Abstract:
According to the present invention there is provided a heat ode imaging element for making a lithographic printing plate having n a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer which top layer is IR-sensitive and unpenetrable or insoluble for an alkaline developer wherein said first layer and said top layer may be one and the same layer and said first layer and said top layer being the imaging layers; characterized in that said imaging layers have a glass transition temperature of at least 57° C.
Abstract:
According to the present invention there is provided a method for the preparation of a lithographic printing plate comprising the steps of exposing with IR light an imaging element comprising on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer which top layer is IR-sensitive and unpenetratable for or insoluble in an alkaline developer wherein said first layer and said top layer may be one and the same layer, said imaging element comprising a siloxane surfactant; developing said exposed imaging element with an alkaline solution; rinsing said developed imaging element with water or an aqueous solution; gumming said developed imaging element with a baking gum solution; subjecting said gummed imaging element to a thermal treatment at a temperature above 50° C.; characterized in that said rinsing is carried out with a brushing and/or with water containing a surfactant.
Abstract:
A method for preparing a lithographic printing plate by means of ink jet is disclosed. The ink jet fluid contains an oleophilizing compound as defined in the description. Preferred compounds are 8-hydroxyquinolines, 7-hydroxybenzimidazoles, and 7-hydroxybenztriazoles.
Abstract:
According to the present invention there is provided a method for preparing a lithographic printing plate, the method including the steps of (1) providing an imaging element including on a lithographic hydrophilic support as contiguous top layer a heat-sensitive coating including a compound capable of converting light to heat and a compound, which becomes more hydrophilic under the action of heat; (2) imagewise exposing the imaging heat-sensitive composition with a high intensity laser emitting a laser beam with an intensity at the surface of the heat-sensitive composition of tat least 2 mW/&mgr;m2 thereby at least partially removing the heat-sensitive composition to expose at least partially the lithographic support.
Abstract:
According to the present invention there is provided a method for the preparation of a lithographic printing plate comprising the steps of exposing with IR light an imaging element comprising on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer which top layer is IR-sensitive and unpenetratable for or insoluble in an alkaline developer wherein said first layer and said top layer may be one and the same layer, said imaging element comprising a siloxane surfactant; developing said exposed imaging element with an alkaline solution; gumming said developed imaging element with a baking gum solution; subjecting said gummed imaging element to a thermal treatment at a temperature above 50° C.; characterized in that said baking gum solution contains at least one surfactant making the contact angle between the baking gum solution and the surface of the plate less than 68° and/or at least one viscosity-regulating polymer making the viscosity of the baking gum solution between 1.7 cP and 5.0 cP.
Abstract:
The present invention discloses an imaging element comprising on a hydrophilic surface of a lithographic base an image forming layer comprising hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder and (ii) a compound capable of converting light to heat, said compound being comprised in said image forming layer or a layer adjacent thereto, characterised in that said image forming layer further comprises a cross-linking agent capable of cross-linking said hydrophilic binder upon heating in a ratio between 1:100 and 200:1 by weight versus the hydrophilic binder. The present invention further provides a method for making a printing plate therewith. According to this method, the above imaging element is preferably exposed by means of a laser and is subsequently developed with plain water or an aqueous liquid.
Abstract:
According to the present invention there is provided a heat mode imaging element for making a lithographic printing plate having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution but not in water and less than 5% by weight versus the polymer, soluble in the aqueous alkaline solution of a hydrophilic polymer and a top layer on the same side of the lithographic base as the first layer which top layer is IR-sensitive and unpenetrable for or insoluble in an alkaline developer wherein said first layer and said top layer may be one and the same layer; characterized in that said top layer contains a compound selected from the group consisting of a polymer in an amount from 30 mg to 500 mg/m2, a triaryl methane dye and a phthalocyanine dye.
Abstract translation:根据本发明,提供了一种用于制造平版印刷版的平版印刷版,所述平版印刷版在具有亲水表面的平版印刷版上具有可溶于碱性水溶液而不在水中的小于5%的包含聚合物的第一层, 相对于聚合物,可溶于亲水性聚合物的碱性水溶液中,并且与作为第一层的平版印刷基底的相同侧上的顶层是顶层对IR敏感且不可穿透或不溶于碱性显影剂,其中所述 第一层和所述顶层可以是同一层; 其特征在于,所述顶层含有选自30mg至500mg / m 2的聚合物,三芳基甲烷染料和酞菁染料的化合物。
Abstract:
According to the present invention there is provided a method for making lithographic printing plates including the following steps a) preparing a heat mode imaging element consisting of a lithographic base with a hydrophilic surface and a top layer which top layer is sensitive to IR-radiation, comprises a polymer, soluble in an aqueous alkaline solution and is unpenetrable for an alkaline developer containing SiO2 as silicates; b) exposing imagewise said heat mode imaging element to IR-radiation; c) developing said imagewise exposed heat mode imaging element with said alkaline developer so that the exposed areas of the top layer are dissolved and the unexposed areas of the top layer remain undissolved characterized in that said top layer includes an IR-absorbing pigment and 3,4,5-trimethoxybenzoic acid or a benzophenone.
Abstract:
According to the present invention there is provided a method for making driographic printing plates comprising the image-wise exposure of a heat-sensitive recording material comprising on an ink-accepting support an image-forming layer containing hydrophobic thermoplastic polymer particles and a compound capable of converting light into heat, said compound being present in said image-forming layer or a layer adjacent thereto and a cured ink-repellant surface layer. After the exposure the printing plate is developed by wiping it with water or an aqueous solution before or after mounting it on the print cylinder of a printing press.
Abstract:
According to the present invention there is provided a radiation sensitive imaging element comprising on a hydrophilic surface of a lithographic base an image forming layer comprising (1) an alkali soluble or swellable resin having a phenolic hydroxy group, (2) a latent Bronsted acid, and (3) an infrared absorber, characterized in that said image forming layer comprises an amino crosslinking agent.