Abstract:
The invention concerns a sleeve with a multiple layer structure for printing presses with king rolls configured as pneumatic cylinders; in particular a sleeve for the flexographic printing process, with an inner tube of reversibly expandable plastic material, whose internal diameter is smaller than the king roll diameter, with an elastic compressible intermediate layer that accommodates the radial expansion of the inner tube during installation, and with an outer layer. The invention concerns also a manufacture procedure for sleeves of this type. The sleeve in accordance with the invention is characterised by a support structure in the sleeve construction between inner tube and outer layer, which completely penetrates the compressible intermediate layer in at least one location in the radial direction and stabilises the outer layer relative to the inner tube in the circumferential direction and/or the radial direction. As a result of the partial bridging of the compressible intermediate layer this is offloaded from forces in the direction of rotation. In this manner the possibility that vibration stripes can appear in the print image is avoided.
Abstract:
A gapped or seamed cylindrical offset printing blanket having pre-made blanket material mounted on a cylindrical sleeve, and a method for making same, are disclosed, wherein conventional, manufactured blanket material in flat form made by methods known in the art is adhered to a cylindrical sleeve to economically produce a blanket. The leading and trailing ends of the flat blanket material are joined in close proximity such that a small gap is formed. A seam may be made with a filler material that fills the remaining gap resulting in a seamed sleeved blanket In use, the seam is aligned with non-print area on the adjacent printing plate, or the adjacent plate cylinder gap of the printing press. Being narrower than the plate cylinder gap, no loss of print length results from the seam
Abstract:
Methods and apparatus are provided for improving the accuracy and streamlining the process of preparing an imaged flexographic printing sleeve. Seam layout details are determined by a controller and transferred to an automated cutting device to cut flexographic precursor sections. The controller can also control a printing device to print indicia on a sleeve substrate for use in aligning the cut precursor sections. The controller can also control a mounting device for the mounting of the cut precursor sections. An imaging engine for imaging a flexographic printing sleeve is equipped with an edge detection system for determining the location of seams between abutting precursor sections.
Abstract:
A printing sleeve for use in flexographic or gravure printing applications is provided. In particular, the printing sleeve contains a bridge layer that is formed from a generally rigid and relatively expandable material, which is disposed adjacent to a core layer. For example, in one embodiment, the bridge layer is made from a polyurethane material having a Shore D hardness of about 20 to about 85. As a result of the present invention, printing sleeves can be formed to be more durable and maintain better TIR tolerances than conventional printing sleeves.
Abstract:
The invention is a simple, inexpensive, wash-free integrated cover for a printing transfer cylinder (preferably, but not necessarily, in a Komori press), comprising a flexible jacket covering permanently attached to a cylinder base cover. The invention provides advantages over T-Y paper and non-tack film in that dampening solution, washing, and cleaning causes failure in both over time, whereas dampening solution is beneficial to the present invention as such is retained in the flexible jacket cover and helps to prevent ink buildup and marking. The flexible jacket covering is moveable relative to the cylinder base cover, thereby further reducing ink buildup and marking. The integrated cover is disposable, which reduces periodic maintenance and cleaning of the transfer cylinder coverings and provides for fresh, clean substrate support surfaces upon each new installation. The flexible jacket covering and cylinder base cover are integrated into a single, convenient unit, thereby speeding and simplifying installation.
Abstract:
A double sided tape for detachably mounting a flexible printing plate to a flexographic printing press cylinder includes pressure-sensitive adhesive layers on opposed sides of a coextruded multilayer carrier having a core formed of a thermoplastic elastomer containing a uniform distribution of voids and one or more skin layers formed of film-forming thermoplastic polymer. The cellular thermoplastic elastomer is constructed to accommodate compressibility loads imposed during printing and to resist shear and tensile loads imposed during tape removal.
Abstract:
The invention relates to a roller (1) for guiding, in particular for pressing and/or for the pressure treatment of web-like materials, with a core (4) which carries an elastic casing (3), wherein the core (4) and the casing (3) are connected directly by a fastening layer (2) provided in an intermediate space between the core material and the casing material.
Abstract:
A lithographic printing method comprises: disposing on a plate cylinder, a block copy sheet and a lithographic printing plate, in this order, wherein the block copy sheet has a front surface that is uneven, the lithographic printing plate has a back surface that is uneven, and the front surface of the block copy sheet and the back surface of the lithographic printing plate are opposed to each other; and carrying out printing with the lithographic printing plate.
Abstract:
This invention relates to a relatively thin cladded graphic arts impression graphic arts impression die plate (20) having a steel layer (22) which is integral throughout the extent thereof with a layer of copper (24) or bronze. A relieved design-defining surface may be formed in the copper or bronze layer by a chemical etching process or by chemical milling. In the case of chemical etching of the graphic arts impression die plate (20), a design-defining layer of photo-resist is applied to the outer surface of the copper layer (24) or the bronze layer and the relieved design is formed in the copper or bronze layer using a conventional ferric chloride etching solution. The etched graphic arts impression die plate may be mounted on an etchant-resistant backing or magnetic support member (28) to present an assembly which increases the thickness of the die assembly sufficiently to permit use thereof on standard stamping and embossing equipment without modification of the die-supporting chase. The magnetic support member (28) has a plurality of pairs of permanent magnets (33, 35) each pair of which is embedded within a respective cavity (32) and that are magnetically bridged by a steel plate (36). The pairs of magnets (33 and 35) attract the steel layer (22) of the graphic arts impression die plate (20) and thereby hold the graphic arts impression die plate on the magnetic support member (28). Etching of a blank cladded metal graphic arts impression die plate (20) is facilitated by provision of a rotatable magnetic support member (64, 164, 264, 364) within die etching apparatus (40) which serves to support the die blank while it is being subjected to the etchant solution. The die blank magnetic support member (64, 164, 264, 364) has permanent magnets (78, 178, 278, 378) embedded therein, or altematively pairs of magnets each pair of which is bridged by a steel plate, which magnetically attract the steel layer (22) of the graphic arts impression die plate (20) to affix the graphic arts impression die plate to the magnetic support member.
Abstract:
A rubber cylinder sleeve for web-fed rotary offset printing machines has a covering layer which is a finite layer having a joint location, the joint location being filled with a compressible material.