  Quark propagators of the unquenched Kogut-Susskind(KS) fermion obtained from
the gauge configurations of the MILC collaboration are measured after Landau
gauge fixing and using the Staple+Naik action. Presence of the $\bar q q$
condensates and $A^2$ condensates in the dynamical mass $M(q)$ and the quark
wave function renormalization $Z_\psi(q^2)$ are investigated. We obtain the
correlation of the renormalization factor of the running coupling taken at
$\mu\sim 6$GeV and that of the quark wave function renormalization
$Z_\psi(q^2)$ of the Staple+Naik action. The mass function $\displaystyle M(q)$
is finite at $q=0$ and its chiral limit is $\sim 0.38$GeV. We compared the
results corrected by the scale of the vertex renormalization and the tadpole
renormalization with the corresponding values obtained by the Asqtad action
without renormalization and observed good agreement.Implication of infrared
finite $Z_2(q)=1/Z_\psi(q^2)$ to the Kugo-Ojima confinement criterion is
discussed.
