incomplete print

Hello everyone,

I hope somebody has experienced this issue or can generally offer some help on this ...

I am running a office network on an AirPort base station, with 3 Macs and 1 Windows machine connected wirelessly, and 1 Brother MFC 9420-CN on USB.

Basically, my issue is that my documents aren't printed completely.

There are no problems from one iMac and the Windows laptop.

But the other iMac and MBA nearly never complete their print. Sometimes it's one full page (of several), sometimes even just a few lines.

I have tried the following:

- restarting the AirPort and Printer and Computers

- updating the AirPort and Computers

- changing the location of the Computers

I am running the following:

- MBA on OS 10.8.5 ... doesn't work

- iMac on OS 10.9 ... doesn't work

- iMac on OS 10.8.5 ... no issue

- Windows machine on Win 7 version something ... no issue

- AirPort on version 7.6.4 (newest)

- Brother MFC-9420CN on Driver version 4.5.0a (newest)

Any ideas? Thanks in advance.