US 5,038,679 A · Dampening fluid application system for lithographic printing

Abstract

A dampening fluid mist application system for lithographic printing comprises a container for the dampening fluid and a rotatable first roller having a rough surface for picking up and entrapping fluid from the container. A rotatable second roller having a brush surface contacts the first roller to transfer fluid from the surface of the first roller to bristles on the brush surface. A deflector bends and releases the bristles to eject fluid thereon and create a mist stream of the liquid. The rough surface on the second roller is employed to provide the desired amount of dampening fluid to the bristles and may be made of wire mesh or a series of spaced projections or knobs, for example. The deflector is made up of a plurality of separate blade segments whose edges contact different brush segments along the full width of the second roller. An adjustment mechanism independently moves the separate blade segments toward and away from the second roller in a coarse adjustment between bristle engaging and disengaging positions, while a fine adjustment in the bristle engaging position varies the degree of bending of the bristles between a minimum and a maximum. The dampening fluid application system is suitable for incorporation into new printing systems or retrofitting into existing printing systems to apply the dampening fluid mist stream to the region between rollers in the train of ink transfer rollers.

Claims12

Dependent claims

A liquid mist application system comprising:

a container for the liquid;
a rotatable first roller having a rough surface wherein the rough surface is a surface selected from the group consisting of a mesh surface and a surface with spaced knob projections, the roller for picking up and entrapping liquid from said container;
a rotatable second roller mounted above the first roller and having a brush surface uniformly covered with bristles and tangentially contacting the first roller, the contact surfaces of the two rollers moving in the same direction at the same speed for transferring liquid from the surface of said first roller to the bristles on said brush surface, the speed of said two rollers being about 50 rpm, the distance between said first and second rollers being adjustable to control the amount of transferred liquid;
and
a separate, adjustable deflector blade spaced apart from the first roller and extending across the width of the second roller for bending and releasing said bristles to eject liquid thereon and create a mist stream of said liquid, said deflector blade being made up of a plurality of separate, adjacent blade segments for contacting different brush segments along the width of said second roller, said separate blade segments being independently movable toward and away from the uniform surface of bristles of said second roller to vary the degree of bending of said bristles and control said mist stream across the width of said second roller.

2 more elements

A dampening fluid application system for lithographic printing comprising:

a reservoir for holding said dampening fluid;
a rotatable rough surface roller wherein the rough surface is a surface selected from the group consisting of a mesh surface and a surface with spaced knob projections, said roller immersible in said reservoir for picking up and entrapping said dampening fluid;
a rotatable brush surface roller tangentially contacting said rough surface roller for receiving fluid from said rough surface roller while the contact surfaces of said rollers move in the same direction at the same speed and transferring said fluid to bristles of the brush surface roller, the speed of said two rollers being about 50 rpm, the distance between said rough and brush surface rollers being adjustable to control the amount of transferred fluid;
and
a separate, adjustable deflector bar spaced apart from the rough surface roller and extending across the width of the brush surface roller roller for bending and releasing said bristles to eject liquid thereon and create a mist stream of said dampening fluid directable onto transfer rollers in a lithographic printing system, the deflector bar being adjustable by a first, coarse adjustment means to engage and disengage said deflector bar from contact with the bristles of said brush surface roller, said deflector bar being made up of a plurality of separate bar segments for contacting different brush segments along the width of said brush surface roller, said separate bar segments being independently adjustable by a second, fine adjustment means for movement toward and away from said brush surface roller to vary the degree of bending of said bristles and control said mist stream.

2 more elements

Dependencies are inferred from the claim text.

Dampening fluid application system for lithographic printing

Life of this patent

Dampening fluid application system for lithographic printing

Life of this patent

Abstract

Claims12