Patent ID: 8283101

Claim:
A multi-layer positive-working imageable element that is a positive-working lithographic printing plate precursor comprising a hydrophilic aluminum-containing substrate having thereon, an inner imageable layer comprising a first polymeric binder disposed on the substrate and an outer imageable layer comprising a second polymeric binder disposed over the inner imageable layer, wherein: the second polymeric binder is different from the first polymeric binder, the outer imageable layer comprises inorganic, non-metallic, inert discrete particles dispersed within the second polymeric binder that is insoluble in alkaline developer before thermal imaging and soluble in said alkaline developer after thermal imaging, said element further comprises a radiation absorbing compound only in the inner imageable layer, and said discrete particles have an average particle size of from 10 nm to 300 nm, and are present in said outer imageable layer in an amount of from about 5 to about 30% based on total outer imageable layer dry weight wherein said discrete particles are composed of silica, aluminum oxide, or titanium dioxide.