EP0771658A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Construction and manufacturing process for drop on demand print heads with nozzle heaters
Assignee: Eastman Kodak Co
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Filing: 1996-10-09
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Granted: —
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Expires: 2016-10-09
Abstract
Abstract A construction and manufacturing process for drop on demand print heads provides electrothermal heating elements which are in close proximity to the tip of the nozzle, and therefore achieve efficient thermal coupling to the ink. The construction utilizes metal layer electrodes formed as part of a CMOS drive circuit fabrication on a silicon wafer. A nozzle tip hole is then etched with an axis generally normal to the electrode layers. A heater substance and a passivation layer are deposited on the wafer. These layers are then anisotropically etched, leaving heater and passivation layers on the vertical sidewalls of the nozzle tip hole. Ink channels and nozzle barrels are then etched in the wafer, preferably using an etchant which has a high selectivity against the passivation layer and heater material, such as EDP.
Inventors
- 👤 Kia Eastman Kodak Co. Silverbrook
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:12
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/135; B41J2/16; B41J2/1621; B41J2/1635; B41J2/14; B41J2/14451; B41J2/1601; B41J2/1603; B41J2/1626; B41J2/1628; B41J2/1629; B41J2/1631; B41J2/1632; B41J2/164; B41J2/1642; B41J2/1645
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
79 words
A process for manufacturing a thermally activated drop on demand printing head (50) said process including the following; (a) forming, on a substrate surface, at least one generally planar electrode layer; (b) etching a nozzle hole through said electrode layer to form separate electrode portions; and (c) forming a resistive heater coating (2027) on the surfaces of said nozzle hole, in such a manner that electrical contact is made between eachof said electrode portions and said heater coating substance.
Claim 2
Dependent Claim
90 words
A monolithic drop on demand print head (50) comprising: (a) a silicon wafer (2020) substrate having a planar surface; (b) a top stratum, including at least one metal electrode layer (2023, 2025), formed over said substrate surface and having at least one nozzle hole extending therethrough in a direction generally normal to said planar surface and at a location dividing said electrode layer into separate electrode portions; and (c) a resistive heater coating formed on the interior surfaces of said nozzle hole and coupled to each of said electrode portions.
Claim 3
Dependent Claim
38 words
The monolithic drop on demand print head as claimed in claim 2 wherein said top stratum comprises a raised rim portion around the opening of said nozzle hole and said heater coating extends around said raised rim portion.
Claim 4
Dependent Claim
101 words
A process for manufacturing a thermally activated drop on demand printing head (50) said process comprising: (a) forming a plurality of electrodes (2023, 2025) on a silicon wafer substrate (2020); (b) forming a surface layer on the top of said substrate (2020); (c) etching a plurality of nozzle tip holes through said surface layer, intersecting said electrodes; (d) coating said nozzle tip holes with a resistive heater substance, in such a manner that electrical contact is made between said electrodes and said resistive heater substance; and (e) selectively removing said resistive heater substance from regions apart from said nozzle tip holes.
Claim 5
Dependent Claim
32 words
The process as claimed in claim 4 further including the step of etching part of said surface layer so that said resistive heater substance forms a rim protruding from said surface layer.
Claim 6
Dependent Claim
47 words
The process as claimed in claim 4 further including the step of coating said resistive heater substance with a passivation layer before removing said heater substance from regions apart from said nozzle tip holes, and removing said passivation layer from regions apart from said nozzle tip holes.
Claim 7
Dependent Claim
16 words
The process as claimed in claim 6 wherein said passivation layer is composed of silicon nitride.
Claim 8
Dependent Claim
34 words
The process as claimed in claim 4 further including the step of etching a plurality of nozzle barrel holes wherein the etchant accesses the front surface of said substrate through said nozzle tip holes.
Claim 9
Dependent Claim
26 words
The process as claimed in claim 4 further including the step of anisotropically etching one or more ink channels from the back surface of said substrate.
Claim 10
Dependent Claim
16 words
The process as claimed in claim 4 wherein said substrate is composed of single crystal silicon.
Claim 11
Dependent Claim
20 words
The process as claimed in claim 4 wherein said substrate is a single crystal silicon wafer of 〈100〉 crystallographic orientation.
Claim 12
Dependent Claim
17 words
The rocess as claimed in claim 4 wherein said surface layer is substantially composed of silicon dioxide.
Claim 13
Dependent Claim
21 words
The process as claimed in claim 4 wherein said nozzle tip hole is fabricated with a radius less than 50 microns.
Claim 14
Dependent Claim
29 words
The process as claimed in claim 4 wherein said substrate is composed of single crystal silicon, and said ink channels are etched exposing {111} crystallographic planes of said substrate.
Claim 15
Dependent Claim
19 words
The process as claimed in claim 4 wherein drive circuitry is fabricated on the same substrate as the nozzles.
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