Developing Roller Position Detection via Toner Density Ripples
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face challenges in detecting the rotational position of developing rollers without complicating the device configuration or increasing costs, as methods like using photo interrupters or encoders are costly and inefficient.
Innovation Solution
A developing device with a screw rotationally driven in sync with the developing roller, utilizing sensors to detect toner density ripples and calculate the rotational position, allowing for detection of the developing roller's position without additional detectors, thereby simplifying the device configuration and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photo interrupter or encoder is installed to detect the rotational position of the developing roller, then the rotational position can be detected, but the device configuration becomes complicated and costs increase
Solution Approach 1:
The developing roller itself generates the detection signal through its runout (out-of-roundness). The existing sensor that monitors toner density or carrier concentration detects periodic variations caused by the roller's geometric imperfection, eliminating the need for separate detection mechanisms like photo interrupters or encoders.
Solution Approach 2:
The sensor acts as an intermediary that indirectly detects rotational position through monitoring toner density or carrier concentration variations. These variations serve as a mediator signal that correlates with the rotational position of the developing roller without requiring direct mechanical or optical coupling.
2Manufacturing precision
If stricter screening criteria are adopted for developing rollers, then density ununiformity is suppressed, but the yield of developing rollers decreases and cost increases
Solution Approach 1:
The system changes the operational parameters (rotational speed, sensor detection timing) to compensate for the geometric imperfections of the developing roller. By adjusting when toner is supplied or when images are formed relative to the roller's rotational position, the system optimizes image quality despite runout variations.
Solution Approach 2:
The sensor provides feedback on toner density or carrier concentration variations that indicate the roller's rotational position and runout characteristics. This feedback enables real-time adjustment of development parameters or compensation algorithms to maintain image quality without requiring perfectly precision-manufactured rollers.
Data Source
AI summary
A developing device is equipped with a developing roller rotationally driven for developing an electrostatic latent image formed on a surface of an image supporting body with toner, a screw rotationally driven of which a ratio of number of rotations to number of rotations of the developing roller being rotationally driven is constant, and a processor. The processor is configured to detect toner density in developer by using a sensor installed facing the screw, during rotationally drive of the screw, and detect information indicating a rotational position of the developing roller, based on ripples which occur in the toner density detected.