Toner Replenishment Control for Image Density Stability
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Solution Overview
Problem
Conventional image forming apparatuses face issues with toner replenishment, where the ratio of toner to developer in the containing unit does not reach the target value due to errors in predicting toner consumption, leading to inadequate or delayed toner replenishment, especially when switching from images that consume small amounts of toner to those that consume large amounts.
Innovation Solution
The solution involves a toner replenishment control system that determines the toner replenishment amount based on the toner consumption amount and density, using an inductance sensor to detect the toner-to-developer ratio and a cumulative value to adjust the replenishment amount, ensuring timely replenishment even when transitioning from low to high toner consumption images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If toner replenishment amount is determined based on theoretically calculated toner consumption amount, then toner replenishment can be performed, but the ratio of toner to developer in the containing unit does not reach the target value due to prediction errors
Solution Approach 1:
The patent applies feedback by detecting the actual toner to developer ratio in the containing unit and using this detected value to correct the toner replenishment amount. The control unit adjusts the replenishment amount based on the difference between the actual ratio and the target ratio, thereby achieving precise control of the toner to developer ratio despite initial prediction errors.
2Manufacturing precision
If correction amount is negative when toner to developer ratio is higher than target value, then toner replenishment amount is suppressed, but the containing unit is prevented from being replenished when images consuming large amount of toner are formed subsequently
Solution Approach 1:
The patent applies preliminary action by calculating and storing the correction amount in advance based on the detected toner to developer ratio, before the actual toner replenishment is needed. When an image requiring large toner consumption is detected, the system can immediately apply the pre-calculated correction amount without delay, ensuring timely replenishment while maintaining ratio control.
Solution Approach 2:
The patent applies dynamics by making the correction amount adjustable and updateable in real-time. The control unit dynamically adjusts the correction amount based on the current toner to developer ratio and the toner consumption characteristics of the image to be formed, allowing the system to adapt to changing conditions and prevent both overshoot and undershoot of the target ratio.
3Ease of operation
If toner replenishment amount is calculated based on predicted toner consumption and correction amount, then toner replenishment can be controlled, but the toner density varies when transitioning from low consumption to high consumption images
Solution Approach 1:
The patent uses feedback to continuously monitor the toner to developer ratio and adjust the replenishment amount accordingly. When transitioning from low to high consumption images, the system detects the ratio change and applies appropriate correction amounts to maintain stable toner density, preventing variations that would otherwise occur during image type transitions.
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 allows for precise control of toner replenishment, maintaining the toner density at the target value, preventing overshoot or undershoot, and stabilizing the image density formed by the image forming apparatus.
Implementation Method 1
an inductance sensor to detect the toner-to-developer ratio
Data Source
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AI summary
An image forming apparatus comprising: an image forming unit including a containing unit; a replenishment means configured to replenish the containing unit with toner; a first determination means configured to determine an amount of the toner consumed in the containing unit; a detection means configured to detect a toner amount in the containing unit; a first calculation means configured to calculates a difference between the toner amount and a target amount; a second calculation means configured to calculate a cumulative value of the difference; a second determination means configured to determine a determination value used for determining whether the replenishment means replenishes the containing unit with toner, based on the consumption amount determined by the first determination means, the difference calculated by the first calculating means, and the cumulative value calculated by the second calculating means; and a controller configured to control the replenishment means based on the determination value determined by the second determination means, wherein in a case where a determination value at a first timing, which is determined by the second determination means at the first timing, is less than a threshold, the second calculating means is prevented, at a second timing following the first timing, from accumulating the difference calculated by the first calculating means on the cumulative value calculated at the first timing.