Capsule Decolorizable Toner Fixing Control
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Solution Overview
Problem
Conventional decolorizable toners with solid-phase components suffer from slow and insufficient color development and erasure processes, necessitating the development of a toner with encapsulated color developable and color developing agents to enhance promptness and efficiency.
Innovation Solution
An image forming apparatus utilizing a capsule-type decolorizable toner with a binder resin and coloring agent, where the coloring agent is encapsulated with a shell material, and a temperature control system that maintains the fixing temperature between the density maintaining threshold and melting threshold temperatures, ensuring efficient color development and erasure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solid-phase color developable compound and color developing agent are used in conventional decolorizable toner, then the toner can be recycled by heating to dissociate components, but the color development and erasing reactions are neither prompt nor sufficient
Solution Approach 1:
The patent changes the physical state parameter of the color developable compound and color developing agent from solid phase to liquid phase by encapsulating them in liquid-filled capsules. This parameter change enables prompt and sufficient color development and erasing reactions, as the liquid state allows for faster molecular movement and reaction kinetics compared to solid phase materials.
Solution Approach 2:
The patent creates a composite toner structure where liquid-filled capsules containing color developable compounds and color developing agents are embedded in a solid binder resin matrix. This composite structure combines the advantages of both liquid (fast reaction) and solid (structural integrity) phases, enabling both prompt color development and reliable recycling through heating.
2Productivity
If conventional decolorizable toner is used, then paper medium can be recycled by erasing image through heating, but the erasing reaction is slow and insufficient
Solution Approach 1:
The patent changes the physical state parameter of the color developing components from solid to liquid by encapsulating them in liquid-filled capsules. This parameter change enables both prompt color development and sufficient erasing reactions when heated, as the liquid state facilitates rapid molecular diffusion and complete dissociation of color components during the erasing process.
Solution Approach 2:
The patent segments the color developing system into separate encapsulated units where color developable compounds and color developing agents are contained in discrete liquid-filled capsules within the toner particles. This segmentation allows for controlled release and complete reaction during both color development and erasing processes, improving both speed and completeness of the erasing reaction.
3Reliability
If fixing temperature is increased to ensure proper toner fixation, then toner melts and adheres to paper, but the coloring agent may decolorize
Solution Approach 1:
The patent changes the melting point parameter of the toner by using a binder resin with a lower melting point than conventional toners. This allows the toner to be fixed at a lower temperature (below the decolorization temperature of the coloring agent) while still achieving proper adhesion to the paper, thereby preventing image decolorization during the fixing process.
Solution Approach 2:
The patent introduces temperature dynamics by controlling the fixing process to occur within a specific temperature window below the decolorization point. The liquid-filled capsule structure provides thermal dynamics, allowing the color components to remain stable during fixing while still enabling proper toner melting and adhesion through the binder resin's phase transition.
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
The apparatus achieves rapid and effective color development and erasure of toner images on paper, preventing image decolorization during the fixing process, allowing for reliable reuse of paper media.
Implementation Method 1
a heating member that heats a toner image formed on a recording medium using a decolorizable toner
Implementation Method 2
a pressing member that is in press contact with the heating member to form a nip portion and that nips and conveys the recording medium in cooperation with the heating member
Implementation Method 3
by heating the toner to a given temperature, a color developable compound and a color developing agent in the ink are dissociated from each other to decolorize the toner, whereby an image is erased
Data Source
AI summary
An image forming apparatus including: a heating member which heats a toner image on a recording medium using a decolorizable toner containing a coloring agent containing a color developable compound and a color developing agent and having a capsule structure covered with an outer shell; a pressing member which is in press contact with the heating member to form a nip portion and nips and conveys the recording medium in cooperation with the heating member; a temperature control section which controls the temperature of the heating member to a temperature not higher than the density maintaining threshold temperature and not lower than the melting threshold temperature; and a conveyance control section which controls the conveying speed of the recording medium such that a time required for the recording medium to pass through the nip portion is 100 msec or more.