Patent ID: 7074314

Claim:
A method for manufacturing a discharge-port-forming member for use in an ink jet head, the member having a plurality of discharge ports for discharging ink and comprising a carbon substrate and an ink-repellent film formed on a surface of the substrate by bonding between carbon and fluorine, said method comprising the steps of: polishing the surface of the carbon substrate to be flat while another surface of the carbon substrate opposite to the surface of the carbon substrate being polished is fixed onto a polishing table; forming the ink-repellent film on the polished surface of the carbon substrate by applying a voltage to the carbon substrate while the polished surface of the carbon substrate is immersed in a molten salt of fluoride and the other surface of the carbon substrate is fixed to the polishing table; and forming the plurality of discharge ports on the carbon substrate having the ink-repellent film formed thereon.