A method for improving printing quality is disclosed. The method includes an application device transmitting an original image including a plurality of printing pixels to a driving device, the driving device setting the plurality of printing pixels as a plurality of first printing dots, the driving device detecting an edge of the original image, the driving device setting a plurality of second printing dots according to a plurality of neighboring pixels corresponding to the edge, and the driving device generating an image to be printed according to the plurality of first printing dots and the plurality of second printing dots.