ink gutter 17 in an alternate printing scheme ink gutter 17 may be placed to block deflected drops 66 so that undeflected drops 67 will be allowed to reach recording medium 18 the heating elements 51 a 51 b of heater 50 may be made of polysilicon doped at a level of about 30 ohms square although other resistive heater materials could be used heater 50 is separated from substrate 42 by thermal and electrical insulating layer 56 to minimize heat loss to the substrate the nozzle bore 46 may be etched allowing the nozzle exit orifice to be defined by insulating layers 56 the layers in contact with the ink can be passivated with a thin film layer 64 for protection the printhead surface can be coated with a hydro phobizing layer 69 to prevent accidental spread of the ink across the front of the printhead heater control circuit 14 supplies electrical power to the heater 50 as shown in fig2 a in the form of electrical pulse trains control circuit 14 may be programmed to separately supply power to the semicircular heating elements 51 a 51 b of the heater 50 in the form of pulses of uniform amplitude.