| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of contamination of a non-image area by ink when printing is started and obtain a starter liquid with good ink-receiving properties to a silver image area, by providing inorganic fine particles of not larger than a specific average particle size and letting the starter liquid contain at least one of substances expressed by specific formulae and hexylene glycol. SOLUTION: Inorganic fine particles of an average particle size of not larger than 0.1μm, e.g. colloidal silica or the like, a water insoluble compound having at least one or more mercapto groups, and compounds expressed by formulae 1, 2 or hexylene glycol are combined. Accordingly, a starter liquid which has remarkably improved initial water-holding properties and good ink-receiving properties and, works as a plate cleaner, that is, removes ink adhering to a printing plate is obtained. (n) is an integer not smaller than 1. R1 is a hydrogen atom, a 1-9C alkyl group, and (n), (m) represent mol required so that an average molecular weight of a polymer is 250 or larger. n/m=0.5-2 is held.
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