Developer Carrier Speed Ratio for Uniform Toner Supply
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Solution Overview
Problem
Existing development devices using a one-component developer face issues with inconsistent developer supply, leading to density differences in images due to varying circumferential speeds between the developer carrier and conveying member, resulting in longitudinal streaks and accelerated developer deterioration.
Innovation Solution
The circumferential speed ratio between the developing roller and the agitating screw is optimized to 1.3≤Vd/Vs≤5.0, ensuring a balanced developer supply and reducing overloading, which stabilizes the toner distribution and prevents image quality defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the circumferential speed of the developer conveying member is set to be less than 1/5 of the circumferential speed of the developer carrier, then the stress subjected to the developer is decreased, but the supply of developer from the developer conveying member to the developer carrier becomes deficient
Solution Approach 1:
The patent applies parameter changes by establishing a specific circumferential speed ratio range (1/3 to 1 times) between the developer conveying member and developer carrier, replacing the conventional approach of using a fixed ratio less than 1/5. This parameter optimization resolves the contradiction by finding the optimal speed relationship that ensures sufficient developer supply while maintaining acceptable stress levels on the developer particles.
2Quantity of substance
If the circumferential speed of the developer conveying member is significantly increased to supply a lot of developer, then the supply amount of developer is increased, but many developer is retained on the back side of the layer adjusting member causing accelerated deterioration and increased driving torque
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the circumferential speed ratio parameter within the range of 1/3 to 1 times. This optimized parameter setting ensures that the developer conveying member rotates fast enough to supply adequate developer to the developer carrier, but not so fast that excessive developer accumulates on the layer adjusting member back side, thereby preventing accelerated deterioration and unnecessary torque increase.
Solution Approach 2:
The patent employs feedback control by monitoring the developer supply condition and adjusting the circumferential speed ratio accordingly. The speed ratio is set within a specific range that provides feedback on the balance between developer supply efficiency and preventing excessive retention, ensuring stable operation without causing developer deterioration or increased driving torque.
3Stress or pressure
If the circumferential speed of the developer conveying member is set to be less than 1/5 of the circumferential speed of the developer carrier, then the stress subjected to the developer is decreased, but the supply amount of developer is deficient in the rotation shaft portion causing longitudinal streaks on the image
Solution Approach 1:
The patent resolves this contradiction by changing the circumferential speed ratio parameter from the conventional less than 1/5 to an optimized range of 1/3 to 1 times. This parameter modification ensures uniform developer supply across the entire developer conveying member surface, including the rotation shaft portion, thereby eliminating the longitudinal streak defects while maintaining acceptable stress levels on the developer.
Data Source
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AI summary
In a development device, a developer carrier arranged in a housing containing a one-component developer has a circumferential surface carrying the developer. A developer conveying path includes one conveying path along the developer carrier in a first direction and another conveying path in a second direction opposite to the first direction. The developer is circulated and conveyed between the conveying paths. A developer conveying member is arranged in the one conveying path and rotationally driven to convey the developer along the first direction and to supply the developer to the developer carrier. A layer thickness adjusting member is arranged at a distance from the circumferential surface to adjust a layer thickness of the developer supplied to the developer carrier. The developer carrier has a circumferential speed Vd and the developer conveying member has a circumferential speed Vs so that a circumferential speed ratio Vd/Vs satisfies a relationship represented by 1.3≤Vd/Vs≤5.0.