The present invention relates to a printhead for thermal inkjet printing and the printing method thereof. The printhead includes: a substrate having a plurality of orifices with a firing element in each of said plurality of orifices, wherein said plurality of orifices are arranged in a single column, and said printhead is disposed at an angle to a horizontal direction along which said printhead scans; and firing circuits for energizing said plurality of firing elements to eject ink on a printing medium by respectively transmitting a plurality of firing signals to said plurality of firing elements. According to the present invention, the print speed and resolution can be improved.