Eastman-kodak Company

Domenico Balbinot

Mathias Jarek

Harald Baumann

Udo Dwars

Christopher D Simpson

James Russell Matz

Celin M Savariar-Hauck

Gerhard Hauck

Andrea Pauls

Johannes Obenauf

Lithographic printing plate precursors have an aluminum-containing substrate prepared using two anodizing processes to provide an inner aluminum oxide layer of average dry thickness of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter of &#x2264;100 nm. An outer aluminum oxide layer is provided with a multiplicity of outer micropores of average outer micropore diameter of 15-30 nm and a dry thickness of 30-650 nm. A hydrophilic layer is disposed on the outer aluminum oxide layer at 0.0002-0.1 g/mand has a (1) compound having an ethylenically unsaturated polymerizable groups; a &#x2014;OM group connected directly to a phosphorus atom, wherein M represents hydrogen, sodium, potassium, or aluminum; and (2) one or more hydrophilic polymers having (a) recurring units comprising an amide group, and (b) recurring units having an &#x2014;OM' group that is directly connected to a phosphorus atom, wherein M&#x2032; represents hydrogen, sodium, potassium, or aluminum.

Lithographic printing plate precursors and method of use

Lithographic printing plate are formed by imagewise exposing a positive-working lithographic printing plate precursor with infrared radiation to form an imaged precursor comprising exposed regions and non-exposed regions, and processing the imaged precursor to remove the exposed regions using a processing solution having a pH of 12 or more, that contains a metal cation Mselected from barium, calcium, strontium, and zinc cations, and is substantially silicate-free. The positive-working lithographic printing plate precursor comprises a grained and anodized aluminum-containing substrate, a first ink receptive layer comprising at least one water-insoluble, alkali solution-soluble or -dispersible first resin, a second ink receptive layer disposed over the first receptive layer, and an infrared radiation absorber in an amount of at least 0.5 weight %, in either or both of the first ink receptive layer and the second ink receptive layer.

Method for making lithographic printing plates

A lithographic printing plate precursor comprises an imageable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye that is defined by Structure (I) shown in the disclosure, which dyes comprise one or more ethylenically unsaturated polymerizable groups in an organic group that is attached to the methine chain. These infrared radiation absorbing dyes exhibit a reduced tendency to crystallize in the imageable layers in the presence of tetraaryl borate counter anions and therefore provide improved shelf life.

Negative-working lithographic printing plate precursors with IR dyes

A lithographic printing plate precursor comprises an imagable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye comprising an infrared radiation absorbing cation and a counter anion, and a polymeric binder. The salt formed between the infrared radiation absorbing cation and a tetraphenyl borate has solubility in 2-methoxy propanol at 20&#xb0; C. that is greater than or equal to 3.5 g/l. The use of these infrared radiation absorbing dyes in the imagable layers provides a reduced tendency of these dyes to crystallize in the presence of tetraaryl borate counter anions.

Negative-working lithographic printing plate precursors

Negative-working lithographic printing plate precursor a negative-working imagable layer and an outermost water-soluble overcoat layer that is disposed directly on the negative-working imagable layer. The outermost water-soluble overcoat layer comprises: (1) one or more film-forming water-soluble polymeric binders, and (2) organic wax particles dispersed therein. The organic wax particles have an average largest dimension of at least 0.05 &#x3bc;m and up to and including 0.7 &#x3bc;m, as determined from a scanning electron micrographic of the dried outermost water-soluble overcoat layer. Useful organic wax particles include fluorinated or non-fluorinated hydrocarbon wax particles.

A lithographic printing plate precursor can be used to prepare a printing plate using thermal ablation. The precursor has a non-thermally ablatable first layer on a substrate. Over the first layer is a thermally ablatable outer layer that includes an IR absorbing compound in an ablatable polymeric binder. The first layer includes a sol gel as a continuous inorganic matrix and a discontinuous inorganic phase (inorganic particles) dispersed therein.

Thermally ablatable lithographic printing plate precursors

Negative-working imageable elements have a hydrophilic substrate and a single thermally-sensitive imageable layer. This layer can include an infrared radiation absorbing compound and polymeric particles that coalesce upon thermal imaging. These coalesceable polymeric particles comprise a thermoplastic polymer and a colorant to provide improved visible contrast between exposed and non-exposed regions in the imaged element, such as lithographic printing plates.

Negative-working thermal imageable elements

Imageable elements can be imaged and then processed using a solution containing core-shell particles that are designed to complex with non-coalesced particles in the non-exposed regions of imaged element. A separate development step is not needed, but the non-coalesced particles and complexed core-shell particles can be removed from the resulting printing plate before using the resulting lithographic printing plate for printing.

Method of processing elements with coalesced particles

Images can be provided using a method comprising thermally imaging a negative-working imageable element to provide an imaged element with exposed regions and non-exposed regions, the exposed regions consisting essentially of coalesced core-shell particles, and developing the imaged element on-press to remove only the non-exposed regions using a lithographic printing ink, fountain solution, or both. The imageable element comprises a single thermally-sensitive imageable layer consisting essentially of an infrared radiation absorbing compound and core-shell particles that coalesce upon thermal imaging. The core of the core-shell particles is composed of a hydrophobic thermoplastic polymer, the shell of the core-shell particles is composed of a hydrophilic polymer that is covalently bonded to the core hydrophobic thermoplastic polymer, and the thermally-sensitive imageable layer comprises less than 10 weight % of free polymer.

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Osterode, Germany

Domenico Balbinot