MX6201 Yellow Print Quality

[OEC]

Hello Gentlemen,

We have a MX6201 with irregular density across the Yellow.

The other colors are working fine with no issues. It appears that the center of the image is fading out, while the rear/front frame edges have solid/heavy density.

What we have tried:

Replacing Y drum
Replacing Y DV
Replacing Primary TX Belt
Removing/cleaning LSU/mirrors (thoroughly)
Removing/Swapping Y LSU Shutters
Swapped the DV unit track (the black plastic piece that the shutter is attached to)


We swapped the M and Y DV/Drums to get the Magenta sample that is attached so it would appear that this is definitely related to the specific position and not to the consumables.

We are currently checking the frame to see if it is level and if there is any warping that would cause this.

Any suggestions would be greatly appreciated!

Thank you for your time and I look forward to your idea.


Attachment 19920

[bilyahn]

Looks like your problem followed the drum. Did you change the entire unit or just the drum? Did you change the charge unit?

Good luck.

Bil

[Akitu]

Check the LSU Solenoid, if it's weak, the shutters won't open all the way. The black and cyan will always be good as they're on the right side end, which is furthest away from the solenoid, so it gets all the tension from the solenoid pulling and rarely fails. As you get closer to the left side with the solenoid, there's less pull tension on the yellow and magenta shutters and causes a faded area around the middle.

Take all the drums/devs out and trip the front cover switch. Run sim 6-01 LSUSS (lsu shutter solenoid) and watch the shutters open/close. They'll probably be sluggish and not opening fully.

There are usually 2 causes:

There is dev inside the solenoid plunger. As the solenoid sits directly below the yellow dev, any severe dev leak previously will cause dev to drop down and when the solenoid activates, its obviously attracted to the magnet of the solenoid and it enters the plunger. This prevents the plunger from fully operating at full power and causes the shutters to not open completely.

There is dev/toner/grease under the rear shutter drive arm (the drive arm at the back which drives all shutters at the same time). Apply a few small drops under that drive arm so it slides on the chassis of the frame much smoother. If there is excess tension on that drive arm when the solenoid is trying to pull the shutters open, they don't quite open all the way, always effecting yellow and mostly magenta too.