Oki C831 white streaks / bands through colours

I purchased an OKI C831 earlier this year, second hand. All of the consumables are completely topped up, the life span of all of it at near 100 percent. It's given me some really great prints in the short time I had all four colours topped up. I gave everything a clean and swapped out a magenta toner after about 2 months of it being empty and not printing any full colour pages (only printing B&W), and this problem developed out of nowhere. This issue wasn't present when I bought it, nor is it present on some colours when printing, but when I print something in full colour bands run through the prints and full colour prints often come out incomplete (e.g. first quarter of a page is printed then the rest is blank).

I was told by OKI support to print the individual CMYK colours on different pages, the results of which I'll show here: https://imgur.com/a/oki-c831-issue-cZZOgNs

I was then told to clean the LED heads and their contacts (which I've done) with no success. The problem area is the same on all 4 colours, although some colours as you can see are more problematic.

Is this a case of replacing the LED heads? Or the Fuser? Seems such a shame to do so when the diagnostic says they're okay.

 

Since the problem is in the exact same place regardless of color, I'd consider changing out the transfer belt as seen in this video since it is shared by all colors. It's always a good idea to clean the LED's, but they are unique to each color.

 

It's not the belt. I can say that much. From the pictures, the issue is in the yellow station exclusively. If the sample prints had been just the primary colors (IE 100% Cyan, 100% Magenta etc) I would guarantee you would only see a defect in the yellow print.

My guess is the yellow charging unit. It could be the drum, but drum errors usually run in the print direction. The charger could be the problem or the power supply. It could be a laser; it would be and expensive fix though.
Replace the charger first, then drum (or both if it's an all-in-one type assembly).

I know it says drum 100% , but maybe the drum was exposed to light before install, or was defective

 

Thanks for this detailed response - apologies for not getting back sooner. I had a fuser in the mail before you responded and replacing that that hasn't solved the issue.
This may sound like a silly question, but what is the charger? I'm assuming this isn't the cable? And if so, what model number would that be for the OKI C831? Also I've done some reading on replacing a laser and it is apparently not worth doing at all. This printer has been a nightmare!

 

Just did some research and have seen the 'Charge Rollers' are built into the drums themselves on the 830 model, which I believe is the same - non replaceable. Should I just go for a drum replacement then?

 

I would. It's only in a single color. The belt is shared by all units, so I really don't think it can be the belt. Go for the drum/charger replacement.
Make sure not to expose the drum to light for longer than it would take you to install it.

It may seem like it's happening in all colors, but if you look at the prints you showed, carefully, you'll see that it's only Yellow giving a problem, and of course any color build that contains yellow.

 

The charge roller (sometimes it's a stationary unit with a charge/corona wire) applies a blanket charge to the drum cylinder. The laser with then discharge (or reverse charge) your image area.
If the charger is failing, or the drum has been desensitized or exposed in some way, you'll either have a massive void in the print, or a huge mass of toner in the area. Depending on how the item has failed.

 

Hi guys. I think this issue to do with PCR rollers that are built in to Drums. Most likely they are dirty/contaminated where image flaws are seen. Unfortunately, I do not think those can be removed and cleaned without destroying body of the Image Drum Unit. Printout the life counter page, see if these are on the last leg, just replace them I guess.
I've seen a very similar image flaws - on one side only like that at customers who print lots envelopes , because logo/return address is on one side only...
On larger Printers/Copiers where Drum can be disassembled similar issue could be resolved by cleaning PCR rollers and installing them back, not the case here.