Dual-Toner Image Fixing for Sheet Reuse via Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for reusing sheets with decolorable colorants are limited, as they primarily rely on overheating to decolor and then overwrite images, lacking versatility in the use of decolorable toners.
Innovation Solution
An image forming apparatus that uses a combination of recolorable and unrecolorable toners, where the recolorable toner is fixed in a decolored state and the unrecolorable toner in a colored state, allowing for temperature-controlled switching between visible and invisible states, enabling multiple uses of the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If decolorable colorant is used for decoloring and overwriting images, then sheet reusing is enabled, but the versatility and utility of the colorant is limited
Solution Approach 1:
The patent combines two types of colorants (decolorable colorant and undecolorable colorant) into a single printing system, allowing both to be fixed simultaneously on the sheet. This merging enables the sheet to serve multiple functions: the undecolorable colorant provides permanent visible content while the decolorable colorant enables reusable features, thereby increasing overall versatility without sacrificing reusing efficiency.
Solution Approach 2:
The decolorable colorant is designed to serve multiple functions: it can be used for creating temporary visible images, for enabling sheet reusing through decoloring, and for creating features that change state with temperature. This multi-functionality resolves the contradiction by making the colorant system adaptable to various uses while maintaining high productivity in sheet reusing.
2Ease of operation
If decolorable colorant is fixed in colored state, then visible image is formed, but sheet cannot be reused without overwriting
Solution Approach 1:
The patent utilizes temperature as a parameter to control the state of the decolorable colorant. By controlling the fixing temperature to be below the decoloring start temperature, the colorant remains in the colored state for visible image formation. During reusing, heating the sheet above the decoloring start temperature changes the colorant state, enabling reuse without overwriting. This parameter-based control resolves the contradiction by maintaining ease of operation while improving productivity.
3Reliability
If high temperature is applied to decolor image, then sheet can be reused, but colorant may be damaged or faded
Solution Approach 1:
The patent applies different temperature thresholds to different colorants: the undecolorable colorant is fixed at temperatures below its decoloring start temperature to maintain stability, while the decolorable colorant is selectively decolored by heating above its specific decoloring start temperature. This localized temperature control ensures colorant stability during normal operation while enabling rapid decoloring for reuse when needed, resolving the contradiction between reliability and productivity.
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 allows for unprecedented uses of the sheet, including recoloring and decoloring images, enabling the sheet to be reused multiple times without the need for overwriting, thereby increasing its utility and extending its lifespan.
Implementation Method 1
The fixing device heats the sheet to fix the recolorable decolorable colorant and the undecolorable colorant on the sheet
Implementation Method 2
a recolorable decolorable colorant, decoloring start temperature of which is lower than decoloring start temperature of the unrecolorable decolorable colorant
Data Source
AI summary
According to one embodiment, an image forming apparatus includes an image forming section, a fixing device, and a control section. The image forming section forms images on a sheet with a recolorable decolorable colorant and an undecolorable colorant. The fixing device heats the sheet to fix the recolorable decolorable colorant and the undecolorable colorant on the sheet. The control section performs temperature control for the fixing device and fixes the recolorable decolorable colorant and the undecolorable colorant on the sheet at temperature higher than decoloring start temperature of the recolorable decolorable colorant to thereby fix the recolorable decolorable colorant on the sheet in a decolored state and fix the undecolorable colorant on the sheet in a colored state.