Image Forming Apparatus Stop Mode Toner Adhesion Control
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Solution Overview
Problem
Conventional image forming apparatuses face issues with residual liquid developer between the developing roller and other roller members leading to toner concentration and adhesion, causing image defects, and toner remaining on cleaning blades deteriorating cleaning performance.
Innovation Solution
An image forming apparatus with a control unit that sets a potential difference between the film forming electrode and the developer bearing member to zero or less after image formation, then stops the developer bearing member's rotation, to reduce toner density and prevent adhesion, incorporating a cleaning roller and removing member to manage toner effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid developer remaining between the developing roller and other roller members is reduced by rotating the squeezing roller in a direction opposite from that during image formation, then the amount of residual liquid developer is reduced, but toner removed by the cleaning blade from the cleaning roller remains on the cleaning blade and concentrates
Solution Approach 1:
The patent reverses the rotation direction of the squeezing roller during stop mode to reduce residual liquid developer. Additionally, it reverses the rotation direction of the cleaning roller to prevent toner concentration on the cleaning blade by changing the flow direction of liquid developer and toner particles during the stopping phase.
Solution Approach 2:
The patent changes operational parameters during stop mode: it sets the potential difference between the film forming electrode and developer bearing member to zero or less, adjusts roller rotation directions and speeds, and modifies the state of liquid developer to prevent toner adhesion and concentration.
2Loss of energy
If the rotation of the developer bearing member is stopped immediately after image formation, then energy consumption is reduced, but toner in the residual liquid developer concentrates and adheres to roller members causing image defects
Solution Approach 1:
The patent performs preliminary actions before stopping the developer bearing member: it reduces toner density in residual liquid developer by adjusting potential differences and roller rotations, and prepares the cleaning roller to remove toner effectively, preventing toner adhesion before the system stops.
Solution Approach 2:
The patent converts the potentially harmful residual liquid developer into a beneficial medium by using it to flush and remove toner from roller surfaces through controlled rotation, transforming what would be a source of contamination into a cleaning mechanism.
3Reliability
If a cleaning roller and removing member are added to manage toner effectively, then cleaning performance is improved, but device complexity increases
Solution Approach 1:
The cleaning roller serves multiple functions: it removes toner from the developer bearing member, prevents toner adhesion through controlled rotation during stop mode, and works with the removing member to manage toner on the cleaning blade, reducing the need for separate dedicated components.
Solution Approach 2:
The cleaning roller and removing member work together in a self-cleaning mechanism where the cleaning roller picks up toner and the removing member eliminates it from the cleaning blade, creating a self-sustaining toner management system without requiring additional complex external mechanisms.
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 toner adhesion to roller members and cleaning blades, preventing image defects by maintaining low toner density in the residual liquid developer and ensuring efficient cleaning, thereby improving image quality.
Implementation Method 1
liquid developer is borne on a rotating developing roller, and the liquid developer borne on the developing roller is used to develop electrostatic latent image formed on the photosensitive member into a toner image. The development of toner image is performed by movement of toner in a layer of liquid developer formed between a developing roller and the photosensitive member according to an electric field formed by application of voltage to the developing roller (so-called electrophoresis).
Implementation Method 2
toner contained in the liquid developer borne on the developing roller that has not been used for developing image is collected from the developing roller by electrophoresis using a cleaning roller abutted against the developing roller.
Implementation Method 3
Toner collected from the developing roller by the cleaning roller is removed mechanically from the cleaning roller by a cleaning blade that is slid against the cleaning roller.
Implementation Method 4
The amount of remaining liquid developer may be reduced with elapse of time by evaporation or flowing of carrier liquid.
Data Source
AI summary
An image forming apparatus includes a control unit configured to execute a stop mode in which, after image forming operation is stopped, a developer bearing member is rotated for a predetermined time with a potential difference between a film forming electrode and a developer bearing member set to zero or smaller than that during image formation, and thereafter, the rotation of the developer bearing member is stopped.