Supply Roller Resistance and Compression for Toner Stability
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining sufficient toner supply for continuous high-density image printing, leading to issues like insufficiency of image density and density unevenness due to inadequate toner distribution between the supply roller and development roller.
Innovation Solution
The development device incorporates a supply roller with an electric resistance range of 1×10^2Ω to 1×10^4Ω and a compression load of 0.2 N to 1.5 N, along with specific hardness and nip area dimensions, to stabilize toner supply and prevent image failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressed amount of the supply roller on the development roller is set within the predetermined range, then stress applied to the toner is reduced and image failures such as toner fogging are decreased, but when high density images are continuously printed, it is difficult to supply a sufficient amount of toner from the supply roller to the development roller, resulting in image failures such as insufficiency of image density and density unevenness
Solution Approach 1:
The patent applies parameter changes by optimizing the electric resistance of the supply roller within a specific range (1×10^2Ω to 1×10^4Ω) and controlling the compression load (0.2 N to 1.5 N). These parameter adjustments enable the supply roller to maintain appropriate toner supply performance while preventing both toner fogging and density unevenness during continuous high-density printing.
2Reliability
If the inner diameter of the hole formed on the surface of the supply roller is made narrower toward the radially inner side, then the toner is prevented from entering into the inner portions of the holes and elastic deterioration of the supply roller due to toner aggregation is suppressed, but the amount of toner stored in the supply roller becomes small, resulting in insufficient toner supply when solid images are continuously printed
Solution Approach 1:
The patent resolves this contradiction by optimizing the hole diameter parameters and their distribution pattern. The holes are designed with specific diameter ranges and non-uniform distribution (narrower toward the radially inner side) that balances toner storage capacity with prevention of toner aggregation, ensuring both supply roller durability and sufficient toner availability for continuous printing.
3Reliability
If the supply roller has higher electric resistance, then toner fogging is reduced, but toner supply performance deteriorates leading to density unevenness
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the electric resistance of the supply roller within the optimal range of 1×10^2Ω to 1×10^4Ω. This parameter optimization ensures that the supply roller maintains sufficient toner supply performance while preventing toner fogging, thereby achieving both image quality and density uniformity.
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 configuration ensures stable toner supply performance, reducing image density insufficiency and unevenness during continuous high-density printing by optimizing the interaction between the supply roller and development roller.
Implementation Method 1
The supply roller has an electric resistance within a range of 1×10^2Ω or more and 1×10^4Ω or less. The supply roller comes into contact with the circumferential face of the development roller in a state where a compression load within a range of 0.2 N or more and 1.5 N or less is applied to the shaft member of the supply roller
Data Source
AI summary
A development device includes a development housing, a development roller, a supply roller and a layer thickness regulating member. The development housing stores a nonmagnetic one-component toner. The development roller is formed by a cylindrical elastic body. The supply roller includes a metal shaft member and a cylindrical foamed elastic body, and supplies the toner to the development roller and collects the toner from the development roller. The supply roller has an electric resistance within a range of 1×102Ω or more and 1×104Ω or less. The supply roller comes into contact with the circumferential face of the development roller in a state where a compression load within a range of 0.2 N or more and 1.5 N or less is applied to the shaft member of the supply roller in a direction perpendicular to an axial direction of the shaft member.