"Ink blot" after Mita copier toner change

[thegreatpain]

Changed toner in my Mita CC35 copier. The quality of the copies it
started making after the change is quite frankly appalling. The more
copies I made, they worse they looked. I opened the thing and had a
look at the drum. Expecting red or green, it was actually almost
completely grey. I cleaned the part I could access with a dry ball of
cotton and made a single copy, which now produced three horizontal
white areas where there had before been only dark grey.

So repeated the steps a few times, making a single copy inbetween every
cleaning since the drum had to be revolved. Gradually the brightness
increased, but was still far from acceptable.

After half a dozen cleanings, this was the resulting copy:
http://img414.imageshack.us/img414/8845/fre0mq.jpg
Made a few more, which gradually worsened until..
http://img161.imageshack.us/img161/4931/efter5ol.jpg

These are only blank copies. If I use printed paper, the resulting copy
looks like the original, but with the "ink blot" on top of it.
It's obvious the machine is charging the drum where it shouldn't (and
perhaps failing to clean it?). Why is this happening, and why did it
happen after a change of toner cartridge? The cartridge is separate
from the drum.

Any insight you can provide would be greatly appreciated!

 

[Tony]

Changed toner in my Mita CC35 copier. The quality of the copies it
started making after the change is quite frankly appalling. The more
copies I made, they worse they looked. I opened the thing and had a
look at the drum. Expecting red or green, it was actually almost
completely grey. I cleaned the part I could access with a dry ball of
cotton and made a single copy, which now produced three horizontal
white areas where there had before been only dark grey.

So repeated the steps a few times, making a single copy inbetween every
cleaning since the drum had to be revolved. Gradually the brightness
increased, but was still far from acceptable.

After half a dozen cleanings, this was the resulting copy:
http://img414.imageshack.us/img414/8845/fre0mq.jpg
Made a few more, which gradually worsened until..
http://img161.imageshack.us/img161/4931/efter5ol.jpg

These are only blank copies. If I use printed paper, the resulting copy
looks like the original, but with the "ink blot" on top of it.
It's obvious the machine is charging the drum where it shouldn't (and
perhaps failing to clean it?). Why is this happening, and why did it
happen after a change of toner cartridge? The cartridge is separate
from the drum.

Any insight you can provide would be greatly appreciated!

I doubt very much that the problem is toner related, you have a repetitive
defect. The vertical distance between the start of the defect and the start of
the next identical defect will coincide precisely with the circumference of a
drum or roller in the copier. Most likely the imaging drum. It is most unlikely
to be anything else, fuser problems do not normally exhibit this variable
behaviour.
I suspect it is coincidence. Cleaning the drum may have made it worse because
some of the lubricant may have been removed during cleaning.
Tony

 

[thegreatpain]

Thanx for the reply!

Got any ideas on fixing this? Without replacing the drum, that is (well
expensive I gather).

I cut power to the copier before the paper had gone through the fuser,
and sure enough it was covered in toner according to the pictures.

It's strange though, the dark areas have vertical white lines in them,
as if something is dragging along the drum, forming patterns on it
(this can be seen on the drum too - it's grey with red lines along it).
The bright lines are also amplified if I print onto the same paper
twice! I don't know how the drum is discharged when it has transferred
the toner onto the paper - is there a corona wire discharging the drum,
and a brush of some sort to collect any residual toner? Could these
brushes be forming the bright stripes?

How is a drum damaged? Chemically? Mechanically? Does it age?

Worth emphasizing; the drum is still capable of forming brighter areas
in all that black, if the original so requires, so there doesn't appear
to be a full breakdown of its conductive abilities.

 

[Tony]

Thanx for the reply!

Got any ideas on fixing this? Without replacing the drum, that is (well
expensive I gather).

I cut power to the copier before the paper had gone through the fuser,
and sure enough it was covered in toner according to the pictures.

It's strange though, the dark areas have vertical white lines in them,
as if something is dragging along the drum, forming patterns on it
(this can be seen on the drum too - it's grey with red lines along it).
The bright lines are also amplified if I print onto the same paper
twice! I don't know how the drum is discharged when it has transferred
the toner onto the paper - is there a corona wire discharging the drum,
and a brush of some sort to collect any residual toner? Could these
brushes be forming the bright stripes?

How is a drum damaged? Chemically? Mechanically? Does it age?

Worth emphasizing; the drum is still capable of forming brighter areas
in all that black, if the original so requires, so there doesn't appear
to be a full breakdown of its conductive abilities.

Firstly the streaks are caused either by a worn drum or a failed wiper blade
(not sure what Mita use but there will be something in the drum unit that
cleans the drum, often called a wiper blade by other manufacturers). If the
drum has very fine lines running around the circumference ("very" fine indeed)
these can collect toner which is not cleaned off, or the wiper blade is worn
and is failing to clean the drum. Your second image indicates both a worn drum
*and* a worn wiper blade. The drum causes the repetitive marks and the wiper
blade causes the continous marks. It is not unusual for both components to fail
in a similar timeframe with some drum units. The white lines in the gray areas
are caused by tiny areas of the wiper blade that have not failed yet, so the
blade is still doing it's job in those areas.
Drums age naturally, they can be damaged by too much exposure to light and
simply through use, wiper blades eventually fail due to mechanical stress and
wear. Both are replaced with a new or properly remanufactured drum unit.
If I thought it was only the drum I would suggest that nothing would be lost
trying a drum reconditioner or (if available for this printer) a generic drum
but since the wiper blade also appears to be failing I am afraid that a
replacement "drum unit" is necessary.
It is typical of drum failure that portions of it fail first and with time it
just gets worse.
Sorry there is no shortcut I am aware of unless you can source a drum and blade
and rebuild the "drum unit", even then there are pitfalls to avoid and I do not
know how easy or difficult it is to dismantle this particular drum unit.
Tony

 

[thegreatpain]

Thank you for your extensive replies Tony. Since I'm not risking
anything at this point, I'm going to open it up.