Disk brakes replacement

I recently replaced the back wheel brake disks and pads. While I had to hammer out the disks they came out relatively easy. However, this is not the case with the front disks. Yes of course I removed the holding screws and banged on the disk until I was fully exhausted, but to no avail. I could heat the disk but I'm worried this may damage the front wheel bearing.
 
QUESTION:
 
a) Will it help if I use a puller?
 
b) Is there a scientific way of removing the disk without damaging the bearing?
 
Thank you for your assistance,
 
Gerry