two axes are coaxial with each other to a displaced parallel position; C. a parallel displacement coupling interlinking thre first and second shafts whereby rotation of the impression cylinder results in a corresponding rotation of the impression cylinder gear regardless of the position of the second shaft relative to the first shaft; D. a plate cylinder rotatable on a third shaft about a horizontal axis parallel to the fixed axis; E. a plate cylinder gear mounted for rotation on said third shaft and having the same diameter as said plate cylinder whereby rotation of the plate cylinder gear results in a corresponding rotation of the plate cylinder, said plate cylinder gear intermeshing with said impression cylinder gear whereby rotation of said impression cylinder is transmitted by said coupling to said plate cylinder and results in rotation of the plate cylinder in the reverse direction to an extent determined by the ratio of said gears; F. elevator means to raise said plate cylinder and the plate cylinder gear associated therewith from a mounting state in which said plate cylinder is separated from said impression cylinder to a proofing state in which said plate cylinder makes contact with said impression cylinder and a print point on said plate cylinder is physically coincident with a print point on said impression cylinder; G. a retractable viewer, and means to shift the viewer to a retracted position in the proofing state and to an operative position in the mounting state in which the viewer occupies a position in which an observation site on said plate cylinder is optically coincident with an equidistant observation site on said impression cylinder, and H. means to shift said arm to an extent causing said impression cylinder gear to ride on said plate cylinder gear and to rotate, the rotation of the impression cylinder gear and to rotate, the rotation of the impression cylinder gear being transmitted by the coupling to the impression cylinder to cause the print point on the impression cylinder to occupy the observation site thereon.