Abstract:
A lithographic printing process which comprises the steps of: imagewise exposing to infrared light a presensitized lithographic plate which comprises a hydrophilic support and a removable image-forming layer containing an infrared absorbing agent having the absorption maximum within an infrared region and a dye precursor having substantially no absorption within a visible region to change the dye precursor to a visible dye having an absorption within a visible region within the exposed area, and to make the image-forming layer irremovable within the exposed area; removing the image-forming layer within the unexposed area of the lithographic plate mounted on a cylinder of a printing press; and then printing an image with the lithographic plate mounted on the cylinder of the printing press. The other processes are also disclosed.
Abstract:
The present invention provides a planographic printing plate precursor, including: a support; and a photosensitive layer containing a polymerizable compound; an oxygen barrier layer; and a protective layer containing a filler (preferably an organic resin particle), the layers being formed in this order on the support. The present invention also provides a stack of planographic printing plate precursors, produced by stacking the planographic printing plate precursors with the photosensitive layer side outermost layer and the support side rear surface of the adjacent plate precursor in direct contact with each other.
Abstract:
A polymerizable negative planographic printing plate precursor including a hydrophilic support, and a polymerizable negative photosensitive layer and a protective layer containing polyvinylalcohol, organic resin fine particles (preferably, having an absolute specific gravity of 0.90 to 1.25 and an average particle diameter of 2.0 to 15 μm) and mica particles (preferably, at an organic resin fine particle/mica particle ratio in the range of 3:1 to 2:3) as a top layer formed on the hydrophilic support in this order.
Abstract:
A method for preparing a lithographic printing plate comprising: exposing a lithographic printing plate precursor comprising: a support having a hydrophilic surface; a photosensitive layer containing a phthalocyanine pigment covered with a polymer having a group represented by the formula (I) or (II) as defined herein in its side chain and a hydrophobic binder polymer having an acid value of 0.3 meq/g or less; and a protective layer provided in this order; and removing the protective layer and an unexposed area of the photosensitive layer in a presence of a developer having pH of from 2 to 10 in an automatic processor equipped with a rubbing member.
Abstract:
A positive planographic printing plate precursor includes a support having disposed thereon a lower thermosensitive layer containing a water-insoluble but alkali-soluble polymer compound and an upper thermosensitive layer containing a water-insoluble but alkali-soluble polymer compound, with alkali-solubility increasing under heat, wherein (i) both the upper thermosensitive layer and the lower thermosensitive layer contain an IR absorbing dye, with the ratio of the IR absorbing dye concentration in the upper thermosensitive layer to the IR absorbing dye concentration in the lower thermosensitive layer is 1.6 to 10.0, and/or (ii) the upper thermosensitive layer and the lower thermosensitive layer contain different IR absorbing dyes, and/or (iii) at least one of the upper thermosensitive layer and the lower thermosensitive layer contains an IR absorbent having, in one molecule, at least two chromophoric groups that absorb IR light, with the chromophoric groups bonding to each other via a covalent bond.
Abstract:
The present invention provides a lithographic printing plate precursor and a lithographic printing method using the lithographic printing plate precursor, which is capable of an image recording by infrared laser scanning and an on-press development and excellent in fine line reproducibility and press life while maintaining good on-press developing properties, the lithographic printing plate precursor comprising: a support; and an image recording layer capable of being removed by a printing ink and/or a fountain solution, in which the image recording layer comprises an infrared absorber and a graft polymer having a specific graft chain.
Abstract:
A positive planographic printing plate precursor includes a support having disposed thereon a lower thermosensitive layer containing a water-insoluble but alkali-soluble polymer compound and an upper thermosensitive layer containing a water-insoluble but alkali-soluble polymer compound, with alkali-solubility increasing under heat, wherein (i) both the upper thermosensitive layer and the lower thermosensitive layer contain an IR absorbing dye, with the ratio of the IR absorbing dye concentration in the upper thermosensitive layer to the IR absorbing dye concentration in the lower thermosensitive layer is 1.6 to 10.0, and/or (ii) the upper thermosensitive layer and the lower thermosensitive layer contain different IR absorbing dyes, and/or (iii) at least one of the upper thermosensitive layer and the lower thermosensitive layer contains an IR absorbent having, in one molecule, at least two chromophoric groups that absorb IR light, with the chromophoric groups bonding to each other via a covalent bond.
Abstract:
A lithographic printing plate precursor comprising a support and an image-recording layer containing at least one infrared absorbing agent of a cyanine dye in which a HOMO energy level of each of substituents present on both terminal nitrogen atoms is −10.0 eV or higher.
Abstract:
A lithographic printing plate precursor comprises an image-forming layer containing a polymerization initiator and a polymerizable compound, and a hydrophilic support, wherein the lithographic printing plate precursor comprises a compound containing at least one functional group having an interaction with a surface of the hydrophilic support.
Abstract:
A hydrophilic substrate comprising: a hydrophilic layer; and a support, wherein the hydrophilic layer contains a hydrophilic particle having a surface area of from 1 to 1,000 m2/g.