Wet Development Device Alternating Bias Toner Dispersion
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Solution Overview
Problem
In wet development devices, toner particles adhere to the development roller surface, leading to increased cleaning difficulty and toner deposits, which are costly to remove and can cause damage due to overcurrent issues when attempting to re-disperse them using alternating bias.
Innovation Solution
A wet development device with a bias applying member that applies alternating bias to the developer carrying member before cleaning, ensuring the bias application range is within the liquid developer supply area, preventing toner deposits and reducing the risk of overcurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alternating bias is applied to remove toner particles from the development roller, then toner dispersion is improved, but toner deposits form on the bias applying roller
Solution Approach 1:
The patent applies alternating bias only in the liquid developer supply area rather than across the entire development roller surface. This localized application ensures toner particles are re-dispersed where needed while avoiding areas where toner deposits would form, thus resolving the contradiction between improving toner dispersion and preventing toner deposits on the bias applying roller.
Solution Approach 2:
The invention extracts the alternating bias application from the general cleaning process and applies it specifically only in the liquid developer supply area. This separation allows the bias to be applied where it is most effective for preventing toner aggregation without causing the harmful side effect of toner deposits on the roller surface.
2Ease of operation
If direct bias is applied to remove toner particles, then toner removal is achieved, but toner particles adhere to the bias applying roller
Solution Approach 1:
The patent uses alternating bias (periodic electrical action) instead of direct bias to remove toner particles. The alternating nature of the electrical field prevents toner particles from adhering to the bias applying roller while still achieving effective toner removal and re-dispersion, thus resolving the contradiction between ease of toner removal and prevention of toner adhesion to the roller.
3Stability of the object's composition
If alternating bias is applied upstream of cleaning blade, then toner aggregation is reduced, but toner deposits form at the cleaning blade
Solution Approach 1:
The patent restricts alternating bias application specifically to the liquid developer supply area, which is upstream of the cleaning blade but limited to where liquid developer is present. This localized application reduces toner aggregation in the developer supply zone without causing toner deposits to form at the cleaning blade, as the bias is not applied in the cleaning blade region.
4Reliability
If larger AC power supply is used to form desired bias, then toner re-dispersion is improved, but overcurrent damage risk increases
Solution Approach 1:
By applying alternating bias only in the liquid developer supply area rather than across the entire development roller, the patent reduces the overall current requirement while maintaining effective toner re-dispersion in the critical zone. This localized approach allows the use of smaller AC power supplies without increasing overcurrent damage risk, as the electrical stress is concentrated only where liquid developer provides protective insulation.
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
Effectively re-disperses toner particles into the liquid developer, reducing toner deposits and minimizing the risk of damage to the development roller, while allowing for cost-effective operation with smaller AC power supplies.
Implementation Method 1
it is effective to bring the alternating bias applying roller into contact with the development roller upstream of the cleaning blade and to form an alternating electric field between the alternating bias applying roller and the development roller
Implementation Method 2
an alternating electric field is formed to allow the toner particles adhering to the development roller to be electrically removed and re-dispersed into the liquid developer
Implementation Method 3
Alternating bias can be formed when liquid developer is present between the development roller and the alternating bias applying roller, because the liquid developer is insulative
Data Source
AI summary
The present wet development device includes a developer carrying member, a supply member that supplies a liquid developer to the developer carrying member, a charger that charges the liquid developer on the developer carrying member, a cleaner that removes the liquid developer on the developer carrying member, and a bias applying member that applies alternating bias in contact with the developer carrying member before removing by the cleaner. In a direction in alignment with an axis of rotation of the developer carrying member, a range to which the alternating bias is applied by the bias applying, member is located within a range in which the liquid developer is supplied onto the developer carrying member.