Ethernet and Airport Problems We have one canon copier machine which is connected to our LAN router via Ethernet cable. Currently, we are connecting to the Internet using a different router. To work with the printer, I need to manually configure the Ethernet connection as follows.

Ip Address: 192.168.1.19
Subnetmask: 255.255.255.0
Router: 192.168.1.1  

When set with the above settings and connected to both the Ethernet network and the Airport (Internet) network, I can print, but I cannot browse the Internet anymore.
Could this be caused by an ip conflict ?

I can setup like this in windows and can use both printer and Internet at the same time. Should I use the same router for both Internet and LAN connections?  Is there any way to solve this?
I'm guessing here, but it your network settings may have the ethernet interface prioritized above the AirPort (this is the default setting), meaning that when both are connected it'll try to reach the internet through the ethernet connection.  You can check this easily be looking at the order the network "services" are listed in the sidebar of the Network system preference pane.  If Ethernet is prioritized above AirPort, change it by selecting Set Service Order from the action (gear) pop-up menu below the service list, then dragging AirPort above Ethernet.  Note that you need to click the Apply button for the change to take effect.