New from New Ulm, MN, US

I recommend against using newspapers because the newsprint contains clay, which prevents the ink from spreading when the paper is printed. Clay, being inorganic, builds up in the bin, making the compost extremely sticky and light in color, and prone to cracking in the way that clay does. These cracks allow air to permeate the bin in a way that is unpleasant to worms, but extremely conducive to fruit fly production (think of a banana peel left on your your kitchen counter for several days, and you will get the idea). Over the past 25 years, I've seen and heard plenty about the nasty results of newspaper in worm bins, and it ain't pretty!
The only paper products I recommend for use in worm bins are: those very rough, unbleached paper towels that look and feel as if they were made by making very thin slices of tree; and plain, brown, unbleached, uncoated, unprinted, unpainted cardboard, shredded.
I never put office paper, or printed paper, or bleached paper in my bins, because the bleaching process can create dioxins, and there is absolutely no evidence that dioxins can break down in a worm bin.