Downloading printer drivers from other than the manufacturers' sites is a bit fraught and you can end up with junk. I used to fix printers in a workshop for a living and we used to download drivers from HP, Lexmark, OKI and every other make you can think of on a daily basis. Some makes such as HP (Dell may too but I'm not sure) has a professional site which you sign up to for the latest and greatest drivers and tech information e.g. service manuals. So, no legal reasons, you own that type of printer and you are entitled to the proper latest and greatest driver, and for a small fee you can get premium access to printer information with some manufacturers' sites.
If the IT department has a problem with this then insist they make a printer driver library which is up to date and they download the printer drivers and put them in the library once the drivers been given the OK i.e. virus checked and functionality checked. Bit of an ache but it keeps everybody happy. If they don't comply you could point out they are not keeping appropriate backups of software and are probably in breach of their own protocols or quality management system if indeed they have one.