I noticed that html2pdf doesn't print special characters. The ones I noticed are the Registered Trademark symbol ® and the TM Trademark symbol ™. There are probably plenty of other characters that don't print as well, specifically accented characters.
I found a good workaround: use the ASCII equivalents using HTML markup or use the actual HTML code for the symbol. In other words for the registered trademark symbol, I can use either [ampersand]reg; or [ampersand]#174; The trademark symbol doesn't have an HTML code for it, but will work with [ampersand]#153; Replace the [ampersand] with an actual ampersand (&).
There's a website http://ascii.cl/htmlcodes.htm that displays the ASCII equivalent codes or otherwise called HTML numbers for all the special characters.
