Magenta banding in Photo RPM after "warm-up"

[nertog]

Hello fellow printer addicts,

I am experiencing a rather strange issue with my Epson PX720 (basically a miniature Epson 1430): when printing in Photo RPM mode, I get random magenta stripes in medium-gray areas. They are barely visible when I print right after switching the printer on, but become progressively more visible when the printer is left on for some time before printing. It seems more like an excess of magenta instead of starvation of another ink.

The printer was bought secondhand and is loaded with fresh Inktec dyes. Either this is an electrical issue that creeps up when something heats up or it is related to ink rheology and temperatures inside the printer. Adjustments through the service prog make no difference. Quickly testing different inks is not that easy, as this printer has stationary cartridges, ink tubes and a pressurized delivery system...so there is a lot of ink stored inside the printer itself.

I included a few pictures of the paper-feed adjustment, where the issue is clearly visible. The nozzle check looks perfect to me without any differences between the "cold" and "warm" state.

Paper-feed printout when cold:



Paper-feed printout when warmed-up:



Magenta nozzles:



Anyone who can shed some light on this?

Cheers,
Wim

 

[Ink stained Fingers]

The 1430 and the PX720 are of a different generation and design, the 1430 does not feed the inks via tubes, and uses a different printhead to my knowledge. Anyway - could you please post both the nozzle checks in the cold and warm condition, there could be slight variations. You are using Inktec inks, do you know which type of ink was used by the previous user ?
You are using the RPM option - do you see a benefit of it or does it just extend the printing time ? Are the reported problems invisible with the other quality settings ? I have seen that some Epson printers put more ink with the RPM option onto the paper than with the other options, but when you create an icm-profile you may see as a surprise that you loose some gamut volume - more ink does not always gives you more solor saturation - there is a point of color saturation reversal , it depends on your paper in use.

 

[nertog]

Did some more experimenting this morning: heating up the printhead area of the printer in its "cold" state produces the same artefacts. Further heating (top printhead at +- 40 deg. C) produced several missing nozzles, first in the magenta channel, followed by all other channels.

@ISF: I'll upload the nozzle checks as soon as I get everything working again. The previous owner had a mix of Epson and cheap 3rd party carts in the printer. All the ink was flushed out with a cleaning solution (service program) before the Inktec inks where introduced.

Regarding the RPM option: I can only speak for the P50 and PX720, but the quality level below "Photo RPM", "Photo", produces visible dots on glossy RC paper. Unacceptable to me. Photo RPM lays down way too much ink on the paper, though. I believe Epson tries to minimize dot visibility by using as much of the light inks as possible before switching over to the higher density C, M and K. Quite a few papers cannot take the ink load...and I could not find the "ink density" option that is typically found in the higher-end models.
And, indeed, I also found that more ink does not always equal a larger gamut coverage. That's another reason why control over the total ink density is a welcome option.

 

[Ink stained Fingers]

Thanks for your feedback, let's separate somewhat the banding issue from the discussion of the RPM option.

- RPM -

Quite a few papers cannot take the ink load...and I could not find the "ink density" option that is typically found in the higher-end models.

Yes, that's a problem - you have to test 3rd party papers for that - some can take the ink load - others do not.
You are right - an ink density option is onlv available on larger format printers - Epson does not let you go away that easily - they won't program an option for you so that you can make better/easier use of 3rd party papers.......Typical RIP software is not available for this class of printers either.
There is a piece of software which might help you and gives you some more access to various parameters - the PrintFab software adds ink limits
www.printfab.net/
There is a Mac and a Windows version.
www.printfab.com/en/
You may give it a try - I don't like it so much and it's rather slow if you run the highest resolutions.

- Banding

You may have a look to my posting on this subject -
www.printerknowledge.com/threads/inks-and-printing-quality.12761/page-5#post-120593

Inks play a relevant role for this banding effect as I found out - Don't consider InkTec inks as premium inks, their fading - UV/ozone - performance is just poor, and their gamut is just average.
The best inks you can get are genuine Epson inks - the inks for the ET7700 Ecotank printer - Epson 106 - are as good as the original Claria inks , I use these 106 inks and dilute the LM and LC with a clear ink and the C and M inks for use in Epson L1800 and L805 printers

 

[nertog]

- Banding -

Here we go:


Nozzle check after cold start


Paper feed adj. after cold start


Nozzle check after 2 hours on-time


Paper feed adj. after 2 hours of on-time

I suspect ink issues as well, but the nozzle checks look identical to me. Inktec is relatively cheap, so I use them for testing. I would like to repurpose this PX720 as my daily smal format printer, but need to make sure that there are no major issues (printhead or electronics) before investing in decent inks.

- RPM -

I am pretty familiar with Printfab. I really like all the options regarding ink limits, selecting the contribution of light inks and even linearization, but I dislike it's very visible raster pattern. It shows up as lines with regular intervals...almost like banding. The Epson driver looks way better. Pity, otherwise it might have been worth the 120 or so Euros.

Thanks for the info, ISF!

 

[Ink stained Fingers]

You are right - the nozzle checks look very clean indeed. I remember from older printers - e.g. R265 - that the driver had an option 'Microweave' which is gone since then. That possibly could have fixed your problem.

I'm running an L1800 - an Ecotank version of the 1400. When I look to the driver there is a hidden option on the uitlity tab - extended settings - on the right side - it states in the English driver version ' Refine screening option' - but when I switch to the German version I get this description - 'Rastermuster verfeinern' = improve dithering pattern which is more explanatory - you may try the effect of that option.

- Ink limit setting

- You typically use the 'No color adjustments' option in the color settings option settings when you print your profile patterns, that setting outputs max ink and the ink output cannot be reduced at this point.
But you can change the mode to 'Color adjustments' , the default settings for the CMY colors are at the middle of a -25 to + 25 slider range. The +25 (%?) settings output about as much ink as with the 'No color adjustment' setting. But you have here the option to reduce the CMY ink density , only adjustments for black are not possible this way. So you should be able to test here various settings to get close to the ink limit of your paper. These are settings for CMY individually, it does not define a total ink limit for mixed colors but it may help.

 

[Ink stained Fingers]

The Microweave option was supposed to compensate for some mechanical tolerances - head movement - aging.
You got the printer second hand, so it printed already some number of pages. Did you try to print and test with the bidirectional printing disabled - fast printing off ? There could be some small slack in the mechanics - in the gear for the paper movement or some small tilting of the head carriage

 

[nertog]

I'm running an L1800 - an Ecotank version of the 1400. When I look to the driver there is a hidden option on the uitlity tab - extended settings - on the right side - it states in the English driver version ' Refine screening option' - but when I switch to the German version I get this description - 'Rastermuster verfeinern' = improve dithering pattern which is more explanatory - you may try the effect of that option.

That option or something similar does not exist in my P50 or PX720 driver.

But you can change the mode to 'Color adjustments' , the default settings for the CMY colors are at the middle of a -25 to + 25 slider range. The +25 (%?) settings output about as much ink as with the 'No color adjustment' setting. But you have here the option to reduce the CMY ink density , only adjustments for black are not possible this way.

That might help to avoid overinking my papers. Let's see if that works!

 

[nertog]

The Microweave option was supposed to compensate for some mechanical tolerances - head movement - aging.
You got the printer second hand, so it printed already some number of pages. Did you try to print and test with the bidirectional printing disabled - fast printing off ? There could be some small slack in the mechanics - in the gear for the paper movement or some small tilting of the head carriage

Unidirectional printing makes no difference. The paper feed adjustment patterns I scanned are printed in a single pass, anyway. All diagnostics look fine, all adjustments are ok, including H and V head alignment, head tilt, bi-dir. alignment and paper feed. Must be the ink...or if I have really bad luck some obscure electrical or printhead issue. The PSU measures 42V, so that seems ok as well. The only thing I cannot easily check is the platen gap. No idea what a wrong platen gap height might do, though...and why would that change with a slight temperature difference?

The printer is old, but printed only 1500 pages...

 

[Ink stained Fingers]

I'm getting the 'Refine screening pattern' option as well with the L805 driver, the tank system version of the P50.



- The printhead, nozzle plate would touch the paper if the platen gap is too small

- Color adjustments - that's a work around - experimental - try it - it's usefulness depends on the printer driver

- Maintenance prints are one thing - do you see a difference in a small actual image print with bidirectional printing - high speed - on or off ?