BH-C-284e, missing Cyan developer

[Hansoon]

Got from a wholesaler, a very good-looking BH-C-284e with a total of only 70K from which is around 40K mono and 30K color. All is good except cyan development. The developing unit is obviously missing developer. White spots and a screw like pattern on the test prints. Also is the mag roller clearly showing empty spots without developer on it. According to the weight compared with the other color units, it's missing around 100gr. So I added 100gr neutral developer and started the toner add function in the service mode. After around 8 minutes, the adding stopped and the test prints became than very good.

My question: Is it likely that the machine has a problem, as often mentioned before here in the panel about issues with missing Cyan developer and the HV unit and/or other items, or could it be that the previous service company grabbed a good unit replacing it with a bad one?

Another indication could be that all developing units are showing an almost clear air suction window on top, but that window of the cyan developing unit is completely clogged with cyan toner from front to rear.

Any reason to worry or take action? Any ideas please?

Hans

[Synthohol]

probably a good time to change the 4 caps. #18 they were notorious for draining a DV unit.
is the WTB full of DV?

https://www.copytechnet.com/forums/attachments/konica-minolta/56308d1659758106-bh-c-284e-missing-cyan-developer-cap-jpg

[Hansoon]

Thanks Synth, WTB was unfortunately missing completely. Likely because of the transportation.

Are those the bushings locking up the subhopper? With less than 30K color already?

Hans

[Synthohol]

as it is augered the cap seal leaks internally and allows DV to bypass the unit and dump in the WTB.
its the stupidest thing but after doing dozens of them i dont question why they work, they just do :)
have a read...

[copyman]

Got from a wholesaler, a very good-looking BH-C-284e with a total of only 70K from which is around 40K mono and 30K color. All is good except cyan development. The developing unit is obviously missing developer. White spots and a screw like pattern on the test prints. Also is the mag roller clearly showing empty spots without developer on it. According to the weight compared with the other color units, it's missing around 100gr. So I added 100gr neutral developer and started the toner add function in the service mode. After around 8 minutes, the adding stopped and the test prints became than very good.

My question: Is it likely that the machine has a problem, as often mentioned before here in the panel about issues with missing Cyan developer and the HV unit and/or other items, or could it be that the previous service company grabbed a good unit replacing it with a bad one?

Another indication could be that all developing units are showing an almost clear air suction window on top, but that window of the cyan developing unit is completely clogged with cyan toner from front to rear.

Any reason to worry or take action? Any ideas please?

Hans

I've had the dev dump many times in the "4" series and have never replaced seals (but good to know). Mostly the cyan dumps. I always added aftermarket cyan developer, changed any over life drums, transfer belt. Made sure levels were good in state confirmation and machines ran fine moving forward. Rarely a call back. If no drums over life I still replaced the cyan drum or drum for what ever dev dumped. Once in awhile I will get a different color that dumps developer but like I posted mostly cyan than black. More rare for magenta & yellow to dump.

[Markks]

Got from a wholesaler, a very good-looking BH-C-284e with a total of only 70K from which is around 40K mono and 30K color. All is good except cyan development. The developing unit is obviously missing developer. White spots and a screw like pattern on the test prints. Also is the mag roller clearly showing empty spots without developer on it. According to the weight compared with the other color units, it's missing around 100gr. So I added 100gr neutral developer and started the toner add function in the service mode. After around 8 minutes, the adding stopped and the test prints became than very good.

My question: Is it likely that the machine has a problem, as often mentioned before here in the panel about issues with missing Cyan developer and the HV unit and/or other items, or could it be that the previous service company grabbed a good unit replacing it with a bad one?

Another indication could be that all developing units are showing an almost clear air suction window on top, but that window of the cyan developing unit is completely clogged with cyan toner from front to rear.

Any reason to worry or take action? Any ideas please?

Hans

see attached bulletins . there is a jig you can get to clean out air duct assembly

[tsbservice]

see attached bulletins . there is a jig you can get to clean out air duct assembly

Unfortunately this jig won't work on low speed 4/4e series machines with ozone filter only.
This is due to lack of toner filter which is big and it's where jig is used.
Also in service manual air paths and fans are different between low high speed machines, don't ask me how I know.
Hans I will remove all devs and drums and clean
from front side air ducts. Then drop cyan tcr by 2 maybe change cyan drum as copyman said and eventually call it a day :)

[REGSIS]

as it is augered the cap seal leaks internally and allows DV to bypass the unit and dump in the WTB.
its the stupidest thing but after doing dozens of them i dont question why they work, they just do :)
have a read...

This bushing is responsible for abnormal low toner density messages C2555, C2557....
There is no way it can cause lack of developer because mixture of toner and developer is supplied together into developing unit.

I don't have the "whole picture" why it's happening but i've noticed that replacing ozone filter really helps.
Also I clean dev unit, vacuum its ventilation ports (ports on backside of the machine are usually clean).
Set TCR C to -1 (6%) (in extreme cases to -2 (5.5%)) but this should only apply to users with low coverage <4%.
For graphic designers with high coverage 8% or more don't lower TCR (leave it on 0).

For all machines replace ozone filter every 150k or 2 years (whichever comes first) and keep cyan drum and dev unit clean at regular PM every 25k. Clean IDC sensors every time + perform stabilization afterwards.
Works for me.

[Hansoon]

Very valuable advice from all of you guys. Many thanks for your efforts.

Still wondering why this could happen to a machine with very low meters.....

Hans

[tsbservice]

Very valuable advice from all of you guys. Many thanks for your efforts.

Still wondering why this could happen to a machine with very low meters.....

Hans

I think one of problems is printing with very low coverage... developer isn't refreshed then from toner.

[copyman]

Very valuable advice from all of you guys. Many thanks for your efforts.

Still wondering why this could happen to a machine with very low meters.....

Hans

Time takes a toll on consumables. Let's not forget the "4e" series is now 10 yrs old. And of course the environment where copier is used has a lot to do with it.

As for 99% of the time being the cyan developer that dumps even Kon/Min doesn't know why it's mostly that color.

[Synthohol]

This bushing is responsible for abnormal low toner density messages C2555, C2557....
There is no way it can cause lack of developer because mixture of toner and developer is supplied together into developing unit.


there is a natural loss of developer during use which is why the toner has developer in it to replenish but when the seal leaks all the replenishing DV is lost as well as it dumps into the WTB and the DV unit gets stripped of all the carrier and leaves the diagonal pattern on the pages.

i didnt mean to suggest it sucks it out of the DV unit itself although thats the result really.

[tsbservice]

I would say I'm agree with REGSIS on this one. White caps/bushings are in front of toner hopper and when fail prevent toner being supplied into developer unit. Then developer unit will loose gradually toner in it together with small quantity of developer of course during printing but there is no way lost developer to be that much to cause diagonal pattern and voids. I see few times machines with TCR 0% and they would eventually code but never had lost significant amount of developer powder.

[Synthohol]

the one experience that stands out is a school we placed like 30 machines and within the first month half got the diagonal pattern from the DV being stripped and not adequately replenishing because it was filling up the WTB. we would replCE THE dv unit but it happens again within 1000 pages or c255x which ever came first.
once the caps were replaced it rarely happened again.
i think those caps initially were a FOC part because they failed in the 1st year.
its very very rare that i see a 4 series that needs these anymore but after that hell week at the school and many many drums and DV units those caps saved the day (and the account)

could also be an arc'd out HV plate too as in the pics in the doc.

its not like the days of starter when toner was just toner but now because of the technology the plastic toner will adhere to the DV powder and get lost/used faster than its supplied sometimes especially with low usage machines according to the bulletin.

[copyman]

the one experience that stands out is a school we placed like 30 machines and within the first month half got the diagonal pattern from the DV being stripped and not adequately replenishing because it was filling up the WTB. we would replCE THE dv unit but it happens again within 1000 pages or c255x which ever came first.
once the caps were replaced it rarely happened again.
i think those caps initially were a FOC part because they failed in the 1st year.
its very very rare that i see a 4 series that needs these anymore but after that hell week at the school and many many drums and DV units those caps saved the day (and the account)

could also be an arc'd out HV plate too as in the pics in the doc.

its not like the days of starter when toner was just toner but now because of the technology the plastic toner will adhere to the DV powder and get lost/used faster than its supplied sometimes especially with low usage machines according to the bulletin.

Some good points and info. Just curious with those machines in the school, was it mostly the cyan that dumped? Do you have an opinion on why mostly cyan dumps?

Agree about the developer being mixed with toner and developer not just being a "carrier" anymore. I would think the developer mixed in with the toner is to maintain print quality having fresh developer all the time.