I thought I’d look at the way the Epson 3880 and the driver resample images at 2880/1440 dpi. I took the now-familiar grating at 700 ppi, and resampled it in Photoshop using nearest neighbor. This is what I got:
Then I printed a 700 ppi image using ABW. Here’s what it looks like:
The pattern of extra white and extra dark lines is not identical, but the spacing appears to be the same between the two images. I’d say that it looks like the printer/driver resamples to 720 ppi before doing the error diffusion.
Just for interest, here’s what the printer does when fed some other gratings.
and 480 ppi:
Note that the 480 ppi image provides a fine example of aliasing.