First use the print head failure test program to check which needle has failed. Then remove the ribbon cartridge, open the print head locking clip, and pinch the print head fins (ie, the housing) from both sides. Lift the print head up to see With two flexible flat cables attached, the print head can be removed by pulling the cable. Wipe the ink in front of the print head with an alcohol swab to see if there is a missing needle.

If it is a broken needle, you need to change the needle. To prepare the tool when replacing the needle, there are tweezers, blades, diamond files, steel rulers, whetstones, and special printhead fixtures (a tool that is specifically designed to remove the printhead heat sink). With a special fixture to withdraw the heat sink, you can see several layers of structure.

With the head down, loosen the positioning claws, remove the top copper cover, and you can see the 12 long needles distributed in a circle. From the test results, distinguish whether the broken needle is a long needle or a short needle and then count the number of broken needles. The position of the long needle is removed with a tweezers; if there is a short needle break, all the long needles are removed, and then the blade is separated along the middle of the yellow copper gasket to expose 12 short needles and removed in the same way. Broken needles. Then remove a good needle (take a long needle or a short needle depending on the change of the needle), use a steel rule to accurately measure the length of the needle, the new needle according to the amount of size, with gold steel fudge (Note After removing the head burr from the needle, insert it from its original position, and then gently press the tail of the 12 needles with your fingers so that the needle protrudes from the front. At this point, you should see the 1st and 24th needles. There is a needle exposed, and there should be a hole between the needle and the needle. If there is a wrong position, it must be readjusted. At the same time, when the fingers are released, the needles can immediately close the needles to ensure that the needles are unblocked.

The long needle can only be installed after confirming that all the short needles are in place. Before closing the copper seat, the positioning pin of each pin should be inserted into the slot, and the positioning hole of the long needle layer should be closed, and the long needle can be installed without checking the gap. The long needle only needs to be inserted in accordance with the position of the corresponding hole. The long needle extends from the tail to the tip of the head, and several guide grooves are required. The uppermost slot is very easy to wear. The second hole is a bit harder. Just go through and the needle will be able to come down and get to where you are. With the thumb pressed against the armature, the needle should be exposed to 1mm, indicating that the needle was replaced. After all the plugs are plugged in, the copper cover should be pressed on. The gap should be gapped. The three-legged positioning claws should be installed and the heat sink should be put on.

Before the test, the ribbon is not loaded, and a single sheet of paper is self-checked to prevent the new needle from scratching the ribbon. Then use the test program to test, and use it only if the result is normal.

(2) AR-3240 Printer

The print head of the AR-3240 is an energy-storage print head that differs from the print heads of other printers. Special attention should be paid when disassembling the AR-3240.

The AR-3240 print head consists of a permanent magnet back cover, a print pin base, a front cover, a print needle guide, and a guide frame. The 24 print pins are fixed on the base of the needle by 24 screws, which is different from other print heads.