This printer came out in 2009 so it's a safe bet it needs service with drums and more. Get estimates as replacement is usually cheaper.
Hi,
My Brother HL-3070CW recently ran out of toner and I replaced all 4 color toner cartridges. Prior to the replacement, yellow was printing unevenly (fading out and even disappearing completely in spots). I thought this was because the toner was low and replacing the cartridge would fix the problem.
However when I replaced the toner cartridge the problem did not go away. I printed a test page using solid color blocks for black, yellow, magenta & cyan (light versions of the colors - I got it from the HP website I think). There is one block for each color and it extends all the way across the page (the blocks are all equal in height and together they fill up an 8.5 x 11" sheet of paper). The other colors all print, although there are varying levels of streaks in the color. The yellow actually looks like there is only a streak of color vertically through the center of the box and maybe some along the lower edge.
I reinserted the old cartridge and it does the same thing. When I printed something last night that had darker yellow spots (the default color for yellow highlighting in Microsoft Word), I was surprised to see them print correctly.
Thinking the problem had resolved itself, I tried printing a brochure that used a light yellow background. The result was a yellow strip vertically down the middle of the page, a lighter one down the right side and lighter horizontal stripes about every 3.3-3.5 inches. There are also a couple vertical stripes between the middle and outside edges, but they don't extend the entire height of the page and they are not equal distances from the center of the page. It is really hard to tell, but I think there might be an extremely light yellow shading over the rest of the page and possibly a little darker strip along the left side.
While trying to troubleshoot the problem, I made a Word doc with random boxes filled with the darker yellow scattered throughout the page - and it printed correctly. When I changed the fill of the boxes to light yellow, only the ones in the center of the page have color.
I also ran a test page with large boxes that extend all the way across the page (similar to the original test page mentioned at the top of this post) filled with darker versions of all the colors. All the boxes are sharp with full color. The only issue is some slightly darker vertical streaks in the middle of the blue box, and possibly also in the hot pink box but it is hard to tell. There are no visible streaks in the yellow or black boxes.
I have cleaned the corona wires and checked everything over to the best of my ability but I don't see anything wrong inside the printer (I am not a printer technician though). Is there something else I need to clean or a part that needs to be replaced?
Thanks.

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