Abstract:
A sheet of elastomeric material that serves as a shock absorber and cushion for use between a printing plate, such as but not limited to a flexographic printing plate, and a printing cylinder during printing for compensating for variations in thickness, height and centricity of the printing cylinder and printing plate to prevent distortions in the image being printed that includes providing an elastomeric material having a longitudinal direction in the direction of circumferential travel of the cylinder circumference that includes a plurality or array of protrusions formed of the elastomeric material of predetermined cross-sectional shape and area and the material having a durometer to cushion the printing plate in such a way to provide the necessary compensation to ensure a high quality printed image at high speed. The cross-sectional shapes and the array of the longitudinal protrusions provide for the material's lateral displacement zones that allows the elastomeric material to be displaced and return relatively instantaneously to its original height or near original height to obtain and maintain high quality printing, thereby compensating for tolerance errors between the drum size and the flexographic plate thickness.
Abstract:
A printing carrier sleeve for mounting printing plates thereon, is formed by cutting a sheet of flexible plastic material having opposite edges into a substantially rectangular shape of desired dimensions such that opposite edges are cut-away to provide complementary tabs and openings that interlock with each other, adhering printing plates on the sheet when the sheet is in a substantially flat condition, securing opposite edges of the sheet together in abutting relation so as to prevent air from passing between the opposite edges, and thereby forming the printing carrier sleeve in a cylindrical configuration, by placing a strip of tape on a forming cylinder, securing one edge of the rectangular sheet on the strip of tape on the cylinder, and wrapping the opposite edge of the sheet about the cylinder into abutting relation with the one edge to provide the interlocking arrangement.
Abstract:
A ferromagnetic foil carrying a layer of a pressure sensitive adhesive for adhesive attachment to a printing plate to be used in a letterpress or flexographic printing operation. The ferromagnetic foil preferably is formed of a cold rolled steel having a thickness in the range of from about 0.001 inch to about 0.007 inch. The metal foil allows the printing plate to be adhered to the outer surface of a magnetized printing cylinder due to the magnetic attraction between the printing cylinder and the ferromagnetic foil. If the printing cylinder is not magnetized, but is formed of a ferromagnetic material, a flexible magnetic pad is applied to the outer surface of the cylinder, and the ferromagnetic foil-backed printing plate is then placed on the flexible magnetic pad. If the printing cylinder is formed of a non-ferromagnetic material, a flexible magnetic pad is first adhered to the outer surface of the cylinder, such as by an adhesive, and the foil-backed printing plate is then adhered to the flexible magnetic pad.
Abstract:
Printing members resistant to handling damage include a porous compressible layer that deforms in response to applied forces, inhibiting overlying layers from tearing or scratching. One type of construction involves ablation-type printing members, wherein pulses from a heat source ablate one or more layers to expose (or facilitate exposure of by cleaning) an underlying layer. A second type of construction utilizes traditional photoexposure-type layers that harden or increase adhesion to adjacent layers in response to actinic radiation. The compressible layer is typically located below the radiation-responsive or imaging layer, but may also serve as that layer.
Abstract:
A gravure plate assembly having an elastomer pad sandwiched between a more rigid base plate and a less rigid metal top plate bearing an engraving surface.
Abstract:
A printing article which includes a rotatable metal support in the form of a cylinder and a compressible laminate mounted upon the support. The compressible laminate has upper and lower surfaces and a substantially uniform thickness and includes a printing face which forms the upper surface and a compressible layer positioned beneath the printing face. The upper surface of the compressible layer is spaced closer to the upper surface of the printing face in the center of the cylindrical support than at the ends. Preferably, this laminate is cylindrical and is in the form of a printing blanket or printing roll. The invention also relates to a method for forming the compressible laminate.
Abstract:
The process for making a press plate having a flat press surface includes applying a liquid synthetic epoxy resin plastic material to a support surface of the press plate; allowing the liquid synthetic epoxy resin plastic material to run freely under action of gravity until it is uniformly distributed on the support surface and a layer with a flat and horizontal surface is formed on the liquid synthetic epoxy resin plastic material; providing projecting support walls along edges of the support plate for retaining and preventing loss of the liquid synthetic epoxy resin plastic material; and allowing the liquid synthetic epoxy resin plastic material to harden without vibration for up to seven days. The liquid synthetic epoxy resin plastic material is hardenable so that the press surface formed on the layer has sufficient hardness and the liquid synthetic epoxy resin plastic material is sufficiently elastic to compensate for expansion of the support plate, while retaining a flat smooth press surface. The press plate consists of the support plate and the single hardened layer, which is resistant to temperatures up to 150.degree. C., resistant to attack by solvents and is mechanically workable.
Abstract:
A method for accurately positioning photopolymer color plates onto print cylinders of a rotary press is disclosed. The photopolymer plates are prepared with the aid of specially prepared color separated films and are mounted onto assigned print cylinders with the aid of index pins. Alignment accuracy is provided in part by producing each color separated film from the same camera film negative on which an image field and reference marks have been photographically transferred from mechanical artwork. Continuity of alignment accuracy is provided by center scribe reference marks utilized together with index holes which are precision located and punched, respectively, onto and through carrier sheets, masks, duplicating film and color separated negatives. Various combinations of pre-punched carrier sheets, masks, contact duplicating film, color separated negatives, and unexposed printing plates are mechanically coupled in precise alignment by pin register tabs throughout the various stages of the plate production process. In particular, superimposed sheets are coupled together and center scribe marks are maintained in alignment by pin register tabs which are received in registration in the precision punched index holes.