Magnet Roller Magnetic Flux Density Distribution for Toner Leakage
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Solution Overview
Problem
Conventional image forming apparatuses using electrophotographic systems face issues with toner sticking and leakage due to excessive contact pressure and inadequate sealing, leading to reduced image density and fogging in magnetic non-contact developing systems.
Innovation Solution
The development apparatus features a regulating blade with a cantilever configuration and a magnet roller with a specific magnetic flux density distribution, including a local minimum portion, to maintain uniform contact pressure and prevent toner leakage by ensuring efficient toner transfer and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the regulating blade is brought into edge contact with the developing sleeve to reduce the take-in portion size, then the toner leakage is reduced, but the contact pressure between the regulating blade and developing sleeve increases excessively
Solution Approach 1:
The patent applies local quality by creating an overlap portion at the longitudinal end of the developing unit where the regulating blade, developing sleeve, and sealing member are arranged sequentially. This local structural modification allows the regulating blade to maintain face contact with the developing sleeve in the overlap portion, reducing contact pressure locally while still preventing toner leakage through the sealed configuration.
2Stress or pressure
If the middle of the regulating blade contacts the developing sleeve to form a face contact configuration, then the contact pressure is reduced, but the take-in portion becomes larger causing toner leakage
Solution Approach 1:
The patent segments the developing unit into a main developing area and an overlap portion at the longitudinal end. The overlap portion is specifically designed with sequential arrangement of the regulating blade, developing sleeve, and sealing member. This segmentation allows different contact configurations in different regions: face contact in the overlap portion to reduce pressure, and edge contact in the main area to prevent leakage.
3Ease of manufacture
If elastic sealing members are used instead of magnetic sealing members to reduce cost, then the sealing effectiveness is reduced, leading to inadequate toner trapping
Solution Approach 1:
The patent merges the sealing function with the regulating blade structure by providing an overlap portion where the regulating blade, developing sleeve, and sealing member are arranged sequentially. This integrated configuration allows elastic sealing members to work effectively in conjunction with the regulating blade's face contact, achieving both cost reduction and adequate sealing effectiveness.
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 configuration effectively suppresses toner sticking and leakage, maintaining image density and preventing fogging by ensuring uniform toner transfer and sealing, thereby enhancing the overall performance of the image forming apparatus.
Implementation Method 1
a magnetic toner is carried on a surface of a developing sleeve internally provided with a magnet roller
Implementation Method 2
the magnetic field generating member has a first area where a value of a magnetic flux density is a predetermined value in the rotation axis direction and a second area including a local minimum portion in which the value is a minimum value
Data Source
AI summary
At an end, in a longitudinal direction, of an opening in a container containing a magnetic developer, an overlap portion is provided in which a developer bearing member, a regulating member, a sealing member, and the container are arranged so as to sequentially contact one another in a direction orthogonal to a rotation axis direction. A magnetic field generating member provided inside the developer bearing member has a first area where a value of a magnetic flux density is a predetermined value in the rotation axis direction and a second area including a local minimum portion in which the value is a minimum value, within a range from an end of the second area connected to the first area to an outer end of the overlap portion in the rotation axis direction.