Image Density Correction in Laser Printers
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Solution Overview
Problem
Conventional image forming apparatuses face difficulties in arbitrarily adjusting image density deviations in the main scanning direction, as they rely on pre-measured light intensity distributions to correct for emission intensity deviations, limiting flexibility in toner density adjustments.
Innovation Solution
An image forming apparatus with separate storage units for first and second light intensity adjustment data, allowing for real-time correction of light intensity in the main scanning direction, using optical density sensors to detect toner density and adjust image density at specific points, enabling precise control over image density deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-measured light intensity distribution correction is used, then light intensity deviation is corrected, but flexibility in adjusting image density at arbitrary points is lost
Solution Approach 1:
The correction data is segmented into two distinct types: first correction data for correcting light intensity deviation across the entire scanning direction, and second correction data for adjusting image density at specific arbitrary points. This segmentation allows each type of correction to be applied independently, resolving the contradiction between overall uniformity and local adjustability.
Solution Approach 2:
The system dynamically selects and combines different correction data based on the specific adjustment needs. The control unit can apply first correction data for general light intensity uniformity, second correction data for specific point adjustments, or both together, providing flexible adaptation to various imaging requirements while maintaining correction precision.
2Manufacturing precision
If light intensity distribution is adjusted based on reference toner image detection, then overall toner density is controlled, but arbitrary deviation adjustment in main scanning direction is difficult
Solution Approach 1:
The correction functionality is segmented into overall toner density control (using first correction data) and specific point deviation adjustment (using second correction data). This allows the system to maintain precise toner density control while simultaneously enabling arbitrary deviation adjustment in the main scanning direction.
Solution Approach 2:
The system uses optical density sensors to detect toner density and provides feedback to the control unit, which then applies appropriate correction data. This feedback mechanism enables both overall density control and specific point adjustment by comparing detected values with target values and applying corresponding corrections.
3Device complexity
If single correction data is used for light intensity adjustment, then device complexity is reduced, but ability to correct both light intensity deviation and image density deviation is compromised
Solution Approach 1:
The correction system is segmented into two independent correction data sets: first correction data for light intensity deviation and second correction data for image density deviation. This segmentation, while increasing data structure complexity, actually simplifies the control logic by allowing each correction type to be applied independently through straightforward addition operations.
Solution Approach 2:
The system changes the correction parameters by applying different correction values at different positions in the main scanning direction. First correction data provides baseline light intensity correction, while second correction data adds position-specific adjustments, together achieving precise image density correction without complex control mechanisms.
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 solution allows for precise adjustment of image density deviations in the main scanning direction, improving image quality by ensuring uniform toner density across the scanning area, reducing irregularities and enhancing the capability to form images with desired density profiles.
Implementation Method 1
a light beam from a light source in an optical scanning device is emitted in the main scanning direction by a deflector, is guided by an optical element, and is then emitted from the optical scanning device to the surface of a photosensitive drum
Implementation Method 2
the capability to form an image is adjusted on the basis of the detection result of the amount of toner adhering in a reference toner image
Data Source
AI summary
An image forming apparatus includes a latent image carrier having a surface that moves, an optical writing unit that scans and emits light in a main scanning direction, a developing unit, a first storage unit, a second storage unit, and a control unit. The first storage unit stores first light intensity adjustment data for adjusting the intensity of light emitted from the optical writing unit such that the deviation of the emission intensity of the light in the main scanning direction due to characteristics of the optical writing unit is corrected. The second storage unit stores second light intensity adjustment data which can be set at each irradiation point in the main scanning direction and is for adjusting the intensity of the light emitted from the optical writing unit such that the deviation of image density at an arbitrary irradiation point in the main scanning direction is corrected.