Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Steve Kale 
<stevekale@b...> wrote:
>
> Why would letting air in be a problem?  Air has to come in else no 
ink can
> come out.  I would think the plugs are simply there to prevent 
spillage if
> the cart not placed in an upright position. Surely leaks at the print 
head
> are an issue with the poppet valves.
> 
> 


Or the "O" ring that seals the cart to the head.