The printer drivers, I believe, are located in /Library/Printers. But deleting something in the OS is not going to automatically cause software update to want to replace it. Software update doesn't work that way. So don't delete anything.
If software update doesn't deem something needs updating then replacing it manually won't accomplish anything.
What printer do you have? Did its printer software come with OS X or from a third party source?
Most printer support software these days consists of many different files, not just a single driver file. It can be very difficult to find just the files relevant to one printer model, & deleting & replacing them may not work. It is best to reinstall the entire package.
How you do that depends on where the software comes from; thus, the questions above.
The recent driver updates are also available as standalone files:
- Canon Printer Drivers v2.9 for OS X (317.12 MB)
- Epson Printer Drivers v2.11 for OS X (983.60 MB)
- Gestetner Printer Drivers v2.3 for OS X (28.43 MB)
- InfoPrint Printer Drivers v2.3 for OS X (798 KB)
- Infotec Printer Drivers v2.3 for OS X (8.77 MB)
- Lanier Printer Drivers v2.3 for OS X (11.59 MB)
- Lexmark Printer Driver v2.8 for OS X (169.14 MB)
- NRG Printer Drivers v2.3 for OS X (10.84 MB)
- Ricoh Printer Drivers v2.3 for OS X (20.26 MB)
- Savin Printer Drivers v2.3 for OS X (10.80 MB)
The files are rather larger than using Software Update because the latter can identify your printer and download only the driver for that, while the ones listed here are generic.