Abstract:
A method of making a relief image printing element from a photosensitive printing blank is provided. A photosensitive printing blank with a laser ablatable layer disposed on at least one photocurable layer is ablated with a laser to create an in situ mask. The printing blank is then exposed to at least one source of actinic radiation through the in situ mask to selectively cross link and cure portions of the photocurable layer. Diffusion of air into the at least one photocurable layer is limited during the exposing step and preferably at least one of the type, power and incident angle of illumination of the at least one source of actinic radiation is altered during the exposure step. The resulting relief image comprises a plurality of dots and a dot shape of the plurality of dots that provide optimal print performance on various substrates, including corrugated board.
Abstract:
Photopolymerizable, preferably digitally imageable photopolymerizable, flexographic printing elements having a PET support sheet of low thermal shrinkage, methods of preparing such flexographic printing elements and their use for making flexographic printing plates by imagewise exposure to light, washing out with organic solvents and drying, wherein said drying is carried out at temperatures of more than 60° C.
Abstract:
Process of manufacturing flexagraphic printing firms using digital flexographic printing elements as starting material by imaging, main exposure in the presence of oxygen, development and finishing. The process comprises an additional embossing step in which the surface of the developed printing form is texturized thereby improving the print quality of the printing form.
Abstract:
A thermally-sensitive, positive-working lithographic printing plate precursor can be used to prepare lithographic printing plates using high pH, silicate-free processing solutions. The precursor has a grained an anodized aluminum-containing substrate including a poly(vinyl phosphonic acid) interlayer. A first ink receptive layer, and optionally a second ink receptive layer, is disposed directly on the poly(vinyl phosphonic acid) interlayer. This first ink receptive layer comprises an aromatic acid dye that comprises at least two aromatic groups in an amount of least 0.5 weight %. In addition, the precursor comprises an infrared radiation absorber in one of the layers.
Abstract:
A method of tailoring the shape of a plurality of relief dots created in a photosensitive printing blank during a digital platemaking process is provided. The photosensitive printing blank comprises a laser ablatable mask layer disposed on at least one photocurable layer which is mountable on a printing sleeve. The method comprises the steps of (1) laser ablating the laser ablatable mask layer to create an in situ negative in the laser ablatable layer; (2) placing a barrier layer on top of the laser ablatable mask layer; (3) exposing the at least one photocurable layer to actinic radiation through the barrier layer and the in situ negative; (4) removing the barrier layer; and (5) developing the imaged and exposed photosensitive printing blank to reveal the relief image therein, the relief image comprising the plurality of relief dots. The presence of the barrier layer produces printing dots having desired geometric characteristics.
Abstract:
An imageable material can be used to form a mask image for providing a relief image. This imageable material has a simplified structure and consists essentially of, in order: a transparent polymeric carrier sheet and a barrier layer comprising a first infrared radiation absorbing compound. A first ultraviolet radiation absorbing compound is provided in the transparent polymeric carrier sheet or the barrier layer. A non-silver halide thermally sensitive imageable layer is disposed on the barrier layer and comprises a second infrared radiation absorbing compound and a second ultraviolet radiation absorbing compound. A relief image is formed by imaging the imageable material to form an imaged mask material, exposing a relief-forming material with curing radiation through the imaged mask material to form exposed regions and non-exposed regions, and developing the imaged relief-forming material to form a relief image by removing its non-exposed regions.
Abstract:
The present invention provides a photosensitive letterpress printing original plate provided with a heat sensitive mask layer having high light blocking effect and durability yet prepared as a thin film. A photosensitive letterpress printing original plate including at least (A) a supporting member, (B) a photosensitive resin layer, and (C) a heat sensitive mask layer that are successively laminated, wherein the heat sensitive mask layer (C) contains carbon black and, as a dispersion binder therefor, a butyral resin as well as polyamide containing polar group selected from the group consisting of polyamide containing a tertiary amine group, polyamide containing a quaternary ammonium salt group, polyamide containing an ether group and polyamide containing a sulfonic group.
Abstract:
A thermally-sensitive, positive-working lithographic printing plate precursor can be used to prepare lithographic printing plates using high pH, silicate-free processing solutions. The precursor has a grained an anodized aluminum-containing substrate including a poly(vinyl phosphonic acid) interlayer. A first ink receptive layer, and optionally a second ink receptive layer, is disposed directly on the poly(vinyl phosphonic acid) interlayer. This first ink receptive layer comprises an aromatic acid dye that comprises at least two aromatic groups in an amount of least 0.5 weight %. In addition, the precursor comprises an infrared radiation absorber in one of the layers.
Abstract:
The invention pertains to a method for preparing a composite printing form from a single precursor that is capable of forming a relief and a carrier. The single precursor can be a single photosensitive element or a single laser-engravable print element having a reinforced elastomeric layer. The single precursor has a size that is at least 70% of a size of the carrier. The single precursor is located on the carrier by approximately positioning the precursor on the carrier that has no registration markings. Precise registration of the single precursor is achieved by using digital information generated from a computer to create the registered image on the composite form. The method is particularly suited for preparing composite printing forms for relief printing, and in particular for preparing composite printing forms for flexographic printing of corrugated substrates.
Abstract:
Disclosed is a flexographic printing plate precursor in which formation of cracks and wrinkles in an infrared ablation layer is suppressed and the scratch resistance of the layer is improved. The precursor includes a support, photosensitive resin layer, and an infrared ablation layer that are laminated in the order presented. The binder polymer contained in the infrared ablation layer contains a polymer (A) and an acrylic resin (B). The polymer (A) contains the same structural unit as the structural unit contained in the binder polymer in the photosensitive resin layer. The mass ratio (A/B) of the component (A) with respect to the component (B) is within a range of 1/3 to 3/1. The difference between a plastic hardness (Ha) of the infrared ablation layer and a plastic hardness (Hb) of the photosensitive resin layer is 30 mN/mm2 or smaller.