Abstract:
A lithographic printing press having a plate cylinder in a substantially light-tight compartment suitable for on-press imaging and developing a laser sensitive plate is described. The plate cylinder as well as certain other press parts is covered by non-transparent and/or safe-light-passing-only covers so that no or only limited amount of unsafe light passes onto the plate mounted on the plate cylinder during on-press imaging and development. The plate comprises on a substrate a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser having a wavelength selected from 200 to 1200 nm. The plate is on-press exposed with the laser, developed with ink and/or fountain solution, and then directly prints inked images to the receiving sheets.
Abstract:
A method of making a heat-sensitive lithographic printing plate precursor is disclosed which comprises the steps of (i) providing a web of a lithographic support having a hydrophilic surface; (ii) applying on the hydrophilic surface of the web a coating comprising a phenolic resin; (iii) drying the coating by supplying heat to the coated web; (iv) a cooling step wherein the web temperature is reduced at an average cooling rate which is higher than if the web would be kept under ambient conditions but not higher than 30° C./s; and (v) winding the precursor on a core or cutting the precursor into sheets. The cooling step provides a significant improvement of the aging behavior of the precursor. A stable sensitivity is obtained shortly after coating.
Abstract:
A lithographic printing plate precursor comprising: a support; an image-recording layer; and a protective layer containing an inorganic stratiform compound, provided in this order, wherein the inorganic stratiform compound contains an organic cation.
Abstract:
The present invention provides a planographic printing plate precursor including a support and a positive recording layer formed on the support and containing: (A) a polymer having a structural unit represented by the following general formula (1), (B) a photo-thermal converting agent, and (C) an amino compound having a methylol group or an alkoxymethyl group; and a positive recording layer whose solubility in an alkaline developer is improved by exposure to light or by heating. In general formula (1), R1 represents an alkyl group or a cyclic group, x represents 0 or 1, and A represents a bivalent bonding group. According to the invention, a positive planographic printing plate precursor for use with infrared lasers having excellent chemical resistance and wide image development latitude can be obtained.
Abstract:
A plate-making system, in which a light-sensitive lithographic printing plate carrying an interleaf paper superimposed thereon and/or an original plate for making a dummy plate carrying an interleaf paper superimposed thereon are processed in a plate-setter provided with an automatic interleaf paper-removing mechanism and an automatic developing machine, is characterized in that it comprises a means for detecting the presence of any interleaf paper on the lithographic printing plate and/or the original plate or a means for discriminating the interleaf paper, the light-sensitive lithographic printing plate and the original plate. A plate-making method of the invention is characterized by irradiating the interleaf paper, the lithographic printing plate and the original plate for making a dummy plate with sensor light rays after they are passed through the automatic interleaf paper-removing mechanism and determining the intensity of the light to thus detect any interleaf paper possibly present on the plates or discriminate the interleaf paper, the light-sensitive lithographic printing plate and the original plate for making a dummy plate from one another. The plate-making method permits the reliable detection of the presence of interleaf papers on light-sensitive lithographic printing plates and/or original plates for dummy plates and the plate-making operations can thus stably be carried out using a plate-setter and an automatic developing machine.
Abstract:
A lithographic printing plate precursor comprising an aluminum substrate, an image-recording layer and a hydrophilic film, the aluminum substrate being subjected to an electrochemical surface-roughening treatment in an aqueous solution comprising hydrochloric acid and provided with the hydrophilic film having a heat conductivity of 0.05 to 0.5 W/mK and/or at least one of a density of 1,000 to 3,200 kg/m3 and a porosity of 20 to 70%; and a lithographic printing plate precursor comprising an aluminum substrate, an image-recording layer and a hydrophilic film, the aluminum substrate having a surface-roughened shape comprising a small pit wherein an average opening size of the small pit is 0.01 to 3 μm and a ratio of an average depth of the small pit to the average opening size is 0.1 to 0.5, and being provided with the hydrophilic film having a heat conductivity of 0.05 to 0.5 W/mK and/or at least one of a density of 1,000 to 3,200 kg/m3 and a porosity of 20 to 70%.
Abstract translation:包括铝基板,图像记录层和亲水膜的平版印刷版原版,所述铝基板在包含盐酸的水溶液中进行电化学表面粗糙化处理,并提供具有导热性的亲水膜 0.05〜0.5W / mK和/或密度为1000〜3200kg / m 3的孔隙率和20〜70%的孔隙率中的至少一种。 以及包含铝基板,图像记录层和亲水膜的平版印刷版原版,所述铝基板具有包括小坑的表面粗糙化形状,其中小坑的平均开口尺寸为0.01〜3μm, 小坑的平均深度与平均开口尺寸的比例为0.1〜0.5,并且具有导热率为0.05〜0.5W / m·K的亲水性膜和/或密度为1000〜3,200 kg / m 3,孔隙率为20〜70%。
Abstract:
A stack of lithographic printing plate precursors, which comprises: at least one lithographic printing plate precursor comprising: an aluminum support having a roughened surface; and an image recording layer comprising (A) an infrared absorber, (B) a polymerization initiator and (C) a polymerizable compound, wherein the image recording layer is capable of being removed with at least one of a printing ink and a fountain solution; and an interleaving sheet interposed between a first one and a second one of said at least one lithographic printing plate precursor, wherein said at least one lithographic printing plate precursor has a dynamic friction coefficient between an outermost surface of said at least one lithographic printing plate precursor and the interleaving sheet of 0.25 to 0.70.
Abstract:
A method for forming an image on a planographic printing plate precursor including a substrate and an image recording layer disposed thereon, the layer including a hydrophobic precursor and a light-to-heat converting agent. The method includes an image exposing process of exposing the planographic printing plate precursor to infrared radiation to form an image on the image recording layer of the planographic printing plate precursor, and a post-heating process of heating the planographic printing plate precursor to a predetermined heating temperature.
Abstract:
Disclosed are a planographic printing plate material and a planographic printing plate preparing process, the planographic printing plate material comprising a support and provided thereon, an image formation layer containing a colorant (a) having an absorption band in a wavelength region of from 700 to 1200 nm, a polymerization initiator (b) and a polymerizable ethylentically unsaturated compound (c), wherein the polymerization initiator (c) is a compound represented by the following formula (1), R1—CX2—(C═O)—R2 Formula (1)
Abstract:
A method for preparing a lithographic printing plate which comprises imagewise exposing to light a presensitized plate useful for making a lithographic printing plate having an intermediate layer and a photosensitive layer on an aluminum substrate in this order and developing the imagewise exposed plate with a developer, wherein said intermediate layer comprises a polymer compound comprising at least a structure unit having an acid group and a structure unit having an onium group and said developer comprises an inorganic alkali salt and a nonionic surfactant having polyoxyalkylene ether group and pH of the developer ranges from 11.0 to 12.7. The method provides a lithographic printing plate, which shows good contrast between an image area and non-image area, no background contamination during printing, good stability with time and good printing durability.