White banding on Oce Arizona 350 GT

[Hoeky1]

Hi all!
I'm a complete newbie and in need of some help please!
I've just leased an Oce 350 GT. I make wood signs. I do 1 coat of paint and then do a white bleed around it.. so I will be using a lot of white ink. Unfortunately the white bands and I don't really know why. I purge purge and then wipe the ink head and do a small 18x18" print and it's fine and then print another bleed piece at 23x35" and get banding. I don't really know much about uv printers...yet..
Thanks! Rebeccah

 

[SignMeUpGraphics]

What are your nozzle checks looking like just before each print?
Our 360 will begin to clog pretty quickly after a print, so always run a nozzle test immediately before prints with white to check to see if they are firing properly. Usually a quick swipe with suction resolves it.

 

[Hoeky1]

What are your nozzle checks looking like just before each print?
Our 360 will begin to clog pretty quickly after a print, so always run a nozzle test immediately before prints with white to check to see if they are firing properly. Usually a quick swipe with suction resolves it.

I believe our white nozzle checks are perfect. It's the one all the way on the right side correct? Okay will do. I take it these white heads require more cleaning than the CMYK ones do! Thank you

 

[AlsEU]

What kind of banding is it? There's banding related to the missing nozzles (but you say the nozzle test is complete). It may be banding from the different printing passes (one pass is more matt, the next one is less matt and if you look from an angle, you see that kind of banding - try to print unidirectionally, this eliminates that kind of banding). It's also possible to see banding from the overlapped printing passes - two passes of the print should lay one next to another, but if the movement calibration (for the gantry movement) is wrong, each pass starts on the ink layer from the previous pass. It looks like a very thin line banding with the exact distance between each line.
Try to print the same file:
- using different print modes
- bi- and unidirectionally
- print a solid white area (i.e. square 1 m x 1 m) and some white shapes, where the amount of ink is much smaller than in the solid (if your printer is brand new, there should be a new white ink filter and strong pump in each channel, but if it's not new, maybe you need a new white ink filter or new pump?).

 

[Hoeky1]

What kind of banding is it? There's banding related to the missing nozzles (but you say the nozzle test is complete). It may be banding from the different printing passes (one pass is more matt, the next one is less matt and if you look from an angle, you see that kind of banding - try to print unidirectionally, this eliminates that kind of banding). It's also possible to see banding from the overlapped printing passes - two passes of the print should lay one next to another, but if the movement calibration (for the gantry movement) is wrong, each pass starts on the ink layer from the previous pass. It looks like a very thin line banding with the exact distance between each line.
Try to print the same file:
- using different print modes
- bi- and unidirectionally
- print a solid white area (i.e. square 1 m x 1 m) and some white shapes, where the amount of ink is much smaller than in the solid (if your printer is brand new, there should be a new white ink filter and strong pump in each channel, but if it's not new, maybe you need a new white ink filter or new pump?).

Thanks for all the suggestions. So our printer is used.. I think 10 years. We had our tech set up our machine and show us the basics. This machine came right from its old owners and never had any service done before it was dropped off to me. I haven't had any other service on the machine other than discovering from printing x10 4x8 foot coloured sheets of coroplast that the magenta was dropping out due to the last chance filter needing some cleaning (we were able to get that fixed as it was covered under the installation cost). I haven't had a chance to do controlled testing but from what we were able to do it seems as if the banding is happening on larger floods (36x24"). I ran a few 8x18" and 12x12" floods all separately and no banding. So I guess I should ask our tech to do a new white ink filter and pump (do you have the specific name of this pump? ). Any other service tips for keeping an older machine in good condition? Thank you

 

[Hoeky1]

I believe our white nozzle checks are perfect. It's the one all the way on the right side correct? Okay will do. I take it these white heads require more cleaning than the CMYK ones do! Thank you

Sorry to bombard you..this is our black printing on MDF which was coated with 1 layer of white flat paint so the base is super chalky. Do you think the black is also in need of some service (nozzle checks are perfect)? I'm not sure why it does it on this. Thanks

 

[AlsEU]

Thanks for all the suggestions. So our printer is used.. I think 10 years. We had our tech set up our machine and show us the basics. This machine came right from its old owners and never had any service done before it was dropped off to me. I haven't had any other service on the machine other than discovering from printing x10 4x8 foot coloured sheets of coroplast that the magenta was dropping out due to the last chance filter needing some cleaning (we were able to get that fixed as it was covered under the installation cost). I haven't had a chance to do controlled testing but from what we were able to do it seems as if the banding is happening on larger floods (36x24"). I ran a few 8x18" and 12x12" floods all separately and no banding. So I guess I should ask our tech to do a new white ink filter and pump (do you have the specific name of this pump? ). Any other service tips for keeping an older machine in good condition? Thank you

Ink filters are the same for all colours - problem is that the white ink is the heaviest of all (due to the titanium used in the white pigment), so you have to remember to shake a white pouch from time to time (without disconnecting it from the socket, just squeeze the pouch a few times to avoid stratification of the ink in the pouch). Ask the previous owner, when he replaced filters in other channels (filters can be replaced by the operator, service is not required for this, just remember to remove the air from the filter according to the procedure in the manual). The ink pump is a different story, the service key is required to perform the replacement procedure correctly.
Try to print the same solid of K:
- without the white underprint
- with the white underprint, but unidirectionally
- as a pure K solid, without any other colours added by the ICC profile (some RIP packages have this option as a standard)
I suppose that such banding can be a result of:
- wrong calibration of the K heads (between themselves)
- wrong calibration of the W heads, which appears on the top layer as banding of the K solid

It's good to prepare a file containing solids in pure CMYKW colours (each of them separately), that will show you each channel as a separate part.
And I'm not sure if you know, that you may use IPA before the flush to clean the nozzle plates. But if you use IPA, it leaves the nozzle plate completely clean and dry, which then creates really bad prints, so if you use IPA on i.e. K channel, clean heads with it, then perform the ink purge (cleaning) on K channel to spread the thin ink layer on the nozzle plate and then try to print the nozzle test.

 

[Hoeky1]

Ink filters are the same for all colours - problem is that the white ink is the heaviest of all (due to the titanium used in the white pigment), so you have to remember to shake a white pouch from time to time (without disconnecting it from the socket, just squeeze the pouch a few times to avoid stratification of the ink in the pouch). Ask the previous owner, when he replaced filters in other channels (filters can be replaced by the operator, service is not required for this, just remember to remove the air from the filter according to the procedure in the manual). The ink pump is a different story, the service key is required to perform the replacement procedure correctly.
Try to print the same solid of K:
- without the white underprint
- with the white underprint, but unidirectionally
- as a pure K solid, without any other colours added by the ICC profile (some RIP packages have this option as a standard)
I suppose that such banding can be a result of:
- wrong calibration of the K heads (between themselves)
- wrong calibration of the W heads, which appears on the top layer as banding of the K solid

It's good to prepare a file containing solids in pure CMYKW colours (each of them separately), that will show you each channel as a separate part.
And I'm not sure if you know, that you may use IPA before the flush to clean the nozzle plates. But if you use IPA, it leaves the nozzle plate completely clean and dry, which then creates really bad prints, so if you use IPA on i.e. K channel, clean heads with it, then perform the ink purge (cleaning) on K channel to spread the thin ink layer on the nozzle plate and then try to print the nozzle test.

Thanks so much! I will get to work on these tests.