Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/135—Nozzles
  • B41J2/16—Production of nozzles
  • B41J2/1606—Coating the nozzle area or the ink chamber

Definitions

• the present invention is concerned with nozzle plates for ink jet printing.
• the plates are coated to improve properties.
• the machine print algorithm has to include a high frequency of maintenance cycles wherein the printhead has to be serviced. Excessive maintenancy results in higher cost and lower print speed.
• a low surface energy coating is applied to both the inside surfaces of the nozzle holes and an outside surface of the nozzle plate. This reduced surface energy causes the ink meniscus to be lower in the ink cavity, i. e., recessed away from the nozzle surface. This results in the following effects:
• the low energy surface coating is a polymer.
• This polymer may include a polyolefin, a poly-(halogenated olefin) or a polyxylylene.
• the preferred materials are the poly-(para-xylylenes).
• the most preferred polymer is poly-(monochloro-para-xylylene), which is commercially available under the trademark Parylene-C from Specialty Coating Systems, a former division of Union Carbide.
• the term "pristine" as an adjective to "polymer” is used in this application to designate a polymer which is substantially undegraded and not oxidized. Such pristine polymers are preferably used in the invention. Polyxylylenes which have been significantly ashed by treatment with a plasma are not pristine.
• Parylene-C is particularly suitable for chemical vapor deposition, and is the most preferred coating for this reason among others.
• Chemical vapor deposition refers to a process by which a monomer gas heterogeneously nucleates and forms a polymer film on any and all surfaces it comes in contact with.
• vacuum deposition is also used for this process by providers of Parylene-C.
• Parylene C when applied by chemical vapor deposition, yields none of the shape distortions typical of liquid based deposition techniques.
• the material is extremely inert chemically, and can withstand the high temperatures used in chip, nozzle plate, and cartridge assembly. Furthermore, this polymer has high hydrolytic stability, low moisture absorbence and low diffusion rates for moisture and oxygen. It is thus an excellent barrier material for preventing corrosion in the underlying base metal, usually nickel.
• the inside surfaces of the nozzle holes and the ink exit side of the nozzle plate are coated with the low surface energy polymer. It is also preferred that the opposite side of the nozzle plate (the side attached to the ink jet cartridge, for example to a heater substrate) is not coated with said polymer, and this side can be masked in the deposition step.
• adhesion promoter While it is not necessary for the nozzle plate to function, it is essential for the durability of the nozzle plate that the polymer coating adhere to it. This is accomplished by the use of an adhesion promoter, many of which are commercially available.
• the preferred type of adhesion promoter for use in the present invention is a silane.
• One such is Z6032, available from Dow Corning.
• a nickel nozzle sheet is dipped into 0.1 M HCl for 15 minutes. It is then rinsed with deionized water, and then with ethanol. The nozzle sheet is dipped in a .25% to 1% solution of the silane adhesion promoter Z6032 for 15 minutes, and hung up to dry in quiescent air. When dry, the sheet is placed in a Parylene coating vacuum chamber and coated with Parylene C to a thickness of about 1.5 microns. (This coating step is conventional, and is described in detail in the equipment manual from Specialty Coating Systems, the manufacturer of the coater, and the side of the plate opposite to the ink exit side can be masked during the coating step). The nozzle plate sheet is then ready for the usual assembly steps.
• the thickness of the polymer coating is not a critical feature of the invention. A thickness of less than a micron is sufficient to work, but in general it is preferred that, for the sake of durability, the thickness be somewhere up to five microns.
• the present invention advances the art by providing nozzle plates which have less leaking, need less maintenance, give better print quality, have good wear resistance, and cost less than those of the prior art.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Particle Formation And Scattering Control In Inkjet Printers (AREA)

Applications Claiming Priority (2)

Publications (2)

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Cited By (3)

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• 1995
  • 1995-11-20 JP JP32504195A patent/JPH08224878A/ja not_active Withdrawn
  • 1995-11-21 EP EP95308310A patent/EP0712726A3/fr not_active Withdrawn

Non-Patent Citations (1)

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