Problem with one of my P400 cartridges

I have an Epson P400. Today I topped off all carts and reset the chips. After running two head cleanings, I did a nozzle check that was perfect except for “PK” (which is matte black ink on the P400). “PK” was mostly blank on the nozzle check.

Since it had been a while since I had done a complete printer maintenance, I did one, including using the dummy cartridge and syringe with PiezoFlush on PK. I ran additional head cleanings, then a nozzle check. The PK nozzle check pattern was still bad. In fact, the nozzle check pattern had 50% gaps, then after a head cleaning, 100% gaps!

This leads me to suspect the problem is in the cartridge, not the print head. Perhaps the cartridge outlet is blocked. What do you think. Is there a procedure to unblock it?

I have an extra set of P400 carts. Should I replace the PK cart? Or is there a procedure I should try first that might fix the problem?

This is not a show-stopper since I only print digital negatives and PiezoDN does not use matte black ink. But I’m hoping to learn something in case this happens to one of my other inks.

Prime the P400 cartridge with a priming syringe or make sure to tap the cartridge on the edge of a table and let it sit a few minutes before placing it back into the printer. Also let it sit in the printer a few mins to settle before running a cleaning and nozzle check.


I’m glad to hear that the priming tip can be used for this. It seemed like the logical solution for a blocked outlet, but the cartridge fill instructions explicitly say only to use it when you fill a cartridge for the first time. I’ll give it a try. Thanks!