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MVPunisher
11-12-2013, 04:54 PM
So I have a 751 that consistently is not accepting a developer change. When it does take one it is fine and it will last right through the pm cycle. Sometimes it takes me a few changes in a row before it accepts one.

And what I mean by accepts one is- if it does not I will get a call back in 5k because it will be severly overtoned and spewing everywhere. Ive done toner control sensor, I have decreased the tcr %. I have enough of these in the field to be confident I am not doing something wrong. All my adjustments are "ok" after replacing.

Hv unit or prcb or something maybe? Any suggestions?

JustManuals
11-12-2013, 06:47 PM
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Frostwolf
11-12-2013, 06:50 PM
I can't resist,

You mean to tell me you have 601/751's that don't dump.

My normal checks are Bias on dev unit, Drum voltage, drum ground, and T&S mylars. I also have had a T&S unit cause dumping on a brand new machine.

We have not been able to completely eliminate dumping on these machines.

MVPunisher
11-12-2013, 07:44 PM
Yea I hear ya on the dumping. This one just on a totally different level. Makes it like 5 k before dev is so overtoned you can't even copy. Thats like 2 day lol. Little different than my normal dev spew.

Discountcopiers
11-12-2013, 08:32 PM
THE MAGNETIC ANGLE ON THE MAIN MAG-ROLL MAY HAVE SHIFTED. IF YO HAVE SEVERAL CONTRACT CUSTOMERS TRY SWAPING DEV UNIT TO9 SEE IF THE PROBLEM FOLLOWS THE UNIT. i KNOW ALL OF YOU ARE SHAKING YOUR HEAD BECAUSE OF DOWN TIME....BUT iF YOU TAKE THE (SUSPECTED)BAD UNIT OUT OF THE MACHINE AT CUSTOMER CLOSING TIME AND SWAP IT WITH OUT WITH THE OTHER MACHINE AT FIRST THING THE NEXT MORNING (WHEN YOUR OTHER CONTRACT CUSTOMER OPENS)..DO YOUR SET UP. GO BACK TO THE FIRST AND TRY A SET UP... YOU HAVE JUST LIMITED THE AMOUNT OF SUSPECTED CAUSES.
ITS WORTH A TRY.

bronco31
08-20-2015, 06:13 PM
So I have a 751 that consistently is not accepting a developer change. When it does take one it is fine and it will last right through the pm cycle. Sometimes it takes me a few changes in a row before it accepts one.

And what I mean by accepts one is- if it does not I will get a call back in 5k because it will be severly overtoned and spewing everywhere. Ive done toner control sensor, I have decreased the tcr %. I have enough of these in the field to be confident I am not doing something wrong. All my adjustments are "ok" after replacing.

Hv unit or prcb or something maybe? Any suggestions?


here it is 2015 and I still get to work on these! joy joy..

MV.. i have a whole host of these alos doing the same .. within 5K .. TOTALLY overtoned (not just yr normal dark copies overtoned)

did you ever get of the bottom of why? thx man!

MVPunisher
08-20-2015, 06:27 PM
Making sure the manual drum voltage is done with a multi meter helps and drum replacement. But sometimes it just doesn't accept the Dev change. Not sure why.

allan
08-20-2015, 07:30 PM
They do work. If these machines work hard. You can get 200K + from a developer.

Its the bais connection that goes bad. Its a bearing.

You can test for this by measuring conductivity between the metal pin on the side and on the mag roller.
There needs to be developed in the tank with a full brush to test this. The resistance should be less than 80Ω.
Otherwise you can modify a piece of spring wire to run against the shaft instead of the circlip. Tug the other end underneath the plate by loosening the screws and clamping it against the plastic. You will get rust from the shaft in a PM cycle or to.

Go thru all the soft switches and set them back to default because that works. Like mentioned dont mess with the mag roller angle. you can adjust it. The tank only does about 900K before the leaking developer chows up a gear on the side.

And if you are using 3de party toner change to original or good stuff. Sounds like toner starting with K.

EarthKmTech
08-20-2015, 10:34 PM
I recently discovered a machine that the customer ignored the PM notification and had never had a single call.

it had 550K on the clock and was still running the original developer and the machine was clean inside.

I went there because of an unrelated matter.

It got the Full PM as per the book and now like every other machine its dumping every 100K. Cant win.

Synaux
08-21-2015, 10:07 PM
I actually have the opposite issue with undertoning...its also burning up the corona wires on the TS assembly very quickly....going to be performing a drum/pm/dev replacement when the PM kit comes in...and yes, I followed the ~10 service mode operations.

To eliminate bias shortage:
30373

Change dipswitch 23-2 and 23-3 from 0 to 1.This decreases toner density by 1.5%.


I thought there was another bulletin about overtoning, but I don't see one; however, the OP might be talking about this known issue:

Solution ID Solution Usage TAUS0900529EN*
Description
The copier outputs gray background after performing the maintenance on the copier.
Solution
Cause: This issue is caused by defection of the image density control in the beginning of the PM Cycle.

Solution: This issue has been addressed with a firmware updated to the following versions:

bizhub 751: Printer controller program (combined) version.32 and above
bizhub 601: Printer controller program (combined) version.32 and above

After completing the update, please be sure to perform the following.

1. Check the DIPSW10-3 is “1”.
2. Replace the Drum and the Developer to the new one.
3. Reset the fixed parts counter of the Drum and the Developer to 0.
4. Execute the Maximum density adjustment.

EarthKmTech
08-22-2015, 01:14 AM
Nice MacGyver modification there.

Doesnt the paperclip end up being worn through pretty quickly ?

allan
08-22-2015, 03:00 AM
Yes thats why i use spring metal instead. The shaft does take a beating but it keeps working.

Synaux
08-29-2015, 01:16 AM
Nice MacGyver modification there.

Doesnt the paperclip end up being worn through pretty quickly ?

Little dielectric grease alleviates some friction and certainly will last a PM cycle. : )

Synaux
08-29-2015, 01:21 AM
Update to my under-toned 601, I noticed after cleaning out the developer unit that the blue loctite was flaking off of the Developer Regulation Blade. Had a friend mail me a very used, but functional developer unit and after performing the PM & drum replacement, Fatso is running like new!

Only took 2 or 3 PMs to figure that one out...

Synaux
08-29-2015, 01:22 AM
Yes thats why i use spring metal instead. The shaft does take a beating but it keeps working.
Spring Metal?

allan
08-29-2015, 05:14 AM
Update to my under-toned 601, I noticed after cleaning out the developer unit that the blue loctite was flaking off of the Developer Regulation Blade. Had a friend mail me a very used, but functional developer unit and after performing the PM & drum replacement, Fatso is running like new!

Only took 2 or 3 PMs to figure that one out...


Jip, I get a lot of these machines second hand. Good machines, but they can be really random at times.
Like you said it takes about a half a million clicks to get all the kinks out of some of them.

Synaux
08-29-2015, 06:08 PM
Jip, I get a lot of these machines second hand. Good machines, but they can be really random at times.
Like you said it takes about a half a million clicks to get all the kinks out of some of them.

Yea...when they run they run. Even with the kinks, this particular machine ran over 120k in a weekend without a single jam. Before I figured out the undertonning issue, I was tempted to suggest an upgrade to a 652 or even a c652. However, given the used machines I was looking at had over 400k, the tranf belt, fuser, and drum would have to be replaced soon relatively soon--which would cost more than the machine itself--the 652 engine is superior in my opinion, but simply more expensive to maintain.

As a side note, I recently started disconnecting the toner recycle clutch so the recycling contraption runs at all times (there is a dip switch too--if you want to deal with that). I find that the tube gets crammed with 'rocks' of toner...hopefully this method will eliminate that issue.

bronco31
03-04-2016, 05:51 AM
i think i found a fix too...
in drum pec adjustment ... set the LD1 and 2 offset to be plenty dark in between the 2 lines when printing out the test chart on letter R or legal....
i think that then causes the patch formed on the drum (it does that right?) to be a pinch dark so the machine decides to not add so much toner to the mix!

allan
03-04-2016, 05:54 AM
I will give that a try. :confused:

Synthohol
03-07-2016, 11:07 PM
Hello, I signed up just to reply to this thread.
I have serviced these hundreds of times and the toner spew can be avoided or at least reduced to a minimum
I only want to suggest pretty much what is in the book.
sometimes its best to start from scratch. if you replace the drum and developer blow off all toner from AIDC sensor board with an aircan, a vacuum can cause it to short out. reset the counters, set the proper drum grid manual charge voltage with a good meter, adjust to what the voltage is stamped on the back flange of the drum (usually in the low 700V range) then run through the auto max density adjustment, laser diameter, do the LD1 and LD2 adjust so there is just a faint box just over the first line. then cart install mode print the 10 sheets.
the bit switches mentioned earlier do help but i would set them after doing these adjustments.
the bad part about the toner dumping is when it collects on the web and grinds a stripe in the UFR!
i actually miss working on these big dinosaurs, now everything these days you dont need the finesse you did long ago.
I hope i've helped.

Synaux
03-17-2018, 04:56 AM
Yeah, yeah, I know this post is ancient, but holy cows, I just discovered a heck of a mess on the 601 I was originally referring to in this post (that I sort of hijacked)!
:rolleyes: Anywho, here is my newest story (read for leisure):

This machine has and will historically undertone for the past several years--no biggie though--run the load checks (1, 5, 50 for ~10 sec and repeat as necessary). Why the toner reservoir continues to deplete, will most likely forever be a mystery--especially when considering the coverage on prints is quite low.

Anyways, I get called in twice in one week which is a little crazy as I would only have to "spike" it when I go to clean/check it every 6months or so.

First visit: The PM is actually nearly 3x the life, but so what! Right!? Because the coronas, drum, web (these will fail at ~250k unless you take emery cloth to the rear spring shaft and grease that POS--FYI) were all still good and when it is toner-upped, the prints are perfect--even halftone. Dev was MEH, but quality was great so I let it be. Now, I did replace the cleaning blade in a rush (because it was running very dirty) so what I found on the second visit certainly might have been overlooked.

Second visit: Only 500 additional clicks. Do the same load checks--PQ perfect (yay!)
Stick around and chat with the owner and drink a beer (after hours--lol) as he ran off about 3 reams of paper and lo and behold the it undertones again. He was running off letterheads... :confused:
So with a beer in one hand, I do the same load checks, run test pattern 12 100x and same reemerges. So I dig deeper and find that about half of what I am going to call the toner-screw-spring-agitator (I am too lazy to look up the proper name) was toner-welded to the housing (not the delivery tube, but the agitator that runs parallel to the drum). After about an hour with a chisel and hammer I finally got it removed and cleaned the housing.
This also caused portion of toner delivery tube housing to melt...

Not really looking for a fix or anything just wanted to share this. The guy is grumbling about replacing the machine. When I told him that aside from what he pays me and toner, nearly 750K for about $300.00 for a PM is pretty dang good! Also the only jam history were in the ADF lol...

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