Liquid Ejection Head Structure for Low-Voltage Diaphragm Displacement

Solution Overview

Problem

Existing bend-mode liquid ejection heads face challenges in achieving sufficient diaphragm plate deformation with low drive voltage due to increased rigidity from protective films and metal coverings, hindering efficient liquid ejection and maintenance operations.

Innovation Solution

A liquid ejection head design featuring a first substrate with a flat surface and uneven second surface, including a drive element, where the second substrate forms pressure chambers with a surrounding region of lower rigidity, allowing for greater diaphragm plate displacement with reduced thickness and improved deformability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If protective films and waterproof films are formed on the substrate surface to fill unevenness, then the cap member can come into close contact for suction and wipe operations, but the diaphragm plates become thicker and harder to deform

Engineering Contradiction:

Improveclose contact for suction and wipe operationsVSAvoiddiaphragm plate rigidity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The substrate surface is divided into two regions: a first region (nozzle-formed surface) that is made flat for cap member contact, and a second region (diaphragm plate area) that maintains its original uneven shape without protective films to ensure deformability. This segmentation allows each region to have the surface characteristics needed for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different surface qualities are applied to different regions of the substrate. The first region (where ejection ports are formed) is made flat to enable close contact with the cap member for suction and wipe operations. The second region (diaphragm plate area) is left with its original uneven shape and without protective films to maintain low rigidity and high deformability.

Inventive Principle:

Principle #3Local quality

2Shape

If metal material is formed on the second electrode to cover the entire substrate, then the surface is flat, but the diaphragm plate becomes more rigid and deforms by a smaller amount

Engineering Contradiction:

Improveflat surfaceVSAvoiddiaphragm plate rigidity

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The substrate surface is divided into two regions: a first region (nozzle-formed surface) that is made flat for cap member contact, and a second region (diaphragm plate area) that maintains its original uneven shape without protective films to ensure deformability. This segmentation allows each region to have the surface characteristics needed for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different surface qualities are applied to different regions of the substrate. The first region (where ejection ports are formed) is made flat to enable close contact with the cap member for suction and wipe operations. The second region (diaphragm plate area) is left with its original uneven shape and without protective films to maintain low rigidity and high deformability.

Inventive Principle:

Principle #3Local quality

3Strength

If the diaphragm plate is made thinner to improve deformability, then displacement increases, but the structural integrity and strength decrease

Engineering Contradiction:

Improvediaphragm plate deformabilityVSAvoidstructural integrity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The substrate thickness is varied by region: the diaphragm plate area is made thinner to improve deformability and displacement, while other structural regions maintain sufficient thickness to ensure overall structural integrity and strength. This local quality differentiation allows the diaphragm to achieve adequate displacement with low drive voltage without compromising the overall structural reliability of the liquid ejection head.

Inventive Principle:

Principle #3Local quality

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

Enables proper displacement of diaphragm plates with low drive voltage, facilitating efficient liquid ejection, effective suction and wipe operations, and maintaining high-definition printing performance.

Implementation Method 1

pressure is generated inside the pressure chamber by application of voltage to deform the piezoelectric element in the in-plane direction and deform the diaphragm plate in the out-of-plane direction (bending deformation)

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12594761B2Liquid ejection head and printing apparatus

Publication Date: 2026.04.07 CANON KK

AI summary

A liquid ejection head being for liquid suction and wipe operations and enabling diaphragm plates to achieve proper amounts of displacement with low drive voltage includes first and second substrates. Ejection ports for ejecting liquid are provided at a flat first surface of the first substrate. Drive elements are provided on a second surface of the first substrate. The second substrate is joined to the second surface of the first substrate, forming pressure chambers configured to be supplied with liquid. Pressure-chamber forming portions of the first substrate form the diaphragm plates. The liquid in the pressure chambers is ejected from the ejection ports upon displacement of the diaphragm plates. The second surface of the first substrate includes the drive elements and is uneven. In the diaphragm plates, second regions surrounding first regions provided with the ejection ports have lower rigidity than the first regions.