Risograph is a digital printing technology that allows artists to get similar results to offset printing at a much lower price, and by using interchangeable drums, they can print more than one color. This is a very different look from standard four-color printing, though, as the colors stand on their own rather than combining to form a number of other colors; in work like this, the initial color choices really define the look. Sands, who also publishes the Electric Ant zine, has his own Risograph printing business.
If you like these, the Same Hat page has a list of links to the artists’ sites as well as to the website of Dosei magazine (all in Japanese), where these pages were published.
And for an American example, check out Hannah K. Lee’s Shoes Over Bills, which is printed by Sands.