Abstract:
A method of producing a printing plate comprises: (a) providing a printing plate precursor comprising a topmost etchable first layer and a second layer located below the first layer, wherein the first and second layers have different affinities for at least one printing liquid; (b) imagewise providing atomized fluid particles in an interaction zone located above the surface of the first layer; and (c) imagewise directing laser energy into the interaction zone, wherein the laser energy has a wavelength which is substantially absorbed by the atomized fluid particles in the interaction zone, and the absorption of the laser energy causes the atomized fluid particles to imagewise impart kinetic energy to and etch the first layer. Lithographic and flexographic printing plates may be prepared according to this method, including waterless plates, negative-and positive-working plates, and processless plates.
Abstract:
A lithographic printing plate precursor comprising a hydrophilic support having thereon a heat-sensitive layer containing at least one of a thermoplastic particulate polymer having Tg of not lower than 60null C., a particulate polymer having a heat-reactive group and a microcapsule containing a compound having a heat-reactive group incorporated therein.
Abstract:
An infrared-sensitive image forming material with which a plate can be directly formed by an infrared laser. The infrared-sensitive image forming material has a support having disposed thereon a recording layer whose solubility in an aqueous alkaline solution is altered by irradiation with an infrared laser. The recording layer has a binder phase formed of a polymer compound, a dispersion phase that is dispersed in the binder phase, and an infrared absorbent present in either one of the binder phase and the dispersion phase. Within a total incorporated amount of the infrared absorbent in the recording layer, a mass present in the dispersion binder is greater than a mass present in the binder phase. Namely, within the recording layer, the infrared absorbent is localized in the dispersion phase.
Abstract:
According to the present invention there is provided a heat-sensitive imaging element for providing a lithographic printing late, comprising a lithographic base with a hydrophobic oleophilic surface and a top layer comprising a compound capable of converting light into heat and a hydrophilic polymer, characterized in that said hydrophilic polymer is crosslinked.
Abstract:
Provided is a lithographic printing plate comprising a support substrate having disposed thereon an ablative-absorbing layer and, optionally, a durable, ink-accepting surface layer that is not ablative-absorbing. The ablative-absorbing layer may contain a high weight percent of an organic sulfonic acid component. The printing plate may further comprise a hydrophilic polymeric layer interposed between the ablative-absorbing layer and the substrate. The printing plate also comprises a primer layer underlying the ablative-absorbing layer with an adhesion-promoting agent, such as a zirconium compound, present in the primer layer. Also provided are methods of preparing such lithographic printing plates, and methods of preparing imaged lithographic printing plates from such lithographic printing plates by imagewise exposure to a laser and a subsequent cleaning step with water or with a cleaning solution.
Abstract:
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.
Abstract:
This invention discloses lithographic printing plates having a thin releasable interlayer interposed between a rough and/or porous substrate and a radiation-sensitive layer. The radiation-sensitive layer is bonded to the rough and/or porous substrate through mechanical interlocking. Insertion of a thin releasable interlayer in such a configuration minimizes cross-contamination between the substrate and the radiation-sensitive layer, protects the substrate from attack by environmental species and reduces ink scumming tendency of the plates while still allowing good bonding between the substrate and the radiation-sensitive layer.
Abstract:
According to the present invention there is provided a method for making a lithographic printing plate comprising the steps of:providing an imaging element 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 comprising an infrared pigment dispersed in a binder;mounting said imaging element on a drum;image-wise exposing said imaging element by means of an infrared laser in an internal or external drum configuration thereby ablating said thermosensitive layer and rendering it image-wise transparent;overall exposing said imaging element with light to which said photosensitive layer has spectral sensitivity;developing said imaging element to leave an ink accepting image of said photosensitive layer on said support.
Abstract:
Wet lithographic printing plates include a protective layer that provides protection against handling and environmental damage, extends plate shelf life, and entrains debris generated by ablation. The layer washes away during the printing make-ready process, effectively cleaning the plate and disappearing without the need for a separate removal process.
Abstract:
Lithographic printing plates suitable for imaging by means of laser devices that emit in the near-infrared region. Laser output either ablates one or more plate layers or physically transforms a surface layer, in either case resulting in an imagewise pattern of features on the plate. The image features exhibit an affinity for ink or an ink-abhesive fluid that differs from that of unexposed areas.