Eastman-kodak Company

Leonid Askadsky

Moshe Levanon

Jianbing Huang

A silicate-free alkaline aqueous developer composition has a pH of at least 12 and comprises a hydroxide alkali agent, a metal cation Mselected from barium, calcium, strontium, and zinc cations, a chelating agent for the metal cation, and an alkali metal salt that is different than the other components. These developer compositions can be used to process imaged positive-working lithographic printing plate precursors to prepare lithographic printing plates.

Method of providing lithographic printing plates

A method is used to prepare lithographic printing plates by developing positive-working lithographic printing plate precursor that has a single imageable layer that comprises a polymer binder having recurring units represented by Structure (Ib) below: wherein the recurring units of Structure (Ib) are present in an amount of at least 25 and up to and including 60 mol %, all based on total recurring units in the polymer binder, and Ris a substituted or unsubstituted hydroxyaryl group in which the hydroxyl group is ortho to the ester linkage, to form exposed and non-exposed regions in the imageable layer. The resulting imaged lithographic printing plate is developed using a silicate-free developer composition having a pH of at least 12 and comprising at least 0.001 gram-atom/kg of a metal cation Mselected from the group consisting of barium, calcium, strontium, and zinc cations.

Methods of processing using silicate-free developer compositions

A silicate-free alkaline aqueous developer composition has a pH of at least 12 and comprises a metal cation Mselected from barium, calcium, strontium, and zinc cations, and a chelating agent that has a complex formation constant (log K) for the metal cation of at least 3.5 and less than or equal to 4.5, and a log K for aluminum ion that is 7 or less. This developer composition can be used to process positive-working lithographic printing plate precursors to provide lithographic printing plates.

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Bat Yam, Israel

Leonid Askadsky