Ink roll for high speed printing

An ink roll, consisting essentially of:

• a microporous roll made of a thermoplastic resin which consists essentially of a blend of a first polymer having particle sizes in the range of 1 to 20 .mu.m, and a second polymer having particle sizes of from 200 .mu.m to 400 .mu.m, wherein both of the first and second polymers are copolymers of PVC and polyvinyl acetate, and the second polymer has more acetate groups than the first polymer so that the second polymer imparts greater strength and abrasion resistance to the roll than the first polymer, wherein the resin has been plasticized and fused in the presence of a plasticizer to form interconnected aggregates forming a substantially uniform, unitary cohesive structure which defines a corresponding open-celled network of small pores both at the surface of the microporous roll and throughout its interior, which pores are small enough to prevent substantial leakage of an ink but large enough to permit ink flow to the microporous roll surface;
• and
• an ink impregnated in the microporous roll;
• wherein the ink roll contains about 14 to 54 wt. % ink, with the balance plastic and absorbed plasticizer, and the ink roll further has a porosity from about 30 to 60% measured as percentage of voids relative to total roll volume, an average pore size in the range of from about 0.5 to 100 microns, a surface penetration strength of from 4 up to 5.9 mm and a cross penetration strength of 3.5 to 6.5 mm as measured by a penetrometer using a 100 gram weight at 77.degree. F., an instron tensile strength of from 60 to 300 pds, and a durometer in the range of 8-30, such that the ink roll has sufficient strength, toughness and flexibility, when the ink roll is rotatably mounted on a bracket in tangential contact with a drive roll and a transfer roll, to deliver the ink from its outer peripheral sruface to the outer peripheral surface of the transfer roll without substantial misting of the ink from the ink roll surface as the ink roll is driven under pressure from tangential contact with the drive roll at a peripheral speed of at least 200 ips.