Here is sample solution code for your case that removes html tags in pdf.

http://hastebin.com/ukiqohixos.php

Thanks for your reply Abu,

I'm not sure to understand. Do you mean to use the function set_pdf_format() ?
There is methods for the pdf format $pdf, but I don't see method for $data.

Thanks for precision.

You only need to set following with html tag column.

$col["on_data_display"] = array("display_comp","");

function display_comp($data)
{
if (isset($_GET["export"]))
return $data["company"];
else
return "<font color='red'>".$data["company"]."</font>";
}

If function callback, i've skipped html tags if GET array has export variable.

Ok, it works, but not perfectly.
Maybe I must use the grouping on the field. But it's ok.

Thanks Abu.