I had exactly this problem with Snow Leopard and my 2400, the first thing to know is that you must not use the gluten print driver it's crap. The following worked for me and my printer is now working fine :-
1. Close any applications that are open.
2. Click on the Apple icon and choose System Preferences. Choose "Print & Fax".
3. Highlight the Epson printer in the list and click the delete button [-].
4. If no other printers are installed, in Print and Fax please hold down the Control key and then in the list if printers, click and hold. That should present the "Reset printing system..." menu. Choose this option and confirm.
5. Disconnect the printer from the computer.
6. We will now remove the EPSON Printer driver from the system and delete the drivers that you downloaded.
Go to the Mac Hard Drive/Library/Printer and move the complete EPSON folder to the trash. Warning this removes all EPSON Printers.
7. Also remove any drivers that were previously downloaded to the trash if the file name does not match that from our web site.
8. Restart the Mac.
9. Empty the trash.
10. Now we will run a repair utility that may take up to 30 minutes to complete so please plan for this. Go to Mac Hard Drive/Applications/Utilities and open the Disk Utility. Note: If you cannot find it this way, use Spotlight to locate it.
11. Select Disk First Aid at the top of the dialog box.
12. Select the Mac Hard Drive Icon in the left hand pane.
13. Select Repair Permissions at the bottom of the dialog box.
14. When this has completed restart the Mac.
Power the printer on and connect it to the Mac. Ensure that it is directly connected to a port (such as a USB port) on the Mac and not via a third party device such as a USB hub.
You will now need to download the driver/s from the Epson website. Connect to the Epson website via the link below:
http://esupport.epson-europe.com/FileDetails.aspx?lng=en-GB&data=zbff+oTjl0EHnix fShyxIHWVn0U002FZyJp6TQAu9H3pjHIU003D&id=324505
Download the printer driver for your printer and ensure this starts in the Download Manager you will need the driver 6.62. Try the following to install and add the driver:
1. Locate the downloaded file and double-click it. This should mount a drive on the Desktop. Double-click this and a window should appear with a blue VISE icon. This is the printer driver installer, double-click this icon.
2. Follow the on screen prompts to install the driver, restarting the Mac once the installation has been completed.
3. Once restarted the driver needs adding to the printer list. To do this click on the Apple icon then System Preferences. Choose "Print & Fax" and ensure it is set on "Printing". If the gutenprint driver is listed here, highlight it then choose the delete option (this can normally be done by clicking the [-] minus sign.
4. Normally, USB printers will add themselves automatically. Check the list for your printer. If listed, highlight the printer and the driver information will appear on the right. Under "Kind" the printer name should be listed, i.e. Epson SP R2400 Series with a version in brackets. If a gutenprint driver is listed or the 'Kind' indicates a different printer model delete this driver.
5. If the Epson driver is not listed, click the add icon button [+] towards the bottom-left of the window. The window that will appear first will be the Printer Browser. Connected printers with a valid driver installed should appear, highlight it and click the "Add" button. Do not choose a different model from the list of printers that may be present. If 'Add' is greyed out, leave the browser open for 10 minutes and ensure that the printer is powered on and connected directly to the Mac. Do not connect it via a third party device such as a USB hub or hub in a keyboard.
6. The printer should now be added to the printer list. Test the printer with a Nozzle Check so ensure paper is loaded. In Print & Fax, double-click the printer name and choose "Utility" from the top of the window that appears. In the Epson Printer Utility, select to print a 'Nozzle Check'.
This is taken direct from Epson support and worked for me
Good luck
Simon