Switching Black MK -> PK ruins head / ink flow

[Clark]

Back with another problem on the Epson SC-P600.

Everything been working fine for the last few weeks. Today I switched to Matte black to run a couple of prints on Archival Matte paper, and when I switch back to photo black, the PK channel is completely f*ed, for want of a better expression.

A nozzle check confirms what was already obvious on the print - only a few scattered 1mm lines showing in the whole PK pattern (90% missing).

Have just run a single clean cycle and the nozzle check shows no improvement. I will wait until tomorrow to perform another check and clean cycle.

Has anyone experienced or heard of switching MK <-> PK messing up the blacks? Any advice on why this may have happened?

[rdonson]

Run the nozzle cleaning another time or two before you panic.

[Mark D Segal]

Never seen this happen in over a decade of Epson printers making PK/MK switches. It's possible that the switch in the damper is messed, but Ron is right - don't panic yet. If the 600 lets you do a power clean of those channels, do it, then leave it overnight.

[Clark]

Of course, I’m sure I can rectify it with enough clean cycles.

I just wanted to learn about why this is happening. It costs a lot time and a bit of money, so I’m keen to know if there’s an explanation 

[Mark D Segal]

Of course, I’m sure I can rectify it with enough clean cycles.
............

Could be a number of things. Can't tell until they're ruled out one by one. What we recommended you do is the first step. In any event don't run more than three cleaning cycles on the same channels in one day.

[deanwork]

Search on Gooogle and you will discover this is a very common problem.

Most likely the issue is a situation that has effected many people on all the Epson printers, including the great 3800  series as well as the large format units.

The Pk and MK channels share the same ink line. There is a switching mechanism that opens the gate leading to both ink carts. For many printmakers one type of paper is used most of the time, so this mechanism is rarely used. If you don’t switch blacks fairly often, ink can clog back in there and that switch becomes frozen, when you do want to switch the black ink from one to another. Sometime it can be freed up, other times it requires a replacement of that switching mechanism. What I do with my two Epsons that have both inks used, is to do a black ink switch once a month and I don’t have a problem. Do you waste ink going through that process, yes. But you need to do it.

I had a long discussion with the Epson reps about 12 years ago at Photo Expo about this black ink switching nussance, and their answer was, if you don’t like ink switching then buy two printers, one for MK and one for Pk. My answer was, I’m going to primarily use Canon and HP’s that have ink lines for both blacks, which is what I did. There are a lot of great things about the Epson system, but that isn’t one of them.

Marks right, don’t do more than a couple of power cleans in one day or you can damage the head.

John

Could be a number of things. Can't tell until they're ruled out one by one. What we recommended you do is the first step. In any event don't run more than three cleaning cycles on the same channels in one day.

[Mark D Segal]

??

[George Marinos]

Search on Gooogle and you will discover this is a very common problem.

Most likely the issue is a situation that has effected many people on all the Epson printers, including the great 3800  series as well as the large format units.

The Pk and MK channels share the same ink line. There is a switching mechanism that opens the gate leading to both ink carts. For many printmakers one type of paper is used most of the time, so this mechanism is rarely used. If you don’t switch blacks fairly often, ink can clog back in there and that switch becomes frozen, when you do want to switch the black ink from one to another. Sometime it can be freed up, other times it requires a replacement of that switching mechanism. What I do with my two Epsons that have both inks used, is to do a black ink switch once a month and I don’t have a problem. Do you waste ink going through that process, yes. But you need to do it.

I had a long discussion with the Epson reps about 12 years ago at Photo Expo about this black ink switching nussance, and their answer was, if you don’t like ink switching then buy two printers, one for MK and one for Pk. My answer was, I’m going to primarily use Canon and HP’s that have ink lines for both blacks, which is what I did. There are a lot of great things about the Epson system, but that isn’t one of them.

Marks right, don’t do more than a couple of power cleans in one day or you can damage the head.

John

I suspected that a black ink switch is not very good somehow for the printer. Thanks for the information!

[schertz]

Is your yellow ink low?

I had this happen to me one time (~ 80% of black nozzles dropped out) and a couple cleans would not help at all. I then replaced the yellow cartridge which was out at that point and left the printer until the next day. When I turned it back on the printer auto-initiated a large clean cycle (all by itself: perhaps it has a way of self diagnosing the problem) and the black came out perfect afterwards.  There does seem to be some precedence for this reported here:

https://forum.luminous-landscape.com/index.php?topic=121763.msg1012514#msg1012514

These are still at the level of anecdotal evidence at this point, but it might be something to try. I haven't had any issues with that printer since, this was at least a year ago for me.

Mike

[Clark]

Hey guys,

Just wanted to come back to report how this was resolved in case it's of any interest / use to anybody:

I ran 3-4 clean cycles over a 72 hour period.

After the 4th cleaning cycle I could see some sign of improvement: Maybe 10% of of the pattern printed, up from 5%, as a guess.

I then decided to change the LK cartridge, on the advice of schertz here. It had the yellow warning triangle so I thought I'd give it a go.

Another nozzle check showed no improvement immediately after the cartridge change alone.

However, I followed this with another head clean, and 90% of the PK black pattern was back.

Another head clean 12 hours later and I've got PK back to 100%.

So unfortunately, it's not really possible to say whether replacing a cartridge had an effect, or if it was just the repeat head cleans that resolved this.

Certainly if I look at the progress at each step of the process, there was a huge improvement shortly following the replacement of the LK cartridge (though not immediately), so there's a sign it may have been a factor, but it's very inconclusive.

I now have a question - should I immediately test switching between MK and PK again? I guess if I want to maintain a healthy printer going forward, I need to begin regular maintenance of both channels, so I should start right away?

[FabienP]

[...]

So unfortunately, it's not really possible to say whether replacing a cartridge had an effect, or if it was just the repeat head cleans that resolved this.

Certainly if I look at the progress at each step of the process, there was a huge improvement shortly following the replacement of the LK cartridge (though not immediately), so there's a sign it may have been a factor, but it's very inconclusive.

I now have a question - should I immediately test switching between MK and PK again? I guess if I want to maintain a healthy printer going forward, I need to begin regular maintenance of both channels, so I should start right away?

This matches the behaviour of my own SC-P600 which only performs substantial head cleaning cycles when all cartridges are above a certain level (around 10%). I suppose this is to prevent getting empty cartridges during the cleaning process, which could lead to air coming into the nozzles and would make the ink clog even more problematic.

There is no power cleaning cycle on this printer but I suspect it might behave like my previous printer did (Epson R2400): if a second cleaning cycle is requested within 15 minutes after performing an initial cycle, a larger amount of ink will be "used" for the subsequent cleaning cycle.

As for your question about immediately retesting the switch between MK and PK, I don't think you need to do this now.  You could do this the next time when you need printing on the other type of paper, assuming this will happen in the next month or so. I seldom change more than four times in a year and never had a problem so far (knocking on wood).

Cheers,

Fabien

[Clark]

Thanks Fabien for the extra info. That could be a plausible explanation indeed.

I think I will aim to switch once per month now. Ideally to run off a few prints (just wish I was busier selling prints and all this would probably be avoided (and paid for) through more regular use!)

Best,

Clark

[John Caldwell]

PK to MK switch killed our 9900's head irreparably.

My mistake was to have used that machine for well over a year in PK only, before the PK.MK switch was made. I suspect had the PK>MK>PK cycle been run somewhat often, the MK lines would not have been particulate containing. The symptom was, of course, a black channel that responded to nothing, and did so with 100% temporal correlation with the black ink swap.

John Caldwell

[nirpat89]

First they make you switch back and forth when you need to use the other paper, wasting expensive ink.  Then if you decide to save ink by keeping the printer on one K as long as possible, they clog the switching mechanism and the head.  So you have to switch periodically even if you don't want to.  Nice racket!

[Daverich]

Well, this thread had me a little worried since I hadn't used the matte ink in my P5000 since I made profiles for it 1 1/2 years ago. Switched it to matte black, nozzle check printed fine, made a print that was fine. Switched back to photo black, nozzle check printed fine. Guess I lucked out from the sound of it.

[deanwork]

Yea, no kidding man. I’ve been saying for many years that this disgusting garbage is intentional. And people said, oh your so cynical, Epson wants good pr and they would never do anything like that.
I had to switch two Epson printers today to do some comparative tests with my thermal printers and it just pisses me off to no end  that I had to waste this much ink for a few tests. Imagine if I had to do that Daily for various jobs! Unbelievable. Or like the guy just said, you need to use a different K for a project after many months or a year and bam your heads are dead. And a 2 grand bill waiting for you for a large format lock up.

Before they set this crazy system up you had to remove the k entirely, replace the new k in the slot and flush out even more ink. Everybody wrote so many emails to them that they included two blacks in the printers but only One Ink Line for Them. Now does that make any sense to anyone in the universe that Canon and Hp can do it but Epson can’t. That Epsons engineers are that stupid? Of course not. It’s a scam.
And I won’t even mention the decade of clogging nozzles due to poor pressure...oops I just did.

John

First they make you switch back and forth when you need to use the other paper, wasting expensive ink.  Then if you decide to save ink by keeping the printer on one K as long as possible, they clog the switching mechanism and the head.  So you have to switch periodically even if you don't want to.  Nice racket!

[nirpat89]

Yea, no kidding man. I’ve been saying for many years that this disgusting garbage is intentional. And people said, oh your so cynical, Epson wants good pr and they would never do anything like that.
I had to switch two Epson printers today to do some comparative tests with my thermal printers and it just pisses me off to no end  that I had to waste this much ink for a few tests. Imagine if I had to do that Daily for various jobs! Unbelievable. Or like the guy just said, you need to use a different K for a project after many months or a year and bam your heads are dead. And a 2 grand bill waiting for you for a large format lock up.

Before they set this crazy system up you had to remove the k entirely, replace the new k in the slot and flush out even more ink. Everybody wrote so many emails to them that they included two blacks in the printers but only One Ink Line for Them. Now does that make any sense to anyone in the universe that Canon and Hp can do it but Epson can’t. That Epsons engineers are that stupid? Of course not. It’s a scam.
And I won’t even mention the decade of clogging nozzles due to poor pressure...oops I just did.

John

I can only imagine how frustrating it would be if you have to deal with this day-in and day-out.  As long as people put up with it, they won't change.  Even less so since Epson and Canon are basically a duopoly now in the prosumer level printers with HP dropping the ball after 9180B.  When I was looking for a new printer after my 9180B died, not wanting to switch being one of the top criteria, I ended up getting the P400 which does have dedicated channels for PK and MK.  My next one (17") will have to be Canon if Epson does not change course and get rid of switching in their future machines. 

:Niranjan.

[loomitz]

here an idea, what happens if we put in the channel that we do not use a cartridge with piezo flush (cleaning solution), maybe this could prevent the change mechanism from cloggs, would put the cartridge say in mk and make the change pk - mk -pk.

[Terry_Kennedy]

Yea, no kidding man. I’ve been saying for many years that this disgusting garbage is intentional. And people said, oh your so cynical, Epson wants good pr and they would never do anything like that.

I don't think it is actually either of the extremes you mention. It seems the vast majority of these printers go to signage shops and not to people printing for photography. A major signage shop I visited this week had 3 or 4 of each of the smaller models of printer, just so they didn't have to change roll paper to different stock for different jobs. If they aren't even going to change the paper between jobs, they definitely aren't going to change ink, regardless of how easy / safe it is.

As you mentioned, Epson printers have evolved over time from cartridge swap to ink line flush to the newest dual MK/PK printheads, like in the SC-P20K / SC-P10K. I'm not sure how much of that technology is going to make its way down the product line to the smaller printers - certainly the $2500 8000-nozzle printhead from those printers isn't going to show up in a 17" roll model. But as Epson designs new heads for the eventual replacements for the smaller printers, I expect we'll see dual MK/PK heads showing up in at least some models.

Until then, you either take your chances with ink swaps, use the P10K, or use a different brand.

[deanwork]

The amount of ink waste, from both ink switching and especially clogged nozzles has been a huge source of profit for Epson for over 15 years, especially with the desktop units as their ink cost is really expensive proportionally.

It does appear that the 10k/20k heads are a significant improvement in both respects, as long as they are used everyday, much like the original 10kCF 44” that wasted no ink ever. I never even had to replace my waste tank in 10 years of use.  And my friends little p800 is not clogging as much as my 3880, but still have to do the ridiculous ink switch which is just unnecessarily expensive over a years time.

I don’t see any of the sign shops around me using any Epson anymore. All the places I see are using Canon IpF or one of those fast HP graphics printers. Epson Photo quality, even at high speed  is overkill for posters and banners.

All I’m saying is if people don’t complain regularly by writing them emails it will stay the way it is.

I don't think it is actually either of the extremes you mention. It seems the vast majority of these printers go to signage shops and not to people printing for photography. A major signage shop I visited this week had 3 or 4 of each of the smaller models of printer, just so they didn't have to change roll paper to different stock for different jobs. If they aren't even going to change the paper between jobs, they definitely aren't going to change ink, regardless of how easy / safe it is.

As you mentioned, Epson printers have evolved over time from cartridge swap to ink line flush to the newest dual MK/PK printheads, like in the SC-P20K / SC-P10K. I'm not sure how much of that technology is going to make its way down the product line to the smaller printers - certainly the $2500 8000-nozzle printhead from those printers isn't going to show up in a 17" roll model. But as Epson designs new heads for the eventual replacements for the smaller printers, I expect we'll see dual MK/PK heads showing up in at least some models.

Until then, you either take your chances with ink swaps, use the P10K, or use a different brand.