Digital BW, The Print

Need a help. I used Epson 2000P printer for 3.5 years without any 
problem printing color and BO images (recently I dedicated  1280 to 
B&W printing only). All of a sudden it started printing horizontal 
thin magenta lines with the interval of 1-2 mm simultaneously
with the image even when BO setting was used.
 Image quality is good as always. I reinstalled the driver
software from Epson webpage, but it did not remove the problem. There 
is no leakage from cartriges, everything looks normal. Please, advice 
me. Thank you. Yume Grot