Exposure Head Light-Emission Correction for Uniform Image Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses using electrophotographic methods face density unevenness due to variations in light amounts among light emitting elements within a chip, which are not adequately addressed by correcting only the differences between neighboring chips.
Innovation Solution
The apparatus includes a photosensitive member with an exposure head containing multiple light emitting chips and elements, each with digital-analog converters and a circuit unit, controlled by a processor to generate image data for individual elements, adjusting light emission based on correction information to equalize light amounts across the elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only the difference between light amounts of neighboring chips is corrected, then the device complexity is reduced, but density unevenness appears in the formed image due to light amount variations among light emitting elements within chips
Solution Approach 1:
The invention segments the correction approach into two levels: chip-level correction (maintaining simplicity) and element-level correction (achieving precision). Each light emitting element within a chip is individually addressed through separate image data, allowing precise control of light amount while maintaining manageable system complexity through the modular chip structure.
Solution Approach 2:
The invention applies local quality by treating each light emitting element within a chip differently rather than uniformly. By generating separate image data for each element and applying element-specific correction values, the system achieves uniform density across the image by compensating for local variations in light emission characteristics of individual elements.
2Manufacturing precision
If light emission is precisely controlled for each light emitting element, then image formation precision is improved, but the device complexity increases due to additional control circuits and processing
Solution Approach 1:
The invention applies preliminary action by pre-calculating and storing correction values for each light emitting element before actual image formation. The correction information is prepared in advance based on measured light amounts, and this pre-processed data is then used during normal operation to simplify real-time control while maintaining high precision.
Solution Approach 2:
The invention introduces an intermediary layer of correction information that mediates between the simple chip-level control structure and the precise element-level light emission requirements. This correction data acts as a bridge, allowing the existing simple hardware architecture to achieve precise control through software-based compensation.
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 effectively reduces density unevenness by precisely controlling light emission, ensuring uniform image quality by correcting light amount fluctuations within and between chips, enhancing image formation precision.
Implementation Method 1
each of the plurality of light emitting chips including a plurality of light emitting elements
Data Source
AI summary
An image forming apparatus includes at least one processor that is configured to generate second image data corresponding to each of a plurality of light emitting elements based on first image data, the second image data indicating whether to cause each of the plurality of light emitting elements to emit light, and based on correction information, change the first image data indicating that the light emitting elements are to emit light to the second image data indicating that the light emitting elements are not to emit light. A circuit unit is configured to supply a current to each of the plurality of light emitting elements based on the second image data.