Printer's blanket

Abstract: A printing blanket having a printing face, a compressible body of material below the printing face and at least one body or reinforcing layer adjacent the compressible layer. The reinforcing layer is a woven fabric having air textured polyester warp and fill yarns therein.

Description: This invention relates to printing blankets and in particular to a so-called compressible printing blanket of the type used in offset lithographic printing. In offset lithography the usual function of a printing blanket is to transfer printing ink from a printing plate to an article such as paper being printed whereby the printing blanket comes into repeated contact with an associated printing plate and the paper being printed. This repeated contact causes compression and permanent set (referred to as compression set) of the blanket with extended use whereby it is important that the blanket construction be such that it is self-recovering or resilient within acceptable limits even with compression set of such blanket to assure satisfactory printing. Ideally it is desirable to provide a blanket that is capable of providing satisfactory printing even with compression set over a wide range of interference between the printing blanket and printing plate, i.e, a wide blanket to plate interference range. It is a feature of this invention to provide a simple and economical printing blanket which is particularly adapted to be used in offset printing, or the like, and which is capable of providing satisfactory printing over a wide printing blanket to printing plate interference range. Another feature of this invention is to provide a printing blanket of the character mentioned capable of operating over a blanket to plate interference range of the order of 0.10 to 0.28 mm (4 to 11 mils) with minimal change in print quality. Another feature of this invention is to provide a blanket of the character mentioned made of a plurality of layers laminated together as a unitary single-piece construction. Accordingly, it is an object of this invention to provide a printing blanket having one or more of the novel features set forth above or hereinafter shown or described. In accordance with the invention, there is provided a printer's blanket comprising: a woven base ply, a rubber printing face and a compressible body disposed between said base ply and said rubber printing face (as is known generally in the art) characterised by: said base ply being composed of substantially 100% polyester yarns with the warp yarns and the fill yarns being air textured to provide stability to said printing blanket. US-A-4,425,398 discloses a base fabric suitable for use in a printer's blanket which comprises a warp knitted base fabric of polyester, relatively coarse inlaid warp yarns of polyester and relatively coarse air-textured insertion weft yarns of nylon or polyester, said inlaid warp and insertion weft yarns being non-interlacing. Other details, features, objects, uses, and advantages of this invention will become apparent from the embodiments thereof presented in the following specification, claims and drawing. Looking now to the drawing, the reference numeral 10 represents the new and novel printing blanket. The blanket 10 comprises a base layer 12 of a woven reinforcing fabric, a compressible body or layer 11 of an elastomeric matrix material 14 and a printing layer or face 13 of any suitable rubber compound used in the art for this purpose and may be of any suitable thickness compatible with the application of the blanket. The compressible layer 11 and the printing layer 13 can be individually coated onto the base layer 12 or can be pre-fabricated and laminated to one another through the use of a suitable adhesive. The woven reinforcing fabric is a substantially 100% polyester fabric with a drawn, polyester air textured warp and fill yarn. In one form of the invention the base layer is a plain woven polyester fabric having drawn, air textured three ply, 16.5 tex (150 denier), 68 filament warp yarns 24 with 22± 1 ends per cm (55 ± 2 ends per inch) and a drawn, air textured two ply, 11 tex (100 denier), 100 filament fill yarn 25 with 22 ± 1 picks per cm (55 ± 2 picks per inch). This fabric has a minimum warp tensile strength of 3393 kg/m (190 lbs/inch) and a minimum fill tensile strength of 1429 kg/m (80 lbs/inch) with no substantial elongation in the warp direction. Another base fabric which can be employed as the reinforcing base layer 12 is a substantially 100% polyester plain woven fabric having drawn, air textured two ply, 16.5 tex, (150 denier), 68 filament warp yarns 24 with 30 ± 1 ends per cm (77 ± 2 ends/inch) and drawn, air textured, single ply, 16.5 tex (150 denier), 68 filament fill yarns 25 with 21 ± 1 picks per cm, (54 ± 2 picks/inch). This fabric has a minimum warp tensile strength of 3393 kg/m (190 lbs/inch) and a minimum fill tensile strength of 1071 kg/m (60 lbs/inch) with substantially no elongation in the warp direction. The base ply 12 of the printing blanket 10 has optimum dimensional stability. In particular, the construction of such base ply is such that is substantially retains its dimensions without undue elongation or instability even under continuously applied operating tension of the magnitude employed in a printing blanket during normal use. The base 12 also is a more uniform gauge fabric with fewer defects and has improved smash resistance in the blanket. Another advantage of the disclosed base layer 12 that it does not cause raised selvages during the manufacture of the blanket.

Claims: A printer's blanket (10) comprising: a woven base ply (12), a rubber printing face (13) and a compressible body (11) disposed between said base ply (12) and said rubber printing face (13) characterised by said base ply (12) being composed of substantially 100% polyester yarns with the warp yarns (24) and the fill yarns (25) being air textured to provide stability to said printing blanket. The blanket of Claim 1 wherein said warp yarns (24) and said fill yarns (25) are drawn before being air textured. The blanket of Claim 2 wherein the warp yarn (24) is a three ply, 16.5 tex (150 denier), 68 filament yarn. The blanket of Claim 3 wherein the fill yarn (25) is a two ply, 11 tex (100 denier) 100 filament yarn. The blanket of Claim 2 wherein the warp yarn (24) is a two ply 16.5 tex, (150 denier), 68 filament yarn. The blanket of Claim 5 wherein the fill yarn (25) is a single ply, 16.5 tex, (150 denier) 68 filament yarn.

Inventors: BURNS ALONZO MERRITT, BURNS, ALONZO MERRITT
Applicants: MILLIKEN RES CORP, MILLIKEN RESEARCH CORPORATION
Application year: 1991
Main classification: B41N10
IPC codes: B41N10