Image Density Control via Feedback Adjustment in Electrophotography
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Solution Overview
Problem
The charge amount of the developer in electrophotographic image forming apparatuses varies due to temperature, humidity, and agitation time, leading to inconsistent image density, especially when updating conversion conditions between image formations.
Innovation Solution
An image forming apparatus with a conversion unit, measurement unit, and feedback mechanism that determines and updates image forming conditions based on multiple measurement images to maintain consistent image density by adjusting the conversion condition before the next image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conversion condition is updated frequently to correct density characteristics, then image density accuracy is improved, but density consistency between successive images deteriorates
Solution Approach 1:
The patent applies preliminary action by determining image forming conditions in advance based on measurement results before actual image formation occurs. The feedback condition is pre-calculated and stored, allowing the conversion condition to be updated smoothly without causing sudden density changes between successive images.
Solution Approach 2:
The patent implements feedback by measuring actual image density using a measurement unit, comparing it with target density, and using the difference to calculate a feedback condition. This feedback condition then modifies the conversion condition for subsequent images, creating a closed-loop control system that maintains density consistency while correcting accuracy.
2Manufacturing precision
If the conversion condition is updated after Nth page image formation, then density correction is achieved, but density fluctuation between Nth and (N+1)th pages increases
Solution Approach 1:
The patent determines image forming conditions and calculates feedback conditions in advance based on measurement results before the actual image formation process. This preliminary determination allows the conversion condition to be updated smoothly, preventing sudden density fluctuations when transitioning from the Nth to (N+1)th page.
Solution Approach 2:
The patent makes the conversion condition dynamic by continuously adjusting it based on real-time measurement results and feedback conditions. This dynamic adjustment allows the system to adapt to changing developer charge amounts and environmental conditions, maintaining density stability across successive pages while achieving accurate density correction.
3Device complexity
If developer charge amount is not controlled, then device simplicity is maintained, but image density consistency deteriorates
Solution Approach 1:
The patent uses a feedback mechanism where measurement results of actual image density are continuously monitored and fed back to adjust the conversion condition. This feedback loop compensates for variations in developer charge amount without requiring complex direct control of the developer charging process, maintaining device simplicity while achieving density consistency.
Solution Approach 2:
The patent changes the conversion condition parameter dynamically based on measurement results and feedback conditions. By adjusting this key parameter, the system compensates for variations in developer charge amount and environmental factors, maintaining image density consistency without needing to directly control or monitor every physical parameter of the developer charging process.
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 fluctuations in image density by dynamically adjusting the conversion condition based on measurement results, ensuring consistent image quality even with changes in developer charge amount.
Implementation Method 1
An electrophotographic image forming apparatus forms an image by converting image data based on a conversion condition, and forming an electrostatic latent image on a photosensitive member based on the converted image data
Implementation Method 2
a measurement unit configured to measure a plurality of measurement images formed by the image forming unit
Data Source
AI summary
An image forming apparatus includes a conversion unit configured to convert image data based on a conversion condition, an image forming unit configured to be controlled based on an image forming condition, and to form an image based on the converted image data, a measurement unit configured to measure a plurality of measurement images, a first determination unit configured to determine the image forming condition based on a first measurement result of a first measurement image, a generation unit configured to generate the conversion condition based on second measurement results of second measurement images and a feedback condition, and a second determination unit configured to determine the feedback condition based on the first measurement result. The image forming unit sets the determined image forming condition in next timing. The conversion unit updates the conversion condition after the generation unit generates the conversion condition and before the next timing.