Image Density Control via Dynamic Measurement Feedback
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Solution Overview
Problem
Existing density correction control methods in electrophotographic image forming apparatuses often perform density correction at unnecessary or missed timings, leading to decreased productivity and image quality due to variations in image forming characteristics not being proportional to the number of image-formed sheets.
Innovation Solution
The apparatus includes a converting unit for image data, a photosensitive member, an exposure unit, a developing unit, a transfer unit, a measuring unit, a generation unit, and determination units to dynamically determine the timing and conditions for forming measurement images, updating light intensity and conversion conditions based on measured data to stabilize image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If density correction control is performed based on a predetermined number of image-formed sheets, then the density correction can be executed periodically, but the correction timing becomes inaccurate leading to decreased productivity and image quality
Solution Approach 1:
The system measures the actual density of measurement images formed on the photosensitive member and uses this feedback to dynamically determine whether density correction is needed. The determination units compare measured density values against reference values to decide on correction execution, ensuring corrections are performed only when actually needed rather than following a fixed schedule.
Solution Approach 2:
The density correction timing and parameters are made dynamic rather than static. The system continuously monitors density variations and adjusts the correction timing and light intensity based on actual measured values. This allows the system to adapt to varying image forming characteristics in real-time, preventing both unnecessary corrections and missed corrections.
2Reliability
If density correction control is performed at unnecessary timing, then the density correction is executed frequently, but the productivity of the image forming apparatus decreases
Solution Approach 1:
The system uses density measurement feedback to determine whether correction is actually needed before executing correction. The first determination unit evaluates whether the measured density deviates beyond acceptable thresholds, and only triggers correction when necessary, avoiding unnecessary corrections that would waste time and reduce productivity.
Solution Approach 2:
The system dynamically changes the correction parameters including light intensity and measurement timing based on actual density measurements. By adjusting these parameters according to real-time feedback, the system optimizes the correction process to occur only when and how it is needed, minimizing productivity loss.
3Productivity
If density correction control is not performed at a necessary timing, then the productivity is maintained, but the quality of output images decreases
Solution Approach 1:
The continuous density measurement and feedback mechanism ensures that corrections are triggered at the exact moment they are needed. The system monitors density variations and immediately initiates correction when deviations exceed thresholds, preventing quality degradation while maintaining productivity by avoiding unnecessary corrections.
Solution Approach 2:
The system performs preliminary density measurements and evaluations to predict when correction will be needed, allowing it to prepare and execute corrections at the optimal timing. This preliminary monitoring ensures corrections are made just in time to maintain quality without disrupting productivity.
4Measurement precision
If multiple measurement images are formed and measured, then the density correction accuracy is improved, but the time and complexity of the correction process increases
Solution Approach 1:
The measurement process is segmented into multiple measurement images with different patterns (e.g., different densities, colors, or positions). Each measurement image targets specific density characteristics, and the results are combined to achieve comprehensive and accurate density evaluation. This segmentation improves measurement precision while keeping the process manageable through systematic organization.
Solution Approach 2:
The measurement system is designed to serve multiple functions simultaneously - measuring different density levels, different colors, and different positions on the photosensitive member using a set of measurement images. This multi-functionality approach improves comprehensive measurement accuracy without proportionally increasing system complexity, as the same measurement infrastructure handles multiple measurement objectives.
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 ensures timely and necessary density correction, maintaining image quality and productivity by adjusting exposure light intensity and conversion conditions in response to measured image density variations, thereby stabilizing output image density.
Implementation Method 1
an exposure unit configured to emit light based on a set light intensity and to expose the photosensitive member to the light based on the converted image data to form an electrostatic latent image
Data Source
AI summary
An image forming apparatus includes: a measuring unit configured to measure a plurality of measurement images, the plurality of measurement images including a first measurement image and second measurement images; a generation unit configured to generate a conversion condition based on second measurement data corresponding to the second measurement images; a first determination unit configured to determine an execution condition based on first measurement data corresponding to the first measurement image; and a second determination unit configured to determine a light intensity based on the first measurement data. A subsequent timing when the plurality of measurement images are to be formed is determined based on the execution condition, and an exposure unit updates the set light intensity to the light intensity determined by the second determination unit when the plurality of measurement images are formed at the subsequent timing.