Digital BW, The Print

Has anyone on the list has this problem with a 1280?

There are fine black lines that resemble a musical staff deposited
randomly on my prints. Just started today, in the middle of printing a
couple dozen prints.  It is not banding. The lines are about 2 pixels
wide, and about 1/32nd of an inch apart. Many cleanings have not helped.
Nozzle checks are perfect. There are 5 to 8 lines, and about 6 inches long.

Jerry