Nozzle Clog Diagnosis Device Without Lenses

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Solution Overview

Problem

Current nozzle-clogging determining devices for inkjet printers face challenges in accurately detecting nozzle clogging with small ink droplets, requiring high-quality lenses and precise positioning, which increases costs and detection time, and often necessitate repeated ejection of droplets to minimize error detection.

Innovation Solution

A nozzle-clogging determining device that uses a light emitter and receiver without lenses to detect the light interception rate of ink droplets positioned within a spot of detection light, allowing for accurate clogging determination without the need for lens condensation or precise positioning, and reduces the number of repeated droplet ejections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If lenses are used to condense laser light to secure S/N ratio for detecting small ink droplets, then detection accuracy is improved, but device cost increases due to requirement of high-quality lenses

Engineering Contradiction:
Improvenozzle clogging detection accuracyVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes the lens component from the detection system. Instead of using lenses to condense laser light, the system uses the laser light directly in parallel with the droplet travel direction, eliminating the need for expensive high-quality lenses while maintaining detection capability for small ink droplets

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the optical condensation mechanism (lenses) with a geometric arrangement where the laser light source and detector are positioned to emit and receive light in parallel with the droplet travel direction. This substitution eliminates mechanical/optical components while achieving the same detection function

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If lenses are used to condense laser light for detecting small ink droplets, then S/N ratio is improved, but device cost increases

Engineering Contradiction:
ImproveS/N ratioVSAvoiddevice cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and removes the lens component from the system. By positioning the laser light source and detector to operate in parallel with droplet travel without lens condensation, the system achieves reliable S/N ratio through geometric arrangement rather than optical concentration, reducing device cost

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a simplified optical path configuration where light travels parallel to droplets without requiring complex lens systems. This copying of the basic light-droplet-interaction principle without additional optical components maintains reliability while reducing cost

Inventive Principle:
Principle #26Copying

3Measurement precision

If high accuracy positioning of head and nozzle-clogging determining device is implemented, then detection accuracy is improved, but device cost increases

Engineering Contradiction:
Improvenozzle clogging detection accuracyVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of positioning the detector to intercept light from droplets passing through a focused beam (requiring high precision), the patent inverts the approach: the laser and detector are positioned to operate in parallel with droplet travel, detecting light interception without requiring precise positional alignment, thereby reducing cost

Inventive Principle:
Principle #13The other way round (Inversion)

4Reliability

If multiple droplets are ejected multiple times to suppress error detection, then detection reliability is improved, but detection time increases

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the repeated ejection mechanism with a single-pass detection system. By using parallel light-droplet geometry, the system achieves reliable detection in one ejection cycle, eliminating the time loss associated with multiple ejection sequences while maintaining accuracy

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

This solution enables cost-effective detection of nozzle clogging with improved signal-to-noise ratio and reduced detection time, allowing for accurate determination of nozzle states without increasing costs or requiring high-precision alignment.

Implementation Method 1

a light emitter configured to emit detection light for detecting passing of the droplets in a direction intersecting with a traveling direction of the droplets, and a light receiver configured to receive the detection light

Methodology Applied
Scientific EffectLight interception: Absorption (EM radiation)

Data Source

PatentEP3144149B1Nozzle clog diagnosis device
Publication Date: 2020.08.05 MIMAKI ENGINEERING CO LTD
  • EP3144149B1 patent drawingFigure 1~2
  • EP3144149B1 patent drawingFigure 3~4
  • EP3144149B1 patent drawingFigure 5

AI summary

An object is to provide a nozzle-clogging determining device capable of detecting nozzle clogging without causing an increase in the cost. A nozzle-clogging determining device (1) is configured to detect passing of droplets ejected from a plurality of nozzles of a head (102) of an inkjet printer, and includes a droplet detector (20) and a determination controller (30). The droplet detector (20) includes a light emitter (21) configured to emit detection light (L) for detecting passing of droplets in a direction intersecting with a traveling direction of droplets, and a light receiver (22) configured to receive the detection light (L). The determination controller (30) consecutively ejects a plurality of droplets from each nozzle of the head (102) at equal intervals, and has a threshold for performing determination on nozzle clogging on the basis of a light interception rate of the detection light (L) which the light receiver (22) receives when droplets are positioned inside a spot of the detection light (L) which the light receiver (22) receives.