Developing Roller Toner Film Removal via Polarity Reversal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrophotographic image forming devices, toner filming on developing rollers leads to unstable charging characteristics, resulting in image quality issues such as stains and reduced density, and existing solutions like flash operations can degrade toner quality and are not suitable for color copiers.
Innovation Solution
A compulsory toner consumption mode is implemented, where a developing bias different from the standard bias is applied to discharge residual toner onto a latent image carrier, using a toner consumption calculation unit and detection units to control the toner adhesion amount, ensuring efficient removal of degraded toner and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a regulating blade is used to regulate toner thickness on the developing roller, then toner layer thickness is controlled, but toner filming occurs on the non-image portion due to repeated pressing
Solution Approach 1:
The patent extracts and removes the harmful accumulated toner from the developing roller surface by applying a reverse polarity voltage. This creates an electrostatic force that actively detaches and removes the toner film that was formed by the regulating blade pressing, thereby eliminating the harmful effect while preserving the thickness control function.
Solution Approach 2:
The patent changes the electrical parameter (voltage polarity) applied to the developing roller. By periodically reversing the polarity from positive to negative, the electrostatic interaction between the roller and toner changes, causing the accumulated toner to be repelled and removed. This parameter change resolves the contradiction by preventing toner filming while maintaining thickness regulation.
2Object-generated harmful factors
If flash operation is performed to remove toner on the developing agent carrier, then toner filming is prevented, but toner quality degrades and it is not suitable for color copiers
Solution Approach 1:
The patent replaces the mechanical flash operation with an electrostatic field-based toner removal method. Instead of using mechanical forces to scrape or brush off toner, the system uses controlled voltage polarity reversal to create electrostatic repulsion that gently detaches and removes toner particles, preserving their integrity and quality while preventing filming.
Solution Approach 2:
The patent introduces an electrical field as an intermediary mechanism between the developing roller and the toner. This electrical intermediary enables controlled toner removal without direct mechanical contact, avoiding the degradation that occurs with mechanical flash operations while still achieving effective filming prevention.
3Stability of the object's composition
If toner is continuously adhered to the non-image portion and pressed by the regulating blade, then toner forms a film, but charging characteristics become unstable
Solution Approach 1:
The patent implements periodic voltage polarity reversal to the developing roller. This periodic action prevents the continuous accumulation and pressing of toner by periodically disrupting the adhesion through reverse polarity, thereby maintaining stable charging characteristics while allowing controlled toner adhesion during normal operation cycles.
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 method effectively removes degraded toner, prevents abnormal images, and extends the service life of the device while providing precise toner detection, even without a toner end sensor, thus reducing costs and maintaining image quality over time.
Implementation Method 1
the toner in the region outside of the image forming portion has nothing to do with developing in a series of developing operations, and merely adheres to the surface of the developing roller by the Coulomb force
Implementation Method 2
an end of a regulating blade, which is used for regulating the thickness of the toner on the surface of the developing roller to make the toner layer thin, is arranged to slidably contact the surface of the developing roller, the toner adhering to the non-image portion of the developing roller is repeatedly pressed by the regulating blade
Implementation Method 3
when the toner, which continuously adheres to the surface of the developing roller and is pressed by the regulating blade many times, receives the pressure from the regulating blade, due to the heat generated by the pressure, the toner becomes film-like and can easily adhere to the surface of the developing roller
Data Source
AI summary
An image developing method is disclosed that is able to efficiently remove degraded toner on a developing agent carrier, prevent formation of abnormal images, ensure good image quality over time, and increase the service life of the device. The developing method includes a step of calculating an amount of consumption of the developing agent during image formation and an amount of consumption of the developing agent in a compulsory toner consumption mode under different calculation conditions between the image formation and the compulsory toner consumption mode. In the compulsory toner consumption mode, a developing bias different from a developing bias used during image formation is applied for a predetermined time period to discharge residual developing agent on a developing agent carrier to a latent image carrier.