Pull line, dripping problem
Pulling lines and dripping ink are common problems that affect product quality and continuous production in the production of UV dtf printers, which are mainly caused by the clogging of the nozzle. Because the nozzle holes and ink dots are very fine (micron level), small impurities, dust, and water vapor are enough to block the nozzle holes or block the ejected ink dots, so clogging is a common defect of uv dtf printers.
1. The nozzle is blocked
Blockage in the nozzle
Generally speaking, clogging is divided into nozzle internal clogging and external clogging. The clogging in the nozzle is generally caused by ink path pollution and ink precipitation. The ink path pollution is generally caused by the incomplete cleaning of newly installed parts. Therefore, when replacing parts, they must be strictly cleaned before starting the machine. At the same time, it is also very important to choose a suitable filter. Too thick will easily cause the nozzle to block, and too thin will cause the filter itself to block. The ink sedimentation is not only related to the suspension of the ink but also closely related to the ink supply system of the machine itself. A good supply system can ensure that the nozzles keep the nozzles unblocked and the ink supply is sufficient in the state of standby, continuous full printing, and small intermittent printing. Otherwise, there will be frequent clogging, uneven spraying of small ink volumes, and insufficient ink supply for large ink volumes, resulting in defects of yin and yang. Although the general external blockage and internal blockage can be handled by automatic or manual cleaning methods, it will be very time-consuming and affect production, so the performance of continuous and stable production is the most important indicator to measure the quality of a uv dtf printer.
Clogged outside the nozzle
External clogging is generally caused by the machine itself or external pollution. External pollution includes dust from the workshop, as well as mud, dust, and water vapor brought in by the bricks. The pollution caused by the machine itself comes from the ink dots ejected from the nozzle, which cannot adhere to the brick surface, and finally falls on the nozzle, and it accumulates more and more. In order to reduce the dirt and dust pollution brought by the printed matter, it is necessary to do a good job in the “bath” treatment of the printed matter in the inkjet machine room. To reduce the pollution brought into the inkjet room by the workshop can be solved by maintaining a positive pressure in the room (note that the air blown into the room must be filtered through dust removal first).
2. Machine maintenance (mainly nozzle maintenance)
Due to the difficulty of manufacturing print heads, so far, whether it is imported from abroad or domestically produced UV dtf printers, imported print heads are used. The print head is also the main cost component of a UV dtf printer, accounting for more than 70% of the cost of the machine. Therefore, the correct maintenance of the nozzle is very important.
The design life of the nozzle is different, the brand is different, and the use condition is different. In a continuous UV dtf printer production line, theoretically, the Xaar system is 2~3 years, and the Polaris can reach 3~5 years. However, since most of the machines currently in use have only 1 to 3 years of use time, this has yet to be verified by time. Generally speaking, nozzle damage mainly includes normal damage (abrasion of nozzle holes, etc.), blockage damage, and circuit board failure. Abrasion is caused by ink and cannot be controlled by the user; the cause of blockage is as analyzed above. To reduce circuit board failures, the main reason is to do a good job in environmental management, do a good job in constant temperature and humidity, and reduce dust pollution.
Common problems and routine maintenance of UV dtf printer
1. Problem: The pattern appears garbled during production
Possible reasons: there is a problem with the code converter or poor contact; solution:
(1) Replace the code converter;
(2) Check whether the wiring of the encoder converter is open.
2. Problem: Ink dripping during production
Possible reasons: ink dripping from the nozzle or insufficient suction force of the suction pipe; solution:
(1) Increase the degree of vacuum;
Analysis: Increasing the suction force of the nozzle on the ink droplets is generally used when the pressure cannot meet the requirements of the installed machine, and the vacuum degree cannot be increased blindly;
(2) Reduce the temperature of the printed matter;
Analysis: If the printed matter is too high, some water vapor will be generated, and the water droplets will combine with the ink to form a precipitate and gradually form ink droplets;
(3) Use automatic cleaning to clean the nozzle;
Analysis: Manual physical cleaning is the easiest and most commonly used emergency treatment method;
(4) Increase the frequency of the suction pipe;
Analysis: It can be applied only when the pressure is large enough.
3. Problem: White lines are generated during the production process
Possible cause: the nozzle is blocked;
Analysis: It may be particles or ink droplets;
Solution;
(1) The vacuum is too high to reduce the vacuum degree;
Analysis: Too high a vacuum will inhibit the normal ejection of ink;
(2) Automatic cleaning and cleaning of nozzles for dripping ink;
Analysis: One of the emergency treatment methods in production;
(3) Wipe the nozzle with a cleaning cloth. Note that the nozzle cannot be wiped back and forth, and can only be wiped in one direction, otherwise, it will damage the nozzle;
Analysis: Generally used to automatically clean the nozzle after no results;
(4) Increase the voltage and continuously print with 100% grayscale pictures;
Analysis: The effect is not very good, but it is possible to open the ink path to make the printing normal;
(5) Replace the inlet and outlet pipes on the nozzle to make the ink flow in the reverse direction;
Analysis: Use it only after the automatic cleaning of the nozzle and the manual wiping of the nozzle are fruitless.
4. Problem: The vacuum is unstable during the production process
Possible reasons: air in the ink cartridge or air leakage in the ink path;
Solution:
(1) Check whether the ink supply pump, defoaming pump, and circulating pump are working properly. Note: When replacing the ink supply pump and the defoaming pump, the inlet and outlet pipes must be clearly seen;
(2) Check whether the defoamer and filter inlet and outlet pipes are leaking;
(3) Whether the clamp of the filter pipe is clamped, re-clamp the pipe;
5. Problem: Ink accumulates or hangs on the nozzle
Possible reasons: the tension of the ink is too small or the voltage of the inkjet machine is too small;
Solution:
(1) Replace the ink with high tension;
Analysis: It is not recommended to use. Discharging the existing ink and cleaning it will incur a lot of costs. If it is not cleaned, different types of ink may react and affect the print head;
(2) Reduce the voltage of the inkjet machine to observe the ink hanging on the nozzle, and pay attention to not too large fluctuations when adjusting the voltage;
Analysis: It is recommended to adjust the voltage to suit the tension of the ink. Generally, it will be adjusted well when the machine is installed.
6. Problem: The color difference or the change in depth during the production process
Possible reasons: ink density changes, ink is not sufficiently shaken or ink performance is unstable;
Analysis: The performance of some domestic inks is unstable and easy to precipitate;
Solution:
(1) Whether the temperature setting has changed, pay attention to the temperature setting can not fluctuate more than 4 ℃, otherwise, the color change will be obvious;
(2) Whether to shake well for 20-30 minutes before adding ink;
(3) Check whether the agitator is working normally;
(4) Check whether the voltage setting of the machine has changed.
7. Problem: Ink shortage occurred in the production process
Possible reasons: the defoamer, the filter is not full or the voltage is too high or the ink viscosity is too low; solution:
(1) Whether the defoamer is full of ink, if not, check whether the defoamer pump is working normally;
(2) Reduce voltage;
(3) Lower the temperature and increase the frequency of ink supply.
8. Problem: The image appears on the belt during the production process
Possible reasons: inaccurate recognition by the electric eye, uneven belt, or fluffing;
Solution: (1) Check whether the height of the electric eye is low or the electric eye is covered by ink, wipe the electric eye with a clean cloth, and adjust the position of the electric eye higher;
Analysis: The uneven belt will have protrusions, and the edge of the imported belt will have fluffing, which may cause the electric eye to misidentify and print.
9. Problem: Obvious deep lines appear in the production process
Possible reasons: the print head card is faulty or the voltage of the print head zone is too high;
Solution:
(1) Remove the nozzle card and observe whether the nozzle card circuit is burned out. If it turns out, replace the nozzle card with a new one;
(2) Whether the partition voltage setting is changed if the change needs to be adjusted.
10. Problem: There is no ink in the overflow pipe and the inkjet machine alarms
Possible reasons: the ink supply pump is not working properly;
Solution: Gradually increase the frequency of the ink supply pump and observe the ink condition of the overflow tube.
11. Problem: The cooling machine is not working properly, and the UV dtf printer gives an alarm
Solution:
(1) Check if the water inlet and outlet pipes of the cooler are blocked, if there is water in the pipes, if there is no water, fill up with water;
(2) Check whether the temperature of the cooler is at the set temperature;
(3) Check whether the coolant in the cooler is lower than the specified amount.
12. Problem: Overlapping or missing sprinkler joints
Possible cause: Whether the setting of the sprinkler joint is changed or the belt moves;
Solution:
(1) Adjust the setting of the sprinkler joints, and add points for missing overlap points;
(2) Check whether the belt is horizontal or on the same straight line. If it is not on the same straight line, you want to adjust the belt.
Micolorprint strictly controls the quality of the materials. The UV dtf printer produced by Japan adopts the fifth-generation double-row nozzle of Japan, which is characterized by high speed, high precision, and low failure rate.
