Development Device Auger Screw Spiral Configuration for Developer Fluidity
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Solution Overview
Problem
Existing development devices for electrophotographic image forming apparatuses face issues with developer fluidity degradation due to compressive stress, leading to reduced image density, as the developer tends to be retained in corners of conveyance paths, causing pressure increases and fluidity issues during cycling conveyance.
Innovation Solution
A development device with a developer tank, toner replenishment port, development roller, and a raking member in the communication paths to alleviate pressure retention, utilizing spiral and circumferential rotation blades to convey developers smoothly between paths without retention, reducing stress and enhancing fluidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first and second auger screws are disposed from upstream end to downstream end in the first and second developer conveyance paths, then the developer can be conveyed efficiently, but the developer is retained in the four corners at the upstream and downstream ends, causing compressive stress and fluidity degradation
Solution Approach 1:
The auger screw is divided into multiple sections along its length, with each section having a different spiral blade configuration. The first section has spiral blades that convey developer forward, while the second section has spiral blades that redirect developer away from corner retention zones, preventing compressive stress accumulation and maintaining fluidity throughout the conveyance path.
2Adaptability or versatility
If the third and fourth auger screws are provided in the communication paths orthogonal to the first and second auger screws, then the developer can be cycled between paths, but the rotating shafts are positioned at different heights causing the spiral blades to be eliminated, which worsens developer retention
Solution Approach 1:
The spiral blades of the third and fourth auger screws are designed with a three-dimensional configuration that accommodates the height difference between rotating shafts. The blades extend vertically and angle appropriately to convey developer between the offset shaft positions, enabling effective cycling between conveyance paths while preventing corner retention and maintaining developer fluidity.
3Device complexity
If the spiral blades are eliminated due to different rotating shaft heights, then the auger screws can be positioned independently, but the developer is easily retained in corners, causing compressive stress and image density reduction
Solution Approach 1:
The auger screws are designed with adjustable and adaptable spiral blade configurations that can dynamically respond to different operating conditions. The blades are positioned and angled to optimize developer flow patterns, preventing corner retention and compressive stress while maintaining the flexibility to position rotating shafts at different heights for effective path cycling.
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 effectively reduces stress on the developer, preventing fluidity degradation and ensuring consistent image density by facilitating smooth developer transfer between conveyance paths, thereby improving the overall performance of the image forming apparatus.
Implementation Method 1
first and second auger screws that are disposed in the first and second developer conveyance paths to mutually convey the developer in opposite directions
Implementation Method 2
a properly-charged toner is obtained by friction between the toner and the carrier
Implementation Method 3
the charged toner is moved to an electrostatic latent image formed on a photoconductive drum from the development roller by an electrostatic suction power
Data Source
AI summary
A development device comprising a developer conveying member and a developer raking member that are rotatably disposed in the developer conveyance path to conveying and agitating the developer in the developer conveyance paths, wherein the developer conveyance path includes first and second developer conveyance paths and first and second communication paths that communicating the first and second developer conveyance paths on both sides, the developer conveying member includes first and second developer conveying members that are disposed in the first and second developer conveyance paths, the developer raking member is disposed in at least one of the first and second communication paths.