Image Carrier Aging Control for Banding-Free Electrophotography
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Solution Overview
Problem
Conventional image forming apparatuses using electrophotographic systems face issues with non-uniform surface potential on image carriers due to varying carrier quantities generated by triboelectrification, leading to banding and stripe defects in printed images.
Innovation Solution
Implementing an aging process that adjusts the surface potential of image carriers by rotating them in a charged state for a specified duration when differences in coverage rates exceed a threshold, using a controller to monitor and execute this process based on area-specific coverage rate variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the image carrier is electrically charged by the charging unit, then the surface potential is increased for image formation, but non-uniform surface potential occurs due to varying carrier quantities from triboelectrification
Solution Approach 1:
The patent applies preliminary action by rotating the image carrier in a charged state for a specified duration (aging process) before actual image formation. This pre-treatment allows the surface potential to stabilize and become uniform by reducing carrier quantity variations, ensuring consistent charging conditions for subsequent image formation without affecting productivity.
2Ease of manufacture
If the cleaning blade scrapes away remaining toner, then the image carrier is cleaned for next cycle, but carrier quantity varies due to triboelectriction during scraping
Solution Approach 1:
The patent implements feedback by detecting coverage rates in multiple areas and using this information to determine when the aging process is needed. The controller monitors the image carrier's charging state and adjusts the aging process accordingly, creating a closed-loop system that maintains optimal surface potential uniformity while minimizing unnecessary aging operations.
3Manufacturing precision
If aging process is executed to uniformize surface potential, then image quality is improved, but additional time is required for the aging duration
Solution Approach 1:
The patent applies parameter changes by adjusting the aging process parameters (duration, timing) based on detected coverage rates. The controller dynamically determines when aging is necessary and sets appropriate aging durations, optimizing the balance between surface potential uniformity and time consumption. The aging process is executed only when coverage rate differences indicate it is needed.
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
Maintains uniform surface potential on image carriers, thereby ensuring stable image quality by minimizing potential variations and preventing banding and stripe defects.
Implementation Method 1
the image carrier would undergo generation of carriers on a photosensitive layer by triboelectrification due to frictional force against a blade
Implementation Method 2
generation of carriers on a photosensitive layer by triboelectrification due to frictional force against a blade
Data Source
AI summary
The image forming apparatus includes an image carrier, a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning blade, and a controller. The controller detects printing-coverage rates on a basis of plural areas divided in the longitudinal direction of the image carrier. Upon occurrence of a difference exceeding a specified threshold value among the coverage rates of the plural areas, the controller executes, for a duration of specified aging time, aging process in which the image carrier is driven into rotation in its charged state.