Liquid Discharge Head Dummy Nozzle Optical Inspection

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Solution Overview

Problem

Liquid discharge heads with dummy nozzles that do not discharge liquid pose challenges in ensuring thorough cleaning and inspection accuracy, as the higher fluid resistance in dummy channels leads to residual liquid remaining due to insufficient cleaning, which can cause issues like liquid mixing and clogging during shipment.

Innovation Solution

Incorporating a nozzle plate with a dummy channel that has a higher fluid resistance than individual channels, made of materials that are transmissible to infrared or visible light, allowing for easier observation and confirmation of residual liquid, thereby improving inspection accuracy and ensuring thorough cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dummy nozzles are added to the liquid discharge head, then the discharge evaluation accuracy is improved, but the cleaning difficulty increases due to higher fluid resistance in dummy channels

Engineering Contradiction:

Improvedischarge evaluation accuracyVSAvoidcleaning ease

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The dummy channel is designed with locally different properties (higher fluid resistance) compared to individual channels, creating a distinct flow characteristic that prevents liquid mixing while maintaining separate flow paths for evaluation purposes

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The liquid discharge head is segmented into individual channels and dummy channels, with the dummy channel serving as a separate evaluation path that does not discharge liquid, allowing independent assessment of discharge performance

Inventive Principle:

Principle #1Segmentation

2Reliability

If dummy channels with higher fluid resistance are used, then the liquid mixing is prevented, but the residual liquid detection becomes difficult

Engineering Contradiction:

Improveliquid mixing preventionVSAvoidresidual liquid detection

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The dummy channel structure utilizes optical property changes (transmissivity to infrared or visible light) to detect residual liquid presence, where the channel material's interaction with light indicates whether liquid remains after cleaning

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The detection method is replaced from mechanical/visual inspection to optical detection using infrared or visible light transmissivity, allowing non-contact and more accurate detection of residual liquid in the dummy channel

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The increased fluid resistance in dummy channels ensures that any residual liquid is more easily detected and removed, enhancing the accuracy of discharge evaluations and preventing issues like liquid mixing and clogging during shipment.

Implementation Method 1

the wall of the lateral channel is transmittable of at least one of infrared ray and visible light

Methodology Applied

Scientific EffectLight transmission: Light

Data Source

PatentUS11247468B2Liquid discharge head, liquid discharge device, and liquid discharge apparatus

Publication Date: 2022.02.15 RICOH CO LTD

AI summary

A liquid discharge head includes a nozzle configured to discharge a liquid, a dummy nozzle configured not to discharge the liquid, a nozzle plate including the nozzle and the dummy nozzle, an individual channel communicating with the nozzle, a dummy channel communicating with the dummy nozzle, and a channel plate bonded to the nozzle plate. The dummy channel includes a lateral channel along an in-plane direction of the nozzle plate, the nozzle plate forms a wall of the lateral channel of the dummy channel, and the wall of the lateral channel is transmittable of at least one of infrared ray and visible light.