You don't need to export it as a JPG just to make multiple print copies.
While in the print module, select the print options of your printer and set the quantity in there. Your printer driver will make the copies for you and print identical copies.
My question is there any way to make a copy of the original and then convert it to a JPEG format?
This doesn't solve the problem. Anything you can do with a JPG you also do with a RAW. It seems that McLion has pointed out the answer.
To answer the original question, you export the raw image and choose the JPEG format. Choose the option to add the JPEG to the catalog. Export to the same folder. You will have the JPEG copy. However, as the others have indicated this isn't going to solve the multiple print issue. It's possible to print multiple copies of any format. But you have to do it by clicking on the Page Setup button, which displays your printer driver controls. It's in the printer driver where you designate the number of copies.
I tried using print settings and print but they didn't do multiple copies. If you go to the printer button (lower right corner in the in the print mode) and make your settings there, it works just fine. I assume that this way must access the printer's drivers rather than Lightroom's.