Oleophobic Coating for Ink Jet Printhead Front Face
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Solution Overview
Problem
Current coatings for ink jet printhead front faces fail to prevent wetting, drooling, and flooding by ultra-violet gel ink and solid ink, leading to nozzle blockages and degraded print quality, and are not robust enough to withstand maintenance procedures.
Innovation Solution
A low adhesion surface coating comprising an oleophobic polymeric material with a low sliding angle, typically less than 30°, is applied to the printhead front face and flexure chute, allowing ink droplets to roll off without residue and maintaining high contact angles for improved holding pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sputtered polytetrafluoroethylene coating is applied to printhead front face, then coating provides basic non-stick property, but ink still flows along the surface and leaves residue film causing wetting and contamination
Solution Approach 1:
The patent changes the surface energy parameters of the printhead front face by applying a low surface energy coating comprising fluorinated silane oligomers and crosslinking agents. This chemical modification reduces the surface energy to below that of the ink, creating extreme ink repellency that prevents wetting, drooling, and flooding, thereby resolving the contradiction between basic non-stick properties and reliable jetting performance.
Solution Approach 2:
The patent uses a composite coating system combining fluorinated silane oligomers with crosslinking agents (such as glycidoxypropyltrimethoxysilane or tetraethyl orthosilicate). This composite material provides both low surface energy for ink repellency and crosslinked network structure for durability, overcoming the limitations of simple PTFE coatings and ensuring both contamination prevention and jetting reliability.
2Object-affected harmful factors
If low surface energy coating is applied to reduce ink adhesion, then ink sliding angle decreases and roll-off improves, but coating must withstand maintenance wiping procedures
Solution Approach 1:
The patent applies the low surface energy coating to the printhead front face before the printhead is put into service. The coating is applied as a wet formulation and then cured to form a durable, crosslinked network. This preliminary action ensures the coating is already in place and bonded to the substrate, providing both ink repellency and durability from the start of operation.
Solution Approach 2:
The patent transforms the coating from a simple low surface energy layer to a crosslinked network structure by adding crosslinking agents. This chemical change increases the coating's mechanical strength and durability while preserving its low surface energy properties, enabling it to withstand maintenance wiping procedures while maintaining ink repellency.
3Reliability
If ink is purged from ink jet channels to clear contaminants, then nozzle blockages are removed, but wetted front face prevents ink from sliding into waste reservoir
Solution Approach 1:
The patent applies a low surface energy coating to the printhead front face before any ink jetting or purging operations. This preliminary protective action prevents ink from wetting and adhering to the front face during normal operation and during purge operations. As a result, purged ink can slide freely off the front face into the waste reservoir without leaving residue, improving purge efficiency while maintaining nozzle clarity.
4Object-affected harmful factors
If wiper blade is used to remove ink residue from front face, then contamination is cleared, but coating must withstand repeated wiping cycles
Solution Approach 1:
The patent uses a composite coating system combining fluorinated silane oligomers with crosslinking agents to create a durable, crosslinked network structure. This composite material provides both the low surface energy needed for ink repellency and the mechanical strength required to withstand repeated wiper blade cleaning cycles, extending the coating's service life while maintaining contamination prevention.
Solution Approach 2:
The patent applies and cures the low surface energy coating to form a durable, crosslinked network before the printhead is put into service. This preliminary action ensures the coating is already bonded to the substrate and ready to withstand maintenance procedures, including repeated wiper blade wiping cycles, throughout the printhead's operational life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coating effectively prevents ink contamination, ensures high-quality printing by reducing misdirected droplets, and withstands multiple wiping cycles, enhancing maintenance efficiency and reducing ink weeping from nozzles.
Implementation Method 1
the coating comprises an oleophobic polymeric material, wherein, when the surface coating is disposed on an ink jet printhead front face surface, jetted drops of ultra-violet gel ink or jetted drops of solid ink exhibit very little adhesion towards the surface
Implementation Method 2
The adhesion is measured by the sliding angle of the ink drop, wherein the lower the sliding angle, the lower the adhesion between the ink drop and the surface
Data Source
AI summary
A coating for an ink jet printhead front face, wherein the coating comprises a low adhesion coating, wherein when the low adhesion coating is disposed on an ink jet printhead front face surface, jetted drops of ultra-violet gel ink or jetted drops of solid ink exhibit a low sliding angle with the printhead front face surface, wherein the low sliding angle is less than about 1° to less than about 30°. In embodiments, the low adhesion coating is an oleophobic coating that exhibits a contact angle of greater than about 35° with ultra-violet gel ink or solid ink. The coating can further be used for an ink jet printhead flexure chute.