Developing Sleeve Groove Geometry for Carrier Replacement
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Solution Overview
Problem
Existing developing devices face challenges in reducing carrier deterioration while minimizing the feeding force per groove, leading to potential image defects and contamination due to carrier clogging and uneven developer feeding.
Innovation Solution
The developing device features a developing sleeve with grooves having a specific shape, where the bottom portion width is greater than the carrier diameter, the opening width is larger than twice the carrier diameter, and the side surface portions have inclination angles less than 45 degrees in the first region and greater than 45 degrees in the second region, facilitating carrier replacement and stable developer feeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the angle of the V-shaped groove is increased to easily replace carrier, then carrier replacement is improved, but the feeding property of developer by the developing sleeve lowers and coating amount becomes unstable
Solution Approach 1:
The groove shape parameters are changed from a simple V-shape to a complex cross-section with specific angle ranges (30-60 degrees for first slope, 60-80 degrees for second slope) and width relationships, optimizing both carrier replacement and feeding properties simultaneously
Solution Approach 2:
The groove cross-section employs asymmetric dual-slope design where the first slope has a different angle range (30-60 degrees) than the second slope (60-80 degrees), creating unequal surfaces that facilitate both carrier ejection and stable developer coating
2Productivity
If the opening width of each groove is decreased to minimize feeding force, then feeding force is reduced, but the carrier in the groove is not readily replaced
Solution Approach 1:
The opening width parameter is optimized to a specific range (0.5-2.0 times carrier diameter) that simultaneously enables carrier replacement through the narrowed opening while maintaining controlled feeding force through the constrained groove geometry
Solution Approach 2:
The groove cross-section combines multiple geometric features (dual slopes with different angles, specific width ratios between top and bottom) into a composite structure that achieves both carrier replacement and feeding force control
3Quantity of substance
If the groove width is increased to carry more carriers, then carrier carrying capacity is improved, but the feeding force becomes excessively high causing gap clogging and image defects
Solution Approach 1:
The groove width parameters are precisely controlled with the top width being 0.5-2.0 times the carrier diameter and bottom width being 0.3-1.0 times the carrier diameter, optimizing carrier capacity while preventing excessive feeding force that would cause gap clogging
Solution Approach 2:
Different sections of the groove have different width characteristics - the top portion is wider to accommodate carrier entry and the bottom portion is narrower to control feeding force, creating localized quality variations that resolve the contradiction
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 design effectively suppresses carrier deterioration and maintains stable developer feeding, ensuring long-term stable image formation without upsizing the developing sleeve, thereby reducing manufacturing costs and preventing image defects.
Implementation Method 1
the developer is carried on a surface of a developing sleeve in which a magnet is provide, and is fed by rotation of the developing sleeve
Implementation Method 2
the electrostatic latent image formed on the photosensitive drum is developed with the toner in the developer
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
The present invention relates to a developing device which comprises a developing container configured to accommodate a developer containing toner and carrier particles; a cylindrical developing sleeve rotatable while carrying the developer in said developing container; a magnet provided in said developing sleeve and configured to generate a magnetic force for holding the developer; and a plurality of grooves provided at a developer carrying surface of said developing sleeve and formed along a direction crossing a circumferential direction of said developing sleeve. In a cross-section perpendicular to a rotational axis of said developing sleeve, each of said grooves is formed by a bottom portion contacting the carrier particle and a pair of side surface portions provided in both sides of said bottom portion with respect to the circumferential direction of said developing sleeve and satisfies the following relationships: r<w<2r, 2×r<L, and r/2≤s<2r. In the above, r is a volume average particle size of the carrier particles, w is a length between both ends of said bottom portion measured in the cross-section perpendicular to the rotational axis of said developing sleeve, L is a width between said side surface portions at the surface of said developing sleeve in the cross-section perpendicular to the rotational axis of said developing sleeve, and s is a depth of each of said grooves.