My Epson 7600 was printing great. I use it a lot. suddenly started printing light but balanced color but when I darkened the image the color balance was not right. then it started having random jets not printing and got worse now when I do a cleaning and all 7 colors are up but a few jets blank it only prints images in Black, Yellow and Light magenta. I have been printing with this and 2 other previous 7600 printers for a long time (16 years) this 7600 only 2 years but was hardly used when I bought it to replace one that had been running for 14 years.This problem is unique and not mentioned in the manual
The cleaning process uses wet ink to clean out the dry ink. There are cleaning fluids sold on the web that are designed for the purpose. Do a search for epson cleaning kit.