Hollow Spiral Conveying Member for Developing Device
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Solution Overview
Problem
Conventional developing devices with agitating screws experience reduced conveying performance due to developer adhesion to the shaft, leading to inefficient transfer between communicating parts of the first and second conveyance paths, especially when the developer's adhesion force increases with deterioration.
Innovation Solution
The developing device incorporates a hollow spiral conveying member with a hollow shape around its rotational axial center, preventing shaft thickening and enhancing developer transfer between the first and second conveyance paths by using a pair of conveying members with opposite conveying directions, ensuring effective communication and distribution of developer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an agitating screw with a shaft portion is used to convey developer, then the conveying structure is simple and easy to manufacture, but developer adhesion to the shaft causes virtual shaft thickening and reduces conveying performance
Solution Approach 1:
The invention extracts and removes the shaft portion from the agitating screw structure, retaining only the spiral conveying elements. This eliminates the surface area where developer adhesion occurs, preventing virtual shaft thickening and maintaining conveying performance over time.
Solution Approach 2:
The hollow spiral structure creates a porous-like configuration where the spiral pieces are arranged around a hollow axial center. This structure provides conveying functionality while eliminating the solid shaft surface that would otherwise cause adhesion problems.
2Reliability
If a hollow spiral conveying member is used to prevent shaft thickening, then developer adhesion is reduced, but developer conveying performance in the axial direction decreases
Solution Approach 1:
The invention applies local quality by creating receiving portions at specific locations where the spiral pieces are denser or more prominent. These localized structures enhance axial conveying capability in critical areas while maintaining the overall hollow spiral configuration that prevents adhesion.
Solution Approach 2:
The spiral pieces are designed with optimized curvature and geometry to effectively engage with developer particles. The curved surfaces of the spiral elements provide both adhesion prevention and efficient axial conveying through their helical geometry.
3Duration of action of stationary object
If the developer's adhesion force increases with deterioration, then the developer becomes more prone to adhering to conveying surfaces, but this reduces transfer efficiency between conveyance paths
Solution Approach 1:
By removing the shaft portion entirely, the invention eliminates the primary surface where adhesion occurs. This ensures that even as developer deteriorates and adhesion force increases, there is no surface for the developer to adhere to, maintaining transfer efficiency throughout the service life.
Solution Approach 2:
The hollow spiral structure acts as an intermediary that facilitates developer transfer between conveyance paths without providing a surface for adhesion. The spiral geometry mediates the transfer process while the hollow center prevents direct contact and adhesion between developer and the conveying member.
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 improves developer transfer efficiency and stability, reducing adhesion issues and maintaining conveying performance even as the developer's fluidity decreases, ensuring consistent supply to the developing roller and photoconductive drum.
Implementation Method 1
The developing device is composed of a housing (10), a developing roller (71), a developer supply path (22B), a developer conveyance path (22F), a pair of communication paths (704, 705), a supply-side conveying member (73), and an agitating-side conveying member (72). The supply-side conveying member (73) and the agitating-side conveying member (72) are so-called hollow screws having a hollow shape in an axial central part.
Data Source
AI summary
A developing device includes a developing roller, a developer supply path, a developer conveyance path, a supply-side conveying member and an agitating-side conveying member. The developing roller is rotatably supported in the housing. The developer supply path is arranged along the developing roller. The developer conveyance path is arranged along the developer supply path. The supply-side conveying member is a conveying member arranged in the developer supply path and includes a first receiving portion arranged to face the communication path at an upstream side in the first direction and configured to receive the developer from the developer conveyance path, and has a hollow spiral shape at a side downstream of the first receiving portion. The agitating-side conveying member is a conveying member arranged in the developer conveyance path and includes a first transferring portion arranged to face the first receiving portion at a downstream side in the second direction.