Indirect printing system and related apparatus

A method for preventing condensation on print heads of print bars in a printing system comprising an intermediate transfer member (ITM), a first print bar including a first plurality of print heads spaced from said ITM by a first gap and having mounted thereon a first blowing mechanism, and a second print bar including a second plurality of print heads spaced from said ITM by a second gap and having mounted thereon a second blowing mechanism said second print bar being disposed downstream of said first print bar, the method comprising:

• blowing, from said first flowing mechanism into said first gap in a print direction, a first gas flow having a first flow rate, thereby to prevent condensation on said first plurality of print heads;
• and
• blowing, from said second blowing mechanism into said second gap in said print direction, a second gas flow having a second flow rate, said second flow rate being different from said first flow rate, thereby to prevent condensation on said second plurality of print heads,
• wherein each of said first and second blowing mechanisms includes a main body defining a first chamber and a first gas flow outlet in fluid connection with said first chamber, and
• wherein said main body of each of said first and second blowing mechanisms includes a second chamber fluidly connected to a third chamber and a second gas flow outlet in fluid communication with said third chamber, the second chamber, third chamber and second gas flow outlet form a second flow path separate from a flow path formed by said first chamber and said first gas flow outlet.

A method for preventing condensation on print heads of an array of print bars in a printing system comprising an intermediate transfer member (ITM), the array of print bars comprising a first print bar, a second print bar adjacent to and downstream of the first print bar, a third print bar adjacent to and downstream of the second print bar, a fourth print bar adjacent to and downstream of the third print bar, a fifth print bar downstream of the fourth print bar, and a sixth print bar adjacent to and downstream of the fifth print bar, each of the first through sixth print bars having mounted thereon a respective blowing mechanism and including a respective plurality of print heads which respectively emit droplets of ink onto the ITM, the method comprising:

• while the ITM is in-motion beneath the print bars, and while print heads of the each of the print bars emit droplets of ink onto the ITM such that some of the droplets of ink are satellite-droplets which each follow a respective parent-droplet, respectively operating each of the blowing mechanisms to blow gas in said print direction and into respective gaps beneath each of the print bars and above the ITM, wherein:
• i. the respective blowing of gas by each of the first through sixth blowing mechanisms respectively prevents condensations on print heads of each of the first through sixth print bars;
• ii. for the first through fourth gas-flow rates, each gas-flow rate is greater than its immediate predecessor;
• iii. a ratio between the second and first gas-flow rates is at least 1.1;
• iv. both of the fifth and sixth gas-flow rates exceed the fourth gas-flow rate;
• and
• v. the sixth and fifth gas-flow rates are equal both to each other and to a threshold value, said threshold value being set as a maximum flow-rate permitted so that no satellite droplet engages past its parent.