LED Exposure Panel Layout for Reciprocity Failure Correction
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in maintaining image quality due to reciprocity failure caused by misalignment of light-emitting elements, leading to higher pixel density and reduced exposure control, especially when arranged in a cyclic manner in the sub-scanning direction.
Innovation Solution
The exposure device employs a panel member with light-emitting elements arranged in groups, where adjacent elements in the main scanning direction are shifted in the sub-scanning direction, and incorporates controllers for density correction by adjusting light intensity and exposure timing to correct pixel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light-emitting elements are arranged in a cyclic manner in the sub-scanning direction to increase exposure amount, then pixel density increases, but image quality deteriorates due to reciprocity failure
Solution Approach 1:
The patent applies local quality by differentiating the arrangement of light-emitting elements based on their position. Specifically, light-emitting elements are arranged in a cyclic manner in the sub-scanning direction for certain regions to increase exposure amount, while maintaining regular arrangements in other regions to avoid reciprocity failure. This localized differentiation allows the system to optimize exposure without uniformly degrading image quality across the entire photoreceptor surface.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the arrangement pattern of light-emitting elements based on exposure requirements. The controller modifies the exposure control parameters for different regions, adjusting light emission timing and intensity to compensate for the cyclic arrangement's impact on pixel density. This allows the system to maintain image quality while achieving increased exposure amount in specific areas.
2Productivity
If light-emitting elements are arranged in a cyclic manner in the sub-scanning direction, then exposure amount increases, but pixel density becomes higher than expected due to reciprocity failure
Solution Approach 1:
The patent implements feedback by using the controller to monitor and adjust light emission based on the cyclic arrangement of light-emitting elements. The controller receives information about the element positions and exposure status, then dynamically adjusts emission timing and intensity to compensate for the increased pixel density caused by the cyclic arrangement. This feedback mechanism ensures that the exposure amount is increased without causing excessive pixel density that would degrade image quality.
3Manufacturing precision
If light emission is controlled to maintain image quality, then exposure uniformity is maintained, but exposure amount is reduced
Solution Approach 1:
The patent applies segmentation by dividing the photoreceptor surface into multiple regions with different light-emitting element arrangements. Some regions use cyclic arrangements to increase exposure amount, while other regions maintain regular arrangements to ensure uniformity. The controller then applies different exposure control parameters to each region, allowing the system to optimize both exposure amount and image quality simultaneously by segmenting the exposure process into distinct zones with different 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 approach maintains appropriate image quality by reducing pixel density through controlled light intensity adjustments, mitigating the effects of reciprocity failure and ensuring uniform exposure.
Implementation Method 1
a panel member having plural light-emitting elements... plural light-emitting elements are arranged in a main scanning direction
Implementation Method 2
exposing the photoreceptor... forms the electrostatic latent image
Data Source
AI summary
An image forming apparatus includes a panel member opposing a photoreceptor and having plural light-emitting elements. The panel member has plural element groups, in which the light-emitting elements are arranged in a main scanning direction along a rotation axis of the photoreceptor. In the element group, the adjacent light-emitting elements in the main scanning direction are disposed such that positions in a sub-scanning direction orthogonal to the main scanning direction are shifted from one end side to the other end side toward one side in the main scanning direction. Density correction is performed to lower density of pixels when the pixels adjacent to each other in the main scanning direction and corresponding to the light-emitting element on one end side arranged at one end in the sub-scanning direction and the light-emitting element on the other end side arranged at the other end in the sub-scanning direction are exposed to light.