C451 black drum replacement

[earendil]

Hi,

I am not technician, but the guys I have bought 2 machines from refuse to further maintain them, so I thought to try and replace the drum and cleaning blade of the black imaging unit.
I am technically vers, but I would had gladly paid for this job. Problem is, they have just sold me a whole machine for spare parts which did the job, but now when I need imaging units refurbishment, they are saying.. better have a new machine.. we have some newer machines in stock.. these black units might not last a day after refurbishment.. etc.

Firstly I tried it on a leaking black unit, just to see what's what. Then I changed the parts of a unit which was doing very very faint prints, but was not leaking..

I did so watching YT videos, but now all the print jobs look like the attachment.

Any advice to what I might have missed or assembled wrong? What should I check or just disassemble and assemble the whole thing again.

thx

[Synthohol]

September 2017 that model is end of life and no longer supported.
If you can get a NEW IU I'd go for it as rebuilding an old dinosaur can be troubling and likely futile.
See if there is a new one available. It's probably your only hope

[sendpiks]

Its looks like you missed spring that press cleaning blade to the drum, or put cleaning blade with the skew so it not press drum firmly.
After this issue the only way is completely disassemble unit and vacuum it and replace developer, and this WILL NOT guarantee that it will work good, this type of problem is very hard to repair. Much easier will be to buy new unit on eBay it will cost about $100 for a new one as this model is out of production about a decade ago.
I have three BH451 in my business and still use it and reanimate units many times.




Hi,

Any advice to what I might have missed or assembled wrong? What should I check or just disassemble and assemble the whole thing again.

thx

[femaster]

I would not recommend doing any type of refurbishing on a C451 black image unit. These do not last beyond about 300K and are famous for dumping developer out the back end, all over inside the copier, down onto the laser unit, and down into the feed units. If this happens, you may as well junk that whole copier. The odds of getting everything cleaned up properly, or even getting those feed units to ever feed again without jamming is nearly impossible without replacing clutches, one-way bearings, etc.

My advice: Just Don't Do It! Locate a NEW image unit if possible...

[copyman]

There was a bulletin with modification for a bracket to hold the drum/dev unit in tighter for better connection. With loose connection it would cause developer to leak & light prints.

[earendil]

Its looks like you missed spring that press cleaning blade to the drum, or put cleaning blade with the skew so it not press drum firmly.
After this issue the only way is completely disassemble unit and vacuum it and replace developer, and this WILL NOT guarantee that it will work good, this type of problem is very hard to repair. Much easier will be to buy new unit on eBay it will cost about $100 for a new one as this model is out of production about a decade ago.
I have three BH451 in my business and still use it and reanimate units many times.

The spring is there and the screws of the cleaning blades are such, that cannot be tightened so that it moves.. that much I figured during assembly.

I have one more black unit with leaking toner and light prints.. so as a light resort I will try to make one of the two.. if not, I will throw out both machines..
Any guide available of what to take care of? Or this is futile ..

How should a good developer roller look like when turning?

[sendpiks]

light print in most cases is just dusted corona mesh. Just take off drum and clean mesh with brush and spray duster air cleaner.
Leaking toner in most cases mean incorrect or chinese toner used, also leaking toner can dirty corona mesh. I recommend NEVER use chinese toners, better refill with genuine toners from production printers like TN615 or so it cost the same but much better.
In your case I think that good idea to try to reanimate first unit before work with second one. I think if you can try to disassemble it, vacuum clean corona mesh and rubbish collector and assemble it back. Before put in copier put some toner on drum and rotate it to be sure that toner cleared.

Good developer drum when developer fur without visible spots or lines, everything else is good


The spring is there and the screws of the cleaning blades are such, that cannot be tightened so that it moves.. that much I figured during assembly.

I have one more black unit with leaking toner and light prints.. so as a light resort I will try to make one of the two.. if not, I will throw out both machines..
Any guide available of what to take care of? Or this is futile ..

How should a good developer roller look like when turning?

[femaster]

There was a bulletin with modification for a bracket to hold the drum/dev unit in tighter for better connection. With loose connection it would cause developer to leak & light prints.

I remember that bulletin. All of ours had the meal bracket on the front to hold the unit in securely, but even with that, right around the 300K mark they'd start leaking developer. That series was one of the only ones where we followed the recommended replacement interval, for the black image unit at least. If that leaked enough, it was a nightmare.

[earendil]

light print in most cases is just dusted corona mesh. Just take off drum and clean mesh with brush and spray duster air cleaner.
Leaking toner in most cases mean incorrect or chinese toner used, also leaking toner can dirty corona mesh. I recommend NEVER use chinese toners, better refill with genuine toners from production printers like TN615 or so it cost the same but much better.
In your case I think that good idea to try to reanimate first unit before work with second one. I think if you can try to disassemble it, vacuum clean corona mesh and rubbish collector and assemble it back. Before put in copier put some toner on drum and rotate it to be sure that toner cleared.

Good developer drum when developer fur without visible spots or lines, everything else is good

I think it is either the contacts with the charge roller / OPC drum .. might have not inserted them in the correct place.. (there was no image at all.. see attached pic in OP) or the developer drum...
For the latter I do not exactly know what is considered a good fur at the developer roll.. when turned against the imaging drum (I guess it should be turning against it?) it looks like the attached .. and briefly when changing direction it is a lot of "fur"

Otherwise the imaging drum is very clean when turned (new blade), so I think spring and mesh (i'd cleaned it at the first rebuild) are ok.

Should there be a measurable by multimeter contact between edge of OPC drum and one of the contacts of the unit?

[earendil]

OK,

I think it was the contacts.. just opened and closed and now it's printing.
Just a bit fainter top side. Attached.

Maybe this is due to something dirty from the bad prints from before or is it still the black unit? OPC and blade is now brand new.
What should I look at?

[copier tech]

You’ve just reminded me how awful the C451 was. Even a new PCDU would & did dump developer. But you maybe able to pick up a cheap C451 PCDU, try eBay.

[sendpiks]

its look like toner and developer leaked from drum and your laser glass is dirty now. Look inside copier and possible you will find pile of toner at far end.
Anyway its good time to clean laser glass


OK,

I think it was the contacts.. just opened and closed and now it's printing.
Just a bit fainter top side. Attached.

Maybe this is due to something dirty from the bad prints from before or is it still the black unit? OPC and blade is now brand new.
What should I look at?

[earendil]

You’ve just reminded me how awful the C451 was. Even a new PCDU would & did dump developer. But you maybe able to pick up a cheap C451 PCDU, try eBay.

In my part of the world there is no cheap PCDU. Min price I can find is about 300 - 600 USD which is not worth it..

Now the machine is back to normal .. hope it lasts another 6 months or so :)

Thank you all for the help