mx7000

[bonnie750]

hello all

One of our guys went out to a mx7000 which needed a primary transfer belt. He was shown copies produced by the machine and they were washed out in places. he replaced the belt and inspected the dev units. the magenta brush appeared to have too little toner in places which could account for the pcq.

when the magenta dev unit was opened there was more dev/toner than normal. it appears to have been overtoning though not calling any errors. the yellow and cyan were the same.


he changed the dev and it setup ok. next day went back to fit a secondary tr.belt and the cp was poor again. he ran 25-02 to see what values it arrived at and 3 colours call EE-EL. when this sim is started the cmy values are around 55, they move up and down and then rapidly up towards 120 near the end of the process but fall back again and the error is called.

we don't want to throw more dev in there without something to go at. does anyone have any input please?

Bill

[vincent64]

hello all

One of our guys went out to a mx7000 which needed a primary transfer belt. He was shown copies produced by the machine and they were washed out in places. he replaced the belt and inspected the dev units. the magenta brush appeared to have too little toner in places which could account for the pcq.

when the magenta dev unit was opened there was more dev/toner than normal. it appears to have been overtoning though not calling any errors. the yellow and cyan were the same.


he changed the dev and it setup ok. next day went back to fit a secondary tr.belt and the cp was poor again. he ran 25-02 to see what values it arrived at and 3 colours call EE-EL. when this sim is started the cmy values are around 55, they move up and down and then rapidly up towards 120 near the end of the process but fall back again and the error is called.

we don't want to throw more dev in there without something to go at. does anyone have any input please?

Bill

Take a look at your drums, make sure they are not worn on the ends, this can cause DV pull and other issues, the grids can also cause problems if they are contamiated. you will see a green build up on them.

[OMD-227]

A low dev number of 55 and poor coverage of the mag roller is a sure sign you have some major overtoning going on.

First thing that should be checked is the CMY drums. If you replaced a color developer and it overtoned straightaway, I'd say you have a very worn drum which is constantly charging.
You could also have a problem with a dev unit density sensor, but if all 3 dev units have given trouble code, then its unlikely.
Is this machine in a very hot or low humidity room? Either of these factors will definitely cause an overtoning on the C-Dragons (even with firmware PCU 01.09.D0 & higher) as these cause an increase in toner concentration. Make sure the firmware is current, as the toner ensity correction control values are changed.
Check 44-14 for the temp & humidity values the machine is detecting. I've had cases where the humidity being detected was either extremely high or low and causing some obvious overtoning. Ensure you dont have either an aircon or heater blowing directly onto the bypass tray section where the sensor is located. .

If you have no trouble codes, I'd be replacing CMY drums/grid units, CMY developer, dev reset, immediately run 25-02 with CMY toners removed, run 44-27, reinstall toners, then fully calibrate with 44-06, 44-26, 46-24, 67-24. That is all it usually is.

** Replace the CMY drums with the usual MX27 drum unit as a complete unit.

[OMD-227]

next day went back to fit a secondary tr.belt and the cp was poor again. he ran 25-02 to see what values it arrived at
Bill

I just re-read your post Bill.

Running 25-02 dev adjust at that stage is a massive no-no.
It should have been 25-01 dev stir only This would have shown the values. 25-02 is for setting up new dev references. If this is done afterwards, while the machine has been operating, then you will be setting up incorrect values, with obvious overtoning.
25-02 must only be done once, straight after dev is replaced, with toners removed. This is the only true way of getting correct values for the new dev. Running 25-02 at any time afterwards will set incorrect values which the machine will always try & aim for.

Its also very important to run 44-27 halftone clear after machine has booted back up after finishing dev adjust. Once that has restarted again, then run full calibration.
With new drums & devs, calibrated correctly, it will come up great.

[graybeard]

Take a look at the section where the contact for the secondary transfer belt is made. Near the rear-frame end of the fuser. Had a guy leave a screw out and it left enough wobble to give us very similar quality issues.

[OMD-227]

Take a look at the section where the contact for the secondary transfer belt is made. Near the rear-frame end of the fuser. Had a guy leave a screw out and it left enough wobble to give us very similar quality issues.

I think you have mentioned that before Graybeard...... I remember reading something about that from you a while back.
Although I cant see how it could cause an overtoning in the dev units, as all process control is done long before anything associated with the secondary belt unit.
What was your issue again with the missing screw?

[Dark Helmet]

In Manitoba we had a 5500 over toning like crazy in the winter. Customers humidity was below 5% and in our case caused nothing but over toning. Sharp gave us special firmware and some adjustments in Sim 8. That helped with the over toning but CQ suffered when it was to dry. When humidity came back over 30% CQ was acceptable.

Bill if this thing was over toning make sure you take out the process control sensors above the primary belt and clean them throughly and then do a full calibration (44-2 44-13 46-24 etc etc.). After all this over toning there was alot of dusting and it caused the us to have color copies/prints.

[OMD-227]

Good advice. We've experienced the same thing here, done the firmware upgrade & associated 8-01 & 8-02 changes and it has always been OK since.

If what Lawrence, Graybeard & myself have suggested doesnt solve this, I'd be very curious to learn what it was...... so would we all.

[bonnie750]

thanks for the info guys. it appears the machine was ok then customer managed to damage the transfer belt, the quality of the copies was poor before the damage caused the machine to stop.. dev changed and setup ok.a day or so later the new dev was overtoned

humidity isn't a problem with this machine,although it is minus 10 and snowing outside the office is always the same. this machine has 1.5 million on it and prints mostly. it is in a large printing company and spends 80% of its time printing a4 labels, the rest test print of jobs before they are printed in the main factory.

i think the transfer belt had been running damaged on the rear side for a while cos there was toner along the back wall of the transfer cavity as if it had sprayed off the belt.


the complete drum unit and other bits and pieces are on order now.

when he gets back and fits them i'll let you know the outcome.

Bill

[Dark Helmet]

Just re read my post. The last bit makes no sense and it won't let me edit! :P

It caused poor densitys and light prints.

[OMD-227]

i think the transfer belt had been running damaged on the rear side for a while cos there was toner along the back wall of the transfer cavity as if it had sprayed off the belt.
Bill

Just like Lawrence said, give the process control sensor unit a good clean. If you've had toner spray coming off either a damaged or non-centered belt, then there is a good chance you've got some level of contamination on it.
A contaminated/dirty procon sensor would force the machine to lay more patches on the belt as its trying to read the toner density of the patches. This would also be another cause of overtoning in the dev. As the machine has trouble reading the patches due to contaminated sensor, it adds more toner in thinking it needs to.

[blackcat4866]

I just re-read your post Bill.

Running 25-02 dev adjust at that stage is a massive no-no.
It should have been 25-01 dev stir only This would have shown the values. 25-02 is for setting up new dev references. If this is done afterwards, while the machine has been operating, then you will be setting up incorrect values, with obvious overtoning.
25-02 must only be done once, straight after dev is replaced, with toners removed. This is the only true way of getting correct values for the new dev. Running 25-02 at any time afterwards will set incorrect values which the machine will always try & aim for.

Its also very important to run 44-27 halftone clear after machine has booted back up after finishing dev adjust. Once that has restarted again, then run full calibration.
With new drums & devs, calibrated correctly, it will come up great.

Agreed. Once developer has been vacuumed out, then installed, you should only run 25-02 once. You can check developer density with 25-01 without affecting the stored reference values. =^..^=