Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d 7 6s 2 4 F 9/2 → 5d 7 6s6p 6 F 11/2 at 351.5 nm were measured for 182−189 Ir, 186 Ir m and the stable 191,193 Ir. The nuclear magnetic moments µI and the spectroscopic quadrupole moments Qs were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of µI was experimentally determined for the first time for the masses 182 ≤A≤ 189 and the isomeric state 186 Ir m. The spectroscopic quadrupole moments of 182 Ir and 183 Ir were measured also for the first time. A large mean square charge radius change between 187 Ir and 186 Ir g and between 186 Ir m and 186 Ir g was observed corresponding to a sudden increase in deformation: from β2 +0.16 for the heavier group A=193, 191, 189, 187 and 186m to β2 ≥ +0.2 for the lighter group A=186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the π3/2 + [402] orbital for the heavier group and with the π1/2 − [541] orbital stemming from the 1h 9/2 spherical subshell for the lighter group. That last state seems to affect strongly the observed values of the nuclear moments.