Printhead Light Intensity Adjustment for Uniform Toner Exposure
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Solution Overview
Problem
Current electrophotography printer technologies face challenges in achieving uniform toner application due to high and low pixel density areas, leading to over or under exposure, as adjusting overall light intensity affects both regions unevenly.
Innovation Solution
A method that calculates a correction factor for each pixel by applying a filter to sum the light intensity contribution of surrounding pixels, comparing this to a development threshold range, and adjusting the light source intensity accordingly to ensure proper toner application across the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If overall light intensity is reduced to prevent over exposure in high density areas, then toner pile-up is reduced, but low density areas become under charged and do not receive toner
Solution Approach 1:
The patent applies different light intensity correction factors to different pixels based on their local charge density environment. By calculating an overlap value for each pixel representing the sum of light intensity contributions from surrounding pixels, the system identifies pixels in high density regions and applies selective correction only to those pixels, leaving pixels in low density areas unchanged. This local differentiation resolves the contradiction by preventing over-exposure in high density areas while maintaining proper charging in low density areas.
2Object-affected harmful factors
If overall light intensity is increased to ensure proper charging of low density areas, then toner reception in low density areas improves, but high density areas experience over exposure and toner pile-up
Solution Approach 1:
The system calculates an overlap value for each pixel that quantifies the cumulative light intensity contribution from surrounding pixels. By comparing this overlap value to a threshold, the system identifies pixels in high density regions that are prone to over-exposure. Correction factors are then applied selectively only to these identified pixels, allowing the overall light intensity to remain sufficient for low density areas while preventing over-exposure locally in high density areas.
Solution Approach 2:
The patent implements a feedback mechanism where the overlap value calculation provides information about the local charge density environment for each pixel. This feedback is used to dynamically adjust the light intensity correction factor on a per-pixel basis, creating a closed-loop control system that automatically prevents over-exposure in high density areas while maintaining adequate charging in low density areas without requiring manual intervention.
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 ensures consistent toner application across all pixels, preventing toner pile-up and improving the linearity between spot density and development, regardless of pixel density regions.
Implementation Method 1
Electro photography printer technology, e.g., a raster output scanner (ROS) that uses a light source such as a laser and a rotating polygon mirror, a light emitting diode (LED) printhead that uses LEDs as a light source, use the light source to charge a photoreceptor drum
Data Source
AI summary
A method, non-transitory computer readable medium, and apparatus for adjusting a light intensity of a printhead are disclosed. For example, the method receives an image comprising a plurality of pixels, calculates a correction factor for each one of a plurality of pixels of the image by applying a filter to each one of the plurality of pixels of the image and summing a contribution of the light intensity of each one of a plurality of surrounding pixels to a pixel being analyzed to calculate an overlap value and comparing the overlap value to a development threshold range and adjusts the light intensity of a light source of the printhead in accordance with the correction factor of each one of the plurality of pixels of the image that require toner.