MPC 6500 7500 Blowing toner

[msaeger]

Today it had 55k they were getting a inch wide band of yellow from front to rear. I pulled out the yellow PCU and the charge roller cleaning roller was totally yellow like way more than normal. There looked to be some lines of some kind on the charge roller. I didn't pull apart the PCU and stuck it back into the machine and they made 300 copies with no issue. I have a feeling I am going to need to rebuild the PCUs but today I had too many calls to mess with i t so since it was working at the moment I just left it.

[Shadow1]

Well, S***
Let me know what you find when you pull it down. I guess I can still hope it was a fluke, but I was hoping for 100k or better.
What mods were in this machine? Obviously the lower drum blade removed, but the Lube Bar springs? The drive cam on the developer waste auger?

[msaeger]

Only the one mod was done this machine never had toner blowing all over.

[Polo-022]

What about Dusty's post, two weeks ago, about the wasted developer drive cams ??
He had to put them again to avoid dev. overflow, toner spillage, etc..
I am reading and following this experiment and i have some questions for the leaders...

[msaeger]

What about Dusty's post, two weeks ago, about the wasted developer drive cams ??
He had to put them again to avoid dev. overflow, toner spillage, etc..
I am reading and following this experiment and i have some questions for the leaders...

I only removed the one cleaning blade on this machine with no other mods. They didn't call me today but this is the kind of place where they will wait until I am there for something else to let me know there is a problem.

I really think these things are affected by low humidity. I was getting tons of calls for charge roller lines in the winter now they have all stopped.

[Shadow1]

I only removed the one cleaning blade on this machine with no other mods. They didn't call me today but this is the kind of place where they will wait until I am there for something else to let me know there is a problem.

I really think these things are affected by low humidity. I was getting tons of calls for charge roller lines in the winter now they have all stopped.

I think its a combination of things, and we're going to have to nail more than one to see any real improvement.

What about Dusty's post, two weeks ago, about the wasted developer drive cams ??
He had to put them again to avoid dev. overflow, toner spillage, etc..
I am reading and following this experiment and i have some questions for the leaders...

Fire away...

[msaeger]

Today they got the yellow blob again so I put the 150K pm kit in there it has been 60K prints.

When I took apart the PCUs and removed the upper cleaning blade holder there was a pile of toner on top of the cover over the lube bar. The charge rollers looked about like normal but the yellow one had the cleaning roller totally saturated with toner way more than normal. The charge rollers had some likes on them but I was not getting the charge roller lines on the copies yet. Not sure what the blob was coming from it was one, one inch wide band on a letter LEF from front to back and was not on every copy. I am guessing it was drum cleaning due to all the toner under the upper blade. No other colors were having a problem maybe I could have just fixed the yellow but I didn't wanna take the chance. I will try it stock now and see how long it goes with the current weather conditions.

Gotta come up with another way to keep that lube stuff off the charge roller.

Didn't think to take a sample and I didn't have a camera so I can only describe in words.

[Shadow1]

New solution for the undertoning problem. I've been having good luck taking the cam off of the overflow developer auger, provided I only modify machines that have a severe problem, and only the colors that are bad. Some people have modified machines that were ok, and have started having overfull developers bind up.

Instead of removing drive completely from the auger, I started modifying the auger by removing most of the coils from the center shaft except for the very end that sits in the overflow tube, and maybe 1 turn visible inside the developer cavity.

I didn't have a camera so I'll try to draw it in text:

The original auger looked something like:

==XNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN>

with the drive cam riding on the == part.
Cutting the coils makes it look something like:

==X---------------------------------------------NNNNNNN>

Put the cam back on and now you're only transporting developer down the tube, and not collecting it along the entire length of the developer assy.
Note, it takes a really strong set of dikes to cut the coil

I still need to modify a machine with cut augers, lower tension lube bar springs, remove the lower drum blade, and use the D082 charge assy at the same time, and see how far one of these beasts runs.

[Dusty]

I haven't got one of these dev units around where I can verify this, but I think the way the waste auger is laid out only the front inch or two of that auger is even exposed to developer - the dev unit cover boxes in almost all of it.

[Shadow1]

There's a fairly high wall around it, but developer can still spill in, and there's "vents" cut into the wall all down the length

[serpico]

Hello,
Try to change SP 2-905-1 (3 to 1) and SP 2-905-2 (2 to 10)
This is to reduce toner pressure inside the dev. station. A tech have very good results about toner scattering after 1 month. (Copier clean)

[coj24]

Re: MPC 6500 7500 Blowing toner

...none of which address the issue most of us are seeing in the field at normal temp and humidity. Light copies, depleted developer, and not just toner scattering (as in a light dusting) but toner being projectile vomited out of the developer unit onto the ITB.

And I think I can explain how it happens - This is TSB_D014_Shandow1_001:

Cause: Under certain humidity conditions, run lengths, and image coverage conditions the static charges created inside the developer material will cause the mixture to "fluff up" and spill excessively into the overflow, thus depleting the developer material. Same principal as opening a box shipped in the winter time, and all the plastic packing peanuts jumping out at you.

Once this condition ends (i.e. end of the run, somebody opens an outside office door, building's heater turns off, etc.) the normal process control will detect light images caused by the insufficient developer and add extra toner to compensate. Since this mixture is only 10% developer the mixture becomes somewhat "richer" with toner - which makes it even more likely to "fluff" the next time the process repeats. If enough toner is consumed and replenished the balance will be restored, and no noticeable problems occur, however, if the conditions that allow excessive developer spillage occur frequently enough the remaining developer is no longer capable of transporting the toner mixture and the machine begins dumping on the ITB.

Solution: Remove the one-way bearing and lever from the overflow auger on machines exhibiting this problem. Vibration and stirring of developer seem to be sufficient to transport excess developer to waste on modified machines.

Alternative solution: Occasionaly lower or remove bias from the developer assembly to "pack" the toner.

...Even if I'm wrong about why this is happening, I know from experience the solution works.

Note: this is not likely to be acknowledged by the engineers because of Not-Invented-Here-Syndrome. NIHS seems to be rampant among engineer types and the only know cure - working on your own product as a field tech for a few days - has been dismissed as quackery by those infected (this behavior has been noted as one of the major symptoms of NIHS)

Hi, wonder if you could clarify the location of the bearing and lever you mentioned to remove. This is becoming more prevalent in our area.

[iany]

Re: MPC 6500 7500 Blowing toner

Hi, wonder if you could clarify the location of the bearing and lever you mentioned to remove. This is becoming more prevalent in our area.

HI cOJ 24,

We have a few of theses beasts doing the same, with sometimes so much toner floating about it is all over the transfer belt, usually its cyan or magenta. Like you we have done almost everything and sometimes, in the worst cases, after fully cleaning out the machine the problem comes back in only a few k copies. The Ricoh rep has said that this is a known problem and they are trying hard to get to the bottom of it ( i hope they do soon).
Interestingly though I got in my inbox this morning a" re-issued " tech bulletin that relates to this problem. So suggest you check it out. It is Ricoh Tech Bulletin Number RD081049c. Hope it helps. WE are going to try it on our own machines.........Here's hoping. Good Luck

Ying

[lganaden]

Re: MPC 6500 7500 Blowing toner

drum unit assembly and dev unit assembly has bad design............u can't do anything with dis machine just keep on cleaning all the time...........

[Shadow1]

Re: MPC 6500 7500 Blowing toner

Hi, wonder if you could clarify the location of the bearing and lever you mentioned to remove. This is becoming more prevalent in our area.

Looking at the developer assy from the front, the auger that transports overflow developer is at the top left - the lever and one way bearing is attached to the front of the auger - it rides on a pin attached to one of the mixers - something like a cam so the auger gets flicked about 1/8 turn ever rotation of the mixer.

Think twice about removing this though - I've had the units run much better for about 5 months, then start packing full when the season and humidity changed again. That's what I was afraid would happen when i was first told of this fix, and was surprised that just vibration seemed to be enough to transport the waste developer. Turns out it isn't always enough.

The lever is not available as a part, and the entire dev unit has to be ordered when this happens.

Before I got moved to a different segment of machines I started testing an alternate solution. Fortunately the auger has a center shaft, so it is possible to cut some of the coils away near the drive end and modify the passages that allow overflow to spill only on the cutaway part. This still provides positive transport of overflow, but makes it work harder to get out.

A stock coil looks something like this:

==+XXXXXXXXXXXXXXXXXXXXXXXXX>

A modified coil would look more like:

==+--------------------------xxxxxxxx>

Again the only "Open" passage for overflow developer should be near the front of the machine around the cutaway part of the auger. That means only the center shaft is flicking the toner around and making it work its way to the exit - should slow the process down considerably, but not bind it up completely, which is what we want.

I didn't get too much chance to experiment with this solution, so no guarantees, but we gotta try something with these pigs and the engineers won't even acknowledge there's a problem.