At present, the liquid level of the general printer is photoelectrically detected. When the liquid level detector is damaged, it will cause periodic fluctuations in the machine pressure, deformation of the printed font, and inaccurate viscosity. How to quickly determine such faults is the basic skill that every newcomer who is just getting started must master. Fault characteristics: The most common ones in our daily maintenance are the damage of the detectors of the ink tank and the solvent cylinder. Their fault performance characteristics are different. When the solvent cylinder detector is damaged, the viscosity of the printer will appear after running for a period of time. Raise, (V1 valve sticking will also cause viscosity increase, but the operating pressure of the machine will not fluctuate) The pressure periodically fluctuates greatly. The detector of the ink tank is damaged. Generally, the viscosity of the machine is normal, but the pressure also fluctuates periodically. .

When we suspect that there is a problem with the liquid level detector, we can directly check the liquid level of the two cylinders, or use the measurement method. When the liquid level is lower than 2 cm but there is no corresponding icon display, it is generally judged to be this test. Damaged.

Maintenance method: Take out the detector from the cylinder and visually check the device for damage. If the appearance is intact, clean the cone glass with a cleaning agent, and observe whether there is ink on the machine screen or the solvent icon is displayed, if it appears on the screen. The corresponding icon indicates that the detector is good and the lens is dirty. If there is still no icon at this time, it means that the detector is really broken and must be disassembled for inspection.

Disassemble the detector and we can see the two diodes hidden in it. The following work is how to find out the bad components and replace them. For those who are skilled in using multimeters to detect components, it is natural to judge such faults. It's a piece of cake, but some colleagues are somewhat uncomfortable with the use of a multimeter to detect the quality of the diode. The internal resistance of such a diode is very large, and it is quite different from the general tube, so it is easier to misjudge, especially the kind The only thing left is that the ink is corroded. We are looking forward to which two are the transmitting ends, and which two are the receiving ends? If it is not recognized correctly, it will delay the time, and it may damage the board.

Test method: the light source of the flashlight is close to the receiving tube (black). If the corresponding icon appears on the screen at this time, the receiving tube is good. You only need to replace the white tube to get it. If no icon does not appear, it indicates receiving. The tube is broken, you can replace it.

From the maintenance experience, the two tubes are rarely damaged at the same time, and the liquid level caused by the I/O board is not detected, so try not to suspect it. Let's take a look at how the diodes are etched away by the ink, leaving only four leads. How to distinguish which two are the transmitting ends and which two are the receiving ends. This method is fast and accurate, and does not require the use of a multimeter. 470 resistor, the power is not limited, one end of the resistor is connected with any one of the leads, the other end and the remaining three leads are respectively connected, when the liquid crystal icon is displayed on which lead screen is connected, then this When connecting with the resistor, the two leads are the liquid level detector receiving end, and the remaining two are the transmitting end. If no icon appears, you can change the lead and try again. Generally, the result can be obtained in two minutes.