When continuously printing on paper sizes smaller than A4-width, the toner may collect on the ribs of the paper transfer exit, causing stripes and bands to form on the front or back side of the paper passing below.
To correct this problem when stripes or bands appear, clean the ribs at the paper transfer exit.
Also, if this problem occurs with A5 LEF paper, to correct this problem clean the ribs and then feed the paper by its short edge (SEF).