  We consider the 2D critical Ising model with spatially periodic boundary
conditions. It is shown that for a suitable reparametrization of the known
Boltzmann weights the transfer matrix becomes a polynomial in the variable
$\csc(4u)$, being $u$ the spectral parameter. The coefficients of this
polynomial are decomposed on the periodic Temperley-Lieb Algebra by introducing
a lattice version of the Local Integrals of Motion.
