Selective Heating Region Control for Toner Fixation

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Solution Overview

Problem

In image forming apparatuses, the use of a split heating type fixing apparatus for reducing power consumption can lead to poor fixation of toner images corresponding to additional images when these images are set on the entire surface of the recording material.

Innovation Solution

The image forming apparatus is designed to reduce fixing failures by selectively heating regions of the recording material based on the image size, ensuring that the toner images corresponding to additional images are properly fixed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If selective heating is carried out according to the image size using the split type heating/fixing apparatus, then power consumption is reduced, but the toner image corresponding to the additional image becomes poorly fixed at a non-heating part or in a region where the temperature is lower than the image part

Engineering Contradiction:
Improvepower consumptionVSAvoidfixation quality of toner image
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the heating treatment for different regions of the recording material. The additional image region receives heating treatment even when it falls outside the main image area, ensuring proper toner fixation. This is achieved by detecting the presence of additional images and adjusting the heating regions accordingly, so that each region receives appropriate thermal treatment based on its specific requirements rather than uniform heating.

Inventive Principle:
Principle #3Local quality

2Reliability

If the entire surface of the recording material is heated, then the toner image according to the additional image is surely fixed, but power consumption increases

Engineering Contradiction:
Improvefixation quality of toner imageVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent segments the heating function into multiple independent heating regions that can be selectively activated. Instead of heating the entire recording material surface, the system divides the heating zones and activates only those regions containing image data (main image or additional image). This segmentation allows the system to maintain reliable toner fixation where needed while avoiding energy waste in empty regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by heating only the specific regions containing toner images (main image and additional image) rather than the entire recording material surface. The heating action is precisely limited to the necessary areas, avoiding excessive heating of empty regions. This partial heating approach maintains sufficient fixation quality while significantly reducing power consumption compared to full-surface heating.

Inventive Principle:
Principle #16Partial or excessive 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 effectively reduces fixing failures of toner images related to additional information, ensuring reliable image formation while minimizing power consumption.

Implementation Method 1

a heater (33) and a pressing roller (32), and the heating/fixing apparatus (30) conveys the recording material (11) while heating and pressing the recording material (11)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3786718B1Image forming apparatus
Publication Date: 2025.05.14 CANON KK
  • EP3786718B1 patent drawingFigure 1A
  • EP3786718B1 patent drawingFigure 1B
  • EP3786718B1 patent drawingFigure 2

AI summary

An image forming apparatus including: an image forming portion that forms a toner image on a recording material; a fixing portion that has a heater unit including a heater and that fixes the toner image on the recording material, the heater being capable of changing a heat generating region; a control portion that controls the heater; and an image adding portion that adds a predetermined additional image to a desired image, wherein the control portion sets the heat generating region according to a width of the desired image in a direction perpendicular to the conveying direction or a width of the recording material in the direction perpendicular to the conveying direction, and the width of the predetermined additional image in the direction perpendicular to the conveying direction is equal to or less than the width of the heat generating region in the direction perpendicular to the conveying direction.