Abstract: Affinity transitions from hydrophobic to hydrophilic states, rather than ablation mechanisms, facilitate the creation of an imagewise lithographic pattern on a printing plate. In various embodiments, a lithographic printing member comprises a topmost “imaging” layer that undergoes, in response to heat, a transition from a hydrophobic and oleophilic state to a hydrophilic state (which may or may not also be oleophilic); and a substrate disposed below the imaging layer. The affinity change in the imaging layer may be due essentially to a foaming agent therein. The foaming agent decomposes upon heating, creating a gas that foams the surface of the imaging layer. The resulting spongelike texture enables the surface to retain water, i.e., renders it hydrophilic.

Abstract: Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical causes an affinity change, thereby facilitating lithographic printing.

Abstract: Permeability transitions rather than ablation mechanisms facilitate selective removal of the imaging layer of a lithographic plate, which allows for imaging with low-power lasers that need not impart ablation-inducing energy levels.

Abstract: Permeability transitions rather than ablation mechanisms facilitate selective removal of the imaging layer of a lithographic plate, which allows for imaging with low-power lasers that need not impart ablation-inducing energy levels.

Abstract: Affinity transitions from hydrophobic to hydrophilic states, rather than ablation mechanisms, facilitate the creation of an imagewise lithographic pattern on a printing plate.

Abstract: Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical inhibits a photoreaction in the top layer.

Abstract: Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical causes an affinity change, thereby facilitating lithographic printing.

Abstract: Solubility transitions rather than ablation mechanisms facilitate selective removal of the imaging layer of a lithographic plate, which allows for imaging with low-power lasers that need not impart ablation-inducing energy levels.

Abstract: Lithographic imaging using non-ablative printing members combines the benefits of simple construction, the ability to utilize traditional metal base supports, and amenability to imaging with low-power lasers that need not impart ablation-inducing energy levels. A representative printing member has a topmost layer that is ink-receptive and does not significantly absorb imaging radiation, a second layer thereunder that is hydrophilic and does absorb imaging radiation, and a metal substrate under the second layer. The printing member is selectively exposed to laser radiation in an imagewise pattern, and laser energy passes substantially unabsorbed through the first layer and is absorbed by the second layer. Heat builds up in the second layer sufficiently to detach the first layer, which is formulated to resist reattachment. But the first layer and, more significantly, the third layer act to dissipate heat from the second layer to prevent its ablation.

Abstract: The present invention is directed to a method for the on-press development and printing of images. The method generally comprises the steps of providing a lithographic printing plate precursor element comprising a lithographic hydrophilic printing plate substrate, a photohardenable photoresist, and a layer of polymeric protective overcoat; imagewise exposing the precursor element to actinic radiation through said photoresist and overcoat layer sufficiently to photoharden the photoresist in exposed regions and provide a latent image in said photoresist layer; placing the precursor element onto a lithographic printing press; and running the press, whereby printing fluid effects removal of the overcoat and development of said latent image. In particular modes of practices, the method utilizes an overcoat having incorporated therein a water or fountain soluble or dispersible crystalline compound. The overcoat can be used as an oxygen barrier and/or to provide a non-tacky surface on the printing plate.

Abstract: Disclosed is a laminar thermal imaging medium, actuatable in response to intense image-forming radiation for production of a pair of images upon exposure of the medium and separation of the respective sheets, the medium including a polymeric hardenable adhesive layer which in its unhardened condition reduces the tendency for the laminar thermal imaging medium to delaminate on application of physical stresses to the medium, and which is hardenable to a durable base for one of said images. Also disclosed is a method of preparing a laminar imaging medium as aforedescribed wherein said medium after lamination of component elements thereof is cut into individual units and, thereafter, the hardenable adhesive layer of such units is hardened to a durable base for an image carried thereon.

Abstract: A lithographic printing plate for use on a printing press, with minimal or no additional processing after photoexposure, comprises a printing plate substrate; a photosensitive hydrophilic layer having a polymeric hydrophilic binder and a photopolymerizable, photocrosslinkable or photorearrangeable compound capable of promoting insolubilization or hardening in areas of photoexposure; and a photosensitive hydrophobic layer having a polymeric hydrophobic binder and a photopolymerizable, photocrosslinkable or photorearrangeable compound capable of promoting insolubilization or hardening in areas of photoexposure.

Abstract: Disclosed is a laminar thermal imaging medium, actuatable in response to intense image-forming radiation for production of a pair of images upon exposure of the medium and separation of the respective sheets, the medium including a polymeric hardenable adhesive layer which in its unhardened condition reduces the tendency for the laminar thermal imaging medium to delaminate on application of physical stresses to the medium, and which is hardenable to a durable base for one of said images. Also disclosed is a method of preparing a laminar imaging medium as aforedescribed wherein said medium after lamination of component elements thereof is cut into individual units and, thereafter, the hardenable adhesive layer of such units is hardened to a durable base for an image carried thereon.

Abstract: A lithographic printing plate for use on a printing press, with minimal or no additional processing after photoexposure, comprises a printing plate substrate; a photosensitive hydrophilic layer having a polymeric hydrophilic binder and a photopolymerizable, photocrosslinkable or photorearrangeable compound capable of promoting insolubilization or hardening in areas of photoexposure; and a photosensitive hydrophobic layer having a polymeric hydrophobic binder and a photopolymerizable, photocrosslinkable or photorearrangeable compound capable of promoting insolubilization or hardening in areas of photoexposure.

Abstract: An image-forming composite image member and subtractive photo process employing that composite, in which composite, a spectrally reflective light-blocking layer, a secondary thin optically functional layer and a subtractive photosensitive layer are carried on a base in an association, in which the reflective layer and the secondary layer cooperate after imagewise exposure and development to define an image member in which the secondary layer and reflector layer may provide a guide to orientation of the composite and may provide a unique polarity-reversing ability to display both a negative and a positive image. In a preferred form, the reflective and secondary layers provide superior uniform light-blocking with a minimum combined thickness, and also cooperate in the photo process during the development to insure rapid and complete clearing of areas with at most minimal mechanical action under portions of the photosensitive layer which are soluble after imagewise exposure and have been removed in development.

Abstract: Bilayer photosensitive imaging articles comprising a substrate coated with an image layer and a resist layer are disclosed. The substrate may be transparent, translucent or opaque to give imaging articles useful in different applications. The image layer which should be from about 0.3-3.0 microns in thickness includes an organic film-forming vehicle from the group of copolymers of the formula: ##STR1## where P is styrene, ethylene or methyl vinyl ether; m is 1-3; n is 1,10; X is OH, OHN.sub.2, ONH.sub.4, OR, ONH.sub.3 R, ONH.sub.2 R.sub.2, ONHR.sub.3, ONH.sub.3 RNH.sub.2, ONa, OK, OLi; R is an alkyl group in the range C.sub.1 -C.sub.10 optionally including a functional group such as ketone, alcohol, esther, ether alcohol or aryl; m=1-3, n=1-10; and the molecular weight is between 1,000-150,000. The image layer may also include a coloring medium. The resist layer, which should be from about 0.5 to about 2.

Abstract: A desensitizing solution and process for using the solution are disclosed to desensitize a diazo photosensitive printing plate after development. The solution comprises a water soluble desensitizing agent capable of reacting with any residual photosensitive diazo on the developed plate to render the diazo incapable of forming an oleophilic substance and a filming agent selected from water soluble aliphatic polyols have less than eight carbon units, the acid derived monoesters of these polyols, and the alkali metal salts of the monoesters.

Abstract: A process for electrolytically forming on a metallic element a protective layer or film in an electrolyte consisting of an aqueous solution of preferably sodium silicate or alternately of other salts rendering the electrolyte substantially basic, the metallic element constituting the anode in the process. The processed metallic element has particular usefulness as a support member for photolithographic printing plate, the electrolytically formed film acting as a barrier layer preventing deterioration of the light sensitive diazo resin, or the like, utilized as a photosensitive coating on lithographic plates.