ZyXEL → Re: A bridge too far?

Yes, through firewall rules you can open doors between the LANS.
I have never done it but would assume you would permit LAN1 to LAN2 (all of LAN1 or a range of IPs - easier than one by one) to the IP of the wireless printer in LAN2.

Now that should let you print but that will not allow I dont think LAN2 to LAN1 feedback from the printer (like ink levels or perhaps other stuff).

UP to you if you want to allow LANIP of the printer on LAN2 access to all your LAN1 PCs, kinda breaks security. So initially just do the one-way and see what happens.