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tpt
01-27-2011, 07:17 PM
I'm working on a C451 that has wavy lines in the output. The worst offender is Cyan, but there are less perceptible lines in the other colors. I have attached the output of the Cyan Half-tone test sheet at 64 density. The lines are in the main output direction.

The cyan IU is relatively new, about 1400 copies and the drum surface looks OK.
I have cleaned the electrostatic wires and the PH windows.
The transfer belt did have some damage (visible lines), so replaced the transfer belt and roller.
I've checked the contacts for the Imaging Unit and they look clean.

So, is there something else I can look at before the PH unit itself?

907tec
01-27-2011, 08:06 PM
It's a little confusing that it is happening with other colors, but this image really looks like a "depleted developer" situation in the Cyan IU. Have you tried running TCR Adjusts or Gradation Adjusts? Check the TCR values for Cyan?

tech51
01-27-2011, 08:28 PM
Looks like dev depletion. Put a magnetic screwdriver in the waste bottle hole for the cyan IU and see if you get dev on it. I had a yellow one do this recently because its lock lever became dislodged when the waste bottle was changed. This allowed IU to move forwards slightly and it lost its bias connection.....

tpt
01-27-2011, 09:23 PM
Ok I tried the gradiation adjustments. it got some better for a few prints then went right back to were I was. I also tried the screwdriver and got developer. is there a way to tell if it is not locking into place?

Stirton.M
01-28-2011, 03:56 AM
In tech rep, Image Process Adjustmen, Increase the TCR Level Setting setting to 1 on the affected colour and then add toner via TCR Toner Supply. Perform a "reset and stabilize" procedure.

Check half tone to see if this corrects the problem.

Increase TCR Level one step higher and repeat if the problem is not corrected. Maximum is 3 levels, plus or minus.

The image unit should recover at one of these settings, at least, in the current state your scan has shown. I have seen units with worse condition recover, but this does not always work. The IU is failing, but you may still get a full life out of it in spite of this. Just remember to change the TCR Level back to zero when you replace the IU with a new one.

The lock lever that holds the unit in place, two black sponge pads, you can increase the thickness of these. I use the laser cleaning pads, cut one strip into little squares and stick those to the black pads. The increased pressure against the unit will keep it from drifting away from the bias contacts, which is usually why the IU fails in this way. The black IU, I triple up on the pad thickness. The black IU is notorious for dumping developer all over the inside where the unit sits, and the cleanup of this can be a serious pain in the ass.

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