Provided are an apparatus and method of controlling jetting of ink of an inkjet printer. The apparatus includes at least one print head chip, which includes a temperature sensor for sensing the temperature of the print head chip and a voltage controlled oscillator (VCO) for converting the sensed temperature to a frequency component. The apparatus may also include a counter, which converts the frequency component to a code information using a reference frequency component, and a controller, which controls the ink jetting operation of the at least one print head chip based on the code information and/or the frequency component.