LED prints get progressively darker

[Alan]

I picked up an old LED printer, an Oki OL400e. It's a small desktop
printer that emulates a HPLJII.

When it first prints, the first 5 or so pages are fine. Then the pages
get dirtier -- grey banding which spread till after about 20 pages the
background is almost as dark as the text.

If I turn it off for a while, the print quality is fine again, but
only for the first few pages, So effectively I have a10 page per hour
printer.

I've thought it might be overheating, but the fan seems to be working,
it's pretty noisy when printing anyway.

The consumables come in two parts, a toner container, which is very
cheap, and a drum etc which is very expensive -- 10 times what I paid
for the printer, and almost enough to buy a decent new laser. So I'm
not about to try replacing the drum.

Any ideas or solutions?

For those interested, the service manual is at
<http://www.eoeminolta.com/downloads/Okidata/Service Manuals/OL Led Page Printers/OL 400-410/>

 

[SleeperMan]

I picked up an old LED printer, an Oki OL400e. It's a small desktop
printer that emulates a HPLJII.

When it first prints, the first 5 or so pages are fine. Then the pages
get dirtier -- grey banding which spread till after about 20 pages the
background is almost as dark as the text.

If I turn it off for a while, the print quality is fine again, but
only for the first few pages, So effectively I have a10 page per hour
printer.

I've thought it might be overheating, but the fan seems to be working,
it's pretty noisy when printing anyway.

The consumables come in two parts, a toner container, which is very
cheap, and a drum etc which is very expensive -- 10 times what I paid
for the printer, and almost enough to buy a decent new laser. So I'm
not about to try replacing the drum.

Any ideas or solutions?

For those interested, the service manual is at

<http://www.eoeminolta.com/downloads/Okidata/Service Manuals/OL Led Pa
ge%20Printers/OL%20400-410/>

It looks like thermostate has failed and it keeps heating. It should stop at
certain point - i think it's about 190 or 200 degrees. Fan may be working,
but if heater isn't turned off, it won't help. Check out if you can see any
light inside (that's heater) and if it turns off at any point. I can see
heater in my Panasonic, so i see when it turns on and off. If it doesn't,
than this is it and means you print a few pages, turn it off quickly for 15
min. etc...
If you are electronic hobbyist, you can TRY to repare, otherwise...