Liquid Discharge Head Bypass Channels Pressure Equalization

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Solution Overview

Problem

The existing liquid discharge heads with nozzles arrayed in a two-dimensional matrix face issues with variations in discharge characteristics due to differences in meniscus pressure along the common main channel, affecting the uniformity of liquid discharge.

Innovation Solution

The liquid discharge head incorporates multiple bypass channels with varying fluid resistances to alternately connect common-supply and common-collection branch channels, reducing the variation in meniscus pressure by adjusting the fluid resistance of these bypass channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple nozzles are arrayed in a two-dimensional matrix with common-supply and common-collection main channels, then the liquid discharge capacity is improved, but variation in meniscus pressure occurs causing discharge characteristic variation

Engineering Contradiction:
Improveliquid discharge capacityVSAvoiddischarge characteristic uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent divides the common main channel into multiple separate bypass channels that connect supply branch channels to collection branch channels. This segmentation allows independent control of fluid resistance in each bypass channel, enabling compensation for meniscus pressure variations across different nozzle groups while maintaining high discharge capacity through parallel flow paths

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent assigns different fluid resistances to different bypass channels based on their positions in the nozzle array. Bypass channels closer to the supply end have different resistance values than those closer to the collection end, creating localized pressure compensation that equalizes meniscus pressure across all nozzles while preserving overall system productivity

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If bypass channels are added to connect supply and collection branch channels, then meniscus pressure variation is reduced, but device complexity increases

Engineering Contradiction:
Improvemeniscus pressure uniformityVSAvoidchannel structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent integrates bypass channels within the same channel plate structure that contains the supply and collection branch channels. Multiple bypass channels are arranged in parallel between the same supply and collection main channels, merging the pressure compensation function into the existing channel architecture without requiring separate additional components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bypass channels serve multiple functions simultaneously: they provide alternative flow paths for liquid circulation, enable pressure equalization across nozzle groups, and allow independent resistance tuning for each position in the array. This multi-functionality reduces the need for additional dedicated pressure control mechanisms

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively reduces the variation in meniscus pressure across the discharge head, leading to more uniform discharge characteristics and improved performance.

Implementation Method 1

a fluid resistance of the first bypass channel is different from a fluid resistance of the second bypass channel

Methodology Applied
Scientific EffectFluid resistance: Electrical Resistance

Data Source

PatentEP3995314B1Liquid discharge head, discharge device, and liquid discharge apparatus
Publication Date: 2023.11.29 RICOH CO LTD
  • EP3995314B1 patent drawingFigure 1~2
  • EP3995314B1 patent drawingFigure 3~4
  • EP3995314B1 patent drawingFigure 5~6

AI summary

A liquid discharge head (100) includes multiple nozzles (111) arrayed in two-dimensional matrix, the multiple nozzles (111) configured to discharge a liquid, multiple pressure chambers (121) respectively communicating with the multiple nozzles (111), multiple common-supply branch channels (152), each communicating with the multiple pressure chambers (121), multiple common-collection branch channels (153), each communicating with the multiple pressure chambers (121), the multiple common-collection branch channels (153) respectively communicating with the multiple common-supply branch channels (152) through the multiple pressure chambers (121), a common-supply main channel (156) communicating with each of the multiple common-supply branch channels (152), a common-collection main channel (157) communicating with each of the multiple common-collection branch channels (153), and two or more bypass channels (191A, 191B) communicating with the multiple common-supply branch channels (152) and the multiple common-collection branch channels (153).