Issues

• Among the most prominent issues with Canon copiers is when the machine produces either full black or white copies. Most users tend to think that the problem lies with an empty ink or toner. If that were the case, however, then they would still receive copies, but the prints would either have unnecessary lines or blurry images. When the copier produces plain white or all black printouts, the problem has to do with internal parts of the copier.
  
  

Causes

• The causes of the production of black or white printouts can be traced to one of two roots: broken corona wires or faulty circuit boards. If the copier has an erratic circuit board, it not only produces all-black copies, it also has a misplaced light/dark slider that has to be manually adjusted in order to produce quality prints.
  
  

Diagnostics

• You can troubleshoot the problems concerning Canon copiers by doing a quick check to see where the problem lies. If you are experiencing intermittent black printouts, see if the bias lamps turn on during printing. These consist of small lamps at the bottom part of the copier drum, where the transfer corona is. The lamps should be not be lit whenever continuous black copies are produced. Faulty circuit boards, meanwhile, can be diagnosed when you have to slam the top-down cover of the machine in order to produce quality, and not blank prints.
  
  

Repair

• When fixing Canon copier issues involving broken transfer coronas and corona wires, the only solution is to have the problematic parts replaced with new ones, as they can no longer function properly. Meanwhile, you can provide a quick-fix for circuit board problems by adjusting the voltage of the machine by one notch higher. This allows the power to give off greater vibration, in turn allowing the copier to function normally. You may also try to increase the toner wheel bias voltage. Either way, you are essentially giving the machine a better shake in order to function normally.
  
  

Maintenance

• To ensure that your Canon copier runs properly and smoothly at all times, it is best to check it's toner and ink levels regularly. Spills and residue inside the machine can cause the corona wires to get dirty, thus leading to a degrading quality in prints. Also, avoid high impact slamming of the top-down cover so that the copier's circuit board won't be shocked and eventually malfunction.