Dynamically create form fields

[link7722]

I am trying to find a way to dynamically create some form fields based on a given number.I have 3 tables, the first stores printers, the second cartridges and the third is for the correspondence of printers to cartridges.In the printers table I have a field where i store the number of cartridges for each printer.To make the matching of printers to cartridges I want to create a form which every time will have the right number of textboxes (or probably dropdown menus) based on the number of cartridges the specific printer uses.

Any help would really be appreciated