Printer common parts inspection and repair skills 1th/3 page _ Hardware Maintenance

Methods and techniques for maintenance of common parts of printers

Printer is a commonly used office equipment, it mainly includes needle-type printers, inkjet printers, laser printers and so on. At the same time the printer is a fault-prone office equipment, and maintenance of the printer is the final part of the repair of its damaged parts, so understand and proficient in various parts of the printer testing and maintenance will undoubtedly be of great significance to our maintenance work. The following for you to introduce common printer parts of the testing and maintenance methods and skills, I hope to be able to repair the work of the printer has some help.

Inspection and repair of needle-type print head

When the needle printer has a leak line failure, mostly because the print head broken needle. can be used without water alcohol wipe out the needle, if there is a lack of space needle is mostly due to broken needles, if no other fault causes no needle, such as signal line circuit breaker, printing sewing ring burning or printing needle guide hole plug. After breaking the needle, you can replace the broken needle and continue to use it.

1. Needle-changing method of several general needle printer

(1) LQ-1900K/LQ-1600KⅢ/LQ-1600K4 print head
LQ-1900K/LQ-1600KⅢ/LQ-1600K4 print head for Double-layer needle arrangement structure, print needle length, short two specifications, each 12, long needle length of 36mm, short needle length of 26mm. The printhead's 24 needles are divided into odd and even double columns. From the Guide panel in front of the print head, the left one is an odd number, and the right one is an even number. The long needles are: 2, 6, 10, 14, 18, 22, 3, 7, 11, 15, 19, 23, and the short pins are: 4, 8, 12, 16, 20, 24, 1, 5, 9, 13, 17, 21.
First use the print head broken needle test program to check out which needle failed, then cut off the printer power, remove the color belt box, with a Phillips screwdriver to remove the two print head fixing screws, from both sides pinch the head of the heat sink (that is, shell), gently lift the print head up to see the attached two flexible flat cable, Unplug the cable to take out the print head. Scrub the ink stains in front of the print head with alcohol cotton balls to see if there is a shortage of needles.
If there is a broken needle, you need to change the needle. Before changing the needle should be prepared tools, mainly tweezers, blades, King Kong file, ruler, oil and print head special fixture (a special for the removal of the print head heat sink tool). First use a Phillips screwdriver to remove the fixed print pin sleeve and heatsink of the two screws, with a dedicated tool to retreat the heatsink, you can see that the print head has several layers of structure, and then in the following order to change the needle:

1 The head of the printhead face down, pick the triangular claw of the fixed and lower two-layer print needles, and remove the top brass cover, can see the circular distribution of 12 long needles, from the test results to distinguish between the needle is a long needle or a short needle, and then determine the position of the long needle, with tweezers to take out the broken needle on one side, if there is a short needle broken needle, To take the long needle all out, and then with the blade along the middle of the yellow copper gasket separated below, exposing 12 short needles, with the same method to remove the needle broken. Then remove a good needle from the print head (take a long needle or a short needle depending on the needle broken), then use the ruler to accurately measure the length of the needle, the new needle in accordance with the size of the scale with a gold file grinding (note the needle head burr grinding away), and then inserted from the original position. Change the end of the 12 needles with your hand. To make the needle from the front of the print head to explore, at this time should see 1th needle and 24th needle position with a needle, and each column needle and needle should be spaced between the hole, if there is a wrong position, must be adjusted. At the same time, when the fingers open after each needle can be immediately retracted, to ensure that each needle is smooth out the needle. Then close the copper seat and notice that each PIN must be positioned into its slot before closing the copper seat.
2 after confirming that the short needle is all in place, the upper coil seat (that is, the long sewing ring seat) is pressed together with the base (copper seat), a group of +10v DC voltages are applied to the drive coils of each group of print needles (the power time is shorter, generally less than 1 seconds, which is equivalent to applying a pulse voltage on the coil), This tests the flexibility of the needle and the consistency of the flight distance for each print needle. Lest you rework the upper print needle (long needle Group) before you install it.
3 Install the upper needle in the original order. Install the long needle position hole together with the coil seat, and check the side without a gap can be installed long needle. The long needle should only be inserted according to the position of the corresponding hole. Long needle from the tail to the head, to go through several channel guide trough, the top slot is very easy to plug down. The second slot is slightly more difficult, as long as through the past, the printing needle can homeopathy, it is easy to reach the location, the same with the fingers of the 12 needle in the tail, the needle should be in front of the print head of the guide plate LMM, indicating that the needle is good to change. After inserting all, check the pins of each long needle must fall into its groove, then close the copper cover, at this time from the side should be seamless. Finally fitted the triangular claw, put on the heat sink, according to the short needle group test method with +10v power supply to check the long needle group, confirmed normal can be loaded to the original printer for testing.
Before testing, do not install the Ribbon, post print a single sheet of paper to prevent the new needle hanging ribbon. Then use the print head broken needle test program to test, to determine the normal can be put into use.

(2) Ar-3200/ar-3200ⅱ/cr-3240ⅱ Print head
Ar-3200/ar-3200ⅱ/cr-3240ⅱ these three kinds of needle printer's print head structure is basically the same, except for the three printing needle reset spring and print needle drive coil resistance is different, all the same, the print needle is a single layer arrangement structure, the length of its print needle is 35. 2mm.
Check the broken pin method with the same Epson LQ series print head. The needle is replaced by the following steps:
1 The head of the print head facing down, remove the black plastic shell of the print head, remove a movable working-type plate and then break the two metal clips with the hand, then remove the back cover plate, the print pin armature pressure reed and the white plastic bracket, then you can see the armature of the 24 printing needles arranged in a circular arrangement.
2 Use tweezers to remove the broken needle (with tweezers to take off the needle, the action should be light, do not put the printed needle under the nylon pin and reset spring out), again from the print head to remove a good print needle, with a rigid ruler to accurately measure the length of the needle, the new needle according to the amount of size, with the King Kong file grinding needle burr, and then inserted from the original position , the armature of 24 needles is pressed with the finger, so that the needle is exposed from the front guide plate and the 24 needles are all out.
3 According to the original order of the white plastic bracket, print needle armature pressure reed, back cover and fixed card, loaded with the print head shell, with a group of +10v DC voltage applied to each group of print needle on the drive coil (method with the LQ series print head), In turn, test the flexibility of the needle out of each print needle and the consistency of the flight distance.
4 Put the print head back to the original printer, do not install a ribbon, self-test printing a single sheet of paper (to prevent the new installation of the printing needle will be hung up), and then use the print head broken needle test procedures for testing, check normal after the use.

2. Trouble shooting of the printing sewing ring

Another common fault with the printhead is that the drive coil is damaged. The way to determine if the drive coil is damaged is to insert one end of a print head cable into the print head. Using a multimeter to measure the other end of the corresponding drive coil DC resistance, the general drive coil DC resistance should be 33 Euro ±2 Europe, if the measured resistance deviation is larger, may be the coil open or short circuit, will cause no needle or out of the phenomenon of weak needle. Testing can be a multimeter of a table pen to the public side, another table pen to the corresponding points of each drive coil, the replacement of a single coil can be used first with a tin-suction device to remove the solder on the coil and then use the blade to cut off the surrounding plastic, remove a single coil, replace it.
The main cause of the open circuit failure of the print drive coil is the damaged print needle drive tube on the motherboard. The drive tube is penetrated short, causing the drive current to be too large, and the drive coil will burn out. To determine whether the drive tube is faulty, use a multimeter to measure the print head cable: Red table pen to the public side (the public side is the driving power of the cathode), black table pen-connected to each corresponding position of the drive tube. Normally, the measured DC resistance should be about 18,000 euro, if the deviation is large, it indicates that the drive tube has been damaged. Each drive tube corresponds to the root print needle, for example, the lql600k printer board has 24 drive tube q1~q24, respectively corresponding to the 1-24 number of the print needle.

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