Abstract A rotary printing machine for fabrics which includes a color box containing a printing paste constituting a liquid electrolyte, a rotatable print roll having an engraved cylindrical outer printing surface, a rotatable brush roll in the color box for supplying to the printing surface an excess of printing paste as the print roll rotates, a steel doctor blade with a horizontally extending longitudinal edge positioned against the printing surface to remove the excess printing paste for gravity flow across one side of the blade in a direction perpendicular to its edge and a printing cylinder traversing and pressing a fabric web against the print roll printing surface following supplying of the printing paste thereto by the brush roll and after removal of the excess by the doctor blade. The doctor blade has a more electropositive strip of metal, such as magnesium, or aluminum, in electrical contact with the steel doctor blade spaced from the edge thereof and extending generally throughout the length thereof on said one side for flow of the excess printing paste thereacross in electrical contact therewith, thereby providing a sacrificial anode to prevent electrolytic corrosion and pitting of the doctor blade edge.
In a rotary printing machine as claimed in claim 1, wherein said doctor blade is of steel.
Claim 2
Dependent Claim
23 words
In a rotary printing machine as claimed in claim 2, wherein said strip of metal is of the class including aluminum and magnesium.
Claim 3
Independent Claim
192 words
The method of preventing electrolytic corrosion in a rotary printing machine for fabrics which includes a color box containing a printing paste constituting a liquid electrolyte a rotatable print roll having an engraved cylindrical outer printing surface a rotatable brush roll in said color box for supplying to said printing surface an excess of said paste as said print roll rotates a doctor blade with a horizontally extending longitudinal edge positioned against said surface to remove said excess for gravity flow across one side of said blade in a direction perpendicular to said edge and a printing cylinder traversing and pressing a fabric web against said print roll printing surface following supplying of said paste thereto by said brush roll and after removal of said excess by said doctor blade comprising providing a strip of metal more electropositive than said doctor blade in electrical contact with said blade spaced from the edge thereof and extending generally throughout the length thereof on said one side for flow of said excess printing paste thereacross in electrical contact therewith, thereby providing a sacrificial anode to prevent electrolytic corrosion and pitting of said doctor blade edge.
Claim 4
Dependent Claim
14 words
The method as claimed in claim 4, wherein said doctor blade is of steel.
Claim 5
Dependent Claim
16 words
The method as claimed in claim 5, wherein said strip of metal is aluminum or magnesium.