Hollow Spiral Developer Conveying Device Octagonal Inner Wall
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Solution Overview
Problem
Conventional developer conveying devices with agitating screws experience reduced conveying performance due to developer adhesion and aggregation, especially in high-temperature environments and when the developer deteriorates, leading to cylindrical aggregation in hollow-shaped screws.
Innovation Solution
The developer conveying device employs a hollow spiral conveying member with a unique inner wall configuration, featuring a substantially regular octagonal shape formed by connecting planar portions at predetermined angles, which applies a cyclically varying pressure to prevent developer aggregation and adhesion, ensuring efficient conveying performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hollow-shaped agitating screw is used to prevent shaft thickening, then developer adhesion to the shaft is reduced, but cylindrical aggregation of developer occurs in the hollow part
Solution Approach 1:
The inner wall of the hollow spiral conveying member is divided into multiple planar portions (first, second, third, and fourth planar portions) that are inclined at different angles. This segmentation creates multiple surfaces that interact with the developer differently, preventing cylindrical aggregation by disrupting the uniform radial pressure distribution that causes aggregation in conventional hollow screws.
Solution Approach 2:
The inner wall structure is designed asymmetrically with planar portions at different inclinations (e.g., first and second planar portions at different angles from the axial direction, third and fourth planar portions at different angles from the circumferential direction). This asymmetry prevents uniform developer accumulation and promotes better conveying performance by creating varied pressure distribution patterns.
2Object-affected harmful factors
If the developer is deteriorated or in high-temperature environment, then adhesion force increases causing developer to adhere to the shaft portion, but using a hollow shape causes aggregation in the hollow part
Solution Approach 1:
The planar portions are designed with different inclinations to dynamically interact with the developer during rotation. The varying angles create changing pressure points and flow patterns that adapt to different developer conditions (temperature, deterioration level), preventing both adhesion to the outer surface and aggregation in the hollow center.
Solution Approach 2:
The rotation of the spiral conveying member creates periodic action on the developer, with each planar portion sequentially contacting and agitating the developer as it moves through the hollow space. This periodic agitation prevents sustained aggregation by continuously disrupting developer clumps.
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 effectively suppresses cylindrical aggregation and maintains conveying efficiency even when developer fluidity decreases, preventing adhesion to the screw and ensuring stable developer supply to the photoconductive drum, thereby enhancing image quality.
Implementation Method 1
a first inner wall portion arranged on an inner peripheral part of the first screw (721), and comprising a plurality of planar portions connected at predetermined angles in a circumferential direction
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A developer conveying device includes a housing (70A), a developer conveyance path (74a, 74b) and a conveying member (72, 73). The developer conveyance path extends between a pair of wall portions. The conveying member includes a spiral member (721, 731), an inner wall portion (721S, 731S) and shaft portions /26, 727, 736, 737). The spiral member is formed by connecting spiral pieces, each forming one spiral turn, in a conveying direction of the developer and includes a hollow interior formed by the connected spiral pieces. The inner wall portion includes a plurality of planar portions which define the hollow interior of the spiral member and are connected at predetermined angles in a circumferential direction of the rotation of the conveying member. The shaft portions are arranged at opposite end parts of the spiral member, rotatably supported on the wall portions and serve as a rotary shaft for the rotation of the conveying member.