C451 spoiling Imaging Units

[CKiiza]

Hi Engineers,
I need you to help me understand this so I can give a sufficient solution to my client.

About 4 months ago this Machine started spoiling imaging units. The black IU first had issues with the developer spilling out on prints, then the image started to gray out(fade) along specific areas on the print which appeared to be due to poor charging. The Unit was replaced and the replacement worked well.
then the fading started in Yellow IU and a tech of mine went and solved it(by some miracle according to him.) The client then ran about 600 copies of books of roughly 80-100 pages each and the next thing I knew was that Y,M,C Units were completely spoilt out of the fade effect. They were all replaced and the machine worked well. I've been informed that the Black unit also ended up dead a few days later and was replaced again.
Now the Yellow unit has faded again and I'm suspecting the High Voltage Board though I'm thinking the problem stems from the volume of work this client is doing in a single printing period.
Thanks so much for your help

[Stirton.M]

There have been a rash of bad IUs lately I've noticed...though I doubt this is related to your problem.

However, you may be right about it being an HV bias related issue. There are a few modification here and there to fix the issue. Mostly to do with modifying the lock tabs for each IU. In one case, the modification is semi-permanent, meaning a bracket and screw are put in to lock the tab itself in the closed position. Another modification would be to use a foam or rubber spacer on the tab to push the IU into the machine with a little more force. It does not have to be very thick...just enough to keep the IU from "walking" as it turns, which more often than not can cause the bias problems you described above.

Others here may have more ideas for you.....

[krazeekidz3]

I've been having the same sorts of problems on a C550. This machine is also doing a very high volume. Maybe even more that the machine can handle. I've been sending IU's back to KMBS left and right! The warranty program is very helpful! I'd like to know if anyone has any tips or solutions.
Thanks!!!

[JSC]

I have had a few of these and they have all been down to the IU's not having a very good bias connection, and as Stirton.M has said you can get the mod iu locks, but I have just used a bit of packing to help keep the iu that bit more secure. Has worked well so far

[quickdraw44]

Remember the 7060 b&w, the developer would wear out in half the time if you ran high volume. It like over heated or beat itself to death.
I think I am having the same probem in the in the bizhub C350.

[Stirton.M]

These colour image units have a finite life, depending on the machine model and colour vs black, typically from 30K to 120K...problem is, they are dying earlier than they should and more often than not, it has more to do with developer bias issues than volume. They can go south within days of being replaced.

[Mr Spock]

I have one that is eating yellow units every other week. SSD is telling me to check the connections on the back of the unit and replace the hv1 pwb. Will update when the board comes in. (ordered 10 days ago).

[big jase]

i had same problem as Mr Spock eating up yellow IU , i took of both hv boards and reseted the hv contacts(springs) that make contact with IU's ,and so far machine has been ok for last 3 months

[quickdraw44]

Got it, I will check this out.

Thanks this could help my c350 problem.

[Stirton.M]

I have one that is eating yellow units every other week. SSD is telling me to check the connections on the back of the unit and replace the hv1 pwb. Will update when the board comes in. (ordered 10 days ago).

Depending on which model you are working with, some can be fixed by simple measures. Remove the HV board....that is the hard part...

Resolder all the HV coil points, as well as the wire connects of the board. Cold solder can cause issues here in the same manner.

And in the case of the C350, and I think a few other machines (cannot recall of the top of my head)...that the board is screwed into place with the contacts to the HV connectors at each screw point, the amount of solder making a connection to the tin conductors the board is screwed to is not enough. I physically solder those little "star" type lock washers to the underside of the board to make sure the contact bites into the tin when put back in the machine. This has helped a few times.

[Mr Spock]

Depending on which model you are working with, some can be fixed by simple measures.

This is a c550 or c650 model. HV1 will be here Monday. I changed this out last year at this time (same issue) and did not change anything. SSD had me change the prcb, HV1, clean and check every contact for the iu's, ohm the harness, recheck the connections on the hv1, flash the machine (only one version back at the time). After all this I replaced the transfer belt unit and the iu at the same time. This fixed it for over 8 months. Then the iu needed to be replaced and now it is back again.

[Stirton.M]

Though it likely will not fix your problem, it might help you deal with the short term.....

SledgeHammer.jpg

[jma676]

Between 40 - 90% one or All Color Fading in Main-Scannig direction, each 2 mm, especially with thick paper?

This happens with all these models C250/C252/C351/C450/C451/C550/C650.

In the (C451/C550/C650) the problem seems to come from the transfer belt, I had repeated calls by this problem .. and well as they say here .. everything and was replaced with a good result at first, but eventually reappears.

Personally I found that the Drive Gear (A00J-Gear 25/25T 2282-00) of theTransfer Belt Cleaning unit was vibrating, it can be seen removing the left cover and then remove the metal Left Cover, right there where is the warning of laser units.

and the other as C250/C252/C351/C450/ can be a problem of Transfer Belt Unit or Stabilization Control.

Nothing more, guys!! I've taken my conclucion, you take out theirs.

[inutelkamo]

Re: C451 spoiling Imaging Units

Any update on this?

[Synthohol]

Re: C451 spoiling Imaging Units

Any update on this?

last post was 7 years ago.
may be best to start your own thread.