ES855 weak solids that have a slight mottle look

[Desert Rat]

Last January I replaced the drum, developer mix and primary corona wire. The copy and prints looked great.
Last April they called for weak solids. I cleaned the scan mirrors and the laser glass. And ran the 200 program
and added toner. I also ran the 290 program. (What does that program do anyway?) Copy looked great.
Today same thing. (She had just replaced the toner bottle today also.)
Weak solids. Today I replaced the primary grid and clean the wire with alcohol. I replaced the
transfer belt and blade. Cleaned all the rollers. That helped, but not like the jet black I'm use to seeing from this machine.
Also I did notice a slight mottle to the solids and the 10% square is just barely visible.
I did adjust the density and the sharpness. Not a lot just a about 10 numbers up.
My question; What did I miss? If I adjust the gamma slope with a higher number do the copies get darker?
I did check the replenisher motors and they all turn easily. The developer rollers turn good. I cleaned the laser glass and
the mirror behind it. I usually keep my machines clean and this one was clean. No toner scattering or dust.

I was able to get it dark enough for the customer to finisher her job.
I just have a feeling that I will be seeing this machine for this again.

DR

[Vincent128]

Yes, you will be back.

So..like..whats the current pm counter states, whats the monthly volume, whats the copy count?...give us information to help you troubleshoot.


It may also be starving itself from toner buildup on the subhopper toner sensor giving false readings.

05-200 is adjusting of the auto toner sensor, to be ran when you replace developer. Developer is a factory calibrated mixture and your setting the toner sensor offset voltage.
05-290 is forced execution of image quality control. ...find an older manual and read the sections on Process Control, if you don't understand Process Control (which they NEEED to TEACH and don't anymore) then you job at a copier tech will be a struggle.

Once the dev unit's toner ratio is out of wack and you get light solid fill; I have never been able to make these machines recover from it without fixing the underlying issue then replacing the developer and running the proper codes.

[Desert Rat]

Vincent128,
Thank you for your reply. The PM numbers, I reset the counters of the items I replaced last January and then the other day
I reset the counters for the items I replaced. I will get the information you requested and post.
This machine is approaching 1.5 mil.
And yes I do have an older manual so I will read up on the forced execution of the image quality control.
Last month I was able to get the solids back. As I recall I did pull that sub hopper sensor and clean it off.
Last time I did not. I did check that all the gears on the replenisher were turning easy. I have seen the sub hopper
bind up with packed toner, but that usually produces a code.
If the sub hopper sensor is giving false readings but still seems to work, sounds like I need to replace that sensor?
What are some of the things you have found that would cause this type of symptom? I agree with toner starvation.
May be it is that sensor?

Thanks

DR

[Vincent128]

At 1.5 Mil you may need to rebuild the dev unit, though generally speaking when the mag rollers conductive bearings stop playing nice, the machines overtone rather than under. A lot of when the dev unit needs rebuilding depends on the volume of the machine. Low volume and really really high volume machines need it more.

An over looked part of PM procedure on machines when doing developer change is remove the vacuum plate in the bottom of the developer and clearing it of toner/developer. Too much of this packed around the TDS sensor in the dev unit will effect its readings. That many copy on the unit may also have worn down the TDS scrapper or there is toner impacted on the sensor face, causing incorrect readings. The MA Pm kit is important, the vac bag and O3 filter are needed for proper airflow and imaging section scatter prevention.

If it's a low volume machine there is little you can do, they always like to run light - manually spike the dev unit will help for a short time. You can manually spike then rerun the 200 but it's only a temporary fix. decrease the process control timing to less copy...i think there was a bulletin for that.

Toner sticks to the subhopper sensor especially in humid or low volume environments. The machine will always think the sub hopper is full and only do the toner bottle bump rather than an actual add toner cycle thereby starving the dev unit.
These machines do not recover from that on their own.

Manually tinkering with density, sharpness, gamma offsets is not a road I would go down unless trying to make a machine that is already working properly fit into a situation where by we are getting around a media issue.
Doing so can really mess up a machines process control and give a ton of unexpected problems, the machine will try and compensate around your tweaking anyway.

If the toner hopper assembly is not installed correctly, the access shutter that opens to feed the developer unit fresh toner will not open or be aligned and thus starve the dev unit. This one can show up as an add toner message but the bottle is full or causing the subhopper to packup with toner and give you an error. Same thing with the recycle pipe.

You ran a 200 on developer that was not new, so you may never recover from light copy fully no matter what you do and it might contribute to some tail chaising.

I would put all the numbers back to where they were, have handy the parts to rebuild the dev unit (TDS, seals, bushings, mag rollers....ect). dump the developer, clean and inspect the unit and rebuild whats needed, make double sure all the HV connections in the machine are clean. The sub hopper sensor I have almost always just cleaned. Per the manual you should not have the toner bottle installed when doing a 200 with fresh developer but I also like to cover the input hole on the dev unit so you don't immediately have toner falling into the dev unit while its calibrating.

The es6530's manual has a pretty good explanation of process control and all that - its in the Image Processing section.

[Desert Rat]

Vincent128,
Thank you for all that info. I may have that 6530 manual.
I will review that section. Even though this is a color machine, I assume they all
use pretty much the same process for the forced execution of the image quality control.
This machine does not do high volume. Last month they only did
25K. Some months will be higher, but some will be lower also.
I usually pull that plate from the bottom of the DV unit on PM's.
I don't see any signs of developer leaking from the seals. Last time
I changed the mix, as I usually do, I poked around in the dv unit with
a plastic feeler gauge to loosen toner packed in the corners. And then
vacuum out as much as I can. I always pull the sensor out before the
vacuuming. I have neglected the filters tho.

Thank you for all that good advice

DR