摘要:
A method for making a lithographic printing plate is disclosed wherein the method comprises the steps of: (i) providing a lithographic printing plate precursor comprising a photosensitive coating on a substrate having a hydrophilic surface, (ii) image-wise exposing said photosensitive coating, (iii) developing said exposed coating to form an image on said substrate and optionally gumming the plate and (iv) baking the image on the plate, wherein said baking step is carried out within a dwell-time of less than 1 minute and wherein the chemical resistance of the coating against printing liquids and press chemicals is improved. This baking step is preferably carried out by exposing the printing plate to an infrared radiation source, preferably in a dynamic configuration.
摘要:
A method for the preparation of a negative working lithographic printing plate by means of ink jet printing is disclosed. This method uses a lithographic printing plate precursor comprising a lithographic support and an image forming layer containing a polymeric binder soluble in an aqueous alkaline developer. The precursor is image-wise printed by an ink jet fluid comprising a compound capable of reducing the solubility of the binder in the aqueous alkaline developer. After development a negative working printing plate is obtained.
摘要:
According to the present invention there is provided a method for making a lithographic printing plate comprising the steps of a) exposing imagewise to IR-radiation a heat mode imaging element having 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 unpenetrable by an alkaline developer and contains a compound capable of converting light into heat, wherein said first layer and said top layer may be one and the same layer; and b) developing said imagewise exposed heat mode imaging element with said alkaline developer whereby the exposed areas of the first and the top layer, which may be the same, are dissolved and the unexposed areas of the first layer remain undissolved characterized in that said alkaline developer has a pH of at least 12 and a surface tension of at least 30 mN/m.
摘要:
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 that is soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer that is IR-sensitive and unpenetrable for an alkaline developer; characterized in that at least one of the first layer and the top layer includes a surfactant.
摘要:
The present invention provides a method for making a lithographic printing plate comprising the steps of:(1) image-wise exposing to light an imaging element comprising (i) on a hydrophilic surface of a lithographic base an image forming layer comprising hydrophobic thermoplastic polymer particles capable of coalescing under the influence of heat and 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;(2) and developing a thus obtained image-wise exposed imaging element by mounting it on a print cylinder of a printing press and supplying an aqueous dampening liquid and/or ink to said image forming layer while rotating said print cylinder.
摘要:
According to the present invention there is provided an imaging element comprising on a support having a hydrophilic surface in the order given a photosensitive layer insoluble in an aqueous alkaline solution and capable of becoming soluble in said aqueous alkaline solution upon exposure with actinic light and a thermosensitive layer comprising a masking dye rendering said thermosensitive layer opaque to light for which said photosensitive layer has spectral sensitivity and said imaging element further comprising a compound A capable of converting light into heat comprised in said thermosensitive layer or a layer adjacent thereto, characterized in that said thermosensitive layer further comprises thermoplastic particles of a hydrophobic polymer.
摘要:
The present invention provides a photosensitive imaging element comprising on a support a two-phase layer, said two-phase layer comprising a disperse hydrophobic photopolymerizable. phase and a hydrophilic continuous phase, characterized in that the hydrophobic photopolymerizable phase comprises a multifunctional monomer with a perfluoroalkyl or perfluoroalkenyl group.
摘要:
The present invention provides a negative-working photosensitive imaging element comprising on a hydrophilic surface of a support in the order given (i) a hydrophobic photopolymerizable composition capable of being irradiated with actinic light through the support and/or through the front and containing at least one unsaturated compound with at least one polymerizable ethylenically unsaturated group, at least one hydrophobic thermoplastic polymer and at least one photoinitiator, and (ii) optionally a receptor layer, characterized in that said hydrophobic photopolymerizable composition comprises in the order given (i) a polymerizable layer contiguous to said hydrophilic surface and comprising at least part of said at least one unsaturated compound and (ii) a hydrophobic photosensitive layer contiguous to said polymerizable layer comprising at least part of said at least one hydrophobic thermoplastic polymer and of said at least one photoinitiator.The present invention also provides a method for obtaining a lithographic plate of high quality with said imaging element.
摘要:
According to the present invention there is provided an imaging element for making a lithographic printing plate comprising on a support having a hydrophilic surface a photosensitive layer and a thermosensitive layer, said thermosensitive layer being opaque to light for which said photosensitive layer has spectral sensitivity and said thermosensitive layer being capable of rendered transparent upon exposure to laser light characterised in that an intermediate layer being soluble or swellable in an aqueous medium is provided between said photosensitive layer and said thermosensitive layer.
摘要:
According to the present invention there is provided a method for preparing a hydrophilic surface of an aluminum lithographic base comprising the steps of roughening and anodizing a side of an aluminum foil and sealing said side of the aluminum foil with hot water within a temperature range from 70.degree. C. to 100.degree. C. for at least 5 seconds and rinsing said side of the aluminum foil with water characterized in that between said hot water treatment and said rinsing said side of the aluminum foil is treated with an aqueous silicate solution within a temperature range from 70.degree. C. to 100.degree. C. for at least 5 seconds.