KM-2550

[banginbishop]

This problem has been discussed before and i even contributed to it but the fault has come back.

I cleaned the optics with solvent (not glass cleaner) to leave a streak free and oil free finish. The problem is a llittle bit different from before in that their was no visible mark on the optics this time (blue haze previous call 1 month ago - giving faded white stripe).

I've checked the optics section and their are no air vents - i presume as the lamp is xenon so it doesn't get as hot like the old type anologues and no filters either.

The mark has reapeared in same position as before (see attachment) not to the side just the middle section.

Its not the ccd or lamp causing the blured/dark image. i'm looking at why it's getting the optics dirty in one place only and whats causing it.

I can try other cleaners but again why does it only give a fault in this one section on the mirrors and not the sides?

The machine has done about 40K.

is the pcb lamp converter causing the problem? - don't know but its the only item in that area.

[blackcat4866]

The 'Blue Haze'

When we would get the 'blue haze' on the Mita analogs, after cleaning the optics with some strong solvent we would take black tape and cover all the unused screw holes in the lower part of the optical cavity, especially over the fuser area.

The theory at the time was that fuser oil vapor was entering the optical cavity and condensing on the cool surfaces of the mirrors. This also fits with your observations that the mirrors always seem to become contaminated in the same areas (nearest the openings in the optical cavity).

The last thing that we used to do is clean the filters for the optical fan (most had squirrel cage fans, that would occasionally seize). As you mentioned, this last part is probably not pertinent since most modern scanners use Xenon or Fluorescent lamps which do not require any cooling (in fact, they require a little heat to start quick enough).

To take this a step further, I believe that ozone may also contaminate the optics. If the other fans & filters are not functioning properly, the ozone is not being cleared from the machine, and finding its way into the optical cavity.

I don't know if this helps you any. What we did on those old Mita analogs did extend the time significantly until the mirrors had to be de-greased again. Let us know how it goes. =^..^=

[banginbishop]

ozone

Hi blackcat,

Thanks for the reply. I've checked the parts manual and searched in case i missed an ozone/filter but the only ozone is on the back of the machine and i still can't see any fans etc in the optics/scanner section.

The only fans i can see are at the rear and side but they look like they push air into the machine near the middle/lower section and it looks like their are normal filters under the scanner section.

I'll take a look when i'm back in their again which might not be to long as its running with non oe toner which is causing fuser problems - i'll leave that issue for another time!