Wrong PDF crop when using the microtype package or zero margin

Question

[UPDATED]PLEASE READ AT THE BOTTOM OF THE POST[UPDATED]

I'm still using TexLive 2010 (ubuntu) and I need to create some tight pdf (using pdflatex and pdfcrop with --hires option).

I need to use microtype, and also I need to work without margins (I want to create some text strips). The problem is that result pdf are wrong, cutting out some piece of text as you cas see from screenshots.

Removing microtype, is working fine in some cases. In others i also need to add some mm to lmargin

This is my geometry setup:

\usepackage[paperwidth=100mm, paperheight=8.5372222276mm, %
marginparsep=0mm, marginparwidth=0mm, columnsep=0mm,tmargin=0mm,bmargin=0mm,lmargin=0mm,rmargin=0mm,headheight=0mm,headsep=0mm,footskip=0mm]{geometry}

Full code

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[italian]{babel}
\usepackage{microtype}
\usepackage[paperwidth=100mm, paperheight=8.5372222276mm, %
marginparsep=0mm, marginparwidth=0mm, columnsep=0mm,tmargin=0mm,bmargin=0mm,lmargin=0mm,rmargin=0mm,headheight=0mm,headsep=0mm,footskip=0mm]{geometry}
\pagestyle{empty}
\setlength{\parindent}{0mm}\setlength{\lineskiplimit}{0pt}\setlength{\lineskip}{0pt}
\begin{document}\frenchspacing
\fontfamily{psb}
\fontsize{20bp}{22}
\selectfont
\textit{``xp}
\end{document}

[UPDATED]PLEASE READ AT THE BOTTOM OF THE POST[UPDATED]

Using mirotype:

Without microtype:

How can I fix it?

[UPDATE]

i made some tests. Please tell me if this solution is correct even in theory: i need for example a 100mm (width) x 10mm (height), so i add (using common word processor margins as model) 0,49cm (4.9mm) as margin in every margin.

\usepackage[paperwidth=109.8mm, paperheight=19.8mm, textwidth=100mm,textheight=10mm]{geometry} 

Then i compile it with pdflatex and cropped using --hires (pdfcrop). Is it a good and clean solution ? Thank's

Answer 1

Here's what I get by compiling

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage{microtype}
\pagestyle{empty}
\begin{document}\frenchspacing
\fontfamily{ptm}
\fontsize{20bp}{22}
\selectfont
\textit{``xp}
\end{document}

and processing the result through pdfcrop --hires (I later added a frame, just to show the the result against a white background). I used Times as I don't have Sabon, but that's not the point. Ulrike is mentioning in her comment that characters may have parts outside their bounding box and that's the case, for example, with quotes.

Here's what's get by compiling Flavio's example and doing pdfcrop --hires

It should be clear what's the correct procedure.