Developing Sleeve Magnet Repulsion Prevents Toner Scattering
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Solution Overview
Problem
High-speed rotation of the developing roller in electrophotographic image forming apparatuses leads to increased internal pressure and toner scattering due to air introduction, causing leakage and deterioration of toner performance, which worsens at higher printing speeds.
Innovation Solution
Incorporation of a magnet with the same magnetic polarity as the developing roller's magnetic poles between the inner wall and the magnetic member to create a repulsive magnetic field, altering the trajectory of the toner and reducing collisions with the inner wall, thereby minimizing toner scattering and maintaining image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developing roller is rotated at high speed to increase printing speed, then productivity is improved, but toner scattering occurs due to air introduction and increased internal pressure
Solution Approach 1:
The patent converts the harmful effect of air introduction and internal pressure increase into a beneficial outcome by using a repulsive magnetic field to redirect the toner-carrying developer. The high-speed rotation that causes air entrapment and pressure buildup is now managed by magnetic forces that guide the developer away from the inner wall, preventing toner scattering while maintaining high printing speeds.
Solution Approach 2:
The patent introduces a magnet as an intermediary element between the developing roller and the inner wall. This magnet creates a repulsive magnetic field that acts as a mediator to redirect the developer flow, preventing direct contact between the high-speed rotating developer and the inner wall, thus eliminating toner scattering without reducing printing speed.
2Productivity
If the developing roller rotates at high speed, then productivity is improved, but toner leakage from the developing roller occurs due to increased internal pressure
Solution Approach 1:
The patent converts the harmful internal pressure increase into a beneficial control mechanism by using magnetic forces. The repulsive magnetic field created by the magnet opposes the pressure-driven leakage, redirecting the toner-carrying developer away from the inner wall and preventing toner loss while maintaining high-speed operation.
Solution Approach 2:
The patent applies a preliminary magnetic field before the developer contacts the inner wall. By positioning the magnet to create a repulsive magnetic field in advance, the developer trajectory is modified before pressure-induced leakage can occur, preventing toner loss proactively rather than reactively.
3Productivity
If the developing roller rotates at high speed, then productivity is improved, but toner performance deteriorates due to scattering and collision with inner wall
Solution Approach 1:
The patent converts the harmful high-speed rotation effects into a beneficial outcome by using the repulsive magnetic field to manage developer flow. The same high-speed rotation that causes toner scattering and performance deterioration is now controlled by magnetic forces that guide the developer smoothly, maintaining both high printing speed and toner performance reliability.
Solution Approach 2:
The magnet serves as an intermediary that protects toner performance by creating a repulsive magnetic field. This magnetic field mediates between the high-speed rotating developer and the inner wall, preventing harmful collisions that would deteriorate toner performance while allowing high-speed operation to maintain productivity.
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
The repulsive magnetic field effectively prevents toner scattering and maintains image density by reducing collision speed and ensuring the toner falls into the developing chamber without hitting the inner wall, even at increased printing speeds.
Implementation Method 1
Inclusion of a magnet with the same magnetic polarity as the developing roller's magnetic poles between the inner wall and the magnetic member to create a repulsive magnetic field
Data Source
AI summary
A developing device including a developing sleeve installed in a developing chamber and partially exposed to an outside of the developing chamber through an opening portion, a magnetic member located inside a developing sleeve and including a separating pole and a receiving pole, the separating pole being located on a downstream side of the opening portion based on a rotating direction of the developing sleeve to separate a developing agent from the developing sleeve, and the receiving pole being located on a downstream side of the separating pole to attach the developing agent to the developing sleeve, and a magnet located between an inner wall of the developing chamber and the magnetic member to face a region between the separating pole and the receiving pole and having same magnetic polarity same as the separating pole and the receiving pole.