Under the pressure of the ink supply pump, the ink passes through the ink pipeline from the ink tank, regulates the pressure, viscosity and enters the spray gun. As the pressure continues, the ink is ejected from the nozzle. When the ink passes through the nozzle, the function of the pressure transistor breaks into a string of continuous ink drops with the same size and spacing. The ink jet continues to move downward and is charged through the charging electrode The ink drop in the electrode is separated from the ink line. A certain voltage is applied to the charging electrode. When the ink drops are separated from the conductive ink line, the negative charge which is in positive proportion to the voltage applied to the charging electrode will be applied in an instant. By changing the voltage frequency of the charging electrode to make it the same as the breaking frequency of the ink drop, each ink drop can be charged with a predetermined negative charge. Under the continuous pressure, the ink flow continues to move downward, passing through the middle of two deflecting plates with positive and negative voltage respectively. When the charged ink drop passes through the deflecting plate, it will deflect, and the degree of deflection depends on the amount of charge, without any charge The electric ink drops do not deflect, fly downward, flow into the recycling pipe, and finally return to the ink tank for recycling through the recycling pipe. The charged and deflected ink drops fall on the object passing in front of the vertical nozzle at a certain speed and angle. The information to be printed can generate different identification information by changing the charge of the ink drop through the processing of the main board of the computer.