Toner Concentration Sensor Layout for Stable Developer Detection
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Solution Overview
Problem
Existing developing devices in electrophotographic image forming apparatuses face challenges in accurately detecting and maintaining optimal toner concentration in the developer, leading to inconsistent image quality due to variations in toner-to-carrier ratios.
Innovation Solution
The developing device incorporates a development container with a first and second conveyance member, each with a helical conveyance blade, and a toner concentration sensor positioned to face one of the blades, featuring a cutout portion to stabilize developer accumulation and a scraper to enhance detection accuracy, ensuring consistent toner concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a toner concentration sensor is installed in the development container to detect toner concentration, then toner concentration can be monitored, but the conveyance blade may interfere with the sensor's detection accuracy
Solution Approach 1:
The patent extracts the conveyance blade material from the facing region between the sensor and the chamber wall, creating a cutout portion. This removes the interfering element (conveyance blade) from the detection path while maintaining the blade's functional presence in other regions, thereby eliminating measurement interference without removing the blade entirely
Solution Approach 2:
The conveyance blade is segmented into multiple regions: a cutout portion in the facing region that allows sensor detection, and remaining portions in other regions that maintain conveyance functionality. This segmentation enables the blade to simultaneously fulfill both detection transparency and conveyance operation requirements
2Strength
If the conveyance blade is continuous without cutouts, then structural integrity is maintained, but toner accumulation occurs near the sensor affecting detection
Solution Approach 1:
The patent extracts material from the conveyance blade to create a cutout portion in the facing region. This removes the source of toner accumulation interference while preserving the blade's structural integrity through the remaining blade portions that continue to provide mechanical strength and conveyance function
3Manufacturing precision
If toner concentration varies in the developer, then image quality becomes inconsistent, but maintaining uniform concentration requires precise control mechanisms
Solution Approach 1:
The patent implements a feedback control system where the transmission type sensor continuously detects toner concentration in the developer, and based on these detections, the system adjusts toner supply to maintain optimal concentration levels. This closed-loop feedback ensures consistent image quality without requiring overly complex mechanical control mechanisms
Solution Approach 2:
The system uses the existing developer circulation and stirring mechanisms to naturally distribute toner, while the sensor provides autonomous monitoring and triggers toner replenishment only when needed. This self-regulating approach maintains uniform toner concentration without requiring continuous active control
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 stabilizes toner concentration detection, maintaining appropriate toner levels and improving image quality by constraining variations in toner-to-carrier ratios within 1%, thereby enhancing the performance of the image forming apparatus.
Implementation Method 1
a toner concentration sensor that detects toner concentration in the developer
Data Source
AI summary
A developing device includes a development container, a first conveyance member, a second conveyance member, a developer carrier, and a toner concentration sensor. The first conveyance member and the second conveyance member are rotatably supported in the development container, and convey the developer, while stirring the developer, in mutually opposite directions along a longitudinal direction of the development container. The first conveyance member includes a rotation shaft and a first conveyance blade helically formed on an outer circumferential part of the rotation shaft. The first conveyance blade includes a cutout portion formed by removing part of the first conveyance blade in a facing region with respect to the toner concentration sensor.