Polished Sub-Plate for Liquid Ejection Head Bonding
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Solution Overview
Problem
Inkjet heads face issues with warping and uneven bonding surfaces due to heat, leading to nozzle plate lift and separation, especially in configurations with multiple head chips and a single nozzle plate, which complicates smooth bonding and affects discharge performance.
Innovation Solution
A liquid ejection head design featuring an actuator plate, a sub-plate with a polished downstream opening surface, and an ejection hole plate, where the sub-plate is polished to ensure smooth stacking and reduce variations in pump length, allowing reliable bonding and improved discharge performance by suppressing nozzle plate lift and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If head chips are bonded to the nozzle plate without polishing, then the manufacturing process is simpler and faster, but the bonding surfaces become wavy with convexes and concaves due to heat warping, causing nozzle plate lift and separation
Solution Approach 1:
The downstream opening surface of the sub-plate is polished in advance before bonding the nozzle plate. This preliminary polishing action ensures that the bonding surface is flat and smooth, preventing warping-induced convexes and concaves from causing nozzle plate lift and separation during operation.
2Reliability
If the actuator plate is polished to make the bonding surface smooth, then the nozzle plate bonding is more reliable, but the drive electrode formed on the inner surface of the channel cannot be polished, affecting processability and discharge performance consistency
Solution Approach 1:
The liquid ejection head is divided into separate components: the actuator plate with the drive electrode, and the sub-plate with the polished downstream opening surface. By segmenting the structure, the polishing operation is applied only to the sub-plate's bonding surface, preserving the drive electrode integrity while achieving smooth nozzle plate bonding.
Solution Approach 2:
The sub-plate acts as an intermediary component between the actuator plate and the nozzle plate. It provides the polished bonding surface for reliable nozzle plate attachment, while allowing the actuator plate with its drive electrode to maintain its functional integrity without polishing interference.
3Productivity
If multiple head chips are stacked with a single nozzle plate, then high-resolution and high-speed printing are enabled, but the bonding surfaces become more difficult to smooth uniformly, increasing lift and separation risk
Solution Approach 1:
Instead of attempting to polish the bonding surfaces of multiple stacked head chips directly, the solution introduces a new dimensional approach by adding a sub-plate layer with a polished downstream opening surface. This sub-plate provides a uniform bonding interface for the nozzle plate across all stacked head chips, ensuring consistent contact and preventing lift and separation in high-density configurations.
Data Source
AI summary
A liquid ejection head includes: actuator plates having discharge channels to be filled with an ink; sub-plates stacked on the −Z-direction end surfaces of discharge channels in the actuator plates along a flow direction of the ink and having communication paths communicating with the discharge channels; and a nozzle plate stacked on the −Z-direction end surfaces of the communication paths in the sub-plates along the flow direction and having nozzle holes communicating with the discharge channels through the communication paths. The −Z-direction end surfaces of the sub-plates are polished.