Abstract: A portable print head module dedicated to one type of printing, for example rotary screen printing, for functionally replacing one print head, dedicated to another type of printing, for example flexographic printing, in a rotary printing press having a number of spaced apart print head stations for transferring multiple images along the length of a continuous web substrate. The rotary print head module is installed by partially retrofitting one of the print head stations. The module can be moved to functionally replace any of the print heads in the rotary printing press. A non-rotating impression bar can be used to back the continuous web instead of a rotatable impression cylinder. A cushion of air is formed on the backing face of the impression bar on which the continuous web can ride.

Abstract: A method and apparatus for making a true butt-welded cylindrical printing screen for a rotary screen printing press, wherein the screen material is rigidized woven metal screen. The method of making the cylindrical screen of the invention includes the steps of cutting a rectangular piece of rigidized woven metal screen material of a size to form a screen of a predetermined size, forming the piece into a cylindrical shape so that two edges are abutting each other to form a butt seam such that sufficient metal will be present to provide a proper weld, mounting the screen on a support bar so that the abutting edges line up with a stationary electrode carried by the support bar, where the electrode includes a tip of narrow width in the range of 0.010 to 0.040 inches, and running an upper electrode along the other side of the butt seam to resistance weld the two edges of the screen material together and form a butt weld.

Abstract: A method and machine are disclosed for screen printing acid-resist mirror inversion images in registration on opposite sides of a metal web with a degree of precision sufficient to permit the incorporation of screen printing techniques in the fabrication of lead frames, electromagnetic core laminations, and other metal plate products by chemical milling processes. A matched pair of upright screen stencils supported in spaced relation on opposite sides of the web is provided with a cooperable pair of squeegees for printing through the image areas of the stencils. The directly opposed squeegees are mounted on a common reciprocable carriage for conjoint movement such that printing on opposite sides of the web is effected synchronously. In preferred forms, a web drive is provided for incrementally advancing the web between the stencils and for holding the web under tension during printing.