MP C7500 charge rollers crap out

[Guvnah]

I have seen a LOT of problems with the charge roller assemblies in the MP C7500 not making it to PM.

The machines I see most are:

1) A production environment where the machines are run hard with >80% coverage on often thick papers

2) An office environment where BW is run heavily and color jobs are more rare (but when they run color, they run it hard for a day or two)

In both cases it seems that streaks start appearing from one or more colors, without a reliable expectation for failure. I'd put failure at about the 40-60K mark for the production environment, and closer to 20K in the non-production environment.

Does anyone have tips for getting longer lives from these?

[Llama God]

Haven't come across this as yet but thanks for the heads-up - useful info!

One of our lads is going on the course in the next week or so and he's going to ask the product specialist for any info.

[jarhead2020]

Machine can't take full bleed use

I have the same problem with these machines, from the factory I have seen seals that are broken off in the PCU's. Fuser that builds up toner after only 23k and lines that are charge roller related all on the same machine.

I have noticed that if you spin the drum counter clockwise and there is any dust on it that means the machine is going to soon coat the charge roller and you will be back for lines again. That means rebuild that PCU and watch the seals.

The waste collection is not enough to get rid of the waste even if it is not over-toned on real color copies won't even get to 75K without crapping out especiall with magenta. I have an appointment with a regional rep about this issue will post their reply.

[Marius]

[Guvnah]

Remove the felt roller

After consulting some of the Ricoh trainers, they have (unofficially) suggested removing the felt rollers from the charge assemblies. Apparently this can extend the life of the charge units.

I need to look at two of these machines today (for streaking, of course) and I will remove all those rollers.

[Jomama46]

but they had neither heard about or seen the problem yourself.

Funny how often that is the answer
Maybe they should monitor these boards.

[zico21]

I literally just got off the phone with the Product Leader here in the states for this model for the same problem. We have two machines that are having repetitive problems. Both are relatively low volume. We had send two sets of charge roller to NJ and just replaced another set on one of the same machines this morning after around 5K color pages.

The Product Leader said he had sample rollers from one other dealer and was sending them all to Japan so hopefully we'll get some information, but I'm not holding my breath. I will say that the Product Leader was sincerely interested and concerned (or else a good actor!).

Cheers

[jarhead2020]

I worked all day with my regional rep and he told me to wax the drum with Rain X Ultra wax car polish (Its in a blue bottle and is a white cream consistensy).

The procedure is to do the PM on each PCU before putting the drum back in. Then take the drum and clean it with water or D-ink to get it looking good and dry it. Then take a webril pad and put alot of wax on that and with a circular motion put a nice coat on the drum. Let it sit for at least 2 min. then put another coat of wax on. After 3 minutes take a clean, non abrasive cloth and buff all the wax off. Then put the drum back in the rebuilt drum unit and as a small bonus you do NOT need to use setting powder on the drum.

The wax helps the cleaning unit work more efficiently (Less medaka) and helps stop fireflies. What we believe happens is the cleaning unit cannot effectively remove all the toner off the drum so it ends up getting on the charge roller and causing it to fail premuturely.

[knightfall]

this is a problem with all Ricoh color copiers the felt roller is a double edge sword, it keeps the charge roller clean until it gets dirty then it keeps the charge roller consistently dirty. I have had great luck if I vacuum or use compressed air to clean the felt roller and clean the charge roller with WD40 and I won't see the problem again. There should be a cleaner for the cleaner.

[stephend]

Charge rollers

From an internal unofficial source I found out that they are working in Japan to replace the toner for this model. The combination toner mixed with developer to "improve" reliability it's a complete failure.
Humidity plays a huge role in this problem. All our machines affected by this problem are in production or design environments where the humidity was no more than 5%.
After we convinced the customers to install humidifiers and to control constantly the humidity levels the situation start to improve a bit.
Removing the charge roller cleaning roller it's a solution that should be considered....using wax (like in old analog days )...it's questionable especially in environments where customers are using special stock...it could work fine or not.

[jarhead2020]

I don't see why the stock would effect the wax since on this model the paper never touches the drums. Its someting to try until the turn the machine into the new one with a slower speed and new toner without the extra DV in it

[stephend]

Arcing

Today I just sent to our product support specialist a set of 3 charge rollers and 3 drums with visible marks on drums and charge rollers. Magenta drum has small holes in it...charge roller the same thing (arcing). 3 months ago the same was down for the same problem but with transfer unit. I rebuilt completely the transfer using the upgraded pre transfer rollers, the new and "improved" cleaning unit and the problem was fixed.

We set up a set of 4 drums with wax how was described in a previous post and together with 3 new charge rollers assy's (without the cleaning roller) for our 7500 demo machine and now will monitor the evolution.
Humidity still at 15% RH, so still low. I'll keep you posted.

[Shadow1]

What does an arc'd charge roller look like - I had a machine with a repeating pattern of small dots around the magenta drum, but I assumed a small piece of grit got stuck on the charge roller. I've never had arcing problems from charge rollers - we got plenty of humidity in Mississippi...