Developing Device Reverse Rotation Toner Aggregation
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Solution Overview
Problem
The magnetic one-component developing method requires sufficient magnetic force to maintain a stable toner layer on the development roller, but the use of a blade magnet can lead to aggregated toner and image defects like white lines due to clogging, which existing removal modes struggle to fully prevent.
Innovation Solution
A developing device with a rotatable developer carrier, a regulating blade, and a magnet member with a blade magnet, capable of executing a developer removal mode where the carrier rotates in reverse, allowing for effective removal of aggregated toner and maintaining a stable toner layer by adjusting the rotation direction and toner composition with specific particle sizes and resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blade magnet is stuck on the regulating blade to improve magnetic force, then toner layer stability and charging performance are improved, but aggregated toner is easily generated around the blade magnet and at the tip of the blade
Solution Approach 1:
The patent applies reverse rotation of the development roller to remove aggregated toner from the regulating blade tip area. By rotating the development roller in the opposite direction to the normal development direction, the toner layer is redistributed and aggregated toner is removed from the critical area around the blade magnet, thereby resolving the contradiction between maintaining magnetic force and preventing toner aggregation.
2Device complexity
If the development roller rotates in forward direction only, then development process is simple, but aggregated developer clogs at the tip of the blade and its vicinity causing image defects
Solution Approach 1:
The patent implements periodic reverse rotation of the development roller at specific intervals during the development process. This periodic action allows aggregated toner to be removed and redistributed without continuously complicating the development process, thereby maintaining image quality while keeping the overall process relatively simple.
3Object-generated harmful factors
If reverse rotation is applied to remove aggregated toner, then image defects are suppressed, but toner layer stability may be affected
Solution Approach 1:
The patent applies reverse rotation for a limited duration and at specific intervals rather than continuously. This partial application of reverse rotation is sufficient to remove aggregated toner and prevent image defects while minimizing the disruption to the overall toner layer stability during the development process.
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 suppresses image defects such as white lines and maintains development performance by stabilizing the toner layer thickness and preventing toner aggregation, ensuring consistent image quality over time.
Implementation Method 1
The magnet member is fixed in a non-rotatable manner inside the developer carrier and has a plurality of magnetic poles disposed along the circumferential direction of the developer carrier
Implementation Method 2
Utilizing magnetic holding power of this fixed magnet body, the toner inside a development container is carried on the development roller
Implementation Method 3
The blade magnet is fixed to the regulating blade and induces a magnetic pole at the tip of the regulating blade
Implementation Method 4
a repulsive magnetic field is generated between the regulating blade and the development roller, and the development roller is rotated in a forward direction
Data Source
AI summary
A developing device includes a developing device case, a developer carrier, a regulating blade, a magnet member, and a blade magnet. The regulating blade forms a regulating part. Toner contains toner mother particles containing binder resin and magnetic powder, and silica particles and alumina particles adhered to surfaces of the toner mother particles. The alumina particles has a primary particle size of 150 nm or more and 400 nm or less, and resistivity of 0.1 Ωm or more and 2 Ωm or less. The developing device can execute a developer removal mode in which the developer carrier is rotated in a reverse direction opposite to a forward direction that is a rotation direction at image forming time, in a range of 1/18 or more and ⅕ or less of an outer circumference length of the developer carrier, so as to remove the developer staying at the regulating part.