B1 Visa Invitation Letter Regard

[kattalai]

I need a help regarding B-1 visa invitation letter from united states:

Inviting company has sent me the invitation letter from U.S, but i dint receive yet.postal delay i suppose.i have my interview scheduled for next week.
They have also mailed me a scanned copy of the letter.Is it enough to produce the printout of scanned letter in interview? or should i reschedule my appoinment for a later date and wait for the original letter?
thanks in advance