View Full Version : Miscellaneous Has anyone ever run into a laser scanner unit that works, but has a weak laser?

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09-29-2016, 07:24 PM
The drum of this copier has too light of toner density (nothing to do with scanned page). The drum is good and getting a good supply of toner. The high voltage is good and have good continuity from HVPS to drum unit. I have cleaned the mirrors and lenses in the laser scanner unit and they were not dirty so thinking that maybe it is just a weak laser. Anyone have any thoughts on this idea?

09-29-2016, 07:33 PM
And what's the make and model you talking about.

Check if the machine has a eco [ toner save ]mode function and if it is turned on.

09-29-2016, 08:19 PM
Xerox WorkCentre 4260 and no econo or saver mode found. I have checked HVPS it is good. Have cleaned the LSU mirrors, lenses, & window but the density of toner attracted to the drum is gray, not black and the drum is good:). I have not got great response on the Xerox thread so I am trying to get more of a theory based answer on where to check next.

09-30-2016, 01:41 AM
I don't know this machine, but i will reply with a theory you are seeking. Dev and drum unit don't last forever. They are rated for a number of prints listed on the service manual ect. The dev could be just plain worn out, the drum life has gone past its time. Another factor could be toner. What type of toner, is it oem or other. I would check on those first before looking at hv boards ect. Also the bias settings, did anyone mess with them. All these could be a factor. the last one may be the most unlikely.

10-03-2016, 01:36 AM
I didn't work on Xerox equipment that long, and I've never seen that model, so take this for what it is worth.
Still, on most of the digital machines I've ever worked on, there's a sensor in the drum cavity that tells the machine about the condition of the drum, and the machine uses the output of that sensor to compensate for the wear on the photoconductive drum coating for a while. There's a chance that sensor has become contaminated with toner or dust, which would make the prints light. If you can find that sensor, clean it.
There's a slight chance the polygon mirror in the laser unit is contaminated, but I'd need to see a picture of the print defect that machine is producing before I'd ever recommend doing something about that, it would be too easy to wreck that thing if I was wrong about that.
Sorry if this was a stupid waste of time.

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