Laser Beam Position Correction for Color Deviation in Image Forming
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Solution Overview
Problem
In image forming apparatuses, predicting and correcting color deviations caused by laser beam irradiation position fluctuations is challenging, especially in complex optical units where temperature changes do not exhibit a straightforward correlation with irradiation position changes, leading to difficulties in maintaining high-quality image formation.
Innovation Solution
An image forming apparatus with a deviation amount calculator that calculates and adjusts the laser beam irradiation positions for each color based on a sophisticated algorithm, using parameter values specific to each color and operating mode, allowing for precise prediction and correction of color deviations regardless of the correlation between temperature changes and irradiation position fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If temperature sensor-based correction methods are used to correct laser beam irradiating position, then color deviation can be corrected without calibration, but the method fails when temperature change and color deviation tendency cannot be approximated by one-to-one correspondence relation
Solution Approach 1:
The patent changes the correction approach from temperature-based to time-based parameter control. Instead of using temperature sensor readings to determine correction amounts, the system uses elapsed time since the last calibration as the primary parameter, combined with operating mode information, to calculate and apply appropriate correction values for laser beam irradiating position.
Solution Approach 2:
The patent creates a virtual model of thermal shift behavior through pre-stored correction data. Rather than directly measuring and responding to actual temperature changes, the system uses predetermined correction values that replicate expected thermal shift patterns under various operating conditions, allowing accurate correction without direct temperature correlation.
2Manufacturing precision
If calibration is performed frequently to ensure accurate laser beam irradiating position, then color deviation is minimized, but calibration time and consumable usage increase
Solution Approach 1:
The patent performs preliminary correction by pre-calculating and storing correction values for various time intervals and operating modes before actual printing occurs. This allows the system to apply appropriate corrections during normal operation without requiring frequent time-consuming calibration procedures, as the correction data is prepared in advance based on predicted thermal shift behavior.
3Volume of moving object
If complex optical units with multiple mirrors and lenses are used to achieve compact size, then miniaturization is accomplished, but thermal shift characteristics become non-linear and difficult to predict
Solution Approach 1:
The patent extracts the thermal shift correction problem from the complex optical system and handles it at the control software level. Instead of attempting to model and correct each individual optical element's thermal behavior, the system extracts the overall effect as a function of time and operating mode, applying a unified correction approach that bypasses the need to understand the complex internal thermal dynamics of the compact optical unit.
4Device complexity
If one optical unit scans multiple laser beams for different colors, then device complexity is reduced, but each color exhibits different thermal shift tendencies making correction difficult
Solution Approach 1:
The patent segments the correction approach by creating separate correction data sets for each color (yellow, magenta, cyan, black) and each operating mode. The system stores and applies color-specific correction values that account for the unique thermal shift characteristics of each color channel, allowing the compact optical unit to maintain accurate color alignment despite different thermal behaviors.
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 enables precise prediction and correction of color deviations, ensuring high-quality image creation with minimal color deviation, even in complex optical units with non-linear thermal shift characteristics, by flexibly coping with varied thermal shift patterns across different colors and operating modes.
Implementation Method 1
a fluctuation in laser beam irradiating position on a photosensitive material which occurs in association with a thermal deformation of an optical unit
Implementation Method 2
a temperature sensor and a color deviation correcting unit for presuming the fluctuation in laser beam irradiating position based on an output of the temperature sensor
Data Source
AI summary
The invention has an image forming apparatus with a deviation amount calculator for obtaining, by an arithmetic operation, by an arithmetic operation, the deviation amount between the laser beam irradiating positions for each color, under the condition that the deviation amount increases gradually according to a time lapse in at least one of the plurality of operating modes, according with a further time lapse, the deviation amount between the laser beam irradiating positions for each color decreases gradually, and according with a further time lapse, the deviation amount between the laser beam irradiating positions for each color is converged.