Electrostatic Latent Image Detection for Color Misregistration Correction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In tandem-type electrophotographic image forming apparatuses, color misregistration due to mechanical factors leads to positional shifts, causing inefficiencies and increased toner consumption during correction processes, which lowers the usability of the apparatus.

Innovation Solution

The apparatus employs a latent image mark detection system using a current detection circuit and high-pass filter to accurately detect electrostatic latent images on photosensitive members, allowing for precise color misregistration correction without consuming toner, by forming electrostatic latent images instead of traditional toner images for detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If position detection toner images are transferred from photosensitive members to an image carrier for color misregistration detection, then color misregistration can be detected, but toners are consumed and cleaning time is required, lowering usability

Engineering Contradiction:
Improvecolor misregistration detection accuracyVSAvoidapparatus usability
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical toner image formation system with an electrostatic field-based detection system. Instead of using toner particles that require mechanical transfer and cleaning, the invention uses electrostatic latent images that are detected through electrical field measurements, eliminating the need for physical toner handling and cleaning operations.

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

Solution Approach 2:

The patent introduces electrostatic latent images as an intermediary medium for detection. Rather than directly detecting toner images or using toner as the detection medium, the system forms electrostatic latent images that serve as a non-consumable intermediary that can be detected electrically without requiring physical transfer or cleaning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If position detection toner images are formed on the image carrier, then color misregistration can be detected, but cleaning processes are required, increasing maintenance time

Engineering Contradiction:
Improvecolor misregistration detection accuracyVSAvoidcleaning time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical toner image formation system with an electrostatic field-based detection system. Instead of using toner particles that require mechanical transfer and cleaning, the invention uses electrostatic latent images that are detected through electrical field measurements, eliminating the need for physical toner handling and cleaning operations.

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

Solution Approach 2:

The patent enables continuous detection operations without interruption for cleaning. By using electrostatic latent images that do not require physical removal, the system can maintain continuous operation, eliminating the periodic downtime required for cleaning toner residues from the image carrier.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If toner images are used for position detection, then color misregistration can be detected, but toner consumption increases

Engineering Contradiction:
Improvecolor misregistration detection accuracyVSAvoidtoner consumption
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical toner image formation system with an electrostatic field-based detection system. Instead of using toner particles that require mechanical transfer and cleaning, the invention uses electrostatic latent images that are detected through electrical field measurements, eliminating the need for physical toner handling and cleaning operations.

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

Solution Approach 2:

The patent creates an electrical copy of the image information in the form of electrostatic latent images. Rather than using physical toner copies that consume material, the system creates electrical field patterns that replicate the image information, allowing detection without material consumption.

Inventive Principle:
Principle #26Copying

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 reduces toner consumption and maintains apparatus usability by enabling accurate color misregistration detection and correction, improving the efficiency and reliability of the image forming process.

Implementation Method 1

A charging roller 23 charges the surface of the corresponding photosensitive member 22 to a uniform potential

Methodology Applied
Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 2

A scanner unit 20 scans the surface of the photosensitive member 22 by a laser beam corresponding to the image data of an image to be formed, thereby forming an electrostatic latent image on the photosensitive member 22

Methodology Applied
Scientific EffectPhotoconductive effect: Photoconductivity

Implementation Method 3

A development roller 24 develops the electrostatic latent image on the photosensitive member 22

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 4

A primary transfer roller 26 transfers the toner image that is formed on the photosensitive member 22 to an intermediate transfer belt 30

Methodology Applied
Scientific EffectElectrostatic transfer: Electrostatics

Implementation Method 5

A secondary transfer roller 27 transfers the toner image on the intermediate transfer belt 30 to a printing medium 12

Methodology Applied
Scientific EffectElectrostatic transfer: Electrostatics

Implementation Method 6

A pair of fixing rollers 16 and 17 heat and fix the toner image transferred to the printing medium 12

Methodology Applied
Scientific EffectThermal fixation: Heating

Data Source

PatentEP2624061B1Image forming apparatus which uses electrostatic latent image for color misregistration correction
Publication Date: 2018.05.23 CANON KK
  • EP2624061B1 patent drawingFigure 1
  • EP2624061B1 patent drawingFigure 2
  • EP2624061B1 patent drawingFigure 3

AI summary

An image forming apparatus includes control means for forming electrostatic latent images for correction for color misregistration correction on a photosensitive member; voltage application means for applying a voltage to process means; current detection means for detecting a current to the voltage application means via the process means when the voltage application means applies the voltage to the process means; and conversion means for converting an output value detected by the current detection means such that a variation range Vp of the output value detected by the current detection means at a formation period Tp of the electrostatic latent image for correction becomes larger than a variation range Vd of the output value detected by the current detection means at a one-rotation period Td of the photosensitive member on which the electrostatic latent image for correction is not formed.