New MP4000 Dev Unit

[Ricoh-ono]

I've started ordering extra vacuum filters to go with my frequent developer changes. I think these machines are toner intolerant.

[techshare]

MP 4000 dev unit

Ricoh has upgraded the dev unit sleeve, and new part # D0092301.

[Jomama46]

Interesting. Is that the whole mag roll assy D009-3100? Did they issue a bulletin? Can you post it if so. Thanks for the info.

[Pandy]

I have been told that new toner is being produced for this model and the B296 previous model that uses it. They have recently released a new part number for dev assy and mag assy parts (TSB:B291-014). I know these are for the B296 only but they could be releasing new mag for the D009 series. What we have been doing is the adjustments, replacing devo, but also cleaning out the grooves in the mag roller with a good sharp picker finger. I have yet to see one of these models go the whole pm without light cq issues.

[zico21]

Here's my take on the whole Ricoh toner density system in general and the unique problems of the MP3500/4500 and MP4000/5000 in particular. I would appreciate any comments corrections, opinions, etc. I apologize in advance for being long winded, but I'm using this opportunity to get things clear in my mind.

When new developer is installed, by design it is assumed that the proper toner developer ratio is present and therefore the developer initialization process "calibrates" the TD sensor so that it has a reference of what the proper toner density should measure.

After that, the current TD reading is compared to the TD reference reading after every print. If the current TD reading is higher than the TD reference then the developer mixture is undertoned and toner needs to be added.

Since the proper toner density of the developer is only one factor of how dense the image will be on the drum, Ricoh uses the ID sensor to measure the other factors in the copy process that can affect print density. The ID sensor is literally measuring the reflectivity of the black patch (using the reflectivity of the bare drum as a reference to somewhat compensate for the ID sensor getting dirty which would affect the readings of the black patch).

Now, the density of the black patch can be affected by any part of the copy process (except paper transfer) so any "normal change" or problem in the charge, drum, developer bias, developer density, ID sensor (mechanical or electrical) etc will affect the density of the black patch. So, under normal conditions, Ricoh is using the ID sensor to compensate for normal changes in these components and conditions. The results from the ID sensor is used to "modify" the TD reference to reflect these changes. As each page is printed, the current TD reading is compared to the now modified TD refernece to determin if toner needs to be added. Also, this information is used to determin how much toner will be added.

When things go wrong and the developer either get overtonned or overtonned, it either a vailure of the TD sensor or its logic (less likely) or anythiing that could affect the black patch (where do we start!).

Now the real world. The big difference in the two latest series is the change in toner and the problem with the buildup on the mag roller. The buildup not only affects the immediate copy process but also changes the black patch which then incorrectly modifies the TD reference whcih leads to developer failure. Apparently, Ricoh's solution is to tread the mag roller to prevent the buildup.

Another comon problem is poor drum ground (through the drum bearing), which again, affects the immediate copy process, but also changes the black patch and therefore, (imporperly) the TD reference, again leading to developer failure. We've been adding a drum bearing grounding strip which assures a good drum ground

A common problem we have come across for the MP4000-5000 is a poor connection for the charge roller current path which again affects the black patch ...blah..blah..blah...... By repositioning the two pieces that make up the charge roller path a much more positive conductive path is achieved.

I've attached two of our in-house bulletins (preliminary) to illustrate what we're doing. Much of this information was passed on to us, but unfortunately, I don't know who to properly give credit to for this. These are not fianlized, but so far taking these steps appears to be successful for us.

Again, the key in my mind is to realize that anything that can affect the copy process can affect the black patch which will affect the TD reference which can lead to developer failure. Also (although obvious), monitoring the SP data for the TD readings and ID sensor readings can be very usefull.

Again, I would appreciate any feedback.

Cheers,

[techshare]

MP 4000 dev unit

Ricoh has upgraded the dev unit sleeve, and new part # D0092301.

according to TSB-034 Reissue on 02/13/09. It is a whole complete dev unit.

[Ollie1981]

I've fitted 3 of my worst offending MP5000s with the modified dev units and because they are major account customers with plenty of other machines under the same roof I'm keeping a watchful eye on them.

Only time will tell though, one machine that was crapping up it's developer at around 15k has gone a further 60k without any subsequent copy quality problems, but to be honest that was only a flying visit as once I had finished the call on the other machine I was working on, the next call I was dispatched to was 60 miles away with 45 minutes left on response so I didn't have time to open up the (absolutely stupidly designed) PCDU to look at the mag roller.

I reserve a special hatred for these machines because boss men catagorise them as an updated Adonis and therefore their excel spreadsheets that reduce your daily toil and sweat down to a simple figure don't account for the stupid useless additions (like the web unit, why is it needed? Even if there was a reason then why make it so labour intensive?) and the fact that most calls, even for jamming, also come with a copy quality issue, every damn time.

It's because I'm lumbered with three major account customers with these POSes that my calls per day and parts spend figures have looked crap for the past 12 months and I'm in serious fear of having the sacking stick pointed at me.

Heaven would be a carpark filled with these things and me making a strafing run in a fighter jet loaded with Napalm.

[Cipher]

Heaven would be a carpark filled with these things and me making a strafing run in a fighter jet loaded with Napalm.

Shocking...

can I be your co-pilot?

[Lagonda]

Thanks Zico,
that made a lot of sense and you explaned it very well, hope you dont mind if I spread it around my techs?

[zico21]

I certainly don't mind, but please post any thoughts you or your fellow techs have. I'm not sure if I explained myself well, or even if my understanding is totally right. i do have confidence in the practical aspects of the post, although I'm not saying it is the total answer.

Cheers

[cobiray]

I certainly don't mind, but please post any thoughts you or your fellow techs have. I'm not sure if I explained myself well, or even if my understanding is totally right. i do have confidence in the practical aspects of the post, although I'm not saying it is the total answer.

Cheers

We've been doing a similar thing with the drum grounds at the suggestion of our last territory rep. I've not seen any noticeable change when adding additional grounding tabs or replacing drum pins and bearings. He also recommended disassembling the bearings and repacking them with conductive grease. Still no dice. We've had better success with changing to the new style dev unit, but that only gets us to about 80k before it needs attention again.

Are you seeing a more positive response from these machines when adding the drum grounds and not changing the developer and/or the dev unit?

[zico21]

In terms of the MP3500/4500, my thinking is that the only difference from the previous series is the toner (and consequently, the developer). The problem with the toner is that it coats the mag roller much more easily. The problem with the mag roller getting coated is that it affects the development of the patch. The improperly developed patch leads to the developer crashing (over/under toned). I think the issue with the drum ground is that it just is one more way to affect the patch being created properly and therefore increases the chances of the developer crashing.

Our experience is that with the MP3500/4500 series most of our problems developed after around 150-200K pages. From what I understand, Ricoh's explanation for the MP3500/4500 toner causing problems is that the toner is easily affected by "contaminants" both in it's manufacturing process and from paper dust within the copier during its normal operation. Hence all the references to thoroughly cleaning the copier of used toner and paper dust.

Another point that was emphasized to me by Ricoh was that the cleaning process used to remove the toner buildup on the mag roller often made the coating reoccur even faster. We had used brass brushes to clean the mag roller (as we do on the 2090's and occasionally the previous 350-3035's) and it was explained that this only aggravated the issue of toner build up with the MP3500/4500 as the small scratches increased the likelihood of buildup. We now only use a non-abrasive cleaner (have tried Katun Formula K, Simple Green or NA Trading Belt Cleaner) and a toothpick to clean the groves and then a treatment with RainX.

If the mag roller can't be cleaned in this process then we replace the mag roller assembly in the MP3500/4500 or the developer unit in the case of the MP4000/5000. Last of all, it is our opinion that there is never any hope of saving devloper that has crashed (either under or over toned) and we replace it as part of the process if it isn't normal on arrival.

So, to answer your question more directly, I think things are getting better but its too soon to say how much better.

In my other long winded post I was trying to express my belief that when dealing with a toner density problem on Ricoh's (which often is disguiessed as a developer crashing problem) that can't be solved by the more obvious steps, the problem usually involves the ID patch not being developed properly and trying to determine what part of the copy process is the problem. What makes troubleshooting difficult is that usually the problem is subtle and not noticeable in the short term, but over 2-10K pages (depending on the model) the developer crashes again.

We've had a number of intermittent issues with toner density on a number of different models that, in the end, have been caused by odd things affecting the patch such as intermittent drum ground, charge roller path (MP4000/5500), charge/bias power pack issues, etc.

Last of all, in quickly looking over the in-house bulletins I posted, I realize that they are one revision old, but the the changes were minor.

Hopefully, by sharing ideas and experiences we all can get though this nightmare.

Cheers

[cobiray]

That's what I was afraid you would say. We are really losing our asses on some of these units. I've been seeing the new dev units to help, but not a cure all. There are even some machines that don't seem to respond to any of the mods for any period of time. I've even tried dropping fuser temps and setting power off rediculously low (10 minutes). I've still got a 3500 that needs developer replaced every 40k even with a new mag, new dev unit and new developer (multiple times).

As posted previously, I've changed some of the 3500/4500 over to B079 consumables, but only on machines we own (rentals or inhouse units).

Did I mention it's utter crap that a fix has taken 2+ years and counting to find a fix for these pigs?

[Cipher]

Our experience is that with the MP3500/4500 series most of our problems developed after around 150-200K pages. From what I understand, Ricoh's explanation for the MP3500/4500 toner causing problems is that the toner is easily affected by "contaminants" both in it's manufacturing process and from paper dust within the copier during its normal operation. Hence all the references to thoroughly cleaning the copier of used toner and paper dust.

Another point that was emphasized to me by Ricoh was that the cleaning process used to remove the toner buildup on the mag roller often made the coating reoccur even faster. We had used brass brushes to clean the mag roller (as we do on the 2090's and occasionally the previous 350-3035's) and it was explained that this only aggravated the issue of toner build up with the MP3500/4500 as the small scratches increased the likelihood of buildup.

Some good points there.

If you look back at the photo I posted you will also notice no scatches on the mag roller after it's cleaned.
Basically if I'm not replacing the dev I just push it off to one side of the mag roller with a brush then use alcohol, with low lint cloth and my finger nail to scrape off one side at a time (takes a while but it comes off easily enough).

Also I always empty the paper dust trap at the reg roller and the recycled toner from the PCU as you will see most of the time the toner looks grey as it is full of paper dust.
I don't normally remove the top of PCU to get to the coil though, I simply turn the PCU over and rotate the toner recycling gear with my finger while gently shaking the PCU.
The recycled toner will just drop out leaving just the edge of blades/mylars to clean (much quicker just as effective).

These models going back to 1st gen NADs have mostly always run dirty and been time consuming to service I guess I've just gotten use to the fact.
I just find it dissappointing that Ricoh after all these years cannot seem to improve the reliability of this engine design.
This fix of a different dev unit and toner mixture is all very well but it still does not take away that us techs shouldn't of had to deal with such a fundamental problem in the field as Q&A testing should of picked up on this and fixed it before they ever rolled the machines off the production line.

[Wishbone]

I wish Ricoh would scrap these models and design something new that works. You can't tell me with the great color products they have in this same segment that Ricoh can't do better. These have not run right since the very first 450's. You can put lipstick on a pig, but it's still a pig.