Vacuum transport roller for web transport system

A printing system for printing on a movable print medium, comprising:

• a first linehead disposed opposite a first side of the movable print medium, the first linehead defining one or more print zones where a liquid is jetted onto the first side of the movable print medium;
• one or more vacuum, transport rollers having a porous sleeve rotatable around a non-rotating core, wherein the rotatable porous sleeve is engaged by the moving print medium that exerts a force on the porous sleeve causing it to rotate the vacuum transport roller(s) being disposed adjacent to a second side of the movable print medium and opposite the first linehead, wherein at least one of the vacuum transport rollers is aligned with one of the one or more print zones of the first linehead;
• the core including a vacuum manifold that outputs a vacuum force that operates on the second side of the movable print medium through the porous sleeve to deflect the movable print medium and causes the movable print medium to wrap around the vacuum transport roller(s) while the porous sleeve is rotating;
• a second linehead disposed downstream of the first linehead such that a liquid jetting direction of the second linehead is parallel to a liquid jetting direction of the first linehead wherein the second linehead defines one or more print zones where a liquid is jetted onto the first side of the movable print medium;
• and
• one or more second vacuum transport rollers having a second porous sleeve rotatable around a second non-rotating core, disposed adjacent to the second side of the movable print medium and opposite the second linehead, and wherein at least one of the second vacuum transport rollers is aligned with one of the one or more print zones of the second linehead, and wherein the second core includes a second vacuum manifold that outputs a second vacuum force that operates on the second side of the movable print medium to deflect the movable print medium causing an increase in a wrap angle of the movable print medium around the second vacuum transport rollers.

A printing system for piloting on a movable print medium, comprising:

• a first linehead disposed opposite a first side of the movable print medium the first linehead defining one or more print zones where a liquid is jetted onto the first side of the movable print medium;
• one or more vacuum transport rollers having a porous sleeve rotatable around a non-rotating core, wherein the rotatable porous sleeve is engaged by the moving print medium that exerts a force on the porous sleeve causing it to rotate, the vacuum transport roller(s) being disposed adjacent to a second side of the movable print medium and opposite the first linehead, wherein at least one of the vacuum transport rollers is aligned with one of the one or more print zones of the first linehead;
• and
• the core including a vacuum manifold that outputs a vacuum force that operates on the second side of the movable print medium through the porous sleeve to deflect the movable print medium and causes the movable print medium to wrap around the vacuum transport roller(s) while the porous sleeve is rotating, wherein the vacuum manifold is positioned asymmetrically relative to a vertical centerline of the vacuum transport roller such that the wrap angle of the movable print medium on the upstream side is different from the wrap angle of the movable print medium on the downstream side of the vacuum transport roller.