  The projectile fragmentation reactions using $^{58}Ni$ $\&$ $^{64}Ni$ beams
at 140 MeV/n on targets$^{9}Be$ $\&$ $^{181}Ta$ are studied using the canonical
thermodynamical model coupled with an evaporation code. The isoscaling property
of the fragments produced is studied using both the primary and the secondary
fragments and it is observed that the secondary fragments also respect
isoscaling though the isoscaling parameters $\alpha$ and $\beta$ changes. The
temperature needed to reproduce experimental data with the secondary fragments
is less than that needed with the primary ones. The canonical model coupled
with the evaporation code successfully explains the experimental data for
isoscaling for the projectile fragmentation reactions.
