Dual Image Forming Units With Temperature-Based Toner Alignment

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Solution Overview

Problem

In image forming apparatuses using multiple image forming units, temperature differences between units can cause misalignment of toner images due to thermal expansion and contraction, leading to inaccurate positioning when adjustments are based on a single temperature sensor.

Innovation Solution

The apparatus employs two temperature sensors to detect temperature differences between adjacent image forming units and uses a detection device to adjust misalignment by forming pattern images on a transport belt, allowing for precise alignment adjustments based on multiple temperature readings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only one temperature sensor is provided in the image forming apparatus and misalignment adjustment is performed based on only the temperature change at one location, then the device complexity is reduced, but the manufacturing precision of toner image alignment deteriorates due to temperature differences between image forming units

Engineering Contradiction:
Improvetemperature sensing system complexityVSAvoidtoner image alignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The temperature sensing system is segmented into multiple independent sensors placed at different image forming units. Each sensor independently monitors temperature at its local position, enabling localized misalignment correction that accounts for temperature variations between units. This segmentation resolves the contradiction by increasing measurement precision without proportionally increasing system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by placing temperature sensors at specific locations around each image forming unit and performing misalignment adjustment based on local temperature conditions. Each image forming unit's misalignment is corrected according to its own temperature environment rather than using a single global temperature reading, thereby improving alignment precision while maintaining reasonable device complexity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If multiple temperature sensors are used to detect temperature differences between image forming units, then the manufacturing precision of toner image alignment is improved, but the device complexity increases

Engineering Contradiction:
Improvetoner image alignment precisionVSAvoidtemperature sensing system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by selectively performing misalignment adjustment only for image forming units where temperature differences exceed a predetermined threshold. Not all image forming units require adjustment at every temperature condition, so the system performs correction only where necessary. This approach improves alignment precision for affected units while avoiding unnecessary operations that would increase device complexity and processing overhead.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically changes the misalignment correction parameters based on detected temperature differences. When temperature variation between units exceeds a threshold, the system activates misalignment adjustment with specific correction amounts; when temperature is uniform, adjustment is skipped or reduced. This parameter-based control optimizes the balance between alignment precision and device complexity by adapting system behavior to actual thermal conditions.

Inventive Principle:
Principle #35Parameter changes

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 effectively suppresses misalignment of toner images and improves alignment accuracy by utilizing multiple temperature sensors and a detection device for real-time adjustments, reducing the time required for alignment and enhancing precision.

Implementation Method 1

Components constituting each image forming unit expand due to a temperature rise inside the apparatus or contract due to a temperature drop. Therefore, a misalignment may occur at an image forming position due to a change in temperature inside the apparatus.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4707932A1Image forming apparatus, program, and image forming method
Publication Date: 2026.03.11 FUJIFILM BUSINESS INNOVATION CORP
  • EP4707932A1 patent drawingFigure 1
  • EP4707932A1 patent drawingFigure 2
  • EP4707932A1 patent drawingFigure 3A~3C

AI summary

An image forming apparatus includes: a first image forming unit that has a plurality of image forming sections and an intermediate transfer body to which toner images formed by the plurality of image forming sections are primarily transferred; a second image forming unit that is disposed adjacent to the first image forming unit and that has a plurality of image forming sections and an intermediate transfer body to which toner images formed by the plurality of image forming sections are primarily transferred; a transport belt that transports paper to a secondary transfer position at which the toner images respectively formed on the intermediate transfer bodies of the first image forming unit and the second image forming unit are secondarily transferred; a detection device that is provided downstream of the two secondary transfer positions in a transport direction in which the paper is transported by the transport belt and that detects pattern images formed by the toner images secondarily transferred onto the transport belt; a first temperature sensor that is disposed to detect a temperature around the first image forming unit; and a second temperature sensor that is disposed to detect a temperature around the second image forming unit, in which a processor is configured to: cause all the image forming sections of the first image forming unit and the second image forming unit to form the pattern images on the transport belt in a case where a temperature difference between a temperature detected by the first temperature sensor and a temperature detected by the second temperature sensor is equal to or greater than a first threshold set in advance; and adjust a misalignment of the toner images formed by the first image forming unit and the second image forming unit by using a detection result of the detection device.