Digital BW, The Print

I am new to black and white printing and this forum, so please forgive
me if this question has been asked before.

Can anyone please tell me if NK7 inks are more prone to print head
blocking than OEM colour inks?

I tried these inks on a R800 and had the greatest difficulty in
getting a complete nozzle pattern.

Eventually, I moved the inks to an R1800. Whilst better, I still get
problems.  Quite often I will have one nozzle showing a small loss,
but when I engage the Epson head cleaning facility, it'd not unusual
to lose most of the other nozzles completely.  It can then take hours
or even days (allowing the printer to rest), before getting a
satisfactory clean again.

I realise there is a manufacturer's forum, but I want unbiased opinion
please.

Many thanks,

Paul