Developing Roller Toner Reservoir Control for Image Quality
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Solution Overview
Problem
Existing image forming apparatuses face challenges in stabilizing toner supply to the developing roller, leading to inconsistent image quality due to variations in dielectric unit resistance and pressure issues, which complicates miniaturization and mass production.
Innovation Solution
A developing apparatus with a conveying member that rotates during non-image-forming periods and stops during image-forming periods to create a stable toner reservoir on the developing roller, using a combination of a shaft portion and a conveying portion to restrict toner and maintain a uniform thickness, along with a control unit to manage the stop position and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a supply roller is used to supply toner to the developing roller, then the thickness of toner on the developing roller can be made substantially uniform, but the device complexity increases and miniaturization becomes difficult
Solution Approach 1:
The invention extracts and eliminates the supply roller from the developing apparatus, using only the developing roller itself to supply toner. The supply guide structure is simplified to work with the developing roller's rotation, removing the need for a separate supply roller mechanism while maintaining uniform toner thickness through the developing roller's own rotational force and the supply guide's geometric constraints.
Solution Approach 2:
The developing roller is given dual functionality: it both develops the electrostatic latent image and supplies toner to itself. By making the developing roller perform both functions, the invention eliminates the need for a separate supply roller, thereby reducing device complexity while maintaining manufacturing precision through the roller's controlled rotation and the supply guide's design.
2Reliability
If the pressure of developer against the front surface of the developer carrying member is increased to improve supply stability, then toner supply becomes more reliable, but aggregated developer forms and hinders supply
Solution Approach 1:
The invention creates different pressure conditions at different locations: the supply guide applies localized pressure at the toner accumulation point to ensure stable supply, while the developing roller's rotation provides gentle mixing and distribution that prevents aggregation. This spatial differentiation of pressure characteristics allows reliable toner supply without harmful aggregation.
Solution Approach 2:
The developing roller's continuous rotation provides periodic motion that repeatedly distributes toner from the supply guide across the roller surface. This periodic action prevents toner aggregation by constantly renewing the toner distribution, maintaining supply reliability while avoiding the harmful effects of static high pressure that would cause aggregation.
3Quantity of substance
If the electric resistance of the dielectric unit is reduced to improve toner adhesion, then more toner adheres to the developing roller, but the toner coat amount becomes unstable due to environmental variations
Solution Approach 1:
The invention changes the electrical parameter (volume resistivity) of the dielectric unit to an optimized range (10^11 to 10^13 Ω·cm) that balances toner adhesion capability with environmental stability. This parameter optimization ensures sufficient toner adhesion while minimizing the impact of environmental variations, achieving both quantity and stability requirements.
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 ensures stable and efficient toner supply to the developing roller, enhancing image quality and allowing for miniaturization and simplification of the apparatus while maintaining desired characteristics for mass production.
Implementation Method 1
the toner is conveyed and accumulated in a space formed between the developing roller and the supply guide, and the toner is supplied with a synergistic effect between the toner self-weight and the rotary force of the developing roller
Implementation Method 2
the toner is supplied with a synergistic effect between the toner self-weight and the rotary force of the developing roller
Implementation Method 3
portions that have different electric resistances or dielectric constants are exposed and mixed on a front surface thereof at a regular and fixed pattern pitch, and in which a number of micro electric fields are formed on the front surface thereof
Implementation Method 4
an appropriate amount of toner can be adhered to the electrostatic latent image on the photosensitive drum
Data Source
AI summary
A toner circulation and a toner reservoir are formed in the vicinity of a developing roller. A member to form a toner reservoir is movable and is stopped during at least an image-forming period.