Optical Sensor for Color Misregistration Detection

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Solution Overview

Problem

Existing optical sensors in electrophotographic image forming apparatuses face challenges in downsizing due to the configuration of light emitting and receiving elements, which affects their accuracy and flexibility in detecting color misregistration and image density, especially under varying temperature and humidity conditions.

Innovation Solution

The optical sensor is designed with light emitting and receiving elements bonded to a common substrate using die bonding and wire bonding, allowing for a reduced size and improved accuracy in detecting specularly and diffusely reflected light, enabling precise color misregistration and image density corrections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If bullet elements are used for light emitting and light receiving elements, then the optical sensor can detect specularly and diffusely reflected light, but the optical sensor cannot be downsized

Engineering Contradiction:
Improvedetection accuracyVSAvoidoptical sensor size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent combines multiple light emitting elements and light receiving elements into a single integrated optical sensor module, merging their functions while maintaining detection accuracy. The light emitting elements and light receiving elements are arranged in a compact configuration where they share common structural support and optical paths, enabling the sensor to detect both specularly and diffusely reflected light without requiring separate bulky components for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent arranges the light emitting elements and light receiving elements in a three-dimensional configuration that optimizes spatial utilization. By positioning elements at specific angles and depths within the sensor housing, the design achieves compact footprint while maintaining the optical geometry needed for accurate detection of reflected light from the image bearing member.

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

2Volume of moving object

If the optical sensor uses a compact configuration, then the optical sensor can be downsized, but the detection accuracy may be compromised

Engineering Contradiction:
Improveoptical sensor sizeVSAvoiddetection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent optimizes the local arrangement of light emitting and light receiving elements within the compact sensor housing. Each element is positioned at a specific location with precise angular orientation to maximize its contribution to detection accuracy. The light receiving elements are arranged to capture reflected light from specific zones on the image bearing member, ensuring that the compact configuration does not compromise the ability to accurately detect color misregistration and image density.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple light emitting elements and light receiving elements are integrated, then the optical sensor can perform multiple detection functions, but the manufacturing complexity increases

Engineering Contradiction:
Improvedetection function flexibilityVSAvoidoptical sensor structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the optical sensor with universal functionality by integrating multiple light emitting elements and light receiving elements that can perform multiple detection tasks. The same sensor module detects both specularly and diffusely reflected light, measures color misregistration, and evaluates image density, eliminating the need for separate detection systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the optical sensor into distinct functional modules, with each light emitting element and light receiving element serving specific detection purposes. This modular segmentation allows for simplified manufacturing and assembly, as each component can be independently positioned and calibrated within the integrated sensor housing.

Inventive Principle:
Principle #1Segmentation

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 configuration enhances the detection accuracy and flexibility of the optical sensor, allowing for precise color misregistration and image density corrections, even under varying environmental conditions, while reducing the overall size and manufacturing costs.

Implementation Method 1

a first light emitting diode 701 and a second light emitting diode 702 as the light emitting elements

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

a first light receiving element 731 and a second light receiving element 732 as the light receiving elements, each having an optical axis orthogonal to the processing surface of the semiconductor substrate 142

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3614208B1Optical sensor and image forming apparatus
Publication Date: 2022.03.23 CANON KK
  • EP3614208B1 patent drawingFigure 1~2
  • EP3614208B1 patent drawingFigure 3A~3B
  • EP3614208B1 patent drawingFigure 4

AI summary

An optical sensor (7) includes a first LED (701), a second LED (702), a first PD (711), and a second PD (712). The first LED (701) and the second LED (702) are configured to irradiate an optical-axis center point of an intermediate transfer belt (5). The first PD (711) is arranged at a position at which specularly reflected light of light emitted from the first LED (701) and diffused reflected light of light emitted from the second LED (702) are received. The second PD (712) is arranged at a position at which diffused reflected light of the light emitted from the first LED (701) is received.