Toshiba 4520c Losing developer

[TTL]

Hi..

I have one Toshiba E-Studio 4520c who is losing black developer, sometimes it lasts about 20k copies others 80k, but it always disappearing.
I try change the main charge, the terminal in the machine, the terminals in the belt, and change the complete drum unit, but stills losing.
The colors are all good.

Some ideas?

[zeeeba]

Re: Toshiba 4520c Losing developer

Hi, we have same problems with that macine type (2330c), when the machine loosing black or color developers. After long searching what is the problem we founded that then toshiba manufactured first machines of that series 4520c, 2330c they putted wrong magnetic roll in developer unit, it have wrong relief and Your machine don't loosing developer but magnetic roll can't handle the developer on it self and then you have problems. Now You just need order new magnetic roll kit for developer unit and you solve the problem. After changing magnetic roll You can use old developer and it works fine.

[Aethanite]

Re: Toshiba 4520c Losing developer

The above post is correct in certain aspects BUT i don't think this is the cause of your issue.

You will have either one or two issues here.

1st check that the developer cover has the pad's still in place at the rear and front of the cover. If these are not there, developer will spill out from these gaps and you will loose developer. Toshiba have modified the cover over time to prevent this, but the earlier machines all had this problem with the pad falling off. Also do a quick check to see if there is any deteriation of the foam along the sides and around the filter as this will also spit out developer.

2nd check that the blinking array (Discharge LED) is working. I've had now 3 machines from the 20 series, all within the black unit, loose dev in weeks due to only half of the lights working. You can see if they are working or not by starting the machine in 0 3 mode (Output test) and using code, i think from memory code "235" will light up the black discharge array. I dare say what you will find is half of the lights are working and the other half arn't. And of course, if the discharge LED's don't work, this problem will occur. 236 is the code for the Y/M/C lamps if your interested as well.

Strangely i've only had this happen on the 20's series machine and only on the black unit.
Let us know how it goes!

[zeeeba]

Re: Toshiba 4520c Losing developer

I don'agree what is not the cause of the problem because, we have technical bulletin (bsi note) from toshiba, where are writen what problem is with magnetic roll in developer unit. And we have about 10 machines this type, and after changing magnetic roll all problem with developer loosing is gone. Yes practically You maybe find the solution but it will be not for long time.

[TTL]

Re: Toshiba 4520c Losing developer

Thank you for the answers.
In this case is not the magnetic roller, is a Knurling-type magnetic roller. The developer cover has all pad's in the right place, and is in good condition.
The discharge led is working, but I never remember that, gonna check if is all working.

This time the machine is working again, gonna wait some more time to have sure that is all ok. I changed the HVT board, and a therminal.

[canonbundy]

Re: Toshiba 4520c Losing developer

Thank you for the answers.
In this case is not the magnetic roller, is a Knurling-type magnetic roller. The developer cover has all pad's in the right place, and is in good condition.
The discharge led is working, but I never remember that, gonna check if is all working.

This time the machine is working again, gonna wait some more time to have sure that is all ok. I changed the HVT board, and a therminal.

Hi TTL, is the Developer Unit actually emptying? Is the Dev migrating to the Waste Toner container, is it dumping inside the machine???

We have a lot of MASH Series Units in the field and this model would be the cleanest of all the Tosh Colour Units made.
One of the main problems was the Mag Rollers got smooth after 100K and therefore unable to hold the Developer, the fix (at the time) was to lightly & evenly roughen the surface of the Mag Roll Sleeve with fine grade emery paper (which worked well) or replace the Mag Roll with the newer Fluted Type Roller (which is expensive, time consuming & eventually unnecessary).

The other guys Posting are on the right track here, so check the above & Post your findings .

Cliff.

[Bicyclerepairman]

Re: Toshiba 4520c Losing developer

Have you tried swapping the dev unit?

[TTL]

Re: Toshiba 4520c Losing developer

yes, I swapped the black unit 2 times, but happened the same. Must be something in the machine.
The developer is not in the machine, I think that is going to the Waste Toner container.
The magnetic rollers are good.

[Bicyclerepairman]

Re: Toshiba 4520c Losing developer

check non image areas on drum for toner, poor drum ground?

[Marcotoshiba]

Re: Toshiba 4520c Losing developer

The above post is correct in certain aspects BUT i don't think this is the cause of your issue.

You will have either one or two issues here.

1st check that the developer cover has the pad's still in place at the rear and front of the cover. If these are not there, developer will spill out from these gaps and you will loose developer. Toshiba have modified the cover over time to prevent this, but the earlier machines all had this problem with the pad falling off. Also do a quick check to see if there is any deteriation of the foam along the sides and around the filter as this will also spit out developer.

2nd check that the blinking array (Discharge LED) is working. I've had now 3 machines from the 20 series, all within the black unit, loose dev in weeks due to only half of the lights working. You can see if they are working or not by starting the machine in 0 3 mode (Output test) and using code, i think from memory code "235" will light up the black discharge array. I dare say what you will find is half of the lights are working and the other half arn't. And of course, if the discharge LED's don't work, this problem will occur. 236 is the code for the Y/M/C lamps if your interested as well.

Strangely i've only had this happen on the 20's series machine and only on the black unit.
Let us know how it goes!

Many thanks Aethanite, your tips are very helpful!

In the last three months i went crazy about this issue: I've checked and cleaned or swapped almost all the stuff around dev unit K: needle electrode, grids, charge assembly,high voltage terminals, cleaner assembly...

Despite all of these actions... even the same empty developer unit (CA00 and so on...) after few weeks.

After reading your post, i found exactly what you have described on two machines in our field: one 4540C and one 2040C: the rear side of black-unit erase lamp is fully off, and even, in the worst case, the half-front side fading and blinking.

Watching very closely the lamps Printed Circuit Board, you can see a sort of some black spots of a kind of corrosion over the copper path to the rear side of the LED array.

In some cases, that corrosion even involves some SMD resistors.

Lamps affected are only under the black units. It's bizarre but it's true.

Thanks again !!!

Marco.