Impressive results. Thanks to Bing translate here is my understanding.
The aluminum foil is used as the heating element. The toner transfer is essentially the same as standard. If you use wax paper, then use wax paper here. The sandwich is constructed to allow (as claimed) an even heat. Particle board is used, presumably because of its insulating properties, and there is an embedded temperature sensing device that allows manual control of the power via the Variac to give controlled and reproducible temperature. Electrical contact to the aluminum foil is made by aluminum bars clamped on both ends. The applied weight is static -- that is, there is no moving around of the pressure points.
The power supply is made with a Variac (aka, variable autotransformer) controlling a home-built, low-voltage, high-current transformer. Output is claimed to be 105A at 1.1 VAC. It looks a little a microwave transformer with a re-wound secondary, but the article mentions 200W, so that is a bit small for modern microwaves. Transfer temperature is 70°C, which seems a little low, but that is at the sensor in the particle board. The actual temperature at where the transfer is happening is probably higher.
I find use of kitchen aluminum foil as a heating element in this manner is interesting.
John
edit#2: I believe the author used multiple secondaries in parallel to get the high current needed. Others who use microwsve transformers just use heavier wire.