Dynamic Potential Difference Control for Developing Roller Ghost Reduction
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Solution Overview
Problem
The developing ghost phenomenon occurs due to triboelectric charge differences between toner on the developing roller at non-printing and printing portions, leading to inconsistent developer coating and image quality issues, despite attempts to stabilize the developer coating by applying a potential difference between the developing roller and the developer amount regulating blade.
Innovation Solution
An image forming apparatus with a developing device that includes a rotatable developer carrying member, a developer supplying member, and a regulating member, where a first power source applies a bias to the developer carrying member and a second power source applies a bias to the regulating member, with control means managing these biases to create a stronger urging force between the regulating member and the developer carrying member at the end of the developing operation than at the start, thereby controlling triboelectric charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a potential difference is provided between the developing roller and the developer amount regulating blade to stabilize developer coating, then developer coating stability is improved, but triboelectric charge difference between after white and after black still generates causing development positive ghost
Solution Approach 1:
The patent applies dynamic control of the potential difference between the developing roller and developer amount regulating blade. The potential difference is not fixed but varies during the developing operation: it is set to a first value at the start of developing operation and changed to a second value at the end of developing operation. This dynamic adjustment compensates for changes in triboelectric charge characteristics that occur during operation, thereby preventing the development positive ghost while maintaining developer coating stability.
Solution Approach 2:
The patent changes the electrical parameter (potential difference value) between the developing roller and developer amount regulating blade during the developing operation. By adjusting the potential difference from a first value to a second value, the patent compensates for time-dependent changes in triboelectric charge distribution, effectively preventing the development positive ghost phenomenon while maintaining stable developer coating.
2Productivity
If mechanical friction between developing roller and developer supplying roller is increased to scrape off development residual toner, then toner removal efficiency is improved, but triboelectric charge difference increases causing developing ghost
Solution Approach 1:
The patent partially replaces the mechanical friction-based toner removal system with an electrical field-based system. By applying a potential difference between the developing roller and developer amount regulating blade, the patent uses electrostatic forces to control toner behavior and reduce triboelectric charging, thereby reducing developing ghost while maintaining adequate toner removal through the combined action of mechanical and electrical fields.
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 solution effectively reduces the triboelectric charge difference between toner at non-printing and printing portions, minimizing the developing ghost and improving image quality by maintaining consistent toner charge levels across the developing roller.
Implementation Method 1
a first power source for applying a bias to the developer carrying member
Implementation Method 2
a second power source for applying a bias to the regulating member
Implementation Method 3
the control means effects control of providing a potential difference between the developer carrying member and the developing blade so that a force for urging the developer from the regulating member toward the developer carrying member acts on the developer
Implementation Method 4
Simultaneously, triboelectric charges are imparted to the developer by friction of the developer with the developer amount regulating blade
Data Source
AI summary
An image forming apparatus includes a developing device including a developer carrying member, a developer supplying member and a regulating member. Also provided are a first power source for the developer carrying member, a second power source for the regulating member, and a controller. In a period from a start of a developing operation to an end of the developing operation for printing an image on a single recording material, the controller effects control of a potential difference between the developer carrying member and the developing blade so that a force for urging the developer from the regulating member toward the developer carrying member acts on the developer at a contact portion between the regulating member and the developer carrying member. The force acting on the developer being is stronger at the end of the developing operation than at the start of the developing operation.