[en] From an electron spin resonance measurement on a single crystal sample of the S = 1 linear chain Heisenberg antiferromagnet Ni(C₃H₁₀N₂)₂NO₂ClO₄ (NINO) containing a small amount of Cu impurity atoms, we have observed two sets of four hyperfine lines, one of which has almost three times larger field splitting than the other. The hyperfine lines are well explained as arising from the hyperfine interaction between the Cu nuclear spin and the Cu electron spin which interact with the S = 1/2 degrees of freedom induced at the Ni sites by the quantum effect. A large anisotropy in the hyperfine constant is observed and analyzed using a ligand field theory with covalency effects. (orig.)