Heavy arrow tips for xy-pic

Question

Arrows in xy-pic have narrow heads, but I need heavy tips for my graphs. I tried the following arrow definition, but the tip of the arrow enters into the circle of graph node.

\documentclass{report}
\usepackage[all]{xy}

\newdir{|>}{%
!/4.5pt/@{|}*:(1,-.2)@^{>}*:(1,+.2)@_{>}}

\begin{document}
\[
\xygraph{
!{<0cm,0cm>;<2cm,0cm>:<0cm,2cm>::}
!{(0,0)}*+=[o]+[F]{1}="1"
!{(1,0)}*+=[o]+[F]{2}="2"
"1":@{|>}"2"
} 
\]
\end{document}

Would you please help me to avoid this problem?

How can I fill insdie the arrow tip? Or preferably get something like:

Answer 1

Just in order to show the solution of your problem with tikz-cd:

% arara: pdflatex 

\documentclass{report}
\usepackage{tikz-cd}
\usetikzlibrary{arrows} 

\begin{document}
\[
\begin{tikzcd}
\tikz{\node[draw, circle]{1}} \arrow[-latex]{r} & \tikz{\node[draw, circle]{2}}
\end{tikzcd}
\]
\tikzcdset{
arrow style=tikz,
diagrams={>=stealth}
}
\[
\begin{tikzcd}
\tikz{\node[draw, circle]{1}} \arrow{r} & \tikz{\node[draw, circle]{2}}
\end{tikzcd}
\]
\end{document}