How is the print job sent. If the browser is doing the print, the client needs to do this in the browsers Print options.
The hard-core solution is to see what data the printer driver is sending to the printer, nad replicate that in your app.
However when Canon changes the driver, you are back to square one.
A last option is to see if the printer allows printing via FTP upload. Sometimes you can setup a userid /password to a specific's department's print queue. However in those circumstances you need to change the print data to PDF(easy) or PCL (never seen it yet). Also your ASP.net server needs to the printer, so if this is will *only*work if the application is an intra-net(internal) application