Semiconductor Laser Driver Shading Correction Circuit
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Solution Overview
Problem
Electrophotographic image forming apparatuses face issues with image quality deterioration due to optical variations and electrical charge variations on the photoconductor, which existing semiconductor laser drivers struggle to address effectively through shading correction.
Innovation Solution
A semiconductor laser driver with a light source comprising multiple laser-beam source units arranged in a sub-scanning direction, grouped in the main scanning direction, incorporates a shading corrector to adjust driving currents based on shading correction values and a light quantity adjuster to optimize laser beam emission, preventing vertical stripes and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual shading correction circuits are provided for each laser-beam source unit, then shading correction precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the laser-beam source units into multiple groups based on their positional relationships. Instead of treating each unit individually, units within the same group share common shading correction control. This segmentation approach reduces the number of independent correction circuits while maintaining adequate correction precision for each group.
Solution Approach 2:
The patent merges the shading correction control for multiple laser-beam source units into a single control mechanism for each group. By combining the correction functions and using shared control signals, the overall circuit complexity is reduced while still addressing the shading variations across different units.
2Manufacturing precision
If individual shading correction circuits are provided for each laser-beam source unit, then image quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the laser-beam source units into groups based on positional characteristics. This allows the system to achieve adequate image quality correction without the need for expensive individual correction circuits for each unit, thereby reducing manufacturing costs while maintaining acceptable image quality.
Solution Approach 2:
The patent adopts a cost-effective approach by using shared, simpler correction circuits for groups of units rather than investing in expensive individual correction circuits for each unit. This trade-off maintains sufficient image quality while significantly reducing the overall manufacturing cost.
3Productivity
If shading correction is performed for all laser-beam source units simultaneously, then correction efficiency is improved, but dot misalignment occurs
Solution Approach 1:
The patent segments the shading correction process by applying corrections to different groups of laser-beam source units at different timings. This staged approach prevents simultaneous correction of all units, thereby avoiding dot misalignment while still achieving efficient correction across the entire system.
Solution Approach 2:
The patent performs shading correction for different groups of laser-beam source units in a predetermined sequence rather than simultaneously. This preliminary, staged correction approach ensures that each group is corrected at an optimal time, preventing dot misalignment while maintaining overall correction efficiency.
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 configuration enables effective shading correction without individual shading correction circuits for each laser-beam source unit, reducing costs and preventing dot misalignment, thereby enhancing image quality and reducing the occurrence of vertical stripes.
Implementation Method 1
a light source including a plurality of laser-beam source units disposed in a sub-scanning direction that serves as a group direction, the laser-beam source units having a plurality of groups arranged in a main scanning direction, each of the laser-beam source units emitting a laser beam of a light quantity dependent upon a driving current
Data Source
AI summary
A semiconductor laser driver and an image forming apparatus incorporating the semiconductor laser driver. The semiconductor laser driver includes a light source including a plurality of laser-beam source units disposed in a sub-scanning direction that serves as a group direction, the laser-beam source units having a plurality of groups arranged in a main scanning direction, each of the laser-beam source units emitting a laser beam of a light quantity dependent upon a driving current, a shading corrector to correct, according to at least one shading correction value, the driving current given to the laser-beam source units for each of the groups, and a light quantity adjuster to adjust the driving current according to a light-quantity adjustment value for the laser-beam source units. The image forming apparatus includes a semiconductor laser drive circuit, and the semiconductor laser driver that serves as the semiconductor laser driver.