Toner Adhesion Detection via Dynamic Wavelength Selection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing image forming apparatuses face challenges in accurately calculating toner adhesion amounts on intermediate transfer belts due to variations in belt color over time and production lots, leading to reduced detection accuracy, especially for black toner, as the reflectance difference between toner and belt changes, affecting the sensitivity of detection methods.

Innovation Solution

An image forming apparatus equipped with a sensor that emits light across multiple visible wavelength regions and an adhesion amount calculator that determines the optimal wavelength for calculation based on the detected color information of the belt, ensuring accurate toner adhesion amount measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a uniform reading wavelength is determined for toner adhesion detection, then the device complexity is reduced, but the measurement precision deteriorates due to belt color variations

Engineering Contradiction:
Improvedetection system complexityVSAvoidtoner adhesion amount detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the reading wavelength adjustable rather than fixed. The wavelength determination unit dynamically selects the optimal reading wavelength based on the detected color information of the intermediate transfer belt, allowing the system to adapt to belt color variations while maintaining detection accuracy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of reading wavelength based on the color information of the intermediate transfer belt. By adjusting the wavelength parameter according to belt color variations, the system maintains optimal reflectance difference for toner detection without requiring complex hardware modifications

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If light with large reflectance difference is used for black toner detection, then the measurement precision is improved, but the reliability deteriorates when belt color changes over time

Engineering Contradiction:
Improveblack toner detection sensitivityVSAvoiddetection accuracy consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback by using the detected color information of the intermediate transfer belt to determine the optimal reading wavelength. This feedback mechanism ensures that the system continuously adapts to belt color changes, maintaining reliable detection accuracy throughout the belt's service life

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary action by detecting the color information of the intermediate transfer belt before conducting toner adhesion measurement. This preliminary detection allows the system to pre-determine the optimal reading wavelength, ensuring accurate measurement from the outset

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

This approach enables high-accuracy calculation of toner adhesion amounts, maintaining consistent image density and reducing errors caused by belt color changes over time, even when black toner has low sensitivity, by selecting the appropriate wavelength for detection.

Implementation Method 1

In most cases, arrangement of a light source and a density sensor causes diffuse reflection. Thus, when the density sensor detects a black toner on a black intermediate transfer belt, a difference in reflectance is small and therefore sensitivity is low.

Methodology Applied
Scientific EffectDiffuse reflection: Reflection

Data Source

PatentEP3067751A1Image forming apparatus and control method for image forming apparatus
Publication Date: 2016.09.14 RICOH CO LTD
  • EP3067751A1 patent drawingFigure 1
  • EP3067751A1 patent drawingFigure 2~3
  • EP3067751A1 patent drawingFigure 4

AI summary

An image forming apparatus (1) includes an image bearer (51) that bears a toner image, a sensor (40), an adhesion amount calculator (73), and a wavelength determiner (72). The sensor includes a light source (100) that emits light onto the bearer, and an image element (102) that detects reflected light that is emitted from the light source and reflected from the image bearer. The adhesion amount calculator calculates a toner adhesion amount of the toner image on the image bearer based on the reflected light having at least one wavelength among wavelengths detected by the sensor. The wavelength determiner determines, based on color information of the image bearer detected by the sensor, a wavelength to be used in calculation of the toner adhesion amount by the adhesion amount calculator.