Positive pressure plenum system for transport belts in a printing device

A printing module, comprising:

• a plurality of printheads;
• a transport belt located below the plurality of printheads to transport print media below the plurality of printheads, wherein the transport belt comprises a plurality of vacuum openings;
• and
• a positive pressure plenum system, wherein the positive pressure plenum system comprises:
• a plate comprising a plurality of ridges and a plurality of troughs, wherein the plurality of ridges run across a width of the plate and are spaced apart in parallel by the plurality of troughs, wherein the plurality of ridges comprise a hollow tunnel inside of the plurality of ridges and a plurality of positive pressure openings on a top surface of the plurality of ridges, wherein the plurality of troughs comprise a plurality of vacuum openings that run through a thickness of the plate, wherein the plurality of vacuum openings do not communicate with the hollow tunnel inside of the plurality of ridges or the plurality of positive pressure openings, wherein the plurality of vacuum openings of the plurality of troughs are located to align with the plurality of vacuum openings of the transport belt;
• a positive air flow source to provide a positive air flow through the hollow tunnel inside of the plurality of ridges, wherein the positive air flow is forced out through the plurality of positive pressure openings against a bottom surface of the transport belt;
• and
• a negative air flow source to provide a vacuum to create a negative air flow through the plurality of vacuum openings of the plurality of troughs and the plurality of vacuum openings of the transport belt to hold the print media against the transport belt as the transport belt travels across the positive pressure plenum system and below the plurality of printheads.