There is a problem with the documented method of creating QR codes in HTML for rQRCode, as background colors are not printed. The suggested method is to use background colors to create the appropriate sequence. Instead, use a border-left on all TD elements and change the width to 0px; Additionally, change the border color of the alternating divs to the appropriate black or white sequence.
Something like this:
td.qr {
border-left: 2px solid #000;
padding: 0;
margin: 0;
width: 0px;
height: 2px;
}
td.qr-black { border-color: #000;}
td.qr-white { border-color: #fff;}
Obviously the sizes will vary with your needs, but this is the general idea.