Hi there and welcome
I want you to run the Drum cleaner please on the printer. To do this
Get on A4 sheet ready (no paper in the printer yet) and make sure the printer is in ready mode
Open the Back cover and then open the manual feed slot cover
Press Clear and Menu at the same time and the drum cleaning message will appear
Use both hands and slide the manual feed paper guide to the width of the A4 paper
Then put the A4 in the manual feed slot and feed it through and the cleaning process will begin.
Once done, let me know if you still get the black stripe please.