Piezoelectric Detection Plate for Foreign Object Sensing

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Solution Overview

Problem

Existing liquid ejecting apparatuses face challenges in accurately detecting foreign objects on the medium surface without damaging the apparatus, as they require complex optical detection mechanisms and precise equipment adjustments.

Innovation Solution

A liquid ejecting apparatus incorporating a detection plate with a piezoelectric film sensor and a sensor cover that detects strain caused by foreign objects or medium curvature, allowing for accurate detection while protecting the sensor and simplifying mechanical adjustments, without the need for optical detection devices or precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an optical detection device is used to detect foreign objects, then detection accuracy is improved, but device complexity and adjustment difficulty increase

Engineering Contradiction:

Improveforeign object detection accuracyVSAvoidoptical detection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the optical detection system with a mechanical detection system using a detection plate that directly contacts foreign objects. The piezoelectric sensor detects mechanical strain caused by foreign object contact, eliminating the need for complex optical components while achieving comparable detection accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection plate serves as an intermediary between foreign objects and the piezoelectric sensor. It converts foreign object contact into measurable strain on the plate, which is then detected by the sensor, providing a simple yet effective detection mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If an optical detection device is used, then foreign objects can be detected, but equipment adjustment becomes more difficult

Engineering Contradiction:

Improveforeign object detection accuracyVSAvoidequipment adjustment ease

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The mechanical detection plate requires no optical alignment or complex adjustments. It simply contacts foreign objects during medium transport, converting contact into strain signals that are automatically detected, greatly simplifying operation and maintenance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection plate automatically detects foreign objects through direct contact during the normal medium transport process, requiring no separate adjustment procedures or specialized operational steps.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If the detection plate contacts foreign objects directly, then detection accuracy is improved, but the risk of damage to the liquid ejecting unit increases

Engineering Contradiction:

Improveforeign object detection accuracyVSAvoiddamage risk to liquid ejecting unit

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The detection plate is positioned upstream of the liquid ejecting unit to detect foreign objects before they can reach and damage the nozzles. This preliminary detection allows the system to take preventive action, such as stopping medium transport, before damage occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detection plate acts as a protective intermediary that absorbs foreign object contact away from the liquid ejecting unit. By placing the detection plate in the contact path, foreign objects are detected and can be addressed before they threaten the expensive nozzle components.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables high-accuracy foreign object detection at an early stage, preventing damage to the apparatus and medium, while eliminating the need for complex adjustments and electrical controls, thus enhancing detection accuracy and reliability.

Implementation Method 1

a piezoelectric film sensor that is provided on a medium-side plate surface of the detection plate portion facing the medium and that outputs an electric signal corresponding to strain of the detection plate portion

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10399365B2Liquid ejecting apparatus

Publication Date: 2019.09.03 SEIKO EPSON CORP

AI summary

A detection plate portion detects an object that can come into contact with a liquid ejecting unit, which ejects a liquid onto a medium, in accordance with relative movement between the liquid ejecting unit and the medium, is formed in a plate shape, and undergoes strain upon contact with the medium. An electric signal corresponding to the strain of the detection plate portion is obtained from a piezoelectric film sensor provided on a medium-side plate surface of the detection plate portion facing the medium. A sensor cover is provided apart from the detection plate portion, and the sensor cover covers the piezoelectric film sensor not to come into contact with the medium-side plate surface.