Liquid Discharge Head Terminal Throttle Resistance Balancing

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Solution Overview

Problem

Ink-jet heads face issues with ink stagnation at the terminal end of the common channel and variations in discharging characteristics among nozzles due to uneven channel resistance connections between pressure chambers and the common ink chamber.

Innovation Solution

The design includes a common channel with a terminal throttle having the same channel resistance as other throttles, extending from the connection between the terminal throttle and the pressure chamber to the terminal part of the common channel, and bypass channels connecting adjacent common channels to manage pressure fluctuations and prevent stagnation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the terminal throttle is connected to the common channel at a position far from the terminal part, then the ink flow path is simplified, but ink stagnation occurs at the terminal part of the common channel

Engineering Contradiction:

Improvechannel connection structureVSAvoidink flow consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The terminal throttle is extended to reach the terminal part of the common channel in advance, ensuring that the ink flow path is optimized before stagnation can occur. This preliminary positioning prevents ink accumulation at the terminal end by establishing proper flow dynamics from the outset.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The terminal throttle acts as an intermediary element that mediates between the common channel and the pressure chamber, ensuring balanced ink distribution. By positioning it at the terminal part, it serves as a flow regulator that prevents stagnation while maintaining simplified connection structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If different throttles have different channel resistances, then the connection structure can be simplified, but variations in discharging characteristics occur among nozzles

Engineering Contradiction:

Improvethrottle connection structureVSAvoiddischarging characteristic uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

All throttles including the terminal throttle are designed to have equal channel resistance values, creating an equipotential flow distribution system. This ensures that each nozzle receives ink under identical pressure conditions, eliminating variations in discharging characteristics while maintaining a simplified symmetric connection structure.

Inventive Principle:

Principle #12Equipotentiality

Solution Approach 2:

The channel resistance parameter of the terminal throttle is specifically adjusted to match the resistance values of other throttles. This parameter standardization ensures uniform ink flow distribution across all nozzles, achieving consistent discharging characteristics through controlled parameter equality.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If additional channels are added to connect the terminal throttle to the common channel, then ink stagnation is prevented, but the device complexity increases

Engineering Contradiction:

Improveink flow continuityVSAvoidchannel structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The terminal throttle serves multiple functions: it acts as a flow regulator for its associated pressure chamber, a stagnation prevention element at the common channel terminal, and a resistance-balancing component. This multi-functionality eliminates the need for separate additional channels, maintaining device simplicity while ensuring ink flow continuity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The functions of the terminal throttle are merged with the common channel structure itself, rather than adding separate additional channels. The terminal throttle's extension to the channel end integrates flow regulation and stagnation prevention into a single unified structure, reducing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11845279B2Liquid discharge head

Publication Date: 2023.12.19 BROTHER KOGYO KK

AI summary

There is provided a liquid discharge head including: a plurality of nozzles arranged in a first direction; a plurality of pressure chambers; a plurality of throttles; and a common channel extending in the first direction and connected to the plurality of throttles. The common channel has: a supply port, and a terminal part which is at least one of both end parts in the first direction of the common channel, the supply port being not provided at the terminal part. A terminal throttle which is one of the plurality of throttles and which is positioned closest to the terminal part among the plurality of throttles has a channel resistance same as a channel resistance of a throttle of the plurality of throttles different from the terminal throttle, and extends from a connection between the terminal throttle and one of the plurality of pressure chambers to the terminal part.