No ink in channels green/orange 7900. Pump problem?

To convert an used 7900 to piezo (with some problems on line green and orange) I followed all the procedure to clean it with piezoflush and with piezoflush refillable cartridges.
After two INIT FILL and some cleaning cycles (powered cleaning, - NO SS cleaning (!)), I discovered that the lines green and orange stay totally empty. The capping station, flushing box are clean. I checked the exit channel of the cartridges, everything is ok, piezoflush enters to the syringe. With your experience, do you think that the problem comes (only) from the pump? or it could be something else?
Thank you for your help.

Do you have a second set of carts that are un-used? If you do and fill the orange/green carts w/ PiezoFlush and prime and put in and run a CL4 (from the maintenance menu) cleaning on the Orange/Green channel pair this will either purge the ink properly (in which case we know the ink carts are faulty) or not (in which case we know either the damper or cleaning assembly is funky).

If the carts are funky we can get you out a replacement set pronto.

If the damper or cleaning assembly is the issue, Pro will still work perfectly. Just use the K4 profiles and we can refund the Very Light Black ink bottles.


Hi Walker, yes I have a second set of carts, I will try your solution. The last owner didn’t use the 7900 for more than 6 months so this channels problem is not a surprise. The end of the green channel is without ink, but the start near the cart is full of green ink, same for orange.

You wrote on the piezography pro forum that an "old firmware does not properly equalize pressure between carts (especially when doing init fills).“
Since I’m using piezo inks I kept always in mind " NEVER make a firmware update, NEVER”… :slight_smile: My actual firmware seems old HN029AA (10/29/10?) Last one: HN124G5 - June 2016.
Do you think that it could help (a little bit) for this problem too?
Thank again for your help.


So I changed the orange and green carts, did two CL4 (after a firmware update). The problem stay the same. Now I wonder if I should not change the damper, I really don’t pay “dearly” the 7900, or keep it like this and go to pro k4. Is the difference between Pro k4 / k5 “significant” or equivalent to k6 / k7?. I’m super happy with my 9800 P2.

The K4 is very similar to the P2/K7 difference but we only have master curves out there in K4. That said, Pro is incredibly linear on all papers even w/ the master curves.


Hi Walker,
master curves is perfect, linearization is a pleasure with PPE :slight_smile:
I found some posts here about “replacing dampers”, the procedure does not seem easy but not too complicated either, I will study it for later…
thank you again


I decided to start with ProK4 and I am really impressed, despite the piezoflush still slightly present, and more visible, in the Gloss chroma. The master curves are really good, but I think linearization remains useful. On P2 the linearization offered me a softness in the passage of gray incomparable.