Image Forming Fixing Control for Borderless Toner

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Solution Overview

Problem

In borderless image forming modes, toner deposited on the edge of the recording material is not readily fixed and easily peels off, causing contamination within the image forming apparatus.

Innovation Solution

The image forming apparatus controls the heating portion to maintain a higher temperature in the borderless mode to ensure proper fixation of toner on the edge of the recording material, using a controller to adjust the heating portion based on temperature detection, with different control temperatures for normal and borderless modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the image forming apparatus operates in borderless image forming mode to form toner image at the edge portion of recording material, then the image coverage is improved, but the toner fixation reliability deteriorates causing peeling and contamination

Engineering Contradiction:
Improveimage coverage areaVSAvoidtoner fixation reliability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the temperature parameter of the fixing member. Specifically, the control unit raises the temperature of the fixing member to a higher level than the normal fixing temperature when borderless image forming is detected. This temperature parameter change enables reliable fixation of toner at the edge portions of the recording material, preventing peeling and contamination while maintaining full-area image coverage.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the temperature of fixing member is increased to fix toner at edge portion, then the toner fixation reliability is improved, but the energy consumption increases

Engineering Contradiction:
Improvetoner fixation reliabilityVSAvoidheating energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by implementing temporary temperature elevation only during borderless image forming operations. The control unit detects when borderless mode is active and raises the fixing member temperature only during that specific period. When normal image forming mode is used, the temperature returns to the standard fixing temperature. This periodic temperature adjustment ensures reliable toner fixation at edges when needed, while minimizing energy consumption during normal operations.

Inventive Principle:
Principle #19Periodic action

3Object-generated harmful factors

If cleaning means is added to clean toner from edge portion, then the contamination problem is solved, but the device complexity increases

Engineering Contradiction:
Improvetoner contaminationVSAvoidcleaning system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of high temperature (which could cause toner degradation or recording material damage) into a beneficial effect for toner fixation. By carefully controlling the temperature elevation to be sufficient for fixation but not excessive, the patent eliminates the need for separate cleaning mechanisms. The elevated temperature itself becomes the solution that prevents contamination at the source, rather than requiring additional cleaning apparatus.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 fixes toner on the edge of the recording material, preventing peeling and contamination, enhancing the reliability and cleanliness of the borderless printing process.

Implementation Method 1

a heating portion for heating the fixing member

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

fixing the toner image on the recording material when the recording material on which the toner image is carried passes through the fixing nip

Methodology Applied
Scientific EffectThermal fixation:

Implementation Method 3

a temperature detecting portion for detecting a temperature of the fixing member or the heating portion

Methodology Applied
Scientific EffectTemperature detection:

Data Source

PatentEP4592763A1Image forming apparatus
Publication Date: 2025.07.30 CANON KK
  • EP4592763A1 patent drawingFigure 1
  • EP4592763A1 patent drawingFigure 2
  • EP4592763A1 patent drawingFigure 3(a)~3(b)

AI summary

An image forming apparatus includes an executing portion for operating in a borderless image forming mode in which a toner image is formed in an edge portion of a recording material and for operating in a normal image forming mode in which the toner image is not formed in the edge portion, an image forming portion, a fixing device, a heating portion, a nip forming portion, and a temperature detecting portion, and a controller. In the case of the borderless image forming mode, the controller controls the heating portion so that a temperature thereof becomes a first control temperature in a first period in which the recording material passes through the fixing nip. In the case of the normal image forming mode, the controller controls the heating portion so that the temperature thereof becomes a second control temperature higher than the first control temperature in the first period.