MPC 6500 7500 Blowing toner

[Gary Bowen]

There are a whole slew of new TSB's addressing toner scattering and toner dusting. The D014/D015 series color copier has 10% developer in the toner cartridge mix; it is a finer powder than the B132/B200 toner with a lower melting point, hence the ventilation and cooling of the inside of the copier is more critcical than with the B132/B200 series. Check out these bulletins.

[Shadow1]

There are a whole slew of new TSB's addressing toner scattering and toner dusting.

...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)

[msaeger]

So does removing the lever stop the toner dumping all over the machine ? I was reading people doing it to stop light copies and I never see that. I get toner dumping all over but it doesn't seem to effect the copies. Pretty much the only thing I have trouble with at the charge rollers but if removing the lever would stop toner dumping with no adverse effects I would try it. Has taking the levers off done anything for helping with the charge rollers ? Those color pcus always seem to be packed with toner and the black never is.

I'm sure NIHS is also caused by them being paranoid about creating another issue too but yeah it seems like they won't listen to anything we tell them.

[Shadow1]

Once it starts dumping you obviously have to put the machine back in good shape, which includes a developer change, but removing the lever will stop it from happening again. It doesn't help the charge rollers, but its one less thing you have to worry about.

The Car Wax idea may help the charge roller problem, but I think the problem would also greatly benefit from a good cleaning roller like what was put in the 35 / 45 Page machines - the "pipe cleaner" roller G7902329 - not the denser one that was more like felt. Those were a more durable version of what's already in this machine and they put lines on the B/W machine's charge roller, which wasn't already handicapped with a lube bar. Somebody already tried swapping one in though, and they don't fit.

NIHS also got us the MP4000 with the same toner as the MP3500, even though we can demonstrate swapping the toner motor and using B079 supplies and developer makes these beasts run to PM.

It's a really bad bad bad disease.

Kidna feel sorry for them.

A little.

O.K. not really, but I'm afraid if I strangle one of them I may catch it.

[Smeden]

I’ve think I have a solution for lines at the charge roller.
First you must remove the developer dropout clutch. (Change developer if needed)
Then you replace all color lubricant bar springs with the springs to the black lubricant bar.
The pressure is less with these springs. And of cause the color charge roller.
We have a brand new MPC7500 witch ran 10k. Then we had to replace the charge roller.
After this fix it’s now running over 40k until now.

[MrRicoh]

I have worked with this problem for 1 year and finally i belive that removing the cam lever is the ultimate solution for now.... I have until today 4 machines that runs just perfect after this removal. And I have also been removing the springs for the lubebar entierly so the only pressure it makes is with its own weight... One of machines witch had 1-2 visits per week has until today worked 22 days and 60 K copies and NO dust what so ever....I keep my fingers crossed....

[Shadow1]

Removing the cam lever solves the low image density and toner barfing problems - that's a grade-A-top-of-the-line-Ricoh-will-never-let-it-see-the-light-of-day-because-it-sure-does-work fix (back to NIHS again...)

For me the jury is still out on the charge roller lines, but only because I haven't had time to see the full results, but I've been stretching springs and hoping to see a major improvement. I'm pretty sure it will work, and as with the cam lever mod, I think I can explain why the lines are happening.

This is TSB_D014_Shandow1_002:

Symptom: Lines on copies from any of the color PCU's. The problem usually starts as small dots spaced at the circumfrence of the charge roller, progresses to small dots resembling perforations as the dot gets passed to the drum and back again, and finally evens out into a line.

Cause: Pressure on the lube bar was increased from the previous model causing deeper ridges to develop along the wear surface of the bar, and more sharp points to develop at the edge of the bar as it is worn down by the brush. The increased pressure also makes it more likely these tiny points and ridges will break off. When this occured on the B132 machines they were generally flushed into the toner collection system along with excess lube and waste toner. Since the D014 machine's lube system is completely seperate from the waste toner system these chunks have nowhere to go, and eventually find their way past the lube blade and onto the charge roller. Since the Charge Cleaning Rollers are so whimpy they couldn't clean melted butter off a teflon frying pan, these chunks of lube eventually get squished into the lines we constantly have to deal with. I should also note there is usually a buildup of toner, lube dust, and the occasional lube chunk just above the 1st drum blade which likely helps the chunks squeeze past the 2nd blade.

Solution for Field Tech: Lowering the tension on the lube bar may allow the ridges and points to be worn away instead of breaking off. This will also reduce the amount of excess lube built up between the 2 blades. Removing the springs entirely may not apply enough lube and cause premature drum wear. I prefer Smeden's idea of swapping springs with Black over my idea of stretching them, but honestly I hadn't noticed they were lighter. If that's the case it would provide more consistent tension and would work better than my crudely stretched springs.

Solution 1 for Engineers: Break out the slide rule and do whatever calculations you like, but the bottom line: Lighter springs.
Solution 2 for Engineers: Open the lube bar & brush section of the PCU to the waste toner so any excess lube and chunks have a place to go other than stuck to the drum and charge roller.
Solution 3 for Engineers: Update the charge cleaning rollers to something that has a snowball's chance in hell at actually working - what's in there now reminds me of dried up shaving cream except its even more fragile - it doesn't have a prayer.

I'm hoping they've done some of this on the MPC6001 and MPC7501, but I haven't seen one yet.

...BTW, If you get the feeling that I'm poking fun at the Ricoh Engineers your right. I AM - They are capable of doing a much better job fixing these kinds of problems - I've seen them do it. Especially when they pull their Cranium out of their Rectal Orifice long enough to listen to a tech and actually acknowledge there is a problem.

I know several techs, myself included, have tried suggesting improvements or fixes for any number of problems. Its very hard to find a path to get a message to the engineers, and the message is either lost along the way, ignored, or "doesn't follow proper procedures" (which noone can find). Much as I hate to resort to something so ugly, its time to see if humiliation is an effective treatment for NIHS.

[msaeger]

I always figured the problem wasn't that this engineers can't figure out how to fix it, it's that Ricoh won't let them take the time/money and instead wants them working on new models. That's kinda how it seems now where we have to wait for a new model to get even a simple thing changed. Like the MPC7501 has "new charge rollers with improved cleaning". How hard would it have been to change the charge rollers for the MPC7500 that's not a major thing like new toner or replacing them with coronas.

[Shadow1]

I've gotten that impression too, except it doesn't explain the MP3500-->MP4000 toner problem, and that SNAFU has done a tremendous amount of damage to Ricoh's reputation in the mid volume copier segments - their bread and butter.

Wherever the problem lies, if those responsible are exposed looking dumb enough to the people who can hold them accountable the problem will get fixed.

[Shadow1]

Brain wave...

I'm going to modify my next machine, but it will likely be a bit before I see one, so if anybody can beat me to this test it. If you pull the lower drum blade completely, you end up with a configuration strikingly similar to the B132 machines with the upper blade acting as a drum blade instead of just a lube blade. All the excess lube and chunks of lube bar can fall down into the waste toner system now, so as long as the waste toner can fall off the upper blade and get whisked around by the brush to drop into the waste... Also, if you don't have to change the lube brush every 150k it saves a hell of a lot of disassembly not having to change the lower blade.