The specs for your model Epson allows you to connect the you network by wireless and by LAN cable.
The specs are as follows :-
Wi-Fi Wireless LAN IEEE 802.11b/g – compatible with 802.11n*
*Transmission rate will be limited to 802.11g and will operate in the 2.4 GHz frequency band
Ethernet Wired LAN IEEE 802.3 (100BASE-TX, 10BASE-T)
WEP – 64bit
WEP – 128bit
WPA – PSK (TKIP) – compliant with WPA2
WPA – PSK (AES) – compliant with WPA2
To connect the printer by a LAN cable you need to configure the Epson for an IP address that suits your network configuration and connect the LAN cable to your wireless router/hub.
The reason why you cannot print using wireless is because the wireless configuration in the Epson is not setup with the router's wireless configuration ie. SSID WPA encryption etc.
For instructions of setting up a LAN network printer, please click on this link and follow my instructions :-
For instructions on setting up a wireless printer, the Epson wireless settings need to be configured with the router's wireless settings. Go into your router's wireless and note the SSID, and encryption settings etc and configure the Epson's wireless settings with the router's wireless settings. This will allow the Epson to connect to the wireless router. Please click on this link for instructions to secure your wireless network, configure the wireless router (if you have not already do so) and configure the wireless card in the computers and wireless printer (the instructions for configuring the wireless card in the printer is the same as for the wireless card in the computers via the printer's menu screen).