C6500 Magenta spots

[Frostwolf]

A tech changed out all 4 drums (DU-104), dev units and developer, charge assy's and 250k pm. Now we have magenta spots showing up on the copies, no pattern, random about 2 to 5 per page.

We have since tried another developer unit with fresh dev, another drum, (swapped with another color first then tried DU-102c). Still spotting. I've now went through to check for good suction, I found the seals in the back are deteriorating and the seals above dev units are gone/deteriorating. We put new seals above the developing units and waiting for new seals to come in for the back. I've read that some people say to remove some filters from the suction filter. Does anyone else have any suggestions.

Only the Magenta is sprinkling.

Thanks in advance

[Rocini.jr]

A tech changed out all 4 drums (DU-104), dev units and developer, charge assy's and 250k pm. Now we have magenta spots showing up on the copies, no pattern, random about 2 to 5 per page.

We have since tried another developer unit with fresh dev, another drum, (swapped with another color first then tried DU-102c). Still spotting. I've now went through to check for good suction, I found the seals in the back are deteriorating and the seals above dev units are gone/deteriorating. We put new seals above the developing units and waiting for new seals to come in for the back. I've read that some people say to remove some filters from the suction filter. Does anyone else have any suggestions.

Only the Magenta is sprinkling.

Thanks in advance

Wich size of page you're printing? a good way is try some A3 pages in sequence, to see if you have a pattern on the spots between the pages.
Did you make the toner density/gamma calibration after the developer change? The developer powder can going out the unit cause the density on unit is too high... or the BIAS used on the dev unit is too high cause the machine is assuming an older dev powder.

[Arcadian]

A tech changed out all 4 drums (DU-104), dev units and developer, charge assy's and 250k pm. Now we have magenta spots showing up on the copies, no pattern, random about 2 to 5 per page.

We have since tried another developer unit with fresh dev, another drum, (swapped with another color first then tried DU-102c). Still spotting. I've now went through to check for good suction, I found the seals in the back are deteriorating and the seals above dev units are gone/deteriorating. We put new seals above the developing units and waiting for new seals to come in for the back. I've read that some people say to remove some filters from the suction filter. Does anyone else have any suggestions.

Only the Magenta is sprinkling.

Thanks in advance

I would also check the corona wires.
Sometime you get a bad one.

[Frostwolf]

Wich size of page you're printing? a good way is try some A3 pages in sequence, to see if you have a pattern on the spots between the pages.
Did you make the toner density/gamma calibration after the developer change? The developer powder can going out the unit cause the density on unit is too high... or the BIAS used on the dev unit is too high cause the machine is assuming an older dev powder.

12x18 shows no repeating patterns. All the calibrations were done by myself, and it appeared the 1st tech did his adjustments correctly. All developer units and developer were new including the dev unit I used to check the Magenta. The spots on the page had no developer, just toner. (see attached for sample)

I would also check the corona wires.
Sometime you get a bad one.

I swapped coronas with another unit, and the problem didn't move.

Possibly Solved: Seals on the inside back of the machine had gone bad, the sponge had deteriorated. (See attached pictures, old on left, new on right and then another old by itself) All 5 pieces swapped out, the cyan and black were worse. Also the seals above the developer units had gone bad, I couldn't order those, so I improvised using C451/C550 Cleaning Pads (6 each of A00J106202) cut into 3 strips. The suction filter I reduced to 4 filters as suggested in another post.

Thanks for the suggestions

(2mb photos of the parts)

[CopyJunkie]

There was a Tech Bulletin (8865) that talked about a very similar problem on C7000 which stated it was caused by bad toner.

[texchar555]

There was a Tech Bulletin (8865) that talked about a very similar problem on C7000 which stated it was caused by bad toner.

got the same thing but when cleaning out the hopper unit and vacumed out the dv unit then adding new dv. I started getting white spots or void spots on magenta test #53 at 255. I think the bad toner is messing up the dv units.

[texchar555]

got the same thing but when cleaning out the hopper unit and vacumed out the dv unit then adding new dv. I started getting white spots or void spots on magenta test #53 at 255. I think the bad toner is messing up the dv units.

09/06/13 new update, did not replaced the magenta dv and dv unit. It turns out that if you go to process fine adj and go to ac dv bias and change the magenta default 0 to -3 it will go away. hhmmmmm must be because the dv has changed.