Eastman-kodak Company

Kodak Polychrome Graphics, Gmbh

Kodak Graphic Communications Gmbh

Dietmar Frank

Gerhard Hauck

Celin M Savariar-Hauck

Ulrich Fiebag

Jianbing Huang

Harald Baumann

Mathias Jarek

Bernd Strehmel

Tanja Ebhardt

Oliver Piestert

Andrea Pauls

Friederike Von Gyldenfeldt

Horst Glatt

Ulrike Dallmann

Lithographic printing plates are formed by imagewise exposing a single-layer or dual-layer positive-working lithographic printing plate precursor. The precursor has an outermost ink receptive layer containing a phenolic resin. The exposed precursor can be processed using a silicate-free developer composition having a pH of at least 12.5. This composition also includes an alkali metal hydroxide; a coating protecting agent that is a quaternary ammonium salt or phosphonium salt, or a mixture thereof, and a moderator for the coating protecting agent that is represented by the following general formula (I): wherein m is at an integer of at least 1 and up to and including 10 and M represents one or more counterions sufficient to balance the negatively-charged sulfonate groups.

Lithographic developer composition and method of use

A thermally-sensitive, positive-working lithographic printing plate precursor can be used to prepare lithographic printing plates using high pH, silicate-free processing solutions. The precursor has a grained an anodized aluminum-containing substrate including a poly(vinyl phosphonic acid) interlayer. A first ink receptive layer, and optionally a second ink receptive layer, is disposed directly on the poly(vinyl phosphonic acid) interlayer. This first ink receptive layer comprises an aromatic acid dye that comprises at least two aromatic groups in an amount of least 0.5 weight %. In addition, the precursor comprises an infrared radiation absorber in one of the layers.

Making lithographic printing plates

Positive-working lithographic printing plate precursors and use

Thermally imagable elements are described comprising on a substrate with hydrophilic surface (a) a first layer comprising a first polymer soluble or swellable in aqueous alkaline developer and insoluble in organic solvents with low polarity and (b) a second layer comprising a second polymer soluble or swellable in aqueous alkaline developer, wherein the first polymer is different from the second polymer and the second polymer comprises vinyl acetal repeating units and pendant acidic groups selected from COOH, &#x2014;SOH, &#x2014;POH, &#x2014;POH, aromatic OH and groups having acidic amide or imide groups.

Dual-layer heat-sensitive imageable elements with a polyvinyl acetal top layer

Phosphono-substituted siloxanes suitable as interlayer material in lithographic substrates and for post-treating developed lithographic printing plates, obtainable by reacting (a) a first organosilicon compound of the general formula (I) and (b) a second organosilicon compound of the general formula (II).

Material for the treatment of lithographic substrates and lithographic printing plates

Heat-sensitive element comprising a) an optionally pretreated substrate; b) a positive working coating comprising (i) at least 40 wt.-%, based on the dry weight of the coating, of at least one polymer soluble in aqueous alkaline developer selected from novolak resins, functionalized novolak resins, polyvinylphenol resins, polyvinyl cresols and poly(meth)acrylates with phenolic and/or sulfonamide side groups, (ii) 01-20 wt.-%, based on the dry weight of the coating, of at least one (C-Calkyl)phenol novolak resin insoluble in aqueous alkaline developer, and (iii) optionally at least one further component selected from polymer particles, surfactants, contrast dyes and pigments, inorganic fillers, antioxidants, print-out dyes, carboxylic acid derivatives of cellulose polymers, plasticizers and substances capable of absorbing radiation of a wavelength from the range of 650 to 1,300 nm and converting it into heat.

Heat-sensitive positive working lithographic printing plate precursor

Positive-working imageable elements and methods for their preparation are disclosed. The elements comprise a hydrophilic substrate; a bottom layer, which contains a positive-working photosensitive composition; and a protective overlayer, which has an overlayer material that reduces the solubility of the photosensitive composition in an aqueous alkaline developer. The overlayer may be conveniently applied by a dip and rinse procedure.

Imageable element having a protective overlayer

A method for producing printing plate precursors by dual-feed technology is described. The obtained printing plate precursors contain polymer particles in the photosensitive layer and show high print run stability.

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Osterode, Germany

Dietmar Frank