Light Source Driver Undershoot Current Control for Image Uniformity
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Solution Overview
Problem
Conventional image-forming apparatuses face challenges in achieving improved image quality due to emission delay times and varying response properties of light sources, leading to uneven images and decreased light output, especially when the light output time is set to short durations.
Innovation Solution
A light source driver is developed that includes a controller which outputs an undershoot current in synchronization with lighting complete timing, ensuring the voltage when the undershoot current is complete equals the initial voltage, and utilizes a driving current generator with both a first and second undershoot current, where the second undershoot current is adjusted based on the light volume to improve response properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the light output time is set to a short time to improve productivity, then the printing speed increases, but the light output becomes smaller than the predetermined light volume, causing uneven images
Solution Approach 1:
The patent applies preliminary action by generating an emission delay time based on the response property of the light source before the light output is actually generated. This pre-compensation mechanism ensures that even when the light output time is shortened for higher productivity, the light source has sufficient time to reach the required output level, thereby maintaining image uniformity and concentration without sacrificing printing speed
2Speed
If conventional emission delay time generation methods are used to improve response property, then the light output timing is adjusted, but the response property deteriorates when light output time is set to short durations
Solution Approach 1:
The patent applies dynamics by making the emission delay time variable rather than fixed. The delay time is dynamically adjusted based on the response property of the light source and the specific timing requirements. This dynamic adjustment ensures that the response property remains consistent and reliable whether the light output time is long or short, preventing deterioration in response consistency across different operating conditions
3Speed
If a fixed undershoot current is used to improve light source response, then the falling of optical output waveform is improved, but the response property cannot be significantly improved when light volume changes
Solution Approach 1:
The patent applies parameter changes by making the undershoot current variable based on the light volume. Instead of using a fixed undershoot current, the system adjusts the current magnitude according to the required light output level. This ensures that the undershoot current remains appropriate and effective whether the light volume is high or low, significantly improving the response property across all operating conditions and enhancing the system's adaptability
Data Source
AI summary
A light source driver includes a controller which outputs an undershoot current in synchronization with lighting complete timing in lighting information, wherein the controller is configured to output the undershoot current such that a voltage in a light source when the output of the undershoot current is complete is equal to a voltage in the light source before being turned on.