3051ci PCR gap/pits

[dolomike]

So I have a Taskalfa 3051ci with just under 100k total prints on it and it has issues with a repeating black "blob" on it. I measured it out and compared against the defect gauge and turns out it's the PCR. I confirmed by swapping it with the yellow PCR so time to change it out. There was a spare PCR in the drawer so I took it out, it looked fine, was clearly unused so I replaced the yellow PCR.

First color test print, another blob, which got slightly larger with each page until it settled at it's final size. See the "PCR-Change" attachment. When I removed the PCR, it clearly has a gap/pit or whatever you want to call it - see the "PCR-Gap" attachment.

Is this just caused by crappy Chinese PCR's, or is there something else going on here? I don't know where the spare PCR came from so I can't say for sure if it is OEM or not. I also can't see anything in the developer or drum unit that would cause any mechanical damage but I'm going take them out and do a full clean just to make sure.

Most of what I've been able to find here refers to "bumps" and potential arcing to the drum with these PCR's, but not so much about the pits. I may cut open the old PCR and see if there is anything under the surface that might allude to the source. I do need to run U930/U464/U410 but I'll wait for proper replacements.

Anyone have any insight on this?

[Ropariva]

Common issue across many platforms for years. Bulletins blame the defects on rust coming from the shaft. Seems they have now fixed the issue with new production as I haven’t had to change a main charge roller for some time now.
I’ve seen old stock come out of the box with pits, so make sure you get ones that were manufactured recently.

[blackcat4866]

Years back I did an autopsy on one of these charge rollers. Sorry, I can't find the photos. The metal core had rusted, and from the inside the outer rubber portion had burned, and collapsed inwards. Kyocera came out with an updated roller that works better. You can see both the older type (lower), and the newer type (upper). This issue can be seen across the entire spectrum of Kyocera products.

I'll keep looking for the photos.

IMG_1385.jpg MC-8720.jpg

EDIT: I found an old post with a photo of the charge roller autopsy. See how it's burned?

Spots-Lumps.jpg

[dolomike]

I did a quick autopsy on the original one I had that was causing the black blobs on the print. I don't have a proper camera for my scope but I think the pictures speak for themselves - it's an oldy! I suspect the replacement PCR I put in has the same issue and just old stock.

Hopefully the replacements are the newer manufactured ones.

Pit on the surface of the roller:
20250514_130904.jpg


Shaft side of the roller under the pit:
20250514_130956.jpg

Surface of shaft after removing lumps of rubber and shaft corrosion:
20250514_131527.jpg

Shaft plating completely destroyed by corrosion. Shaft pitted and lumpy:
20250514_131708.jpg

[blackcat4866]

Very nice. You went several steps further than I did. The explanation that I heard was that the shaft had not been adequately cleaned before plating, then making the rubber coating. Those places start arcing first.