What you need is a way to fully control printing at the client side from ASP.NET so you can send raw commands (e.g. ESC/P if your printer does support it) and these are the two solutions I can think of:
jZebra or qz-print[
^] which requires JAVA VM to be installed at each client machine. Client Cross platform and open-source
WebClientPrint[
^] which requires to install a small utility at each client machine. Client cross platform but commercial
Using any of these you'll have full control on the client printer for sending raw commands. HTH,