Computers in sleep mode use less than 10% of the energy they do when hard at work or waiting for you.
Unless you know that your copiers and printers have low power sleep modes (you've read the tech specs, those modes are enabled and operating properly), switch them off at the end of the working day. You'll save 10-30 kg of Carbon Dioxide per week for a large

copier, 5-8 kg/week for a large printer. Projectors use up to 300 Watts (producing about 0.3 kg of Carbon Dioxide/hour). Dimming or switching off lights while using the projector can save as much energy as it uses.
Paper makes up more than 50% of office waste. Guess how much double-sided printing saves?