Liquid Discharge Head Diaphragm Protrusion Width Variation
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Solution Overview
Problem
Existing liquid discharge heads exhibit varying response times and discharge speeds across different positions in a nozzle array, leading to inconsistent liquid droplet discharge.
Innovation Solution
The liquid discharge head incorporates a diaphragm with protruding portions of varying widths, where the widths are larger in the center portion of the nozzle array and decrease towards the ends, optimizing pressure application and discharge speed uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform piezoelectric elements are used across the nozzle array, then the device structure is simple, but the discharge speed varies between center and end nozzles due to pressure distribution differences
Solution Approach 1:
The patent applies local quality by making the protruding portions of the diaphragm have different widths at different locations. Specifically, the protruding portions at the center of the nozzle array have a first width, while those at the ends have a second width that is smaller than the first width. This local variation compensates for the natural pressure distribution differences, ensuring uniform discharge speed across all nozzles while maintaining a relatively simple overall device structure.
2Manufacturing precision
If the response time difference between center and end piezoelectric elements is reduced, then discharge speed uniformity improves, but this requires complex compensation mechanisms
Solution Approach 1:
The patent introduces the diaphragm with varying protruding portions as an intermediary element between the piezoelectric elements and the liquid chambers. This intermediary structure passively compensates for the response time differences by creating different pressure transmission characteristics at different locations, eliminating the need for active control mechanisms or complex compensation systems.
3Manufacturing precision
If larger protruding portions are used at the center, then pressure application is optimized for center nozzles, but the diaphragm structure becomes more complex
Solution Approach 1:
The diaphragm structure implements local quality by having protruding portions with different widths at different locations. The center protruding portions have a larger first width to provide optimized pressure application for center nozzles, while the end protruding portions have a smaller second width. This localized variation is integrated into a single diaphragm component, achieving pressure optimization without requiring multiple separate parts or complex assembly.
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
This configuration minimizes the difference in discharge speeds across the nozzle array, ensuring stable and consistent liquid droplet discharge.
Implementation Method 1
The liquid discharge head includes a nozzle plate, a liquid chamber plate, a diaphragm, and laminated piezoelectric elements. The laminated piezoelectric elements change the pressure inside liquid chambers such that the liquid in the liquid chambers is discharged as liquid droplets from nozzles.
Implementation Method 2
The multiple diaphragm portions vibrate by the pressures applied by the multiple piezoelectric elements via the multiple protruding portions, respectively.
Data Source
AI summary
A liquid discharge head includes a nozzle plate, a channel plate, piezoelectric elements, and a diaphragm. The nozzle plate has a nozzle array having nozzles from which liquid droplets are dischargeable. The channel plate has pressure chambers respectively communicating with the nozzles. The piezoelectric elements apply pressures to the respective pressure chambers to discharge the liquid droplets. The diaphragm seals one face of the pressure chambers. The diaphragm includes protruding portions to receive pressures from the respective piezoelectric elements and diaphragm portions to vibrate by the pressures applied by the piezoelectric elements via the respective protruding portions. The piezoelectric elements are disposed opposite to the pressure chambers with the diaphragm in between. Widths of the protruding portions in a center portion of the nozzle array in a nozzle array direction are larger than widths of the protruding portions in each ends of the nozzle array in the nozzle array direction.