Cal. Gov. Code § 27280.5

The names of parties required to be indexed appearing in any instrument, paper, or notice presented for recordation shall be legibly signed, typed, or printed therein before acceptance by the county recorder. The names of all persons executing or witnessing a document shall be legibly signed or shall be typed or printed to the side of or below the signature. The absence or neglect to legibly sign, type, or print the names shall not affect the notice otherwise imparted by recording.