Mp 9000 random smudge... I'm gone mad!

[exCSER]

Re: Mp 9000 random smudge... I'm gone mad!

Hey I don't work on that particular model, but just to throw it out there: because one edge of the smudge looks straight, maybe part of the smudge has been cleaned by the drum blade, and if so, could it be on the drum after printing. Therefore, caused by a blanking lamp (or whatever it is referred to in that model). Charge not being completely eliminated from the drum? Just a thought.

[Codex]

Re: Mp 9000 random smudge... I'm gone mad!

What part of new do you not understand.

Of course we have all new parts... But first i want to understand the problem, to change the faulty part with an new one. The drum i've swapped have 100k clicks.

Inviato dal mio SM-G935F utilizzando Tapatalk

[Codex]

Re: Mp 9000 random smudge... I'm gone mad!

Does the smudge appear when coping through the ADF only ,off the platen glass only , print only?

Do you have an sample copy for the different times the problem occurred?
Lets say a sample of the fault for Monday, and a sample of the fault for Friday.
Can you overlay the sample copies one on top of the other, hold them up to the light; is the fault blurb an exact match ?
If the blurbs are an exact match you can rule out insects or rodents moving around in the optics.

I would lean toward quenching lamps/laser.
Maybe paper dust build up behind the rego roller???

The above might jog a light bulb in someone.

The smudge appear in print and copy, it's ever on the same "line", but not on the same place, if i overlay two sheets the blurb doesn't match. If you look the fotos there are taken at different days

Inviato dal mio SM-G935F utilizzando Tapatalk

[slimslob]

Re: Mp 9000 random smudge... I'm gone mad!

The smudge appear in print and copy, it's ever on the same "line", but not on the same place, if i overlay two sheets the blurb doesn't match. If you look the fotos there are taken at different days

Inviato dal mio SM-G935F utilizzando Tapatalk

My guess is that the smudges are roughly the same distance from the front edge of the drum. Since you say it does it with 2 different drums, I would say that the smudge from the two drums are not the exact same size, shape and distance from the front edge. They are smudges on the surface of the drums caused by mishandling the drum when first installing, possibly a palm print. Tje straight line on one edge of the smudge is from the edge of the protective paper that is wrapped around a new drum.

[Codex]

Re: Mp 9000 random smudge... I'm gone mad!

My guess is that the smudges are roughly the same distance from the front edge of the drum. Since you say it does it with 2 different drums, I would say that the smudge from the two drums are not the exact same size, shape and distance from the front edge. They are smudges on the surface of the drums caused by mishandling the drum when first installing, possibly a palm print. Tje straight line on one edge of the smudge is from the edge of the protective paper that is wrapped around a new drum.

The smudges doesn't match each other but they are exactly on the same height on the sheet... The strange thing is they appear for some copies... Than disappear for days or sometimes weeks... And then back again.... Without touching or removing the pcu unit

Inviato dal mio SM-G935F utilizzando Tapatalk

[keithxxiii]

Re: Mp 9000 random smudge... I'm gone mad!

Although we can say it is an electrical problem, probably from the charge, do not discount the dirt that is stuck from the web assembly. Poor cleaning on the unit may cause the build up on the cover when paper jam occurs.

[NeoMatrix]

Re: Mp 9000 random smudge... I'm gone mad!

The smudge appear in print and copy, it's ever on the same "line", but not on the same place, if i overlay two sheets the blurb doesn't match. If you look the fotos there are taken at different days

Inviato dal mio SM-G935F utilizzando Tapatalk

Gecko or cockroach in the optics....

Swat the little sod...

.
.
.
Dunno with the print side of it....

What happens when you run a 100 pure blank(white) copies or prints ?
Does the blurb enlarge or reduce when you size up or size down ?
Any difference with a double patterned blurb/smudge when using A3 paper ?

[eccelobo]

Re: Mp 9000 random smudge... I'm gone mad!

It is very similar to the kind of smudge produced by sunlight over the drum. I know it's almost impossible, but could it be that some light is getting through to the drum?

Enviado desde mi SM-G920V mediante Tapatalk

[kleankopy]

Re: Mp 9000 random smudge... I'm gone mad!

I have definalty seen this before and I will look for my notes but iam thinking it was the transfer belt unit.

[Codex]

Re: Mp 9000 random smudge... I'm gone mad!

It is very similar to the kind of smudge produced by sunlight over the drum. I know it's almost impossible, but could it be that some light is getting through to the drum?

Enviado desde mi SM-G920V mediante Tapatalk

The machine is in a very dark environment... My idea was some kind of flash or light caused by a spark i side the machine... But i have no proof of this

Inviato dal mio SM-G935F utilizzando Tapatalk

[Bantams]

Re: Mp 9000 random smudge... I'm gone mad!

Could be condensation on the drum due to blocked or completely over pm ozone filters

[JDYAL]

Re: Mp 9000 random smudge... I'm gone mad!

Could be cause by an arc of electricity near the corona block. That would explain the straight edge of the blob. I would pull the power packs and check the connectors. A small crack in these connectors can cause arcs.

[Lagonda]

Re: Mp 9000 random smudge... I'm gone mad!

Could be condensation on the drum due to blocked or completely over pm ozone filters

Plus one with that one.
My unproven theory is that it is caused by change of temperature and humidity over night while the drum sits in one place with a poor air flow over its surface. The straight line is caused by the cleaning blade blocking the air flow. We see the same often on copiers with drums nearing the end of their life, usually as a blurred patch that comes and goes and occasionally a dark patch like yours.
The only remedy is a new drum and filters then change the filters when they should be changed at every PM around 300k.

[NeoMatrix]

Re: Mp 9000 random smudge... I'm gone mad!

Plus one with that one.
My unproven theory is that it is caused by change of temperature and humidity over night while the drum sits in one place with a poor air flow over its surface. The straight line is caused by the cleaning blade blocking the air flow. We see the same often on copiers with drums nearing the end of their life, usually as a blurred patch that comes and goes and occasionally a dark patch like yours.
The only remedy is a new drum and filters then change the filters when they should be changed at every PM around 300k.

Thanks for the headsup....

You're talking about a Hydroscopic moisture type of effect . Given the warmth of the machine and cooling down at night
its an interesting probability.

Re. Drum Sweat Burn, Light Burn or Arc burn.
Wouldn't the smudge/blurb be a static constant and the exact same pattern on the drum every time for each copy?

It's interesting in that the blurb on the copy comes and goes over time with some type of regularity.

I wonder if they run a lot of labels or foils through the machine. It may account for aluminium or glue around the drum ?

.
.
.
Like a well oiled TV soap opera, I'm waiting for the next exciting episode of this thread so I can find out what the fault was...

[Mark Bbb]

Re: Mp 9000 random smudge... I'm gone mad!

interesting phenomena!
Why was there no charge at that particular place at that particular time?
1. something came between drum and charge (piece of paper?) => unlikely
2. charge went away due to power supply unit or power pack failure. => possible
3. in wich conditions is the machine standing? In a normal office? What is temperature overnight?
What is the exact time when the dot is printed? Perhaps another big machine in the factory is than put to on...?