QTR-Quadtone RIP

You are not alone, I have also noticed similar fine banding issue with
my R2400 print using QTR (absolutely not clogging with nozzle checks). 

For now, I have resorted to using Epson Advanced B/W Photo. To my
amazement, I was able to get neutral prints using one of the Epson
Premium paper types with MIS K4. More tweaks are needed with other
paper types.

I am wondering if this is a QTR issue with R2400? I have not had any
issue at all with QTR on my 2200 printer.