Example of laser Printer maintenance

Laser printer is the laser scanning technology, electronic technology, electrostatic imaging technology, such as integration of the printing and output equipment. It has the characteristics of fast printing, good printing quality, high resolution and low noise, and it is an important computer peripheral equipment. With the advent of network printers, it has become more and more widely used in office automation, printing, publishing, scientific research and other industries. Examples of maintenance failures are as follows:

Fault one: A laser printer image obviously side black, one side white. After the replacement of the toner cartridge, the parts are all clean after the failure or still exist.

Overhaul method: By maintaining the optical portion of the laser printer, the fault is solved, the main is to open the shell of laser printer, take apart the black plastic box, with clean lens paper carefully wipe multiple shuttle mirror a few of the reverse smooth, and then a few optical lens wipe clean, remove the plastic box to restore, pay attention to the wiring card connectors installed. After the boot, printed out the handwriting is very full.

Fault two: A Canon St Laser printer often appears heating lamp does not light the fault, after the boot only one power supply light, the machine can not work properly.

Repair method: Through the inspection found that the problem is not a fixer, is not a power supply, small relay problems, but the power box next to a small box tube heating a 102J small resistor and circuit board contact is not good, because it is both sides of the circuit board, to both sides of the welding, electric chrome welding after troubleshooting. This fault in the St laser printer is very common, but sometimes the heating lamp is not bright is the power control part of one-way thyristor failure. Fixing the lamp, thermistor, heat protector fault is also more common. If the measurement fuser lamp burned out, the thermistor performance is not good, the heat protector open circuit to replace.

Fault three: A Canon Bxⅱ laser printer's heating lamp sometimes bright, sometimes not bright.

Overhaul method: When the heating lamp is not bright, must use the MULTIMETER Examination 2 Tube's connection line to be broken not, also has 7 thin wires to be broken not, because Bxⅱ and the KT laser printer fixing part and the host connection is active, several wires often disassemble and dismantle easily. If the heating lamp is often not bright, but after a long period of cooling can be used normally, this is the thermistor out of the question. Replace the new thermistor.

Fault four: The output image color is shallow, cannot see the handwriting clearly

A Canon LBP type laser printer, the output image color is shallow, the basic can't see the handwriting clearly. Try to adjust the contrast knob to the maximum file, the output proofs are still unclear, consider the mirror dirty, with alcohol cotton ball will mirror and focus lens wipe clean, the fault is still. Check the transfer electrode wire is normal, did not see abnormal, and the electrode wire clean, the fault has not been ruled out. Check the powder box charging electrode wire, good and normal, check high pressure and high pressure contact also no problem, indicating that the fault is not related to electrode wire.

Further inspection, found that the laser-driven circuit of the sensitive sensor switch of a spring piece fracture, resulting in the printer does not shut down when the failure of the fault. After replacing the new spring slice, troubleshoot.

Failure five: fixing heating is not normal

A Canon laser printer, power-on power indicator light, ready/waiting for the flashing light is extinguished, fixing heaters only shining once also no longer heating, and sometimes the power-on fuser heater does not work at all.

Depending on the symptom, the fuser heater is suspected to be poorly contacted or damaged. Remove the Fuser heater part, use the multimeter resistor to detect both ends of normal, detect thermistor and temperature sensor and protection circuit, no problem found. Check the main control Board interface circuit is also not abnormal.

Further check the heating drive circuit, found that the SCR has problems. After the replacement of the new SCR, the fuser heater work back to normal, troubleshooting.