Dual Toner Image Forming Apparatus for Color Consistency
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Solution Overview
Problem
Current electrophotographic methods for forming full-color images struggle with achieving consistent color reproduction and image quality, particularly in forming secondary colors like red, due to limitations in toner properties and interactions.
Innovation Solution
An image forming apparatus with separate developing units using toners A and B, where both contain a binder resin with a high percentage of polyester, an amorphous polyester with an alkyl side chain, and a crystalline polyester, with specific relationships in flow tester ½ effluent temperature and aluminum content, ensuring similar colors and improved image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional toners are used for full-color image formation, then the basic color reproduction is achieved, but the consistency of color reproduction and image quality deteriorates
Solution Approach 1:
The invention divides the conventional single toner system into two separate toner systems (toner A and toner B) with different binder resin compositions. Toner A uses a binder with higher melting point while toner B uses a binder with lower melting point. This segmentation allows independent optimization of each toner's properties, enabling consistent color reproduction and stable image quality that cannot be achieved with conventional single-toner approaches.
2Ease of manufacture
If multiple color toners are stacked to form secondary colors, then full-color images are achieved, but the control of gloss and fixing properties deteriorates
Solution Approach 1:
The invention changes the key parameter of binder resin melting point by creating two distinct toner formulations. Toner A has a binder resin with melting point of 70-90°C while toner B has a binder resin with melting point of 50-70°C. This parameter differentiation enables precise control over gloss and fixing properties during the image formation process, allowing optimal performance when multiple color toners are stacked to create secondary colors.
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 enhanced image quality and consistency by optimizing toner interactions, allowing for precise control of gloss and fixing properties, thereby improving the reproduction of full-color and secondary colors.
Implementation Method 1
when a glass transition temperature of the amorphous polyester is defined as Tga, the crystalline polyester has a melting temperature Tma of about (Tga+10)° C. or more and about (Tga+30)° C. or less
Implementation Method 2
the crystalline polyester has a melting temperature Tma of about (Tga+10)° C. or more and about (Tga+30)° C. or less
Implementation Method 3
an electrostatic latent image is formed (electrostatic latent image forming step) on an electrostatic-latent-image holding body by a charging and exposing step
Implementation Method 4
the toner image formed by the development is transferred onto a recording medium through or not through an intermediate transfer member (transferring step)
Data Source
AI summary
An image forming apparatus includes plural developing units separately containing a toner A and a toner B that satisfy relationships (1) and (2) and have similar colors. The toner A and the toner B each contain a binder resin containing a polyester about 90 mass % or more of the binder resin, and about 90 mass % of the binder resin of the toner A and about 90 mass % of the binder resin of the toner B are the same resin. The polyester contains an amorphous polyester having an alkyl side chain and a crystalline polyester. The relationship (1) is Ta (toner A)>Tb (toner B) in terms of flow tester ½ effluent temperature. The relationship (2) is Aa (toner A)>Ab (toner B) in terms of an amount of an aluminum (with reference to net intensity) measured with fluorescent X-ray.