To reduce or eliminate artifacts of printed images without depending on an expensive, cost-increasing image processing method and without adding additional hardware to an existing device.

In a method for reducing the naked eye-visible artifact of a color-printed image, the imaging of each plate surface to be used in different color planes is started by using different imaging beams. It is also possible to start the imaging of each plate surface to be used in different color planes by using different sets of imaging beams. The present method does not need the operation of image data. In the method, some error is diffused over the whole printed image to prevent the error from being imaged and or printed, so that the perception of the artifact can be reduced or eliminated.