Two sided imaging of a continuous web substrate with moving fusers

In a duplex web printing system for printing both the first and second sides of a continuous web print substrate having two sides with a print engine having at least one imaging member generating controlled sequences of print images for both said first and second sides of said continuous web print substrate and an image transfer system for transferring said print images to said continuous web print substrate substantially at a defined process velocity, and a fusing system for fusing said transferred print images to both sides of said continuous web print substrate, the improvement comprising;

• said image transfer system comprising first and second image transfer stations positioned for transferring said print images to said first and second sides of said continuous web print substrate respectively at said first and second image transfer stations,
• a continuous web print substrate supply system providing controlled variable feeding in a defined movement direction of said continuous web print substrate to said first and second image transfer stations for said image transfers,
• said continuous web print substrate supply system having a web feeding system for feeding said continuous web print substrate into said first image transfer station and then into said second image transfer station and forming a segment of said continuous web extending between said first and second image transfer stations,
• said continuous web print substrate supply system web feeding system providing variable movement of said continuous web in said web segment between said first and second image transfer stations,
• and said fusing system comprising separate first and second web fusing systems,
• said first web fusing system fusing said print images on said first side of said continuous web after said first image transfer station, and said second fusing system fusing said print images on said first side of said continuous web print substrate after said second image transfer station,
• at least said first fusing system being reciprocally movable at a movement velocity relative to said continuous web in said defined movement direction of said continuous web print substrate, and
• said movement velocity of said said first fusing system being less than said defined process velocity;
• wherein said continuous web print substrate supply system web feeding system provides alternate expansion and contraction of said web segment between said first and second image transfer stations, and said reciprocal movement of said first fusing system relative to said continuous web print substrate is coordinated with said variable movement of said continuous web in said web segment between said first and second image transfer stations.