Developing Device Friction-Based Developer Recovery
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Solution Overview
Problem
Conventional developing devices for electrostatic latent images in image forming apparatuses face issues with maintaining image quality over long periods due to ghost noise caused by development history, as they struggle with developer charge differences and durability-related problems, leading to visible printing history and image degradation.
Innovation Solution
A developing device with a rotatable developer carrier, a conductive developer supply and recovery member, and a conductive charging member, where DC biases are applied to manage developer movement and contact pressure is set between 0 kPa and 5.0 kPa to ensure efficient developer recovery and distribution, preventing ghost noise and image degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional developing devices use electrostatic forces to recover residual developer, then developer recovery is achieved, but printing history becomes visible when developer charge decreases due to impaired durability
Solution Approach 1:
The invention changes the recovery mechanism from purely electrostatic forces to mechanical force through friction. By rotating the developer supply and recovery member in the opposite direction to the developer carrier rotation, relative motion is created that generates friction force. This mechanical recovery method remains effective even when developer charge decreases over time, maintaining reliable operation throughout the device's lifespan.
Solution Approach 2:
The invention replaces the electrostatic recovery system with a mechanical friction-based system. Instead of relying on electrical charges to recover residual developer, the oppositely rotating conductive developer supply and recovery member creates friction that mechanically transports developer, eliminating the dependency on developer charge durability.
2Reliability
If a conductive mesh member is used to level developer after development, then printing history is reduced, but developer turnover on the developer carrier becomes difficult and developer deteriorates more readily
Solution Approach 1:
The invention replaces the static mesh leveling system with a dynamic mechanical turnover system. The conductive developer supply and recovery member rotates in the opposite direction to the developer carrier, creating friction that actively turns over and refreshes the developer on the carrier surface. This mechanical action is more effective at preventing developer deterioration than passive leveling.
Solution Approach 2:
The invention introduces dynamic motion to the developer recovery process. Instead of using a static mesh that merely levels developer, the oppositely rotating recovery member creates continuous relative motion and friction, actively turning over the developer layer on the carrier to prevent deterioration and maintain productivity.
3Reliability
If contact pressure between developer carrier and recovery member is increased to improve developer recovery, then developer distribution improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention applies a moderate contact pressure that is sufficient to generate the necessary friction for developer recovery without requiring excessive force. The oppositely rotating recovery member creates relative motion that enhances the effectiveness of the contact pressure, allowing efficient developer recovery at lower pressure levels that are easier to implement and manufacture.
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 solution stabilizes image quality over long periods by preventing ghost noise and maintaining image clarity, ensuring efficient developer recovery and distribution, thus enhancing the performance of image forming apparatuses like copiers and printers.
Implementation Method 1
A DC bias is applied to the conductive charging member in a direction in which regularly-charged developer on the developer carrier moves towards the developer carrier
Implementation Method 2
A DC bias is applied to the conductive developer supply and recovery member in a direction in which regularly-charged developer on the developer carrier moves towards the conductive developer supply and recovery member
Data Source
AI summary
A developing device for developing an electrostatic latent image on an image carrier by supplying a one-component developer to the image carrier. Good images can be obtained over long periods of time, without printing history becoming apparent on account of residual developer. The developing device has a developer carrier that is rotatable and disposed facing an image carrier; and a conductive developer supply and recovery member rotatably arranged so as to abut the developer carrier. The rotation direction of the conductive developer supply and recovery member is opposite to the rotation direction of the developer carrier at a position where the developer carrier and the conductive developer supply and recovery member abut each other. A contact pressure P between the developer carrier and the conductive developer supply and recovery member is set so as to satisfy the relationship 0 (kPa)<P<5.0 (kPa).