troubles printing

Hi

I have just buy a Brother DCP J132W printer that works fine in my Mac Book Pro with OSX 10.6.8 and with other PCs but in my iMac with osx 10.6.8

Blotted out all my documents. Have I ever gotten the test page goes well but others not at all. I have tried in all usb ports and not resolved in either.

Any idea where to investigate?

My Best regards