bizhub 250 gray/black background after cleaning

[stw]

Hello,

I had quality issues with a bizhub 250, printing slightly black areas on each copied page and thus decided to clean the image unit. I therefore disassembled the whole thing - didn't really touch the developing unit, but disassembled and cleaned the whole photo conductor unit.

After I put everything together again and tried a few copies I got the shocking result: The copied page background was nearly all-black. Although the copied text was clear and sharp, it is barely visible due to an greyish-black background. So my cleaning attempt made everything much much worse and I'm now wondering what I did wrong?

Is the photo conductor ruined because it saw too much light or it didn't like the cleaning alcohol?
Is the charge corona somehow electrically bad - contact issue?
Got the cleaning blade somehow damaged by cleaning it with alcohol?
Did I do something wrong when re-assembling everything?
Did I misconfigure something in the service-settings?

I attached an image of how the printed sheets look like now.
53302
as you can see the page is now white at any place, even when printing a completely white page (rightmost page in the picture) there's a lot of greyish-black areas.


If you have an idea what could be wrong please let me know - Thanks a lot!

Best regards,
stw

[tmmdmmm]

To me it looks like the alcohol killed your drum, or at the very least left a haze so its not getting a constant charge. But someone else can chime in, the 250 might be a different theory than the newer ones I know.

[femaster]

Drums don't particularly like alcohol. Generally it won't ruin a drum, but it does change something with the surface. We used to clean the drums on older machines, that were designed to be rebuilt, using 99.9% isopropyl alcohol. You should not use standard rubbing alcohol, which is generally only 65%. After cleaning with alcohol, you would need to "lube" the drum surface by dusting it with either drum powder or clean toner so the cleaning blade would not stick to it. It doesn't hurt to apply a little to the edge of the cleaning blade as well. For a short time after cleaning, it would exhibit slightly strange behavior (some light streaking, shading, and faded areas) for about the first 30 to 50 pages and then level back out to normal. I've never seen one create copies this bad before though, so it's likely there is more than one issue here.

If the drum was out in bright light for more than a minute, or in moderate light for more than 2, it probably has at least some light fatigue now, especially if that is an older worn drum. Drums can recover slightly from this with use, but if the fatigue is bad enough, there is no coming back. Next thought, did you re-lube (prime) the drum with either drum powder or clean toner so that the cleaning blade doesn't stick to it? This is very important if you've cleaned the drum surface with something like alcohol. Also, make sure the charge saw-tooth and grid are completely clean and free of even the smallest cloth fiber, especially the grid. And a final thought, there is a metal grounding tab (See image below) in the drum unit that needs to be placed on the cleaning blade in the unit when reassembling. The tab generally will not end up in the proper location on it's own, you will need to help guide it in place when reassembling.

Beyond that, that's all the advice I have for you at the moment.

53303

[tsbservice]

This is not a drum failure. Will it be drum those areas will move on the pages.
Get back yor steps and find what is wrong or better call a tech.

[stw]

Thank you all for your answers! Especially femaster for the very detailed one.

After reading your answers I'm aware of a few things I did wrong now:

I didn't know that I had to "lube" the cleaning blade with toner powder and thus it probably didn't clean the drum properly. After putting toner powder both on the blade and on the drum the print changed quite a bit (see picture below).
I probably exposed the drum way too long to light, can't exactly tell how long, but it was definitely way more than 1-2 minutes (only light from a fluorescent tube, no sunlight, but I guess that doesn't change a lot), rather something like 20 minutes. I knew it was sensitive to light, but I didn't know that it's that sensitive. And the drum also is quite old (same as the copier itself).
I used a wrong substance for cleaning, it wasn't 99.9% isopropyl alcohol, but some less "pure" one.
I already noted the grounding tab when putting it together the first time, but couldn't remember how it was positioned initially, thus I tried both above and below the cleaning blade, but it didn't really make a difference.
(+ possibly some more I'm not aware about yet?)


This is how the prints look now (white page for reference):
53304
(yes, this is from the same device!)
Still very bad, but the pattern changed quite a bit. One can clearly see a pattern repeating with each turn of the drum. The black parts now are only located at certain parts of the page, seems the cleaning blade is doing it's job properly now and the "lubing" was indeed very important.

Can the remaining issues be explained by a bad drum? Or must there be some other issue? (additionally?)

You mentioned that even the 99.9% alcohol already does change the surface a bit, so I guess there is some better way of cleaning? (compared to what you wrote, not what I did :rolleyes:).

Regarding the grounding tab I wasn't sure how it's supposed to be located, is this correct:
53305
?

In hindsight I shouldn't have done that cleaning attempt, as I surely did more harm than good.

Thanks again for your answers, I already learned quite a lot and looking forward to learn even more from your future answers!

[copyman]

Thank you all for your answers! Especially femaster for the very detailed one.

After reading your answers I'm aware of a few things I did wrong now:

I didn't know that I had to "lube" the cleaning blade with toner powder and thus it probably didn't clean the drum properly. After putting toner powder both on the blade and on the drum the print changed quite a bit (see picture below).
I probably exposed the drum way too long to light, can't exactly tell how long, but it was definitely way more than 1-2 minutes (only light from a fluorescent tube, no sunlight, but I guess that doesn't change a lot), rather something like 20 minutes. I knew it was sensitive to light, but I didn't know that it's that sensitive. And the drum also is quite old (same as the copier itself).
I used a wrong substance for cleaning, it wasn't 99.9% isopropyl alcohol, but some less "pure" one.
I already noted the grounding tab when putting it together the first time, but couldn't remember how it was positioned initially, thus I tried both above and below the cleaning blade, but it didn't really make a difference.
(+ possibly some more I'm not aware about yet?)


This is how the prints look now (white page for reference):
53304
(yes, this is from the same device!)
Still very bad, but the pattern changed quite a bit. One can clearly see a pattern repeating with each turn of the drum. The black parts now are only located at certain parts of the page, seems the cleaning blade is doing it's job properly now and the "lubing" was indeed very important.

Can the remaining issues be explained by a bad drum? Or must there be some other issue? (additionally?)

You mentioned that even the 99.9% alcohol already does change the surface a bit, so I guess there is some better way of cleaning? (compared to what you wrote, not what I did :rolleyes:).

Regarding the grounding tab I wasn't sure how it's supposed to be located, is this correct:
53305
?

In hindsight I shouldn't have done that cleaning attempt, as I surely did more harm than good.

Thanks again for your answers, I already learned quite a lot and looking forward to learn even more from your future answers!

Why not just do it right and get a aftermarket drum, drum cleaning blade & developer for well under $100. Follow the Image unit rebuild instructions and do the dev adjustment in service mode. You will have perfect prints! If you are end user you received some good free info from all the techs that replied. The rest is up to you!

[femaster]

Regarding the grounding tab I wasn't sure how it's supposed to be located, is this correct:
53305
?


The tab should be on top of that. It's still touching it, but I can't say for sure if it would have an affect on what you are seeing. I'm guessing that the drum you are using is just too worn out and the light exposure probably did it in. There may still be other things adding to the quality issues you are seeing, but my advice would be to seek out new parts.

[stw]

Any recommendations (for central europe, Austria) where to get a replacement drum from? I found cheap chinese parts on AliExpress, but not sure at all whether that's a good option? What also makes me wonder is that all those cheap drums are branded as both DR310 / DR411 - so the same replacement for different original models? Those branded as DR310/DR411 also usually don't list the bizhub 250:
example: Mitsubishi OPC Drum For Konica Minolta Di 250 350 251 351 2510 3510 Bizhub 222 282 362 223 283 363 423 OPC Drum DR411 DR310|Printer Parts| - AliExpress (https://aliexpress.com/item/1005003125163874.html)
What's the difference between DR310 and DR411? And would such a drum work in my bizhub 250?

How about quality? I guess chinese ones are quite bad? Is there any way to detect good/bad ones?


Why not just do it right and get a aftermarket drum, drum cleaning blade & developer for well under $100. [...] An original DR310 kit is already nearly $100, the DV310 additional $40 (and badly available) - can you maybe give an example which products to buy?

[femaster]

Any recommendations (for central europe, Austria) where to get a replacement drum from? I found cheap chinese parts on AliExpress, but not sure at all whether that's a good option? What also makes me wonder is that all those cheap drums are branded as both DR310 / DR411 - so the same replacement for different original models? What's the difference between DR310 and DR411? And would such a drum work in my bizhub 250?

While I can't help you with locating parts in your area, I can hopefully help you to understand things a bit better. My knowledge is with the US market, so there may be some discrepancies with the information I provide, as sometimes KM likes to change things up a bit in different markets for some reason...

The DR310 fits the 200/250/350/222/282/362 models, while the DR411 fits the 223/283/363/423 models. Neither will fit in place of the other due to differences in the physical housing of the units. The only real difference between the two units is the housing itself, and a slightly different piece of mylar attached to the charge assembly in the drums. The mylar difference is there because the xx0 and xx2 models use actual incandescent bulbs as erase lamps where as the xx3 series moved over to LEDs. Beyond the housing and mylar differences (and a different angle to the waste toner tube), everything else is identical. The drums, cleaning blades, charge saw-tool and grid, can used in either style drum.

If you can locate a DR411 cheaper than buying a rebuild kit, you can pull the parts out of the DR411 and install them into your DR310. Again, the charge assemblies have different mylars, so you would not be able to swap the whole charge assembly (despite the fact that it will fit), or you will end up with dirty black background similar to what you have now. You would need to just swap the saw-tooth and the grid over to the original charge unit in your DR310.

Just remember, the drums are sensitive to light. Keep the drum covered until the moment you go to install it into the housing. Generally what I do is take 5 or 6 sheets of large paper (11x17 in the US) and lay it out on top of the drum while I'm working to put the unit back together. It's not perfect, but it helps to shade the drum from the light. Avoid bright direct light in your work area if at all possible.

Hopefully this info will help you out.