Inkjet Printhead Roof Mechanical Seal

The patent applies different surface properties to different locations: the exterior ink ejection face is made hydrophobic to prevent flooding, while the interior nozzle chamber surfaces are kept hydrophilic to allow proper ink flow. This is achieved by selectively coating only the exterior surfaces with hydrophobic material and using etch-selective layers to protect interior surfaces during fabrication.

The patent introduces an etch-selective intermediate layer between the hydrophobic coating and the nozzle chamber structures. This intermediate layer acts as a mediator that allows the hydrophobic coating to be applied to exterior surfaces while preventing it from being deposited inside the nozzle chambers during the ashing process, thus maintaining the desired surface characteristics in different locations.

The patent employs composite material structures combining polymeric seal elements with metal components. The polymeric material provides the necessary flexibility and sealing capability, while the metal components provide structural support and durability. This composite approach expands the versatility of the seal design by combining the advantages of different material classes.

The patent utilizes the ability to change polymeric material properties through parameter adjustments such as cross-linking density, molecular weight, and composition ratios. By modifying these parameters, the seal can be optimized for different operating conditions while maintaining the fundamental polymeric-based sealing mechanism.