Alternating Laser Driver ICs for Scanning Uniformity
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Solution Overview
Problem
Image forming apparatuses with optical scanning systems experience scanning unevenness due to temperature variations among driver ICs, leading to inconsistent exposure amounts and image quality issues, particularly in images with horizontal stripes and halftones.
Innovation Solution
The implementation of a dual-driving IC system, where two PWM ICs control alternating groups of laser elements, ensuring that both ICs receive the same image data to synchronize their temperature changes and maintain consistent light emission, thereby distributing the exposure process evenly between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple driver ICs are used to drive multiple light sources for high-speed scanning, then productivity is improved, but temperature variations among the ICs cause scanning unevenness and exposure inconsistency
Solution Approach 1:
The patent implements periodic alternation of image data supply between multiple driver ICs. Specifically, odd-numbered primary scanning lines are supplied to one driver IC while even-numbered lines are supplied to another driver IC, creating a periodic pattern that ensures each IC processes a consistent distribution of scanning lines. This periodic action balances the thermal load across all driver ICs, preventing temperature variations that would otherwise cause exposure unevenness while maintaining high-speed multi-beam scanning capability
Solution Approach 2:
The patent changes the parameter of image data distribution by implementing alternating supply patterns between driver ICs. Instead of supplying all image data to a single IC or distributing it statically, the system dynamically alternates which IC receives which scanning line data based on a periodic pattern. This parameter change in data distribution ensures uniform thermal characteristics across all driver ICs, resolving the contradiction between high productivity through multi-IC parallel operation and manufacturing precision through uniform exposure
2Device complexity
If different driver ICs drive different groups of light sources, then device complexity is reduced through component standardization, but temperature differences among ICs lead to light emission inconsistencies
Solution Approach 1:
The patent applies periodic alternation in supplying image data to different driver ICs based on the primary scanning line number. Odd-numbered scanning lines are assigned to one driver IC while even-numbered lines are assigned to another, creating a periodic distribution pattern. This ensures that each driver IC processes a balanced mix of scanning lines over time, maintaining consistent thermal conditions and light emission characteristics across all ICs, thereby ensuring reliability while using standardized components
Solution Approach 2:
The patent changes the parameter of image data allocation by implementing an alternating assignment pattern between driver ICs. Instead of fixed assignment where each IC handles specific light sources continuously, the system dynamically changes which IC receives which scanning line data based on the line number parity. This parameter change in data allocation ensures uniform operational load and thermal characteristics across all driver ICs, maintaining light emission consistency while allowing use of standardized components
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 significantly reduces scanning unevenness and light power variations, resulting in improved image quality by minimizing temperature differences between the ICs and maintaining consistent exposure across the photosensitive member.
Implementation Method 1
A semiconductor laser has a plurality of light sources that emit laser beams for forming an electrostatic latent image on the photosensitive member
Implementation Method 2
A deflecting unit deflects a plurality of the laser beams so that the laser beams emitted from the plurality of light sources scan the photosensitive member
Implementation Method 3
The developing unit may develop the electrostatic latent image formed on the photosensitive member using toner
Data Source
AI summary
A light source array includes a first group of light sources having laser elements and a second group of light sources having laser elements. A first laser driver drives the laser elements and a second laser driver drives the laser elements. The first group of light sources and the second group of light sources execute multiple exposure. For example, the second group of light sources executes a first exposure and the first group of light sources executes a second exposure. In other words, the first group of light sources and the second group of light sources are driven by the first laser driver and the second laser driver, respectively, so as to expose the same position.