Ink jet head and ink jet printer
An ink jet head includes a nozzle plate substrate having a nozzle for ejecting ink toward a recording medium and an oil repellent film on a surface of the nozzle plate substrate, the surface facing the recording medium. The oil repellent film comprises a fluorine compound having a first end and a second end, the first end comprising a perfluoroalkyl group with 3 to 5 carbon atoms per each molecule of the fluorine compound, and a ratio of a density of CF2 groups in the oil repellent film with respect to a density of CF3 groups in the oil repellent film is between 1.5 and 4.0 as measured by X-ray photoelectron spectroscopic analysis.
1. An ink jet head, comprising:
a nozzle plate substrate having a nozzle for ejecting ink toward a recording medium; and
an oil repellent film on a surface of the nozzle plate substrate, the surface facing the recording medium, wherein
the oil repellent film comprises a fluorine compound having a first end and a second end, the first end comprising a perfluoroalkyl group with 3 to 5 carbon atoms per each molecule of the fluorine compound, and
a ratio of a density of CF2 groups in the oil repellent film with respect to a density of CF3 groups in the oil repellent film is between 1.5 and 4.0 as measured by X-ray photoelectron spectroscopic analysis.
2. The ink jet head according to claim 1 , wherein a density of CF 6 groups in the oil repellent film and a density of CF 7 groups in the oil repellent film are substantially zero as measured by X-ray photoelectron spectroscopic analysis.
3. The ink jet head according to claim 1 , wherein
the second end of the fluorine compound comprises a bonding group bonded to the nozzle plate substrate and a bonding group of an adjacent fluorine compound bonded to the nozzle plate substrate.
4. The ink jet head according to claim 3 , wherein
the nozzle plate substrate includes a functional group on a surface thereof, the functional group being selected from a hydroxyl group, an ester bonding group, an amino group, and a thiol group, and
the bonding group comprises a reactive functional group selected from an epoxy group, an amino group, a methacryl group, a vinyl group, and a mercapto group.
5. The ink jet head according to claim 3 ,
wherein the fluorine compound further has a spacer linking group linking the first and second ends.
6. The ink jet head according to claim 5 , wherein the perfluoroalkyl group at the first end is C 3 F 7 , and the spacer linking group is —(OCF2CF2CF2) 24 -O—(CF2) 2 -.
7. The ink jet head according to claim 5 , wherein the perfluoroalkyl group at the first end is C 3 F 7 , and the spacer linking group is —(OCF2CF2CF2) p -O—(CF2) 2 -, p being a value from 1 to 50.
8. The ink jet head according to claim 1 , wherein
the fluorine compound is bonded to a surface of the nozzle plate substrate by a siloxane linkage.
9. The ink jet head according to claim 1 , wherein the nozzle plate substrate is made of resin.
10. An ink jet printer comprising:
a nozzle plate substrate having a nozzle for ejecting ink toward a recording medium; and
an oil repellent film on a surface of the nozzle plate substrate, the surface facing the recording medium;
a medium holding mechanism that faces the nozzle plate substrate and holds a recording medium; and
a wiping blade that rubs the surface, wherein
the oil repellent film comprises a fluorine compound having a first end and a second end, the first end comprising a perfluoroalkyl group with 3 to 5 carbon atoms per each molecule of the fluorine compound, and
a ratio of a density of CF2 groups in the oil repellent film with respect to a density of CF3 groups in the oil repellent film is between 1.5 and 4.0 as measured by X-ray photoelectron spectroscopic analysis.
11. The ink jet printer according to claim 10 , wherein
the second end of the fluorine compound comprises a bonding group bonded to the nozzle plate substrate and a bonding group of an adjacent fluorine compound bonded to the nozzle plate substrate.
12. The ink jet printer according to claim 11 ,
wherein the fluorine compound further has a spacer linking group linking the first and second ends.