BAR CODE MARKING METHOD

摘要

PURPOSE: To provide such marking method of bar code as enables bar code parts to be clearly identified from its background so that the read-out ratio is improved. CONSTITUTION: In the marking method in which a bar code 2 is formed on a metallic material 1 by the scanning of a laser beam 4; first, the bar code part 2 is formed by making the peak value of the laser beam output 4 the same or slightly larger than the background part and making the repeated frequency high so as to evaporate and discolorate the metallic surface. Next, the background part 3 of the bar code is formed by making the repeated frequency of the laser beam output 4 low and evaporating the metallic surface.