hostnames of static ip's are missing in ARP table. others are missing at all

[wsxws]

Hi all,
why is it, that the hostnames of networkdevices using dhcp are visible in ARP-table and and those with static IP's do not show ?
and even a bit more important than an explanation: is there a way to show them ?

and my printer isnt shown at the table at all (yes, it is connect, turned on and it works. also networkscan done from my laptop shows it)

regards

PS: btw: hostnames on the NPD-table would be handy