White hard UV ink is printing with an ivory/yellowish tint

[MrGift]

Hi, I have an A3 flatbed printer, based on Epson 1390 and all was ok until I had to change the print head.

Everything went well and white was bright white as it should be for a couple of weeks, then I noticed the white is not bright anymore, it has an ivory/yellowish off-white tint to it.

When printing, it appears to print bright white, but as the UV passes over it, it gains this horrible tint to it that makes it look like old white paint!

The white I was using was ok, so when started to print with a tint, I thought it was an ink issue, I ordered more ink with expiry date as April 2025 but is still same issue. Sometimes the tint is darker than other time. As the cyan and magenta is laid on top of the tinted white, the blue colours look green and the red colours look orange.

I would love to be able to fix this. I have been on to service, but they have tried connecting via Team Viewer and using different software, but not fixed. They are now suggesting it could be the UV lamp running too hot?

The image attached shows the bright white as it used to be on the right with the tinted white on the left. When first noticed in August 2024, I was using same ink as before although it did say exp 10/2024. But new ink expires 04/2025.

Any ideas to rectify this would be greatly received.

Many thanks
Jimmy

 

[signheremd]

White ink has some issues, which is why many printers have a motor to stir the ink and/or recirculate ink. It does yellow as it ages as well. Strictly speaking, you should print a block using white ink once per day (maybe 12"x12") and be prepared to purge the white ink out and add fresh ink every 6-9 months. Also, be sure to shake up new ink well. This is how we do it on our FluidColor flatbed. On our new Mimaki, once per week we take the bottle out and shake (when prompted) and the machine does a recirculation daily.

 

[petepaz]

you should shake your white ink everyday. the more white sits unused in any printer it shortens it's life span. also like signheremd said you should print a white bar or box from time to time to keep everything flowing properly.
not saying i do this everyday but we are pretty regimented that it gets done like 3x a week but for the most part we print white 3-5 days of the week regardless.
also check all the lines and dampers make sure no ink is leaking from somewhere contaminating the white
how is your test print, does the white look tinted when you do a test print

 

[compu6199]

Shake/circulate the white ink daily.

 

[MrGift]

Thanks all.

Not really had any issues with white until August when I noticed the tinted colour. I purchased new ink and shook well and installed with new ink sacs.

Nozlle check looks white and there are no gaps.

I've realised as I've watched it print, that the first printing of the white layer prints pure white. The second white layer is tinted. So I swapped the two ink sacs but it's same. First layer is pure white, second layer tints ivory/yellow.

In this image, I printed a 15cm white square which was tinted. I tried again and noticed the pure white printing first and the second layer tinting. You can see approx 10mm of white print before second layer is applied, so looks like ink is ok?

 

[signheremd]

That sounds more like as layers are added the opacity of the white is reduced and the yellowish tint becomes more pronounced. There are many different shades of white - some with blueish tint, pink tint, or yellow tint. I am thinking your base white ink leans toward yellow and this is why as you add layers a yellow tint becomes visible.

 

[MrGift]

Thank you. But the original white ink I had did print pure brilliant white as expected, then for some reason started to develop the horrible yellow tint. I thought was out of date so bought new ink, but still same tint.

 

[MrGift]

Ps. Also the image previous shows a print I did twice. So 2 layers first time and tgen again. As you can see, the brighter white band would be the third layer and the fourth layer tinted again

 

[MrGift]

I think I've resolved the yellow tint.

The UV lamp may be faulty and running too hot which is scorching the white ink. I covered half of the lamp and white is bright white again as it should be.

So just waiting for new UV lamp to arrive.

FIngers crossed!

 

[SGC]

I think I've resolved the yellow tint.

The UV lamp may be faulty and running too hot which is scorching the white ink. I covered half of the lamp and white is bright white again as it should be.

So just waiting for new UV lamp to arrive.

FIngers crossed!

That was going to be my concern