Image Forming Apparatus Toner Replenishment Control
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Solution Overview
Problem
In image forming apparatuses, large toner replenishment often results in insufficient agitation of carrier and toner, leading to inadequate toner charging, which affects image quality.
Innovation Solution
The apparatus independently controls the rotational frequency of the developing roller and agitating rollers based on toner concentration, adjusting the ratio of their rotational frequencies to ensure sufficient toner agitation and charging during replenishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of toner is replenished from a toner cartridge, then the toner concentration is restored, but the carrier and toner are not agitated sufficiently, resulting in inadequate toner charging
Solution Approach 1:
The patent applies dynamics by making the rotational speed of the agitating roller variable rather than fixed. The control unit adjusts the rotational speed based on the replenishment amount detected by the toner concentration sensor. When large amounts of toner are replenished, the agitating roller rotates faster to ensure sufficient agitation and charging, resolving the contradiction between replenishment quantity and agitation effectiveness.
2Reliability
If the rotational frequency of the agitating roller is increased to improve toner agitation, then sufficient toner charging is achieved, but the device complexity increases
Solution Approach 1:
The patent implements feedback control where the toner concentration sensor continuously monitors the toner concentration in the developing device and provides this information to the control unit. The control unit then adjusts the rotational speed of the agitating roller based on this feedback. This closed-loop feedback system ensures reliable toner charging without requiring overly complex control mechanisms, as the system automatically adapts to actual toner replenishment conditions.
3Loss of time
If toner replenishment is performed quickly to reduce replenishment time, then productivity is improved, but the carrier and toner are not agitated sufficiently
Solution Approach 1:
The patent resolves the time-quality contradiction by dynamically adjusting the agitating roller's rotational speed during the replenishment process. Rather than using a fixed slow speed that ensures charging but takes time, or a fixed fast speed that is quick but insufficient for charging, the system varies the speed based on real-time toner concentration measurements, achieving both speed and quality.
Solution Approach 2:
The patent changes the operational parameter (rotational speed of the agitating roller) based on the replenishment condition. When the toner concentration sensor detects that a large amount of toner has been replenished, the system increases the rotational speed parameter to ensure proper agitation and charging, thereby maintaining reliability while minimizing replenishment time.
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 a sufficient toner charging amount, improving image quality and reducing toner replenishment time, especially during high print ratio operations.
Implementation Method 1
a developing device which includes an agitating roller to agitate developer
Implementation Method 2
a developing roller to transfer toner of the developer on a surface of the image carrier
Implementation Method 3
an exposure portion to expose a surface of an image carrier to form an electrostatic latent image
Data Source
AI summary
An image forming apparatus that includes an exposure portion to expose a surface of an image carrier to form an electrostatic latent image; a developing device which includes an agitating roller to agitate developer, a developing roller to transfer toner of the developer on a surface of the image carrier and a toner concentration sensor to detect a toner concentration, the developing device developing the electrostatic latent image formed on the image carrier to form a toner image; a drive source to independently drive to rotate the developing roller and the agitating roller; and a control unit to control the drive source to change a rotational frequency of at least one of the developing roller and the agitating roller depending on the toner concentration detected by the toner concentration sensor.