Developing Device Blade Structure for Toner Mixing and Sensing
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Solution Overview
Problem
Existing developing devices in image forming apparatuses face challenges in achieving both sufficient developer conveyance speed and uniform dispersibility, leading to uneven image density and inadequate toner concentration sensing.
Innovation Solution
The developing device incorporates a conveying member with a helically formed conveying blade that has a cut portion and a dispersing portion with a larger circumferential end surface than the blade section, promoting developer dispersion and stabilizing toner concentration sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional conveying blade is used, then developer conveyance speed is maintained, but developer dispersibility is insufficient leading to uneven image density
Solution Approach 1:
The conveying blade is divided into multiple blade sections along the rotation direction, with each section having a specific width. This segmentation allows the blade to effectively disperse developer while maintaining conveyance speed, resolving the contradiction between speed and dispersibility.
Solution Approach 2:
Different portions of the conveying blade have different local characteristics - the blade sections are designed with specific widths and spacing to create localized dispersion zones. This local quality variation enhances developer dispersibility in critical areas while preserving overall conveyance efficiency.
2Productivity
If developer conveyance speed is increased, then productivity improves, but toner concentration sensing becomes inadequate
Solution Approach 1:
The conveying blade sections are designed to preliminarily disperse developer before it reaches the sensing region, ensuring that toner concentration is adequately mixed and sensed even at high conveyance speeds. This preliminary dispersion action maintains measurement precision while preserving productivity.
3Device complexity
If a continuous conveying blade is used, then device complexity is reduced, but developer dispersibility is insufficient
Solution Approach 1:
The conveying blade is segmented into multiple blade sections with defined widths and spacing, creating a structurally complex but functionally effective design that enhances developer dispersibility while maintaining reasonable device complexity.
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 enhances developer dispersibility and maintains adequate toner concentration, ensuring uniform image formation with suppressed uneven density and accurate toner concentration sensing.
Implementation Method 1
The conveying blade is helically formed on an outer circumferential part of the rotation shaft
Implementation Method 2
The dispersing surface has an area larger than the sectional area of the conveying blade
Data Source
AI summary
A developing device includes a developer container, a conveying member, and a developer carrying member. The conveying member has a rotation shaft, a conveying blade, a cut portion, and a dispersing portion. In the cut portion, the conveying blade is partly cut off along the longitudinal direction of the developer container. The dispersing portion is formed on an outer circumferential part of the rotation shaft, so as to face the cut portion, and extends along the radial direction of the rotation shaft. The dispersing portion has a dispersing surface having an area larger than the sectional area of the conveying blade.