Liquid Ejecting Head Valve Wall Elimination
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Solution Overview
Problem
Conventional liquid ejecting heads have a configuration with walls between valve units, increasing the size of the head and leading to variations in ejection characteristics due to unequal supply pressures between nozzle rows.
Innovation Solution
The design eliminates walls between valve units, allowing them to be positioned closer together and ensuring equal intervals between the nozzle plate and valve elements, which reduces the size of the liquid ejecting head and uniformizes ejection characteristics by equalizing supply pressures across nozzle rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If walls are provided between adjacent valve units inside the carriage cover, then the valve units are isolated and protected, but the size of the liquid ejecting head increases in the direction in which the valve units are arranged
Solution Approach 1:
Adjacent valve units share a common downstream chamber space by removing the partition wall between them. The downstream cover member of each valve unit defines part of the downstream chamber, and these cover members face each other across the shared space. This merging of spaces eliminates the need for separate enclosed chambers for each valve unit, reducing the overall head size while maintaining functional isolation through the cover members.
2Strength
If walls are provided between valve units, then structural support is provided, but the intervals between the nozzle plate and valve elements become unequal, causing variations in ejection characteristics
Solution Approach 1:
The configuration ensures that all valve elements have equal intervals to the nozzle plate by positioning them symmetrically with respect to the nozzle plate. The downstream cover members are disposed to face each other and are displaced equally in accordance with pressure changes in the shared downstream chamber. This creates equipotential conditions for pressure distribution, ensuring equal supply pressures to all nozzle rows without requiring partition walls.
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 size of the liquid ejecting head while ensuring uniform ejection characteristics by eliminating walls between valve units and equalizing supply pressures, thereby enhancing the precision and efficiency of liquid ejection.
Implementation Method 1
The downstream cover member is disposed so as to face each other and is displaced in accordance with a pressure in the downstream chamber
Implementation Method 2
a valve mechanism including a valve element, a nozzle plate, and a holder and opens and closes the valve element in accordance with a pressure in a channel downstream from the valve element
Data Source
AI summary
A liquid ejecting head includes a first-valve-mechanism, a second-valve-mechanism, a nozzle plate, and a holder housing the first-valve-mechanisms and the second-valve-mechanisms. When a direction perpendicular to the nozzle plate is a first-direction, the nozzle plate extends in a second-direction and a third-direction. The first-valve-mechanism and the second-valve-mechanism arranged in the third-direction, with a space therebetween. The first-valve-mechanism includes a first-valve-element and a first-downstream-cover-member defining a first-downstream-chamber downstream of the first-valve-element. The second-valve-mechanism includes a second-valve-element and a second-downstream-cover-member defining a second-downstream-chamber downstream of the second-valve-element. The first-downstream-cover-member faces the second-downstream-cover-member. An interval between the nozzle plate and the first-valve-element is equal to an interval between the nozzle plate and the second-valve-element in the first-direction. The holder has no wall in an area of the space between the first-valve-mechanism and the second-valve-mechanism, the area overlapping the first-downstream-cover-member and the second-downstream-cover-member as viewed from the third-direction.