Planographic printing master

摘要

A novel printing master and method for producing the same is disclosed which comprises the coating of a suitable substrate with an uncured silicone gum composition containing an activating proportion of a "blowing" or "foaming" agent. A particulate image pattern such as a toner image pattern, is transferred to the uncured silicone layer, followed by curing of the gum to an elastomeric ink releasable film. Activation of the "blowing" agent occurs during curing of the silicone to cause imagewise "foaming" of the silicone layer. After removal of the deposited image pattern, a "foamed" image is formed which is ink receptive and provides an imaged printing master suitable for use without a need for aqueous dampening solutions to provide ink release in non-imaged areas of the master.