xvfb continue to run even the process completes using wkhtmltopdf

finished process using Xvfb by wkhtmltopdf continue to run even if the process completes. Generating much process untill the server memory depletes. Running processes looks like this;
Xvfb -kb -screen 0 1024x768x24 -dpi 96 -terminate
Add a ";kill $!" at the end if you want to make doubly sure that the background X server you started is ended after wkhtmltopdf is ran... The -terminate should handle that automatically, but you never know.