There's nothing mystical about importing goods into Australia. Over a certain (small) limit, customs will charge you 10% GST on the Australian dollar value of the imported item, even if it's for personal use and not for re-sale. And as far as I know, the application of GST on import has nothing to do with where the item was originally manufactured.
It can be worth the effort for some goods, such as film and lenses that have a high value but a small size and/or weight for their price (and hence low shipping cost for their value). You may find though that with the GST and the shipping cost your savings will be minimal compared to buying a big printer like the Z3100 in Australia.
If you want answers straight from the horses mouth, you should contact Customs directly....they will give you the answers you are looking for.
Hope this helps......
Cheers
Jeremy