Process Cartridge Roller Layout for Low Residual Developer
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Solution Overview
Problem
Existing process cartridges in electrophotographic image forming apparatuses face challenges in reducing residual developer while maintaining efficient developer supply, often requiring additional stirring members that increase complexity and parts count.
Innovation Solution
The process cartridge design includes a developer supplying roller with a driving force receiving portion at its shaft end, movable in a direction crossing its shaft, and a first driving force transmitting portion on the developer supplying roller, with the developing roller rotating in the opposite direction and having a higher surface speed, reducing the need for a separate stirring member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a stirring member is provided in the developing chamber to improve developer circulation, then residual developer is reduced, but the number of parts and device complexity increases
Solution Approach 1:
The invention extracts and eliminates the stirring member from the developing chamber, achieving developer circulation through the rotational movement of the developer supplying roller alone. This removes the unnecessary component while maintaining the circulation function.
Solution Approach 2:
The developer supplying roller is given a dual function: it both supplies developer to the developing roller and simultaneously circulates developer within the developing chamber through its rotational movement. This eliminates the need for a separate stirring member.
2Loss of substance
If the developer supplying roller rotates in the same direction as the developing roller, then the structure is simpler, but developer circulation is insufficient and residual developer increases
Solution Approach 1:
The invention inverts the conventional approach by rotating the developer supplying roller in the opposite direction to the developing roller. This counter-rotation creates effective developer circulation that reduces residual developer, demonstrating that sometimes the opposite approach yields better results.
3Productivity
If the surface speed of the developer supplying roller is increased to improve developer supply, then developer circulation is enhanced, but the risk of developer leakage increases
Solution Approach 1:
The invention optimizes the surface speed parameter of the developer supplying roller, setting it to be higher than the developing roller's surface speed to enhance circulation, while simultaneously optimizing other parameters such as roller hardness and contact pressure to prevent leakage despite the higher speed.
Data Source
AI summary
A process cartridge includes a photosensitive drum, a rotatable developing roller, a rotatable toner supplying roller provided in contact with the developing roller, and a rotatable feeding member provided in the toner chamber and configured to feed the toner from the toner chamber. A coupling is configured to receive a driving force for rotating the feeding member, the developing roller, and the toner supplying roller. A plurality of gears are configured to transmit the driving force received by the coupling to at least one of the feeding member, the developing roller, and the toner supplying roller.