Creo, LLC

Kodak Graphic Communications Canada Company

Creo Srl

Jonathan William Goodin

Yisong Yu

John Emans

Keith Christall

David A Morgan

Brian J Collister

Jacqueline L Ricafrente

Graham Darling

Livia Tatiana Memetea

Jon Alfred Bjork

A radiation-sensitive medium comprises hydrophilic polymer particles, the particles comprising a thermally softenable hydrophobic polymer, a hydrophilic polymer and a bonding compound capable of chemically bonding to the hydrophobic polymer and to the hydrophilic polymer. Th radiation-sensitive medium further may comprise a substance capable of converting radiation into heat. The radiation-sensitive medium is aqueous-ineluable when coated and dried, and becomes hydrophobic under the action of heat. The polymer particles are made by polymerization of at least one hydrophobic monomer and at least one bonding compound in the presence of the hydrophilic polymer. The radiation-sensitive medium may be provided as a coatable composition to be applied to substrates to form a processless radiation-imageable lithographic printing precursor. The processless radiation-imageable lithographic printing precursor so created may be imaged using absorbed radiation that is imagewise converted to heat, resulting in areas of hydrophobic property, while unimaged areas retain their hydrophilic property. This allows the latent image so formed to be employed in creating a negative-working lithographic printing master. The negative-working lithographic printing master so created is irreversible, does not require a substrate of controlled hydrophilicity and provides great toughness in the exposed areas. The radiation-sensitive medium may be coated on-platesetter or on-press onto a suitable substrate, including the drum of the press. It may also be coated off-press on a suitable substrate to create a precoated processless radiation-imageable lithographic printing precursor.

Layers in printing plates, printing plates and method of use of printing plates

A positive-working radiation-sensitive composition for use with a radiation source comprises one or more polymers capable of being eluted in an alkaline aqueous solution and a development-enhancing compound. The invention provides a positive-working photosensitive composition of good sensitivity for use with one or both of ultra-violet radiation and an infrared laser radiation source. The composition is stable in its state before exposure and has an excellent handling property. The sensitivity of a radiation-sensitive coating based on the composition of this invention is increased without compromising the handling characteristics. Radiation-sensitive elements based on the composition of the invention have good development latitude. A positive-working lithographic printing precursor is based on the radiation-sensitive composition coated on a hydrophilic surface. The precursor is developable using an alkaline aqueous solution, and may be used with a radiation source in lithographic applications, such as conventional imaging systems, computer-to-plate systems or other direct imaging applications. The precursor is stable in its state before exposure and has an excellent handling property.

Dual-wavelength positive-working radiation-sensitive elements

A gravure printing element is fabricated using a negative-working thermally-imageable coating that is exposed using commercially available diode lasers, the coating being insensitive to ultraviolet light, daylight or visible light, and developable using aqueous media. A gravure etch mask is formed on a printing precursor by applying a coating of thermally-imageable material, curing the coating, imagewise illuminating the cured coating with a laser and removing with a developer the areas of the coating that were not illuminated. The masked precursor is then chemically etched to produce a gravure printing element.

Preparation of gravure and intaglio printing elements using direct thermally imageable media

In accordance with the present invention there is provided an imaging element for lithographic offset printing. The imaging element comprises hydrophobic polymer particles in an aqueous medium, a substance for converting light into heat and an inorganic salt. The imaging element may be used for printing long run lengths on lower quality paper and in the presence of set-off powder. The imaging element may be imaged and developed on-press and may be sprayed onto a hydrophilic surface to create a printing surface that may be processed wholly on-press. The hydrophilic surface may be a printing plate substrate or the printing cylinder of a printing press or a seamless sleeve around the printing cylinder of a printing press. This cylinder may be conventional or seamless.

Thermally convertible lithographic printing precursor

Method for obtaining a lithographic printing surface

Polymer materials are described that undergo a 2-level 3 dimensional crosslinking process. During this process, hydrophilic polymers are crosslinked at two levels, the first results in a low level of crosslinking which leads to a toughening of the layer preventing dissolution by the fountain solution but with the layer remaining hydrophilic. The second level of crosslinking is higher and is the result of exposure to a laser diode thermal imaging device. The crosslinking at this second level results in a loss of hydrophilicity and provides instead an oleophilic image capable of accepting and transferring oil based ink. The polymer materials are particularly useful in lithographic printing systems where they may used in articles such as a printing plate comprising a substrate having coated thereon a layer that becomes that becomes less hydrophilic upon exposure to thermal energy (e.g., heat, particularly heat applied by a laser, other columnated light, or thermal printhead) that effects crosslinking (initial crosslinking or increased crosslinking) in the layer, the layer comprising a mixture of a crosslinked polymer and a thermally active crosslinking metal compound (e.g., a metal salt, metal ester or metal oxide).

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Tsawwassen, Canada

Jonathan William Goodin