Thanks Walker, I printed out Tip #2 for easy reference as I went through the steps. I did all the steps (sponge pad, rubber gasket around pad, wiper blade) as carefully as I could, but my K cartridge pattern remains exactly the same. In fact, the magenta position nozzle check is now showing gaps as well. I thought maybe that cart was low but it doesn't show as low in the ink level diagram. All carts are about 1/3 full. And the InkThrift CL EasyFill key does not have a transparent side for a visual check.
Before reading this document I had performed an underhead cleaning (aka shoe-shine). I was gentle but I hope I didn't scratch the head's under surface with a portion of the paper towel that was not soaked in Piezoflash. Is there any way to check that?
Any suggestions as to how to proceed would be most welcome...