US 5,103,732 A · Doctor blade head assembly and printing apparatus therewith

Abstract

A doctor blade head assembly, particularly for use in a flexographic printing press, has a head body pivoted to a support frame with an inflatable air tube disposed therebetween. The air tube extends along a channel having a bottom formed with spaced apart raised portions which cause the air tube to bulge out at these locations. In this way the air tube essentially only presses against the head body at these spaced apart locations, for example at the center and adjacent the ends, which reduces the tendency of the head body to bend along its length. This provides a more uniform ink film on the ink roll being inked by the doctor blade head assembly. End seal arrangements at the ends of the head body each include a resilient block seal and a resilient pad seal with which greased edge portions of the doctor blades slidably engage. The doctor blades overhang the ends of the ink roll, and an ink outlet passageway extends through each end seal arrangement independently of the seals.

Claims28

Dependent claims

A doctor blade head assembly, comprising:

a head body having at least one doctor blade mounted thereon, said doctor blade extending in a lengthwise direction along said head body;
a support frame on which said head body is movably mounted;
an inflatable air tube disposed between said support frame and said head body, and extending in said lengthwise direction, said air tube urging said head body away from said support frame when said air tube is inflated;
and
said air tube when inflated having a plurality of bulges spaced apart along said lengthwise direction with said bulges acting upon said head body.

2 more elements

A doctor blade head assembly, comprising:

an elongate head body having two doctor blades mounted thereon and defining an ink reservoir therebetween, said doctor blades extending in a lengthwise direction;
end seal assemblies mounted on opposite ends of said head body to provide ends for said ink reservoir;
a support frame on which said head body is mounted to pivot about an axis parallel to said lengthwise direction;
a channel extending along said support frame in said lengthwise direction, said channel having a bottom formed with a plurality of rigid raised portions spaced apart in said lengthwise direction;
an elongate inflatable air tube disposed in and extending along said channel over said raised portions, said air tube being disposed adjacent said head body and when inflated being forced against said head body at spaced apart locations where said air tube extends over said raised portions;
means biasing said head body to pivot towards said air tube;
and
said air tube when inflated acting upon said head body to pivot said head body in a direction away from said air tube, said air tube essentially acting upon said head body only at said spaced apart locations to mitigate bending of said head body by said elongate inflated air tube.

5 more elements

Dependencies are inferred from the claim text.

Doctor blade head assembly and printing apparatus therewith

Life of this patent

Doctor blade head assembly and printing apparatus therewith

Life of this patent

Abstract

Claims28