i had a machine giving a light strip about 1 inch wide in the middle of a4 paper .ok printing ,ok on glass,just through adf .after trying everything else i moved the two springs on the pinch rollers on the top (black )cover to the middle position and it fixed the problem .thought this might help someone else.

I had an issue with a dp-410 on a cs-1650, changed out the laser unit, cleaned the optics, put everything back together, and fead through the adf to check things out. all dark copies with just bearly seeing the print. scanned off glass, internal prints okay. it was not doing it before I dismantled machine. tracked my steps and found that when i cleaned the optics, i wiggled either the mirrors, or the ribbon cable to the scanner lamp. If i had a dime for everytime i cleaned the optics on these machines i could retire. WEIRD ! to sum it up - be carefull when cleaning the optics on some of these models.

We had this problem late last week and it was a buildup of something on the underside of the slit glass and on the mirrors below. Cleaned it and all is good. Not sure what it was.

Problem has re-occured. Kyocera recommended filter for right side air vent. See how it goes.

Terry, Lower the temps of the fuser by about 10 degrees and replace the feed shift pulleys on the left side door, they are probably all deteriorating and turning to a chalky powder. We have had this problem on the 2050s also and this seems to fix it.

Have had this fault on multiple machines.
It is a area on the mirrors getting fogged from what I believe is steam rising up off the fuser into the optics through the cutout in the frame.

We now cover the cutout in the frame on the left side in centre. Seems to have resolved it.

That's not "Fog" it's the material that the white feed shift pulleys are made from. They deteriorate, essentially they cook from the fuser heat, then the fumes carry up into the optics area from natural convection and then they condesate out on the center of the underside of the slit glass and sometimes on the mirrors. Replace these shift pulleys and lowering the fuser temps by around 10 degrees does wonders. Most customers we have with these machines have complained that the copies come out too hot anyways so lowering the temp appeases them also.

Great, now if we could figure out why Muratecs do the same thing, the fuser is way over on the other side of the machine, and yet, the underside of the slit glass and platen glass are constantly blue with fog/haze!