Exposure Unit Light Amount Adjustment for Density Uniformity
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Solution Overview
Problem
Existing image forming apparatuses face increased downtime due to the time-consuming process of recalibrating the maximum exposure amount in the main scanning direction to adjust for uneven density, as the number of scanning regions increases, requiring sequential adjustments of the laser exposure amount across multiple smaller regions.
Innovation Solution
An image forming apparatus with a control unit that adjusts the light amount of the exposure unit over a portion of regions rather than all regions when forming toner patches, using a detection unit to detect uneven density and adjust the light amount accordingly, thereby reducing the downtime required for recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser scanning region is divided into multiple smaller regions to adjust the maximum exposure amount for each region, then uneven density is reduced, but the time required for recalibration increases
Solution Approach 1:
The patent divides the laser scanning region into multiple smaller regions along the main scanning direction, allowing independent adjustment of maximum exposure amount for each region. This segmentation enables precise control of density uniformity by addressing local variations in the photosensitive drum characteristics, developer properties, or optical path differences across different scanning positions.
Solution Approach 2:
The patent implements partial action by adjusting the maximum exposure amount for only certain scanning regions that exhibit density unevenness, rather than uniformly adjusting all regions. The control unit identifies specific regions requiring calibration and applies exposure adjustments selectively, reducing unnecessary recalibration operations and minimizing downtime while maintaining density uniformity.
2Manufacturing precision
If the number of divided scanning regions is increased to adjust the maximum exposure amount more finely, then uneven density is further reduced, but the downtime for forming toner patches and performing recalibration increases
Solution Approach 1:
The patent segments the scanning region into multiple zones and assigns different maximum exposure amounts to each segment based on detected density characteristics. This allows fine-grained control of density uniformity while limiting the number of regions requiring active recalibration, thereby balancing precision with time efficiency.
Solution Approach 2:
The system performs self-calibration by automatically detecting density unevenness through toner patch formation and analysis, then autonomously adjusting the maximum exposure amount profile without requiring manual intervention. This self-service mechanism reduces overall downtime by eliminating manual recalibration steps while maintaining precise density control across multiple scanning regions.
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 reduces the downtime needed for recalibration by selectively adjusting the light amount in key regions, improving the efficiency of the image forming process while maintaining even density across the scanning direction.
Implementation Method 1
an exposure unit configured to form electrostatic latent images by scanning light on the image bearing member
Implementation Method 2
a detection unit configured to detect the toner patch
Data Source
AI summary
Included is an image bearing member; an exposure unit configured to form electrostatic latent images by scanning light on the image bearing member and to change the amount of light along the scanning direction of the light; a forming unit configured to form a toner patch on the basis of the electrostatic latent image formed by a plurality of different light amounts, to adjust the light amount of the exposure unit; a detection unit configured to detect the toner patch; and a control unit configured to adjust the light amount of the exposure unit along the scanning direction of the light depending on the detection result by the detection unit. The control unit changes the light amount of the exposure unit along the scanning direction of the light over a portion of regions rather than all regions in the scanning direction when forming the toner patch.