Patent ID: 7950759

Claim:
A method of operating an inkjet head to eject an ink droplet, wherein the inkjet head comprises a pressure chamber that is contracted and expanded in a particular period, a membrane included in one side of the pressure chamber, and a nozzle connected to the pressure chamber, the method comprising: (a) decompression-operating the membrane such that the volume of the pressure chamber is increased in correspondence with the period in which the pressure chamber is expanded; (b) compression-operating the membrane to eject a first ink droplet such that the volume of the pressure chamber is decreased in correspondence with the time point at which the pressure chamber is converted from an expanded state to a contracted state and a constructive interference is created; (c) decompression-operating the membrane such that the volume of the pressure chamber is increased in correspondence with the period in which the pressure chamber is contracted; and (d) compression-operating the membrane to eject a second ink droplet such that the volume of the pressure chamber is decreased in correspondence with the time point at which the pressure chamber is converted from a contracted state to an expanded state and a destructive interference is created, wherein the second ink droplet is ejected slightly out of the nozzle and then imbibed back inside, such that the second ink droplet catches a tail portion of the first ink droplet and draws the tail portion inside the nozzle.