Thank you for your interest in Syncfusion products.
Could you please check if you have Internet Explorer version 9 installed in your machine? HtmlConverter makes use of MSHTML (IE rendering engine) to convert the webpage to image. With IE 9 there is a known issue that it generates only raster image which when drawn in PDF appears blurry and splitting could not be done properly. You can get more information on this from the following link:
As explained, to solve this, the key FEATURE_IVIEWOBJECTDRAW_DMLT9_WITH_GDI should be updated in the registry. Please run the utility placed in the following location to perform the above changes automatically.
Please try this and let me know if you have any questions.