Windex and other ammonia and/or alcohol cleaners can be great for cleaning, but are not good for the long-term health of your printer, especially the print head (which is one of the most important parts of your printer). For cleaning the bottom of the print head, it's best to use our PiezoFlush solution, or even warm distilled water is pretty good at cleaning without harming the head. I believe using ammonia or alcohol cleaners on the capping station, flushing box and wiper blade is probably ok, but I personally use PiezoFlush to clean all the internal parts of all our printers, and have several printers that are 7+ years old and still working very well after a history of good maintenance routines.
You are doing auto nozzle checks, where the printer prints the blocky nozzle check, then reads the printed pattern and either does a cleaning cycle (if it senses any gaps), or prints the next section of four positions (if the first four printed well). I personally never do auto nozzle checks and always do manual nozzle checks (all positions print on one line, with horizontal dashes for each nozzle, which I examine visually).
If you haven't already, I recommend you clean the capping station, wiper blade, flushing box, and bottom of the print head using Bounty White paper towels and either warm distilled water, or PiezoFlush for even better cleaning power.
Also, when were the dampers last replaced in this printer? How often do you agitate the ink cartridges to maintain in-suspension pigment? On average, how often do you use the printer vs. how long does it sit unused? What is the humidity level in your printing environment?
Please let me know so I can help you get past this and back to happily printing.
Best regards~ Dana