Asymmetric Grid Electrode for Uniform Photoconductor Charging
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Solution Overview
Problem
Existing image forming apparatuses face challenges in achieving uniform electrostatic charging of photoconductor drums due to uneven charge distribution caused by symmetric grid electrode patterns, leading to image quality issues such as periodic dark and light areas.
Innovation Solution
A discharger with a grid electrode having asymmetrically arranged holes in two regions, each inclined at different angles relative to the discharging member, with a boundary in between, which reduces the variation in opening ratio and prevents bristle loss during cleaning, thereby improving charge uniformity and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a symmetric grid electrode pattern is used, then the manufacturing process is simplified, but uneven charge distribution occurs causing periodic dark and light areas in images
Solution Approach 1:
The patent applies asymmetry by designing the grid electrode with two different regions: a first region with holes arranged at a first inclination angle and a second region with holes arranged at a second inclination angle different from the first. This asymmetric arrangement prevents the periodic dark and light areas that occur with symmetric patterns, while maintaining manufacturing simplicity through the regular geometric arrangement of holes in each region.
2Device complexity
If the grid electrode holes are arranged at a single inclination angle, then the structure is simpler, but bristle loss occurs during cleaning operations
Solution Approach 1:
The patent introduces asymmetry in the hole arrangement by creating two regions with different inclination angles. This asymmetric design prevents bristle loss during cleaning operations by eliminating the conditions that cause bristles to become trapped and pulled out, while maintaining reasonable structural complexity through the systematic arrangement of holes.
3Productivity
If the opening ratio varies significantly across the grid electrode, then contamination removal is enhanced, but charge uniformity deteriorates
Solution Approach 1:
The patent applies local quality by dividing the grid electrode into two regions with different hole inclination angles. Each region has its own local characteristics optimized for specific functions: one region prioritizes contamination removal while the other maintains charge uniformity. The boundary between regions is arranged to extend in the extending direction of the discharging member, creating a balanced overall performance.
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
The asymmetric grid electrode design reduces uneven charge distribution and bristle loss, resulting in improved image quality and reduced maintenance needs by maintaining a consistent opening ratio and efficient contamination removal.
Implementation Method 1
a discharging member and a grid member. The discharging member is disposed facing a member to be charged and discharges electricity by applying voltage thereto
Implementation Method 2
The grid member is disposed between the discharging member and the member to be charged and regulates electric discharge from the discharging member when voltage is applied between the grid member and the discharging member
Data Source
AI summary
A discharger includes a discharging member that faces a member to be charged and discharges electricity by applying voltage; and a grid member that is disposed between the discharging member and the member to be charged and regulates electric discharge from the discharging member. The grid member has holes with a predetermined shape and extending through the grid member from the discharging member toward the member to be charged, and has a first region with the holes arranged at a first inclination angle, a second region with the holes arranged at a second inclination angle, and a boundary between the first and second regions and extending in the extending direction of the discharging member. When the first region is symmetrically projected onto the second region with respect to the boundary, an arrangement pattern of the holes in the first region and an arrangement pattern of the holes in the second region are positionally displaced relative to each other.