US 4,527,479 AGranted

Ink removal, circulating and distributing system

OwnerHarold P. Dahlgren, James E. Taylor +1inventors

InventorsHarold P. Dahlgren, James E. Taylor, Dwight W. Peters

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Abstract

A method and apparatus for continuously using ink and dampening fluid in a printing system includes removing ink and dampening fluid from a form roller after the form roller engages the printing plate. Mixing of the removed ink and dampening fluid to form a substantially homogeneous printing liquid is accomplished by circulating the removed ink and dampening fluid to a reservoir where it is mixed with ink in the reservoir by an auxillary blender. The homogeneous mixture is further circulated to the center of a metering nip between two rollers and flows longitudinally of the rollers at a rate to prevent separation of the dampening fluid from the ink. Unused printing ink and dampening fluid is returned to the reservoir with the ink and dampening fluid removed from the form roller.

Claims18

Dependent claims

A method of applying an emulsified printable mixture of ink and dampening fluid to a lithographic printing plate comprising the steps of:

depositing an excess of the emulsified mixture of ink and dampening fluid in a central portion of a nip between a transfer roller and a metering member such that the emulsified mixture flows longitudinally of the nip toward opposite ends of the transfer roller;
rotating the transfer roller to meter a thin film of the emulsified mixture between the metering member and the transfer roller onto the surface of the transfer roller;
delivering the film from the transfer roller to the lithographic printing plate;
maintaining flow of the mixture longitudinally of the nip to prevent accumulation of the dampening fluid adjacent said nip;
causing the mixture to cascade over opposite ends of the transfer roller into opposite ends of a reservoir to remove the mixture from the nip adjacent opposite ends of the nip;
depositing ink and dampening fluid remaining in a portion of the film of ink and dampening fluid which is not accepted by the lithographic printing plate into the reservoir;
pumping the mixture which has cascaded over ends of the transfer roller and the portion not accepted by the printing plate from a central portion of the reservoir to form a homogeneous mixture and to deposit the homogeneous mixture in a central portion of the nip between the transfer roller and the metering member to circulate ink longitudinally of the nip and at a rate sufficient to prevent accumulation of dampening fluid separated from the ink in the nip as a result of pressure between the transfer roller and the metering member.

4 more elements

In a printing system having a printing plate, a form roller engaging the printing plate, and apparatus to apply ink and dampening fluid to the printing plate, the improvement comprising:

an ink transfer roller;
an ink metering roller;
means urging said ink transfer roller and ink metering roller into pressure indented relation to form a nip;
means metering ink from the surface of the transfer roller onto the surface of the form roller;
dispensing means for delivering ink into a central portion of said nip such that ink flows longitudinally of the nip in opposite directions and cascades over opposite ends of said transfer roller and metering roller;
means for removing a mixture of excess ink and dampening fluid from said form roller after said form roller engages the printing plate;
a collection reservoir positioned to receive ink cascading over ends of said rollers into opposite ends of the collection reservoir and to receive the mixture of ink and dampening fluid removed from said form roller;
means removing ink from a central portion of said collection reservoir;
means sensing the level of ink in the collection reservoir;
means to add fresh ink to ink in the collection reservoir when the level of ink in the collection reservoir falls below a predetermined level;
and pump means between the means removing ink from a central portion of the collection reservoir and said dispensing means, said pump means having sufficient capacity to circulate ink longitudinally of said nip at a rate sufficient to prevent accumulation of dampening fluid in said nip and sufficient to mix ink cascading over ends of said rollers with fresh ink periodically added to the collection reservoir and the mixture of excess ink and dampening fluid removed from the form roller to assure that a substantially homogeneous mixture of ink and dampening fluid is dispensed into the central portion of the nip.

8 more elements

Dependencies are inferred from the claim text.