Surge protectors are designed to protect the equipment from voltage surges in the supply, typically they block or divert the supply at voltages over 3xnominal (e.g. at 330V on a normally 110V supply).
The typical threat is a lightning strike on the power line nearby. "An average bolt of negative lightning carries an electric current of about 30,000 to 100,000 amperes (30-100 kA) at a voltage of over a billion volts." (Wikipedia) Of course this is much reduced by the time any voltage surge reaches your surge protector but this is the type of event for which surge protectors were intended.
A Laser printer, or other device, drawing a very high current (20-40 A) for 10-20 mS will not cause a voltage RISE in the supply, it is more likely to cause a short-duration voltage DROP in the supply (e.g. from 110 V AC to 90 V AC)