Is It Time For a New Print Head?

7880
piezography

#1

My 7880 is equipped with the P2 Selenium ink set.

About a month ago, I replaced all eight Ink Holder Assemblies. Everything was running perfectly until yesterday. In the past week, I made about twenty-five perfect 13 x 19 prints.

But, while applying GO to one of those last prints, I got some black ink polluting the first half inch of the leading edge. I figured ink had built up on the print head, so, I performed Dana’s Piezoflush cleaning procedure on the print head, cap station, wiper blade, and box unit.

Then, I did an Auto Nozzle Check (see attached). It’s clean except it clearly shows the Light Black channel losing dots with each attempt to automatically correct the problem.

So, I’ve performed multiple power cleanings from the Adjustment Program— no improvement.

I replaced the Light Black damper—still no improvement.

The Epson 7880 service manual states the following:

When the dots missing appears in particular colors.

Check the Head Cleaner for any dirt. (did that‚ it’s clean as a whistle)

Check the junctions of the ink cartridges, Ink Holder, tubes, dampers, and the printhead for any abnormality. (Ink may be leaking by loosened fixing nuts, deformed or damaged O-ring. (no visible leaks, air pockets in tubing, or damaged O-rings)

Check if the printhead is defective. (not sure how to do this)

Perform the power cleaning again.

If the trouble still occurs even after performing all the troubleshooting described above, replace the parts listed below and check if it returns the printer to normal.

• PRINT HEAD
• BOARD ASSY., MAIN

Would you kindly share any tips for checking the printhead for possible defects? Or, any other remedies for missing dots in one channel?

Thanks!


#2

It looks to me like the LLK cartridge is losing pressure at the ink bay and the cleaning assembly is essentially getting less and less out each time creating back-pressure. If you look at the ink lines, you will most likely see clear air going quite a ways back well above the print-head.

It’s rare that a head dies with Piezo in it (especially an x880 head). My gut feeling is this is a back-pressure problem caused by something wonky on the ink-bay side.

Please look at the LLK ink line if you would.

best regards,
Walker


#3

Also, turn Auto Nozzle Check off. That can be a waste of ink. A quick manual nozzle check is the way to go to save $$$.


#4

Thanks, Walker. The LK ink supply tube is full of ink right up to the print head without air gaps. And there’s ink visible in the damper. But the pressure must be weak—it’s not making it into the print head—I pulled out the print head holder to confirm this visually.

On your hunch, I’ve just ordered a replacement ink tank valve assembly—and a back up. After reading your comment, I remembered that actually I had replaced only 7 out of 8 valve assemblies previously. One replacement valve had been delivered defective, so I left the old one in place; it must be the old one that has finally failed!

Thanks for your advice. I can’t wait to start printing again.