Question service call 0400 [0001]

Hello everyone!

I have a Roland TrueVis SG300 that I got about 2 years ago.

In January it started making stripes when printing and when performing the test print the blue had lots of gaps.
I did the manual cleaning and calibration which usually is enough to get everything back to normal but somehow it didn't work.

So I called the techs who told me to do a manual cleaning again and a powerful cleaning, to hold a new soaked swap in cleaning fluid against the heads and the cap tops but nothing worked.

Meanwhile an error started showing, it said 'service call 0400 [0001]', so i ended up calling the tech to come take a look. After he checked everything he ended up replacing the damper which at the time made the printer print perfectly again and the test print was ok again.
Butttt, 2 days later the same error showed up again, so they came back and did the process of 'empty damper' and 'fill damper', which made everything fine once again. But 3 days later, the same error AGAIN.

And that is where we stand now, the error shows up (every 2/3 days or so) and i get in the tech menu and do only 'fill damper' and then normal cleaning (that's what the tech told me to do) and it prints perfect again.

I would like to know if anyone has any ideia of what it might be, the tech says that the next step is to replace the head because they don't know what else to do. But it is so weird that the printer prints so well when the error is not showing.
I don't want to believe that it might be the head. Also i have this machine for only 2 years so this shouldn't happen, as i am super carefull when using it, it is so frustrating!

Any help is really appreciated!

Thank you in advance everyone

Inês