Wake up a networked Mac when needed by Time Machine or for printing?

Basically, I have an iMac and a Macbook Pro, and I want to wirelessly back up my Macbook Pro via time machine by connecting the drive to the iMac, but when the iMac is asleep I can't do this. Also, I print via this iMac, and whenever the computer is asleep I have to all the way upstairs and jiggle the mouse, which is a huge pain in the donkey. Is there anyway to wake up the iMac when a print is being requested, or when Time machine wants to gain access to the drive? Obviously I can not let the computer go to sleep, but I'd rather not do this.


Thanks!

Tortoise

 

The wake on lan looks helpful and easy, but it's not automatic.... having the computer automatically turn on would be nice.... I guess I'll just have to settle for backups when someone is using the computer, which is frequent, or set it to sleep at certain times.