Alternating current energized printing system utilizing a dielectric covered resilient impression roller

In a system for assisting the transfer of ink, carried on a metal printing cylinder connected to ground potential, to a web of substantially non-conductive material as the web passes along a web path through a nip between the grounded printing cylinder and the outer perimeter of a resiliently covered metal impression cylinder, including the combination of:

• an electrically conductive layer of resilient material of annular cross section on said impression cylinder,
• means insulating said electrically conductive layer of resilient material on said impression cylinder from ground potential,
• an outer sleeve of dielectric material of homogeneous continuous annular cross section forming the outer perimeter of the impression cylinder and disposed directly at said web path for direct contact with the web at said nip over the operative width of said outer perimeter of said impression cylinder, and having a resistivity substantially greater than that of said conductive layer, and
• means comprising an electric circuit connected with said electrically conductive layer for applying an electric potential between said electrically conductive layer and said grounded printing cylinder,
• the entire operative width of the outer perimeter of the impression cylinder which is to contact the web being formed entirely by said dielectric material of said outer sleeve, said dielectric material having a thickness less than one-eighth of an inch and having a dielectric constant between twenty and one hundred, and said electric circuit comprising an alternative potential source for applying an alternating current electric potential between said electrically conductive layer of resilient material and said grounded printing cylinder to produce an alternating reactive current from said electrically conductive layer through said dielectric material of said outer sleeve over the entire operative width of said impression cylinder.