Image Density Correction via Sensor Conversion Tables
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Solution Overview
Problem
Image forming apparatuses face challenges in accurately correcting image density due to measurement errors from sensors, leading to inconsistencies in the desired image density, especially when environmental conditions or sensor calibration change.
Innovation Solution
The implementation of a control method and apparatus that utilizes a density detection sensor with a light-emitting diode and photodiodes to measure image density, coupled with conversion tables and gamma look-up tables to correct image data, allowing for real-time adjustments and compensation for measurement errors, ensuring accurate density control across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to measure image density for correction, then correction control can be performed, but measurement errors occur leading to inaccurate density correction
Solution Approach 1:
The patent introduces an intermediary conversion process that transforms sensor output values through conversion tables and gamma LUTs before applying correction. This intermediary step allows for error compensation and more accurate density correction despite sensor measurement errors.
Solution Approach 2:
The patent changes the parameter representation by converting sensor output values through multiple transformation stages (conversion tables, gamma LUTs) rather than using raw sensor values directly. This parameter transformation enables more accurate correction control.
2Adaptability or versatility
If correction condition is adjusted based on sensor measurement, then image density can be controlled, but environmental conditions or sensor calibration changes cause inconsistency
Solution Approach 1:
The patent implements a feedback mechanism where sensor measurements are continuously converted and used to adjust correction conditions. The conversion tables and gamma LUTs provide a stable reference framework that maintains consistency while adapting to changing conditions through iterative correction.
Solution Approach 2:
The patent performs preliminary conversion of sensor output values through conversion tables and gamma LUTs before applying correction. This preliminary processing establishes a stable reference framework that maintains measurement consistency even when environmental conditions change.
3Device complexity
If direct sensor measurement is used for correction, then the process is simple, but measurement errors cannot be compensated
Solution Approach 1:
The patent segments the correction process into distinct stages: sensor output conversion through conversion tables, gamma correction via LUTs, and final correction application. This segmentation allows each stage to be optimized independently while maintaining overall simplicity.
Solution Approach 2:
The patent introduces intermediary conversion tables and gamma LUTs that act as mediators between raw sensor measurements and correction application. These intermediaries enable error compensation without significantly increasing operational complexity.
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 enables precise correction of image density, reducing measurement errors and maintaining desired image quality even when environmental conditions or sensor calibration changes occur, thereby ensuring consistent and accurate image formation.
Implementation Method 1
a density detection sensor 5 having a light-emitting diode 51 and photodiodes 52, 53
Implementation Method 2
photodiodes 52, 53 that receive the light L and output sensor output values corresponding to the intensity of the light L
Data Source
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AI summary
An image forming apparatus includes: correction means (60) correcting image data based on a correction condition; image forming means (10) forming an image based on the corrected image data; transfer means (9) transferring the image onto a sheet (P); measuring means (5) measuring a measurement image on an image bearing member (6); converting means (30) converting a measurement result of the measurement image, based on a conversion condition; first generating means (30) generating the correction condition based on the converted measurement result; acquiring means (30) acquiring a measurement result of a test image formed on the image bearing member; controller (30) forming a test image on the sheet; receiving means (80) receiving instruction based on user comparison of a sample image and the test image transferred on the sheet; and second generating means (30) generating the conversion condition, based on the instruction and the acquired measurement result of the test image.