This work is a part of the development of a laser ion source (LIS) for multiply charged ion injectors. This experiment is devoted to the investigation of the effect of a metal grid on the extracted ion characteristics. The energy spectra of the ions in the plasma expanding into a drift tube with and without a grid have been compared. Plasmas of two different target materials, carbon and tungsten, were generated by the CO2 laser pulses with the focal power density on the target of about 1011 W/cm2. The time-of-flight method with an electrostatic energy analyzer installed just behind the grid is used to measure the charge states and energy distributions of ions. A significant effect of the grid on the ion energy distributions has been observed. This effect depends strongly on the ion mass and should be taken into account when designing a LIS, especially in the case of heavy ions.