Several general needle printer printing head needle change methods
(1) LQ-1900K\/LQ-1600KⅢ \/ LQ-1600K4 print head
The LQ-1900K\/LQ-1600KⅢ \/ LQ-1600K4 print head is a double-layer needle arrangement structure, and the printing needles are divided into two specifications, 12 each, the length of the long needle is 36mm, the length of the short needle is 26mm. The 24 pins of the print head are arranged in odd and even double columns. From the perspective of the guide plate in front of the print head, the left side has an odd number and the right side has an even number. The long needles are: 2, 6, 10, 14, 18, 22, 3, 7, 11, 15, 19, 23; The short needles are: 4, 8, 12, 16, 20, 24, 1, 5, 9, 13, 17, 21.
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First of all, use the print head broken pin test program to check which number of pins are faulty, and then cut off the printer power supply, remove the ribbon box, remove the two print head fixing screws with the crosshead screwdriver, pinch the heat sink of the print head from both sides (that is, the shell), gently lift the print head, you can see the two flexible flat cables connected, remove the cable and take out the print head. Scrub the ink on the front of the print head with an alcohol cotton ball to see if there are any missing needles.
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If any needles are broken, replace them. Tools should be prepared before changing the needle, mainly tweezers, blades, diamond file, steel ruler, whitetstone and print head special fixture (a special tool for removing the print head heat sink). First use a crosshead screwdriver to remove the two screws fixing the print needle sleeve and heat sink, use a special tool to remove the heat sink, you can see that the print head has several layers of structure, and then change the needle in the following order:
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1) Put the head of the print head downward, pick out the triangular claws fixing the upper and lower layers of print needles, remove the top back copper cover, you can see the 12 long needles distributed in a circle, distinguish from the test result whether the broken needle is long or short, and then determine the location of the broken long needle, remove the broken needle with tweezers and put it aside; If there are short broken needles, take out all the long needles, and then separate them with a blade along the yellow copper gasket in the middle, exposing 12 short needles, and remove the broken needles in the same way. Then take a good needle from the print head (take a long needle or a short needle depends on the broken needle), and then use a steel rule to accurately measure the length of the needle, the new needle according to the size of the amount of diamond file to grind (pay attention to the head of the needle to grind away the burr), and then insert from the original position. After the replacement, gently press the tail of the 12 needles with your hand to make the needles protrudes from the guide plate in front of the print head. At this time, you should see that there are needles in the positions of No. 1 and No. 24 needles, and there should be a hole between the needles in each column. If there is a wrong insertion, it must be readjusting. At the same time, when the finger is released, each needle can be immediately withdrawn to ensure that each needle is smooth. Then close the copper base, note that before closing the copper base must also let the positioning pin of each needle into its slot.
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2) After confirming that all the short needles are in place, the upper coil seat (that is, the long needle coil seat) and the base (copper seat) are pressed together, and a set of 10V DC voltage is applied to the drive coil of each group of printing pins respectively (the power-up time should be short, generally less than 1 second, which is equivalent to applying a pulse voltage on the coil). This tests the flexibility of each print needle and the consistency of the flight distance. Avoid reworking after loading the upper print needle (long needle group).
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3) Install the upper pins in the original order. Install the positioning hole of the long needle layer together with the coil seat, check that there is no gap on the side, and then install the long needle. The long needle only needs to be inserted according to the corresponding hole position. From the tail to the head, the long needle goes through several guide slots, and the top slot is easy to insert. The second slot is a little more difficult, as long as it is passed, the print needle can go down, it is easy to reach the position, also press the tail of the 12 needles with your finger, the needle should be from the guide plate in front of the print head out of the lmm, indicating that the needle is good. After all insertion, check that the positioning pin of each long needle must fall into its slot, and then close the rear copper cover, at this time there should be no gap from the side. Finally, install the triangle claw, cover the heat sink, according to the test method of the short needle set with 10V power supply to check the long needle set, confirm the normal can be installed on the original printer for testing.
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(2)AR-3200 \/ AR-3200 II\/CR-3240 II print head
AR-3200 \/ AR-3200 II\/CR-3240 II These three kinds of needle printer print head structure is basically the same, in addition to the three print needle reset spring spring and print needle drive coil resistance values are not the same, the other are the same, the print needle is a single-layer arrangement structure, the length of the print needle is 35.2mm.
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The method of checking broken needles is the same as the EPSON LQ series printhead above. Change the needle as follows:
1) Put the head of the print head down, remove the black plastic shell of the print head, remove a movable I-plate, and then break the two metal fixing clips by hand, remove the back cover, print pin armature press reed and white plastic bracket, then you can see the armature of 24 print pins arranged in a circular line.
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2) Remove the broken needle with tweezers (when removing the broken needle with tweezers, the action should be light, do not bring out the nylon dowel and reset spring below the print needle), similarly remove a good print needle from the print head, measure the length of the needle accurately with a steel ruler, put the new needle according to the measured size, use a diamond file to grind the needle burr, and then insert it from the original position. Gently press the armature of 24 needles with your finger to expose the needle from the front guide plate and observe whether all 24 needles come out.
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3) Install the white plastic bracket, print pin armature press reed, rear cover plate and fixing card in the original order, install the print head housing, apply a set of 10V DC voltage to the drive coil of each set of print pins (the method is the same as LQ series print heads), and test the flexibility of each print pin and the consistency of flight distance in turn.
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4) Install the print head back to the original printer, first do not install the ribbon, self-check to print a single page of paper (to prevent the newly installed print needle will hang up the ribbon), and then use the print head broken needle test program to test, check normal before use.