Epson 1010 User Manual page 177

Note: Press lightly on both sides of the cartridge to make sure
the hooks are properly inserted.
7. Use a pointed object, such as a ball point pen, to guide the ribbon
between the print head and ribbon guide while you turn the
ribbon-tightening knob to help feed the ribbon into place. Be
careful not to puncture the ribbon.
Replacing the Ribbon
Maintenance 6-7