3110cn dark horizontal lines

I am suprised that the cartridge was not the cause of this problem.

The only other parts which are isolated to the black and have seperate parts for the colour are:

The transfer belt (user replaceable)

Printhead.

beyond that perhaps a strange power supply fault.

Power off the printer and pull the affected cart(s) out. If you still have the orange cover(s) that came on the cart(s), attach it back to the face to cover the drum surface. If you don;t have the covers, 3-4 pieces of paper taped around the cart and covering the drum surface will do the job.

These drums are LIGHT SENSITIVE and more than about 3 minutes exposure will cause notable print defects.

Longer periods can cause permanent damage...... horizontal print defects called "banding".

After the cart has been removed, find and clean all metal parts at each end of the cart, including shafts.

Look inside the printer; find and clean all the mating metal parts that connect to the cart when inserted.

All these metal parts are the high voltage connections. Dirty HV connections can cause horizontal print defects.

If this doesn't help, do you know of anyone that has a machine just like this one (or the 3115cn, same carts) and swap their cart into your machine for a quick test? This would be the quickest way to eliminate whether this is a machine or cart problem.

If not, when diagnosing print quality issues, pictures speak a thousand words.
If you can, please scan or take some pictures of your defective images and post them with your reply. You'll need a website on the internet to host the pictures from. If you don't have one, www.Flickr.com is one that works great, among others.
fyi...... max image width allowed in this forum is 460 pixels.

OBTW..... when you post an image to FLICKR, just right-click in the center of the picture then copy/paste the URL info and include that in your reply.

Thank you llynster!!

I pulled the black cartridge as you suggested and cleaned all metal parts and the shafts.  I had to do it a couple times, but it seems to have corrected my problem with horizontal lines. 

Thanks again.

Glad it worked out for ya !!

:smileyvery-happy:

I have the same horizontal black print on every page, but on my printouts, it appears on every page, color and black/white.  I have done all of what you have suggested with no change.  Please help.

Have cleaned everything a couple of times and no change - on my second cartridge - one was older so thought it was just the cartridge - any other settings that I should know about.