Developing Device Developer Circulation Ratio Optimization
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Solution Overview
Problem
Electrophotographic image forming apparatuses face challenges in maintaining efficient developer circulation and image density uniformity when reducing the amount of developer, leading to uneven image development and increased environmental loads.
Innovation Solution
A developing device with a developing roller and at least one conveyor, where the ratio of developer borne on the roller to the developer stored in the casing (M1/L1 > 0.56 g/cm) and the ratio of developer borne on the roller to the total developer (M1/M2 > 0.50) are optimized, ensuring sufficient developer upstream from the developer regulation point for stable image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the amount of developer is reduced, then environmental load is decreased, but image density uniformity deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the developer circulation passage configuration, specifically setting the ratio of the length of the developer circulation passage to the width of the developing roller (L1/W1) to 0.56 or more, and controlling the developer amount ratios (M1/L1 > 0.56 g/cm, M1/M2 > 0.50). These parameter optimizations enable uniform image density to be maintained even when the total developer amount is reduced, thereby resolving the contradiction between reducing environmental load and maintaining image quality.
2Object-affected harmful factors
If the amount of developer is reduced, then environmental load is decreased, but developer circulation efficiency deteriorates
Solution Approach 1:
The patent optimizes the circulation passage geometry parameters, specifically designing the passage cross-sectional shape and dimensions to achieve a length-to-width ratio (L1/W1) of 0.56 or more. This parameter optimization ensures efficient developer circulation even with reduced developer amounts, resolving the contradiction between environmental protection and circulation efficiency.
Solution Approach 2:
The patent introduces a developer circulation passage with optimized dynamic flow characteristics, where the passage configuration (length L1, width W1, and cross-sectional area S1) is designed to maintain appropriate flow velocity and circulation patterns. This dynamic optimization ensures that developer circulation efficiency is maintained even when the total developer amount is reduced, thereby resolving the contradiction between reducing environmental load and maintaining circulation efficiency.
3Object-affected harmful factors
If the developer amount is reduced, then environmental impact is minimized, but image formation stability deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the developer distribution parameters, specifically controlling the developer amount per unit length (M1/L1 > 0.56 g/cm) and the ratio of developer on the roller to total developer (M1/M2 > 0.50). These parameter optimizations ensure stable image formation even with reduced total developer amounts, thereby resolving the contradiction between environmental protection and image formation stability.
Data Source
AI summary
A developing device includes a casing to contain developer and define a developer circulation passage, a developing roller to bear the developer, and at least one developer conveyor to convey the developer. The developer conveyor is disposed in the developer circulation passage and lower than the developing roller. The developing device satisfies M1/L2>0.56 g/cm and M1/M2>0.50, where M1 represents an amount of developer borne on the developing roller, L1 represents a width in which the developing roller bears the developer in a longitudinal direction of the developing roller; and M2 represents an amount of developer stored in the casing and excluding the amount of developer borne.