3880 black ink swap, residual ink in lines

[Jeff-Grant]

I have been using Cone K7 inks in my 3880 and only printing matte for some months. I just swapped to PK and ran a linearity check straight after the swap. The linearity check shows that it is off compared to the last time I used PK. It occurs to me that swapping inks must leave residual ink in the lines that need to be flushed. I would love to know how much printing needs to be done to clear all the other ink.

I assume that the same issue must exist with Epson inks, I'm just not in the habit of checking as I am with the K7 inks. Can anyone confirm that the same applies to Epson inks. I've never read of it as an issue but I also have never looked for it.

[Jager]

I've not experienced that, Jeff, either in my 3880 running Cone's K7 or in my P800 running OEM inks.  I do switch between matte and photo inks fairly often, rarely going more than a couple weeks.  So perhaps that makes a difference?

Presumably your linearity improves after making a (throwaway) print or doing a power-clean?  You shouldn't have to do either, of course - you would expect Epson would have dialed in how much ink must be flushed on each changeover, but who knows.

[Jeff-Grant]

Thanks Jeff, it's certainly happening on K7. I've started a thread on IJM which is focussed on K7. I was really wondering whether and how this works on OEM inks. I may not have noticed except that I was printing 21x4 targets.

[howardm]

I've not experienced that, Jeff, either in my 3880 running Cone's K7 or in my P800 running OEM inks.  I do switch between matte and photo inks fairly often, rarely going more than a couple weeks.  So perhaps that makes a difference?

Jeff,
How long have you been switching inks in the 3880?  I've heard that the ink selector valve/switch in the 3880 is a weak spot so I switch very infrequently.

[Some Guy]

This is from the online spec sheet on the P800 so maybe similar to the 3880:

Ink Used during switch:
Matte to Photo Black    Approx 4.6ml
Photo to Matte Black    Approx 1.6ml

When I had mine torn apart, there were 8 ports under the PK/MK switching affair on the head.  One is the shared MK and BK and it has the dampening pads so most likely some remains in there as well as the exit ports on the valve.

When I first got my K7 piezo kit I had an awful time clearing the yellow and magenta colors from the K7 inks.  Actually, the first full $500 set flushed the lines so it was an expensive flush kit.  I wish I had installed the K7 inks to begin with as the colors tended to linger far longer than I had wished.  Sometimes a blob of yellow would show in the highlight tones in the first kit.

My last MK to PK on the color printer was a mess in that I lost the PK ink for a new print right after the switch.  Nozzle check showed nothing in PK land.  Had to do several cleanings and letting it sit overnight before they began showing up again.  Lots more ink lost, and I had to do a maintenance cart switchout too.

Personally, I wish Epson would combine their PK and MK inks somehow and ditch the silly and wasteful switching (Least they benefit from sales of the $$$ stuff.).  I put an overcoat (Premier Art spray, or another run or two through with the G.O.) on all mine so the gloss or dullness is sort of neutralized anyway.

SG

[Jeff-Grant]

Thanks SG, this sort of stuff makes me long for a universal black ink. I know we are meant to suffer for our art... Having read about getting rid of yellow, I got a new 3880 and put K7 in it from the outset. I hope not to have the same dramas that you have had.

[Jager]

Jeff,
How long have you been switching inks in the 3880?  I've heard that the ink selector valve/switch in the 3880 is a weak spot so I switch very infrequently.

I've been switching inks since I got the printer, Howard - about 2 1/2 years ago.  I had a 3800 before that which I, likewise, switched fairly often.  I print with photo-black probably 70% of the time.  But it's rare that I would go more than a few weeks between switches.  Haven't yet seen any problems from the frequency of changes.