A stenciling apparatus is provided with a screen formed as an endless band trained about and tensioned on four sprockets and driven by a shaft on which two of said sprockets are mounted. The sprockets are adjustable to vary the longitudinal and transversal tension of the screen. The objects to be printed on are brought into contact with the outer face of one flight of the screen band, while a scraper, in contact with the inner face of said flight, urges printing ink across the screen and onto the object.
A continuous screen printing apparatus of the type having an endless screen mounted on spaced parallel cylinders for printing insignia on a flexible web supported on a movable platen adjacent said screen. Means are provided for laterally and longitudinally adjusting the tautness of the screen and for maintaining the screen taut in the area between the rolls.
Three rollers are mounted on a support for rotation about parallel axes which are respectively located at the corners of an imaginary triangle. A flexible printing screen is trained about the rollers to be frictionally entrained thereby. Mounting arrangements are provided at the opposite axial ends of the rollers, journalling the same for rotation, and intermediate these mounting arrangements there are provided supplementary mounting arrangements which engage each of the rollers intermediate the main mounting arrangements.
A rotary printing screen, for mounting in a rotary screen printing machine, which has a support member at each end of its screen cylinder. The support member uniformly supports each endring against the longitudinal tension applied to the screen cylinder by the tensioning device so that the endrings remain in parallel. The support member, made from a heat-shrinkable plastic, such as polyethylene terephthalate, is selectively a heat-shrunk plastic sleeve or a heat-shrunk device endwise extension of the screen cylinder. Each embodiment extends over at least a portion of the shoulder of the endring to form a lip which has progressively greater thickness and decreasing circumference, terminating in a circular bead. As a sleeve, the support member fits over each terminal portion of the screen cylinder and covers its adhesive joint with the underlying cylindrical surface of the endring.
A screen printing machine includes a pair of transversely spaced first rollers mounted for rotation about axes located in a common substantially horizontal plane, and a second roller which is mounted for rotation about a second axis substantially paralleling the first axes and being located in a higher second plane. An endless printing screen is placed about the rollers to be entrained by the same; in the space between the first rollers it defines a printing run. First adjusting arrangements are provided by means of which the second roller can be raised and lowered with reference to the first rollers, and second adjustments are provided by means of which the second roller can be displaced in its horizontal plane transversely of its axis of rotation.
An endless printing screen is trained about two or more guide rollers for traveling an endless path. Abutment members in form of longitudinally continuous or discontinuous elements are mounted on the respective lateral edge portions of the screen, extending from one of the screen surfaces. Tensioning units are mounted adjacent these edge portions and are provided with grooves through which the abutment members travel. Each tensioning unit at one of the lateral edge portions is connected with a tension unit at the opposite lateral edge portion by an arrangement which makes it possible to move the tensioning units apart from one another in direction transversely of the travel of the printing screen, thereby tensioning the printing screen. The thus-connected tensioning units can also be moved in toto in direction transversely of the travel of the printing screen.
