uneven black line bizhub 750

[cristian]

Minolta bizhub 750.I have an uneven black line 0-5 mm thick on the upper part of allmost all copies.

[blackcat4866]

It sounds like a dirty primary charge wire or grid. Scan a page. =^..^=

[cristian]

I have done it.The scan is OK.Cleaned also the grid and all wires .the result is the same.an uneven line exact at the top of the page (2-3 mm), uneven as thicknessand... plus another line with interruptions 1 cm below (0-5 mm).

[minimerlin]

Minolta bizhub 750.I have an uneven black line 0-5 mm thick on the upper part of allmost all copies.Fuser rollers damaged by dev /toner spills?

[blackcat4866]

No, ... I meant scan a sample page, then attach it to this thread. =^..^=

[cristian]

190351903619037

[cristian]

fuser rolls are clean, both

[blackcat4866]

I'm sticking with my dirty grid diagnosis. You know, all it takes is a microscopic fiber of lint to discharge the grid to the drum. They can be very hard to see even when you know it's there. =^..^=

[cristian]

You are right.I have cleaned again the wires with a small piece of fibreglass (indeed was a small knot) and the problem was solved.Thank you .
PS. Another problem that i have seen on this machine.The drum is starting to take damage (matt and screched) for 3 cm from the inside part.The transfer rubber roller is also a little damaged.Think is from the toner leeks...but is also badly screched .Last time when i have check the machine i have cleaned the developper, but the damage is extended.Any ideas?

[cristian]

Thank you again. A little bit difficult machine....

[blackcat4866]

... PS. Another problem that i have seen on this machine.The drum is starting to take damage (matt and screched) for 3 cm from the inside part.The transfer rubber roller is also a little damaged.Think is from the toner leeks...but is also badly screched .Last time when i have check the machine i have cleaned the developper, but the damage is extended.Any ideas?

Are we talking about the same machine? The bizhub 750 has a transfer wire, not a transfer roller.

I'm very confused. :confused::confused::confused:

=^..^=

[cristian]

Sorry about the delay.It was 3 a.m. when i have post you the last message.Yes, is the same machine.It is the toner guide roller and not the transfer roller .Anyway i have saw some drums before became mat but no one so scretched... unless the developer contain some foreign particles. So, 1 week ago i have put the developer through a sieve and seems to be clean,also i have cleaned the toner guide roller with a soft cloth, but the mat area and the scretches are growing.I have also search the contact points who could cause the scretches and i have find that the owner use the machine also for A4-R, and when it does, there are some toner leaks in the precise area of the scretches, and the metal is also screthed according to the position from the photo.Think maybe this is the cause.19039

[Darren King]

There are mylar "drum protection sheets" on each end of the transfer corona. They are about 4mm wide and wrap around the transfer entrance guide. They become worn and need to be replaced regularly. When they are worn the metal of the guide contacts the drum and causes damage.
Check these small mylars and replace if needed. KonMin sells these mylars. I can't remember the part# off hand.
Just found part# 56AA17840

[cristian]

Thank you.I will check them.

[Toner Boy]

Your drum wear could have been caused by the corona block cover not being completely seated (yeah, did it myself once), caused grid to ride too close to drum with light contact on the front side. Could this be your drum wear issue? Maybe its solved since you cleaned the grid again...

[JustManuals]

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[methogod]

2-3 MM line at top of page, i need to have you run that with a test sheet off the glass...


write...

numbers like this...

1 2 3

4 5 6

7 8 9

it doesn't have to be perfect, make copies running as letter and letter-R. need to see results.

I think its your "slit glass", there is a clip, that acts as a stop spring, sometimes when you close the process unit you can push it in too far or not far enough. Alliteratively it can be dirty, some toner spilled... either way my first place to look, it its on both copies and prints.

[Toner Boy]

Crap, I just ran into this problem with the 'drum protect strips'. It killed a new drum in only 20K pages. There was no listing for this part number in my parts guide, 56AA17840. The front one is damaged and left no space between the drum and transfer unit guide. Live and Learn I guess.

[EarthKmTech]

if the lock tight(ed) factory alignment screws come loose and vibrate out of position this will also end up with a scratched drum. It's cheaper to simply change the transfer charge unit for a NEW one instead of continually risking new drums which are more expensive. (unless you are using crappy katun drums, then who cares)