There are two printing modes, that are selected through the Printing Mode menu:
Internet Explorer Printing Engine
Embedded Printing Engine
Previous HTMLPrint versions only printed using the Embedded Printed Engine, which is fast and reliable but doesn't support HTML as advanced as Internet Explorer. See Limitations for more information about that topic.
To learn about the different configuration options for both printing modes, look at the Options and Footer/Header Tabs, where the different options are explained in detail.
The default printing mode uses the Embedded Printing Engine, and unless the printing is not looking well, there is no reason to use Internet Explorer Printing Engine, since the default printing mode uses less resource than Internet Explorer Printing Mode.
But if printed documents do not look well selecting Internet Explorer Printing Engine as the default mode will fix the problem.
Badly looking printed pages when using the Embedded Printing Engine may be caused either for using some advanced HTML that is not supported by the Embedded Printing Engine, or because the page code have errors. Internet Explorer can handle pages with many errors, but the Embedded Printing Engine requires clean HTML.
Note: To generate images or metafiles from HTML documents the only way is by using the Embedded Printing Engine.