Failed printing in more printers in same process

[Fausto70]

I need to print to several printers in the same process . For example I need to:

• send the text file A to Printer 1
• send the text file B to Printer 2
• send the text file C to Printer 3 With 'same process' I mean that when the user clicks on the "Print" button, the php server send to print the 3 files to the 3 printers.

Problem:

• the text file A in Printer 1is successfully printed
• the text files B and C in Printers 2 and 3 are failed I can also invert the sequence; for example if I print first in Printer 2, Printer 2 is OK and Printer 1 and 3 are not OK; so, only the first printer of sequence is OK.

I also tried to put a delay (sleep(5)) of 5 seconds between the sending, but nothing changed. Please help me, this is a big problem for my application. Thank you in advance Fausto