HP Latex 310 print magenta very lightly

The problem started recently, about 3-4 months ago. Magenta began to print very lightly. This affects other colors. Printer print calibration tests have also changed. I enclose screenshots of printing tests on PP paper a year or six months ago and now on vinyl. You can see that the yellow test is sealed in red, but at the beginning of the test it is printed in yellow, as it should be. Filling with red occurs after about 3 centimeters during color calibration. Firmware updated to version 16 (last version), Flexiprint print program 19. Head status OK. The head test is good. The printer printed over 2k square meters. What could be the problem?

I have been printing a little lately. Cartridges expired for 1 year. But the magenta cartridge that was installed printed well, at the time of the test, 223 ml remained in the cartridge. The cartridge has been in the printer for a year now.

It is possible for significantly expired ink to fall out of solution, meaning the solids (including pigments) are no longer in suspension and have separated from the ink's base (water). It is sort of like Italian salad dressing that has not been mixed , where the oil separates from the vinegar.

Based on the images, it appears that several of your inks could be significantly past their expire date. Inks do not immediately fall out of solution on their expiry date, but as they age, it eventually becomes more likely. You can get the expire date for each color from the printer front panel, under the ink icon.

There are roughly 20 ml of each ink in the IDS tubes, and another 20 ml per color reservoir for each color in the printhead itself. It is possible to 'print' expired ink through the system, or to pull with a syringe. The latter option might be better suited for a service engineer to perform, as they should have the proper syringe and adapters needed.

#2 I did not notice this immediately, but the blue and yellow colors print lightly, also like magenta. At the same time, light magenta and light cyan on the new tests seem darker than before. How to explain that the yellow color bar on the right is sealed in red in the color calibration of the printer? The yellow bar is not sealed if you use a faulty printhead LM-LC, where only LM nozzles are faulty.