Suprasetter imaging very thin horizontal lines.

Hi, i'm facing a problem on Suprasetter A75 (1 laser head). the plates imaged have very thin vertical lines, invisible to naked eyes but when magnified 25-40 x there are vertical lines all across the plates. so to overcome the problem i have to over devlop which results in over washed and early wear of plates.

The lines are reduced when drum speed is reduced but this makes plate imaging very slow.

Can anyone help ?

 

Did you changed the plate manufacturer recently?