Ink Absorber Detection Using Wavelength-Selective Light Emission

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Solution Overview

Problem

Existing recording apparatuses face issues with accurately detecting ink accumulation on absorbers due to varying light absorption wavelengths based on ink color, leading to erroneous detection or failure to detect accumulation states, especially with black ink which absorbs light across all visible wavelengths and colors like cyan and yellow that do not absorb red light.

Innovation Solution

The solution involves discharging a specific color of ink, such as yellow or black ink, onto the absorber before detection, allowing the detection sensor to differentiate between ink accumulation and adhesion by adjusting the threshold values based on the output from the sensor, ensuring accurate detection and reducing ink accumulation through targeted discharge of accumulation reduction ink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If light emitting unit emits light to detect ink accumulation on absorber, then detection capability is provided, but detection accuracy deteriorates because ink color varies light absorption characteristics

Engineering Contradiction:
Improvedetection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of light wavelength to resolve the detection accuracy issue. By selecting a specific wavelength (e.g., red light) that does not overlap with the absorption bands of common ink colors (cyan, magenta, yellow), the system achieves accurate detection regardless of ink color. This parameter change transforms the detection from being color-dependent to being wavelength-selective, solving the contradiction between providing detection capability and maintaining detection accuracy.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If ink is discharged to absorber for marginless recording, then recording capability is improved, but ink accumulation occurs on absorber surface

Engineering Contradiction:
Improverecording capabilityVSAvoidink accumulation
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by discharging test ink before actual recording to detect and prevent accumulation. The system performs a preliminary discharge of a small amount of ink onto the absorber, then immediately detects the accumulation state using the light emitting unit. This preliminary action allows the system to identify when the absorber is full before normal recording begins, preventing excessive ink accumulation during productive recording operations.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If accumulation detection is performed continuously, then monitoring accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvemonitoring accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements periodic action by performing accumulation detection at specific intervals rather than continuously. The detection is triggered by predetermined events such as the completion of a recording task, the discharge of a certain amount of ink, or scheduled maintenance intervals. This periodic detection approach maintains monitoring accuracy for practical purposes while significantly reducing the complexity of the detection system and avoiding unnecessary continuous operational overhead.

Inventive Principle:
Principle #19Periodic 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

This method prevents erroneous detection of ink accumulation and effectively reduces ink accumulation by using the discharged ink to distinguish between accumulation and adhesion states, ensuring accurate monitoring and maintenance of the absorber.

Implementation Method 1

the wavelength of light to be absorbed varies depending on a color of the ink. For example, a black ink has absorbability of light in all the wavelength regions as long as the light has a wavelength in a visible light region. Nevertheless, for example, while a cyan ink tends to absorb light in a wavelength band of red (i.e., a complementary color of cyan), a red and yellow inks do not tend to absorb light in a wavelength band of red.

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3659809B1Recording apparatus comprising means to detect ink accumulation on an ink absorber and method thereof
Publication Date: 2023.08.16 CANON KK
  • EP3659809B1 patent drawingFigure 1
  • EP3659809B1 patent drawingFigure 2
  • EP3659809B1 patent drawingFigure 3

AI summary

A recording apparatus discharges an ink in a first color to a position at which an accumulated state on an ink absorber is to be detected. After that, a light is emitted onto the position from a light emitting unit, and reflected light is received by a light receiving unit.