Maintaining laser printer optical path
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by: fredwherhouser23
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Word Count: 471
Date: Mon, 14 Feb 2011 Time: 12:29 PM
Within my personal Las Vegas Copier Servicing repair experience filthy optics has been the they most frequent failure in older laser printers with Canon machines. Be careful mainly because the optics are delicate and very easily damaged. Use an air bulb to blow off any loose dust or toner. And then use rubbing alcohol and a cotton swab or lens tissue to clean the exposed surfaces. DO NOT disassemble any optics elements since the alignment may be crucial.
Hence it's a good idea to clean the entire optical path from the laser diode and forward. Most of this is inside of the scanner module and there may also be a long external reflector. With time these surfaces become covered with a film of toner or dirt and the laser beam reaching the drum gets weaker and diffused. Print quality suffers and scanner failure errors will occur, which may be intermittent at first, but gradually they will shut the printer down totally.
So open up the scanner module and softly clean all the prisms, mirrors and lenses. I say gently because the mirrors are front coated and the lenses may be plastic which can be scratched by aggressive cleaning with cotton swabs. Clean the external mirror if there is one. There is also a beam detection sensor which in turn will have it's own small lens or prism which must be cleansed. Good luck.
Fuser rollers can also develop a band of baked-on toner which is tricky to remove because it is harder than the fuser's PTFE coating. I have developed a cleaning method which has worked well for me so far. First, wipe the roller with a swab or soft cloth and a few drops of isopropyl alcohol.
Following, stick a piece of packing tape onto the roller where the toner has adhered and rub it so that it sticks well. Ultimately, pull off the tape in the direction of a tangent line to the curve of the roller so it 'snaps' off rather than peeling it off. It may require a few tries, but the toner should come off in large pieces. A blast of cold spray can help with determined deposits. It isn't important to remove the roller from the fuser with this method--just work in small sections and turn the roller a bit more each time.
With extended exposure in toner cartridges long term direct exposure to light will influence the photoconductive layer. We even cover areas of some scratched after-market drums and uncovered them to sunlight to see how it effected them. It takes extended exposure to show an effect. The printer will not detect the trouble and the printer will probably print dark for the basic constructive image laser printer.
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