Epson 4000 "misfiring" nozzles?

[fh1969]

Hello everyone!

My Epson Stylus Pro 4000 suddenly printed pictures (matte Bk) which seemed to have not as much black as they should have.
I did nozzle checks (normal/auto) and everything was ok but not the Matte Black:
 
[attachment=18051:NozzleCheck.jpg]

The black lines are not always like a "stair": sometimes there are two with no offset.

[attachment=18052:NozzleCheck2.jpg]

The black printed block shows small areas of white and on the uppermost and lowest part there are white stripes all over the block.

I did: cleaning, power-cleaning (several times) with NO CHANGE in the pattern of the black block in auto nozzle check.
I did SSCL-Cleaning 3 times with some minor changes in the pattern but it even seemed to get worse...
I did the "drain some window cleaner in the parking-pad" and the "wet paper towel thing" but there is no change.
I did all the (vertical) alignments.

Is this something of "misfiring" nozzles that have changed the firing direction somehow?
Why ONLY on Matte BK?
How to repair???

PLEASE help me if you can  

Thank you!

[Michael Boyd]

It looks like all the "nozzles" are open, they just look out of alignment. Did you try the "auto-alignment". Was there recently a head strike?

If the printhead alignment doesn't work I would contact tech support. Just my two cents.

Hope you get it resolved though and good luck!

[fh1969]

Michael, thank you for your reply!

We moved the printer from one room to another (carefully) but without fixing the print head...
I will try the auto-alignment. If there is some change (for better) I will report.

Franz