Method to remove unwanted, unexposed, radiation-sensitive layer in a lithographic printing plate
AssigneeKodak Polychrome Graphics LLC
InventorsKevin B. Ray, Jianbing Huang, Joanne Ray
Life of this patent
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Abstract
A method for forming a printing plate from a printing plate precursor having a radiation-sensitive layer, sensitive to radiation in a first frequency spectrum such as the far or near infrared, and to radiation in a second frequency spectrum other than the first frequency spectrum such as visible or ultraviolet. The plate is exposed twice. Once to imaging radiation in the first frequency spectrum and again to radiation in the second frequency spectrum. The second frequency spectrum exposure is done only to the areas of the plate undesirably shaded during the imagewise exposure.
Claims27
A method for forming a printing plate comprising a printing plate precursor comprising a radiation-sensitive layer, said radiation sensitive layer exhibiting sensitivity to radiation in a first frequency spectrum and to radiation in a second frequency spectrum other than said first frequency spectrum, the method comprising imagewise exposing said printing plate precursor to said radiation in said first frequency spectrum and exposing to radiation in said second frequency spectrum any areas of said plate subject to undesirable shading during said imagewise exposure.
A method for forming a printing plate comprising a heat sensitive printing plate precursor said precursor also exhibiting sensitivity to at least one of visible and ultraviolet radiation, the method comprising exposing by imagewise heating said printing plate precursor and also exposing to at least one of said visible and ultraviolet radiation any areas of said plate undesirably shaded during said imagewise heating exposure of said precursor.
A method for forming a printing plate, the method comprising the steps of:
- (a) exposing a printing plate precursor comprising a radiation sensitive layer over a support with radiation in a first frequency region and forming exposed and unexposed regions in the radiation sensitive layer,
- in which the radiation sensitive layer exhibits sensitivity to radiation in the first frequency region and to radiation in a second frequency region, and wherein the first frequency region and the second frequency region are not the same;
- (b) exposing at least one of the unexposed regions with radiation in the second frequency region, and forming at least one additional exposed region;
- and
- (c) developing the printing plate precursor with a developer to form the printing plate.
Dependencies are inferred from the claim text.