I have black lines approx. every 2 inches running horizontally across my paper. it just started yesterday. the lines are about 1" wide

What about it?!

Get rid of it! I started out with the small black smoky line, went to two horizontal line, , , , I now have a 10 " line half way across the screen in two places and the rest of the line is 4-6". Contact Samsung three times on line and they responded with " we do not understand the problem, please explain. Oh yeah, TV was 2.5 years old. Never will buy Samsung again.

My guess would be the fuser. If the lines are consistent its either the fuser or bad toner cartridges.

Filter capacitors (more than 1) in the main power supply

Clean the nozzles, align the print heads, turn it off for about an hour. You may need to do this twice, but it works for me.

Bad scanner block, sorry. Very expensive if you can find one.

on the drum unit that you put your toner inn, There is a blue or green slide lever move the slide back and fourth 10-15 times. If you have some van air blow that area out ( F.Y.I. if you do this some toner will fly out ) if this does not take care of it the drum unit my be bad,

do a 1/2 print test. copier something with a lot of print. open front cover when the paper is 1/2 way through the machine remove drum. Look art the paper and the green drum if the marks are on the paper & drum then the drum is bad. If not the fuser asm is bad, the part that gits hot when melting the toner on the paper,

Have you tried with a new scart or htm lead?

Is there any debris under the printhead nozzle plate?

On the KDFE55A20 this sounds like a bad Q-Box. I would get an estimate from a Sony authorized servicer as this part may be quite expensive. On the 55A10 model this may be the B-Block and is also quite expensive. Getting an on-sit estimate would be the first step I suggest. Again go with an authorized Sony servicer. Call Sony or go to Sony.com for customer service. Good Luck