Developing Sleeve Groove Segmentation for Stable Developer Coating
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Solution Overview
Problem
Conventional developing sleeves with surface grooves or recessed portions for image forming apparatuses face challenges in maintaining stable developer coating without decreasing the gap between the developer carrying member and the regulating member, leading to issues like clogged regulating blades, unstable developer feeding, and density non-uniformity in images due to excessive groove depth or number.
Innovation Solution
A developing sleeve with a combination of first and second groove portions, where the first grooves have a depth and width greater than or equal to the carrier particle size, and the second grooves have a depth and width less than the carrier particle size, are strategically placed to stabilize developer coating while maintaining a sufficient gap between the developer carrying member and the regulating member, thereby preventing clogging and density non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the level difference of surface unevenness is increased to stabilize developer feeding power, then the developer feeding power becomes stable, but the amount of developer on the developing sleeve increases requiring a smaller gap between developing sleeve and regulating blade
Solution Approach 1:
The developing sleeve surface is segmented into multiple groove portions with different depths. Specifically, the surface includes first groove portions with a first depth and second groove portions with a second depth greater than the first depth. This segmentation allows different regions to serve different functions: shallower grooves provide stable developer feeding while deeper grooves control the overall developer amount, thereby maintaining both feeding stability and an adequate gap between the developing sleeve and regulating blade.
2Manufacturing precision
If the gap between developing sleeve and regulating blade is decreased to reduce developer amount, then image quality improves by avoiding graininess, but the regulating blade becomes clogged with foreign matter and developer coating becomes unstable
Solution Approach 1:
The groove portions are segmented into at least two different depth levels. The first groove portions with smaller depth help maintain adequate gap distance, preventing regulating blade clogging, while the second groove portions with larger depth provide sufficient developer feeding power. This depth segmentation enables the system to maintain both image quality and regulating blade functionality without requiring an excessively small gap.
3Reliability
If sandblasting is used to form surface unevenness, then developer feeding power is improved, but the unevenness is abraded over time shortening device lifetime
Solution Approach 1:
Instead of relying on sandblasted surface unevenness that degrades over time, the invention uses groove portions with different depths that are structurally integrated into the developing sleeve surface. These grooves provide consistent developer feeding power throughout the device lifetime without being subject to abrasion, thereby improving both reliability and durability compared to sandblasted surfaces.
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 ensures stable developer coating and feeding power, preventing clogging and density non-uniformity, while allowing for a broader gap between the developer carrying member and the regulating member, thus enhancing image quality and reliability.
Implementation Method 1
a magnet fixedly provided to a casing is disposed inside the rotating developing sleeve, and the developer is held on a surface of the developing sleeve by a magnetic force
Implementation Method 2
the developer is fed on the developing sleeve to the neighborhood of the photosensitive drum while being magnetically attracted
Data Source
AI summary
A developing sleeve includes first axially extending groove portions which satisfy D1≥2R and W1≥2R, where 2R is a volume-average particle size of a carrier, D1 is a maximum depth of each first groove portion and W1 is a width an opening of each first groove portion with respect to a circumferential direction of the developing sleeve, and second axially extending groove portions. Each second groove portion satisfies D2<2R, where 2R is the volume-average particle size of the carrier and D2 is a maximum depth of each second groove portion. Each or a plurality of the second groove portions are disposed between the first groove portions with respect to the circumferential direction of the developing sleeve.