摘要:
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 having on a lithographic base with a hydrophilic surface a first layer including a polymer, soluble in an aqueous alkaline solution, a compound capable of converting light to heat and a top layer on the same side of the lithographic base as the first layer which top layer is unpenetrable for an alkaline developer containing SiO.sub.2 as silicate;b) exposing imagewise the heat mode imaging element to actinic light;c) developing the imagewise exposed heat mode imaging element with the alkaline developer so that the exposed areas of the top layer and the underlying areas of the first layer are dissolved and the unexposed areas of the first layer remain undissolved characterized in that said top layer includes an organic quaternary ammonium salt.
摘要:
According to the present invention there is provided a heat sensitive imaging element comprising a lithographic base with a hydrophilic surface, an image forming layer including a hydrophobic thermoplastic polymer latex and a compound capable of converting light into heat being present in said image forming layer or a layer adjacent thereto, characterized in that the heat-sensitive imaging element comprises a barrier layer between the lithographic base having a hydrophilic surface and the image forming layer, said barrier layer and said image forming layer being removable in an aqueous solution with a pH of at least 5.
摘要:
According to the present invention there is provided a method for making a lithographic printing plate comprising the steps of: (1) image-wise exposing an imaging element having of a flexible film support in the order given (i) a uniform ink-repellant layer comprising a cross-linked hydrophilic binder and (ii) a photosensitive layer comprising a diazonium salt or a diazo resin; (2) and developing a thus obtained image-wise exposed imaging element by mounting it on a print cylinder of a printing press and wiping it with a disposable absorbing tissue moistened with water or fountain solution.
摘要:
The present invention provides a lithographic base comprising on a hydrophobic support a subbing layer and a hydrophilic layer containing a hydrophilic (co)polymer or (co)polymer mixture and being hardened with a hydrolyzed tetraalkyl orthosilicate crosslinking agent characterized in that said subbing layer contains a hydrophilic binder and silica, the surface area of the silica being at least 300 m.sup.2 per gram.
摘要:
The present invention provides a lithographic base comprising on a hydrophobic support a subbing layer contiguous to a hydrophilic layer containing a hydrophilic (co)polymer or (co)polymer mixture and being hardened with a hydrolyzed tetraalkyl orthosilicate crosslinking agent characterized in that said subbing layer contains a hydrophilic binder and silica and is applied at a solids content of more than 200 mg per m.sup.2 but less than 750 mg per m.sup.2.
摘要:
A method of making a lithographic image is disclosed, which comprises the steps of providing a lithographic imaging material comprising a support and a heat- or light-sensitive coating; image-wise exposure of the coating to heat or light, thereby obtaining a latent image in said coating, the latent image consisting of a set of exposed areas in the coating and a set of non-exposed areas in the coating; development of the latent image by supplying a processing liquid to the coating and evacuating, by means of a suction device, the processing liquid together with (i) substances removed from the exposed areas without removing such substances from the non-exposed areas or together with (ii) substances removed from the non-exposed areas without removing such substances from the exposed areas. The method is especially suitable for processing a lithographic printing plate while it is mounted in a plate-setter or a printing press, without the risk of damaging or contaminating electro-optical components of such equipment.
摘要:
According to the present invention there is provided a heat mode imaging element for providing a lithographic printing plate consisting of a lithographic base with a hydrophilic surface and a top layer that is sensitive to IR-radiation, comprises a polymer soluble in an aqueous alkaline solution, and is unpenetrable for an aqueous alkaline developer, characterized in that said top layer comprises a polysiloxane surfactant.
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 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 aqueous alkaline developer wherein said first layer and said top layer may be one and the same layer; characterized in that the surface of said element upon exposure and treatment with an aqueous alkaline developer is such that a) the contact angle between the unexposed areas of the imaging element and the aqueous alkaline developer changes for at most 6° during the first minute of contact with said developer; b) the contact angle between the exposed areas of the imaging element and the aqueous alkaline developer changes more than 15° during the first minute of contact with said developer; c) the difference in contact angle between on the one side the unexposed areas and on the other side the exposed areas of the imaging element with the aqueous alkaline solution at the onset of the measurement is not higher than 10°.
摘要:
According to the present invention there is provided a method for making a lithographic printing plate comprising the steps of: (1) image-wise exposing an imaging element having on a plastic film support in the order given (i) a uniform ink-repellant layer comprising a cross-linked hydrophilic binder and (ii) a photosensitive layer comprising a diazonium salt or a diazo resin; (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 photosensitive layer. The present invention also provides a method for making multiple copies of an original comprising the steps of: (1) image-wise exposing an imaging element having on a plastic film support in the order given (i) a uniform ink-repellant layer comprising a cross-linked hydrophilic binder and (ii) a photosensitive layer comprising a diazonium salt or a diazo resin; (2) mounting a thus obtained image-wise exposed imaging element without development, on a print cylinder of a printing press; (3) rotating said print cylinder while supplying an aqueous dampening liquid and/or supplying ink to said photosensitive layer of said imaging element and (4) transfering ink from said imaging element to a receiving element.
摘要:
The present invention provides an imaging element comprising on a support in the order given a coated composition of at least two hydrophilic layers being in water permeable contact with each other and each containing a hydrophilic (co)polymer or (co)polymer mixture and having been hardened with a hydrolyzed tetraalkyl orthosilicate and a light sensitive layer containing a diazo resin or a diazonium salt characterized in that the ratio by weight in the top layer of said package of said hydrophilic (co)polymer or (co)polymer mixture versus said hydrolyzed tetraalkyl orthosilicate (expressed as silicon dioxide) is at least 1.1 and the ratio by weight in an underlying layer of said package of said hydrophilic (co)polymer or (co)polymer mixture versus said hydrolyzed tetraalkyl orthosilicate (expressed as silicon dioxide) is not higher than 0.9.