Very frequent horizontal banding in multiple colors during the job with L25500

Hi,

I have a very annoying issue with my L25500 latex printer.

I get narrow horizontal bandings in most of the colors (but not all) starting somewhere in the middle of the job and then continues until I clean all printeheads or/and do an automatic printhead allignment.

The problem is that it happens very often, I would say each day after restart or after each 5m or 8m printed media length. I always print on self adhessive vinyl media with 16 passes.

Is it normal?

Do u have any suggestions how to solve such issue?

All printheads are new (about 300ml workload each) - although I had already 2 times warnings to replace different printheads which disapeared after few printhead cleanings.

I've done also advanced printhead checks - all printheads have defect nozzles - but count is below 60 for each printhead.

Thank you for your help.

Best regards,

Solved! Go to Solution.

Hi HP-MarcM,

Thank you for your quick suggestions.

Please find additional info about my issue:

- Firmware Version:GG-CAL_7.0.0.4

- Error/Warning: None, just quality issues in form of horizontal bandings

- Affected printheads: imho, all

- Affected colors: light greys, light blues, light green, yellow, light brown,...

- Not effected colors: satured red, satured green, satured blue, dark orange ... to provide you some examples that visible issue occurs not on all colors.

- I've atatched an example image where you can see narrow horizontal bandings on light blue and light orange colors.

According to sleep mode: my printer is set to minimal value of 30 minutes. And to be honest I never let it run in standby. My workflow is to print all jobs once or twice per day and to shut down the printer after last job. So I don't even wait for 30 Minutes, not to speak about 2 hours.

Do u have any other suggestions or ideas?

Thank u and best regards

I might be able to help here. On our L28500 & L260, we were having the same problem on long areas of solid colour. It had us baffled for a while, until I remembered that when the techs first set them up, they said "we turn the 'Extra Printhead Cleaning' off, because it's not needed". So, switched this on for both machines, and we haven't had the problem since. Not sure if the L25500 has this same "Extra Printhead Cleaning" option, but if so, and it's currently turned off, turn it on and see.

Hi Morkel,

Thank you for the suggestion. I really hoped that it would help. Unfortunately it did not

I cleaned the printheads, activated advanced printhead cleaning and started my jobs ...

And just after 5 meters of plot I got same narrow horizontal bandings in many colors again.

Do u have any other suggestions or solutions?

Thank you and best regards,

Sorry it didn't help, worth a try.

I wonder then if something is causing head strikes? I don't mean the media itself, as you'd be able to tell as the edges would be torn & have ink on them. I'm thinking maybe an edge holder that you've left in there to one side that might have a corner bent up, or anything else in the path of the print head? Looking closer on the photo you posted, it does look like a band of nozzles that are out, not just random scattered nozzles. It would make sense that it would print for a bit, then deteriorate, and then the nozzles return with a clean. It could even be something on the printhead carriage itself. If you pull out each of the printheads, have a look in the slots that they each go in and make sure there isn't any gunk in there that could be protruding down, dropping dry or sticky ink somewhere that the heads then scape over.

For what it's worth, it definitely looks like it's the light magenta that's playing up. I'm guessing this because the lighter blue areas have less magenta in them where the banding is, same with the oranges. However the deep red and darker blue doesn't seem to be affected. That might be the first place to look if you wanted to pull the print heads out and see if anything is there.

Hi delx,

In addition to what Morket suggested you, I will like to recommend you to include spit bars in the plot (you can do this from the RIP) in order to check which is the printhead causing the issues. If this doesen't work either, I 'll strongly recommend you to contact your support source.

Hi,

Short update: HP-MarcM suggestion was correct.

The issue was indeed not to shut down the printer just few minutes after all jobs are completed for the day. My HP technician recommended me to wait at least for 2-3 hours to ensure the printheads pressurized while they cool down.

I could not believe this at first, but I don't have the described issues anymore since months.

Nevetheless, overall I'm dispointed with the need of such "solution". For me the first generation is a real eco and comfort killer - keeping the printer running idle for 3 hours while still consuming about 70 W and producing a noise like a helicopter is not really a good design. At least with the 3rd generation the iddle power consumption and noise is significantly better.

Our 260 has a similar issue. We have to clean frequently and cannot leave the machine unattended. We have had engineers in but without the required results.

I notice that the 360 discussion around the same issue suggests a firmware fix. Is this available for the 260?

HP is suggesting firmware 6.0.1.6

We are currently running SP 12.0.0.5

Thanks

Upgrade Firmware to the latest version always is a good recommendation. However, fixes included for 360 are completely different that the ones included on L25500, because these products are completely different.