Angled Protective Openings in Liquid Ejection Heads for Nozzle Recovery
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Solution Overview
Problem
In high-speed printing using a line-type liquid ejection head, print media can float and contact the printing element boards, causing damage, and protective members can impair recovery performance and clog nozzles.
Innovation Solution
A liquid ejection head with a protective member featuring elongate openings angled to reduce contact damage and facilitate effective maintenance, using materials like stainless steel and alumina, and a maintenance mechanism that scans in the longitudinal direction for efficient ink recovery and dust removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective member is bonded to the ejection orifice formation surface, then damage to the liquid ejection head from floating print media is prevented, but the protective member may impair recovery performance and cause nozzle clogging
Solution Approach 1:
The protective member is divided into multiple sections corresponding to different color nozzles (K, C, M, Y nozzles separated). This segmentation allows the recovery unit to access each nozzle group independently, maintaining recovery performance while providing protection. The segmented structure prevents dust accumulation at single endpoints and enables targeted maintenance of each color channel.
Solution Approach 2:
The protective member acts as an intermediary between the print media and the ejection orifices. It provides physical protection while incorporating openings that allow ink ejection and recovery unit access. The mediator structure includes inclined surfaces that guide dust and debris away from the nozzles, preventing clogging while maintaining the protective function.
2Reliability
If a protective member is bonded to the ejection surface, then contact damage from floating print media is reduced, but adhesive may climb up into openings and clog nozzles
Solution Approach 1:
The openings in the protective member are formed with inclined surfaces before bonding the protective member to the ejection surface. This preliminary design of the opening geometry prevents adhesive from climbing up into the openings during the bonding process. The inclination angle is specifically designed to guide adhesive away from the nozzle openings, preventing future clogging while maintaining structural integrity.
3Reliability
If a protective member is bonded to the ejection surface, then print media contact is prevented, but dust accumulation at the end of the protective member can clog nozzles
Solution Approach 1:
The protective member is segmented into multiple sections with separate openings for different color nozzles. This segmentation eliminates single endpoint dust accumulation zones and distributes dust collection points across multiple sections. The recovery unit can access each section independently, preventing dust buildup that would occur at a single endpoint of a continuous protective member.
Solution Approach 2:
The openings in the protective member are designed with inclined surfaces that extend in the longitudinal direction. This dimensional design creates a gradient that guides dust and debris away from the nozzle openings toward the ends of the inclined surfaces, where the recovery unit can effectively remove them. The inclined geometry transforms the dust accumulation problem from a two-dimensional surface issue to a three-dimensional flow path solution.
Data Source
AI summary
A liquid ejection head includes a printing element board having an ejection surface in which an ejection orifice array is formed to eject liquid; and a protective member having an opening corresponding to the ejection orifice array, wherein the shape of the opening is an elongate shape having a longitudinal direction and a transverse direction in the case of viewing from the ejection surface, the opening has a first side surface parallel to the longitudinal direction and a second side surface parallel to the transverse direction, and the protective member is fixed to the ejection surface such that the first side surface has an inclination angle with the ejection surface.