Shallow relief photopolymer printing plate and methods

Claim 2

A phtopolymerizable element comprising a laminate of photosensitive composition supported on a substrate; said laminate including a first photopolymerizable layer adjacent said substrate and a second photopolymerizable layer disposed over said first layer; and said first layer including an array of preopolymerized portions distributed throughout substantially its entire area sufficient upon subsequent exposure and development of said photopolymeriable element to create a corresponding array of protrudent dots in the recessed background areas of the developed element, said protrudent dots having a height less than the height of the raised image areas of the developed element and a density sufficient to reduce the amount of bottoming in the developed element.

Claim 3

The photopolymerizable element of claim 1 wherein said array has a density in said first layer of at least 1 per square centimeter.

Claim 4

The photopolymerizable element of claim 1 wherein said array has a density in said first layer in the range of from about 100 to about 2000 per square centimeter.

Claim 5

The photopolymerizable element of claim 1 wherein each of said polymerized portions have an approximate transverse dimension of less than 0.008 inch.

Claim 6

The photopolymerizable element of claim 1 wherein said laminate has a thickness of less than about 0.020 inch.

Claim 7

The photopolymerizable element of claim 1 wherein said laminate has a thickness in the range of from about 0.005 to about 0.015 inch, said first layer has a thickness in the range of from about 0.001 to about 0.014 inch, and said second layer has a thickness in the range of from about 0.001 to about 0.014 inch.

Claim 8

The photopolymerizable element of claim 6 wherein said first layer has a thickness of about 0.004 inch and said second layer has a thickness of about 0.003 inch.

Claim 9

A photopolymerizable element comprising a laminate of photosensitive composition having a thickness less than about 0.020 inch and supported on a substrate; said laminate including a first photopoymerizable layer adjacent to said substrate and a second photopolymerizable layer disposed over said first layer; and said first layer including an array of prepolymerized portions throughout substantially its entire area, said array having a density in the range of from about 100 to about 2000 per square centimeter and being sufficient upon subsequent exposure and development of said photopolymerizable element to create a corresponding array of protrudent dots in the recessed background areas of the developed element, each of said protrudent dots having a transverse dimension less than about 0.008 inch and a height about 0.004 inch less than the height of the raised image areas of the developed element.

Claim 10

A photopolymerizable element comprising a laminate of photosensitive composition having a thickness less than about 0.020 inch and supported on a substrate; said laminate including a first photopoymerizable layer adjacent to said substrate and a second photopolymerizable layer disposed over said first layer; and said first layer including an array of prepolymerized portions throughout substantially its entire area, said array having a density in the range of from about 100 to about 2000 per square centimeter and being sufficient upon subsequent exposure and development of said photopolymerizable element to create a corresponding array of protrudent dots in the recessed background areas of the developed element, each of said protrudent dots having a transverse dimension less than about 0.008 inch and a height about 0.004 inch less than the height of the raised image areas of the developed element.

Claim 11

A photopolymerizable element comprising a layer of photosensitive composition supported on a substrate, said substrate having formed thereon an array of protrudent dots which extend into said photosensitive layer and which are sufficient upon subsequent exposure and development of said photopolymerizable element to create a corresponding array of protrudent dots in the recessed background areas of the developed element that extend to a height less than the height of the raised image areas of the developed element.

Claim 12

A photopolymerizable element comprising a layer of photosensitive composition supported on a substrate, said substrate having formed thereon an array of protrudent dots which extend into said photosensitive layer and which are sufficient upon subsequent exposure and development of said photopolymerizable element to create a corresponding array of protrudent dots in the recessed background areas of the developed element that extend to a height less than the height of the raised image areas of the developed element.

Claim 13

The photopolymerizable element of claim 9 wherein said substrate is a metallic sheet and said protrudent dots are embossed thereon.

Claim 14

The photopolymerizable element of claim 9 wherein said protrudent dots have a height in the range of from 0.002 to about 0.005 inch.

Claim 15

The photopolymerizable element of claim 9 wherein said array of protrudent dots has a density of at least 1 per square centimeter.

Claim 16

The photopolymerizable element of claim 9 wherein said array of protrudent dots has a density in the range of from about 50 to about 200 per square centimeter.

Claim 17

The photopolymerizable element of claim 9 wherein said photosensitive layer has a thickness of less than about 0.020 inch.

Claim 18

The photopolymerizable element of claim 9 wherein said photosensitive layer has a thickness of from about 0.005 to about 0.015 inch and said substrate is a metallic sheet having said protrudent dots embossed therein, said array of dots having a density of about 100 per square centimeter.

Claim 19

The photopolymerizable element of claim 15 wherein said protrudent dots have a height in the range of from about 0.002 to about 0.005 inch.