Nail Printer Ejection Device Optical Contact Detection

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Solution Overview

Problem

Conventional nail printers face issues where the print head cannot avoid contacting the nail, leading to potential damage and contamination, especially when the nail has decoration materials that protrude, causing the fingertip to move and resulting in contact between the print head and the nail or decoration.

Innovation Solution

An ejection device is designed with a light projecting part and a light receiving part that form a light path inclined at a predetermined angle, preventing the print head from contacting the nail by stopping its operation when the light is blocked, thus ensuring safety and preventing contamination and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the distance between the print head and the nail is decreased to improve printing precision, then the manufacturing precision is improved, but the reliability deteriorates because the print head may contact the nail or decoration materials causing damage and contamination

Engineering Contradiction:
Improveprinting precisionVSAvoidcontact avoidance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The light path is established before the printing operation begins, creating a safety zone that predicts the potential contact path of the print head. This preliminary detection allows the system to identify nails or decoration materials that protrude into the print head's movement path before printing starts, preventing contact damage while maintaining close printing distance for precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A light path acts as an intermediary detection mechanism between the print head and the nail. The light path indirectly detects the presence of objects in the print head's potential contact zone without requiring direct contact, enabling the system to maintain both close printing distance and safety through optical detection

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a push switch is used to detect finger presence and stop printing, then the reliability is improved by stopping operation when finger moves away, but the object-generated harmful factors worsen because protruding decoration materials can still cause contact when the finger is pressed

Engineering Contradiction:
Improveoperation controlVSAvoidcontact contamination
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The detection method transitions from a one-dimensional push switch (detecting only vertical finger pressure) to a two-dimensional light path detection system. The light path extends across the printing area, detecting objects in the print head's potential contact zone regardless of whether the finger is pressed down, thereby detecting protruding decoration materials that the push switch would miss

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The light path detection operates continuously or periodically to identify potential contact hazards before the printing operation proceeds, rather than relying solely on the push switch to detect finger presence. This preliminary detection of protruding objects prevents contact contamination even when the finger is pressed and the push switch indicates normal operation

Inventive Principle:
Principle #10Preliminary action

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 solution effectively prevents the print head from contacting the nail, ensuring safety and preventing contamination and damage to both the nail and the print head, while enhancing detection performance by increasing the irradiated area and using reflective parts to improve detection over a wider range.

Implementation Method 1

a light projecting part projecting a light between the discharge part and the object to form a light path across the object; a light receiving part receiving the light projected by the light projecting part

Methodology Applied
Scientific EffectLight propagation: Light

Implementation Method 2

a reflecting part that reflects the light projected by the light projecting part to propagates across the object at least one time

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3121019B1Ejection device
Publication Date: 2020.01.01 FUNAI ELECTRIC CO LTD
  • EP3121019B1 patent drawingFigure 1
  • EP3121019B1 patent drawingFigure 2
  • EP3121019B1 patent drawingFigure 3

AI summary

An ejection device (10) capable of preventing a discharge part (30) from contacting an object (NL) is provided. The ejection device (10) has a discharge part (30), a light projecting part, a light receiving part and a controller. The discharge part (30) discharges a droplet to an object (NL), for example a nail of a finger. The light projecting part projects a light between the discharge part (30) and the object (NL) to form a light path across the object (NL), and the light receiving part receives the light projected by the light projecting part. The controller stops driving the discharge part (30) when the light receiving part does not receive the light.