Fixing Unit Temperature Control for Toner Gloss

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Solution Overview

Problem

Existing image forming apparatuses using electrophotographic recording methods face challenges in increasing the gloss level of toner images without increasing the number of heating and pressurization processes, which results in longer printing times.

Innovation Solution

The apparatus employs a fixing unit with a heater and rotary members that perform multiple heating processes on the recording medium, with the target temperature of the fixing unit set based on image information to enhance gloss levels without increasing process counts, allowing for higher heat application and improved surface smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the number of heating and pressurization processes is increased to increase gloss level, then the gloss level of toner image is improved, but the printing time is increased

Engineering Contradiction:

Improvegloss levelVSAvoidprinting time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent changes the temperature parameter dynamically by setting a higher target temperature for the second heating process compared to the first heating process. This allows achieving higher gloss level with the same number of heating processes, thereby avoiding the need to increase the number of processes and the associated printing time.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the target temperature of the fixing unit is increased to enhance gloss levels, then the surface smoothness is improved, but hot offset issues may occur

Engineering Contradiction:

Improvesurface smoothnessVSAvoidhot offset

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent performs a first heating process at a lower target temperature before the second heating process at a higher target temperature. This preliminary heating action melts the toner and bonds it to the recording medium, preventing hot offset during the subsequent high-temperature heating that is necessary for achieving high gloss levels.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses periodic heating actions with different temperature levels - a first heating process at a lower temperature followed by a second heating process at a higher temperature. This periodic variation in heating intensity allows achieving high surface smoothness while preventing hot offset by controlling the timing and intensity of heat application.

Inventive Principle:

Principle #19Periodic 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 increases the gloss level of toner images while maintaining or reducing the number of processes, thereby shortening printing times and preventing hot offset issues.

Implementation Method 1

a fixing unit configured to fix the toner image formed on the recording medium onto the recording medium by executing a heating process for heating the recording medium

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS11392064B2Image forming apparatus capable of increasing gloss level of toner image without increasing number of processes performed by fixing unit

Publication Date: 2022.07.19 CANON KK

AI summary

An image forming apparatus sets, in a case where a mode for executing a heating process a plurality of times is set, a target temperature of a fixing unit during a second heating process depending on image information about a toner image to be formed on a first surface of a recording medium immediately before a first heating process.