HP Latex - Color Consistency and Print Head Life

[rdm01]

We're experiencing issues with our latex printers. Currently we run both a 370 and a 570. Neither seem to be able to produce consistent colors. For example, a recent wrap had each panel printing progressively lighter, which wasn't noticed until they were laminated and laid out next to each other.

Ultimately, this appeared to have been caused by an aging optimizer print head. Once the head was replaced, color seemed to revert to a more accurate and consistent representation of the actual color. However, now we would need to reprint the entire wrap if we wanted to get accurate color - not an efficient work flow.

I believe most our issues regarding consistency are related to print head health. There may be other factors, and if anyone has other thoughts I'd certainly like to hear.

Regarding print head health, how do you know when to replace them? Do users preemptively replace them at a certain interval to ensure color accuracy? If waiting until there appears to be an issue, how would one resolve the issue outlined above. Often color changes so subtly it is impossible to notice until it is well too late?

What other thoughts have helped users obtain consistent color?

 

[ColoPrinthead]

The printers will tell you when they need to be replaced, but often they need to be replaced before that happens. Warranty of 300 series heads is 1000ml and I am usually able to anywhere from 2-5000ml out of a head before replacing depending on much printing I have been doing.

I would say that with the 300 and 350 I have most of the time I am deciding it is time to replace a head before the printer tells me or I have a head damaged by a strike on rigid material.

 

[Bly]

When I had mine we'd change them at 3 litres.
They are a consumable so factor the cost into your ink cost calculations.

 

[rdm01]

I understand they are consumables - changing preemptively seems like the only way to guarantee you won't slowly start losing a head and getting a color skew, only to notice after a substantial amount of vinyl needs to be reprinted.

I'd be curious to know how many people go this route versus how many wait until an issue is visibly noticeable, and how you would prevent reprints in this instance.

 

[Reveal1]

I mentioned this on several similar posts, but we do planned changes in the 3800-4200 range. Usually try to time it to change several at a time so we can recalibrate profiles at same time. So much better than chasing color issues. Not sure optimizer really causes color shift, but your test patterns will show if they are degrading.

 

[rdm01]

When you say calibrating color profiles, are you doing this through the RIP, or are you referencing the on-board color calibration?

 

[rdm01]

Additional Considerations:
Do ink levels (low cartridges) have an affect on color?
Would an aging or nearly full maintenance cartridge be an issue?

Currently, all our print heads are 2,500ml or lower, yet our last wrap has varying color from panel to panel.

 

[Reveal1]

When you say calibrating color profiles, are you doing this through the RIP, or are you referencing the on-board color calibration?

In the on-board HP printer profile. You would do that for every frequently used profile any time you change a head (hence the preference to change multiple heads) . I think some on here even re-calibrate daily or weekly although that seems excessive to me.

Also, you mentioned panels not matching. As mentioned elsewhere in this forum, rotating every other panel 180 will lessen the appearance of color shift panel to panel. (e.g. - bottom of panel 1 is followed by print of bottom of panel 2) Haven't had that issue but we do that anyway as a best practice.

 

[eahicks]

Ultimately, this appeared to have been caused by an aging optimizer print head. Once the head was replaced, color seemed to revert to a more accurate and consistent representation of the actual color.

I don't see how the Optimizer head would cause a drastic color shift. ANY of the color heads, sure.

 

[Reveal1]

Additional Considerations:
Do ink levels (low cartridges) have an affect on color?
Would an aging or nearly full maintenance cartridge be an issue?

Currently, all our print heads are 2,500ml or lower, yet our last wrap has varying color from panel to panel.

Far from 'expert' but we have been using latex going on 10 years. Pretty certain low ink not an issue - except perhaps if the printer has sat for a very long time without use or user failed to shake ink cartridge before installing. We always let ink run completely out before changing cartridge, and even though HP says it can be noticeable mid-print, we've NEVER had that issue even mid-printing dark solids.

Maintenance cartridge - not sure but intuitively would not seem to impact as basically it wipes the heads and collects excess ink. Maybe someone else has better knowledge on this.

 

[TomK]

HP Latex owner here. I've never had the printer tell me to change the head before I noticed banding, offset colors, etc. I think the logic on the printer is more based on the warranty date and the amount of ink passed through the head.

I have had the printer tell me to replace a print head that was out of warranty but still printing fine. I notice print quality problems and then have to work backwards to determine which print head was causing the issue and change it out.

One time, working with HP support on some issues, they had me change out all my print heads, didn't fix the problem, then had me change out maintenance cartridge that was still showing 25% life left. Problem didn't go away, and they didn't pay for all the print heads except for 1 and didn't replace my maintenance cartridge. That was $1300 bucks out of pocket, without the problem solved.

 

[eahicks]

HP Latex owner here. I've never had the printer tell me to change the head before I noticed banding, offset colors, etc. I think the logic on the printer is more based on the warranty date and the amount of ink passed through the head.

Not totally true... I still have printheads WAAAY out of warranty and WAAAY past what I would normally run them and the printer has never suggested once to change a head.

 

[jimmmi]

Try to print CMYK only without light colors. Of course calibrated before doing panel jobs.
In panelling jobs CMYK only, seems to be more stable. Light colors are only for grainess. Gamut is the same.I always print a wide side bar for keeping printheads hot. Enable long run consistency so the printer will preheat and keep stable temperature.

 

[DrunknMonk]

always print the CMYK bar down the sides of the print, we click the calibrate button every morning before we print anything, flip your printed tiles, we have a 365 not noticed any colour change on the same batch of prints.

 

[rdm01]

Thinking this has to do with color shift as well. The printer said there .22 liters of ink left. Checked the bag to find it was nearly completely empty and it seemed to be starving the system of cyan, considering the bag was fully sucked to the outflow tube.

Guessing we be more closely monitoring ink levels, physically checking the bag?

 

[jimmmi]

Thinking this has to do with color shift as well. The printer said there .22 liters of ink left. Checked the bag to find it was nearly completely empty and it seemed to be starving the system of cyan, considering the bag was fully sucked to the outflow tube.

Guessing we be more closely monitoring ink levels, physically checking the bag?

Did you open the cartridge?

 

[rdm01]

Did you open the cartridge?

Yes, we took it apart to peak inside. I believe there would have been constriction on the flow of ink due to the bag being sucked up like that. There certainly wasn't a quarter liter left.

 

[jimmmi]

I think the only quick check for something like that is to weight a brand new ink cartridge, a totally empty cartridge,know how much ink weights because its ml not grams, and make the calculation without opening it.

 

[rdm01]

So, are others seeing their inks run out prior to the on-screen warning? How does one check for this without substantial time commitment (weighing boxes, opening and reviewing prior to changing)?

 

[chester215]

Nope, ours is usually pretty close.
We usually wait for them to get down to about 10ml and change them out.