Clearly this is the category you want to be in. Everybody and their uncle has a different way of writing this, so I can't tell you exactly what to look for, but the gist will be the same. Well, not just yet. You might need to flip a switch or turn a knob or sacrifice a chicken or something to change from U.S. to European. A lot of new computers are like this, especially Apples.
Few printers are dual-voltage.
By this I mean something you can either run off batteries or plug in. This is the interesting case. You can treat them normally, but if you only have one or two and don't want to shell out for a transformer, there is a cheaper option. If your equipment was made by a big exploitative multinational corporation, you will probably be able to purchase the analogous part in Britain, viz. Ok, so you do need a transformer for your appliance.