Image Forming Apparatus Preheating Control for Toner Fixation

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Solution Overview

Problem

Image forming apparatuses face challenges in simultaneously fixing decolorable and non-decolorable toners on a sheet without decoloring the decolorable toner, as the high fixing temperature required for non-decolorable toner can exceed the decoloring temperature of the decolorable toner, leading to either decoloration or fixing failure.

Innovation Solution

The apparatus incorporates a preheating control section that preheats the sheet before image formation in a second image forming mode, allowing for the simultaneous fixing of decolorable and non-decolorable toners at a lower temperature than the decoloring temperature of the decolorable toner, using a fixing device with a heat roller and pressing member to control the temperature and ensure proper toner fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the set temperature is increased to fix non-decolorable toner, then the fixing reliability is improved, but the decolorable toner may be decolored

Engineering Contradiction:
Improvefixing reliabilityVSAvoiddecoloration of decolorable toner
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by preheating the sheet before transferring the toner image. This preheating prepares the sheet in advance to receive the toner at a lower fixing temperature, thereby preventing decoloration of the decolorable toner while still achieving reliable fixation of the non-decolorable toner.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the temperature parameter by reducing the fixing temperature to below the decoloring temperature of the decolorable toner. This parameter change is made possible through the preheating step, which modifies the initial state of the sheet to enable successful fixing at lower temperatures.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the set temperature is decreased to avoid decoloration, then the decolorable toner color is preserved, but fixing failure may occur

Engineering Contradiction:
Improvedecoloration preventionVSAvoidfixing reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The preheating step performs a preliminary action on the sheet, preparing it in advance to enable effective toner fixation at lower temperatures. This preliminary preparation ensures that even at reduced fixing temperatures, the toner can be properly fixed without failure.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If color printing is performed with high set temperature, then the non-decolorable toner is fixed reliably, but subsequent monochrome printing with decolorable toner may cause decoloration

Engineering Contradiction:
Improvefixing reliabilityVSAvoiddecoloration in subsequent printing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By applying preheating before each printing operation, the system prepares the sheet in advance, enabling reliable toner fixation at lower temperatures even after color printing. This preliminary action prevents decoloration in subsequent monochrome printing while maintaining fixing reliability.

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If preheating is applied before image formation, then the fixing temperature can be reduced below decoloring temperature, but additional processing time is required

Engineering Contradiction:
Improvedecoloration preventionVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent merges the preheating function with the existing fixing device, combining two functions (preheating and fixing) into a single apparatus. This integration allows the preheating process to be efficiently incorporated into the overall printing workflow, minimizing additional processing time while achieving decoloration prevention.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables the simultaneous fixation of both toner types without decoloring the decolorable toner, improving printing efficiency by reducing temperature fluctuations and preventing fixing failures, while allowing for decoloration of the decolorable toner when needed.

Implementation Method 1

The fixing device fixes the toner image on the sheet by heating and pressing the toner image

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

The preheating control section preheats the sheet before image formation in the second image forming mode

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3023841B1Image forming apparatus, control method and non-temporary recording medium
Publication Date: 2021.06.09 KK TOSHIBA
  • EP3023841B1 patent drawingFigure 1
  • EP3023841B1 patent drawingFigure 2
  • EP3023841B1 patent drawingFigure 3

AI summary

In accordance with an embodiment, an image forming apparatus, ,comprises an image forming section configured to include at least one decolorable toner and at least one non-decolorable toner, and form a toner image selectively using the decolorable toner and the non-decolorable toner;a mode determination section configured to determine, from a plurality of image forming modes including a first image forming mode in which a toner image is formed on a sheet with one decolorable toner and a second image forming mode in which a toner image is formed on a sheet with two or more toners of the decolorable toner and the non-decolorable toner , a designated image forming mode; and a preheating control section configured to execute the preheating of the sheet before image formation in the second image forming mode, and execute no preheating of the sheet before image formation in the first image forming mode.