My black ink is only on the top and bottom page very light in the middle.

sounds like your cartridge is leaking. I'd try replacing the cartridge

Ink tends to overflow at the bottom guide rollers and the roller gets coverd in ink and causes the black line!The best will be to take it to a dealer and have it cleaned!Good Luck!

Dev. Home error can be fixed by stretching out a solenoid spring on the power cord side of the printer. The solenoid acts as a clutch to stop the spinning developer actuator at the right spot.

The problem is that the spring gets weak over time / the cogs round out over time and the solenoid finger is overcome by the spinning cogs, and resulting in selecting the wrong developer.

Open up the right side (power cord side) of the printer (take off top cover, then take off side cover). Then, find a solenoid (little metal square) that touches the white plastic vertical spur gear. Take the spring off the solenoid. Now, put the spring back on - only this time you will attach one anchor point to the middle of the spring as to pre-stretch the spring for more tension.





More pictures of the solenoid on Facebook:
http://www.facebook.com/#!/photo.php?pid=55779771&id=2257206&fbid=10100154259704133

One or both ink cartridges is failed.Replace first color cartridge if problem persist replace black too.

They are not in the middle as shown in the manual. I still can't find them. God! this printer is only that big and I spent three days looking at every possible corners and gaps and still can't see where the ink cartridges are. Will not buy this Canon printer again.

The suspected problem in the imaging unit. If you have problem in one of the color (likely black) Then you have to change the black developer part in the imaging unit

You need to change the color settings of the printer to print using color and black ink. Refer to printer help.

i had the same problem and just repeated the cleaning and testing, eventually the black showed up but took more than a few repetitions

This is usually due to the imaging unit going out, but can also be a problem with the main board itself...unfortunately that means rma is really the only option...which is NOT going to be fun fyi as samsung has poor customer service.

just for info my printer wasn't printing much of anything black and color. If you hold down the middle button till the light on the top blinks twice it will give you a color test page. it should give you a grid to the right and to the left it should have the letter H and two blocks. If it doesn't you hit the middle button until the light blinks once and that is the cleaning. I have had to do almost 25 cleanings just today to finally get some results. Hope this helps you.