Trickle Developing Device Toner Concentration Control
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Solution Overview
Problem
Conventional trickle developing devices using two-component developers face issues with toner concentration fluctuations and volume level changes, leading to uneven developer supply and poor image quality due to inaccurate toner concentration detection and insufficient developer replenishment.
Innovation Solution
A developing device with stirring members, a toner concentration detecting sensor, a discharging mechanism, and a control unit that performs forced consumption and replenishment operations to maintain optimal toner concentration and developer level, using a developer replenishing tank and a developer holder to supply fresh developer and remove excess, thereby preventing screw irregularity and ensuring consistent image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the volume level of developer inside the developing device is maintained approximately constant by discharging excessive deteriorated developer, then the charging performance of the carrier is maintained, but the toner concentration becomes inaccurate leading to uneven supply
Solution Approach 1:
The patent changes the developing device from a static volume-maintenance system to a dynamic toner-concentration-controlled system. The control unit continuously monitors toner concentration and dynamically adjusts the replenishment amount of fresh developer, allowing the volume level to fluctuate within a range while maintaining accurate toner concentration. This resolves the contradiction by making the system adaptive rather than rigid.
Solution Approach 2:
The patent introduces a feedback control mechanism where the toner concentration detecting sensor continuously monitors the actual toner concentration in the developer, and the control unit uses this feedback information to adjust the replenishment amount. This closed-loop control ensures that toner concentration remains accurate even as the volume level changes, preventing the screw irregularity phenomenon.
2Duration of action of stationary object
If fresh developer is gradually replenished and deteriorated developer is discharged to maintain constant volume, then carrier charging capability is maintained, but toner concentration detection accuracy is insufficient leading to poor image quality
Solution Approach 1:
The patent employs a feedback control system where the toner concentration detecting sensor provides continuous monitoring data to the control unit. The control unit processes this feedback and adjusts the replenishment amount accordingly, ensuring that toner concentration remains within the optimal range for high-quality image formation throughout the developer's life cycle.
Solution Approach 2:
The patent performs preliminary replenishment of fresh developer based on predicted toner concentration trends and usage patterns. By proactively adjusting the developer composition before concentration deviations occur, the system maintains optimal toner concentration and prevents image quality degradation.
3Stability of the object's composition
If the volume level of developer is maintained constant, then the developing device operates stably, but when toner concentration is detected high, developer replenishment is delayed causing volume to drop and creating uneven supply
Solution Approach 1:
The patent transitions from a static volume-maintenance approach to a dynamic concentration-control approach. The control unit continuously monitors toner concentration and dynamically adjusts both the replenishment amount and timing, allowing the volume level to vary within an acceptable range while maintaining optimal toner concentration for high-quality image formation.
Solution Approach 2:
The patent changes the primary control parameter from volume level to toner concentration. By monitoring and controlling toner concentration rather than volume, the system can replenish developer more frequently in smaller amounts, maintaining both volume stability and concentration accuracy, thereby preventing screw irregularity.
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
The solution effectively stabilizes toner concentration and developer level, preventing uneven supply and maintaining high-quality image formation by continuously monitoring and adjusting the developer amount, thus enhancing the longevity and performance of the developing device.
Implementation Method 1
The concentration of the toner inside the developing device is detected using, for example, a toner concentration detecting sensor that detects the permeability of the developer.
Implementation Method 2
stirring members for stirring a developer-tank-contained developer containing toner and carrier inside a developer tank while conveying the developer
Implementation Method 3
the two-component developing system in which toner and carrier are used as the main components of the developer, in which the toner and carrier are charged by friction contact therebetween to predetermined polarities
Data Source
AI summary
A developing device and an image forming apparatus capable of carrying out image formation for a long period by making fluctuations in toner concentration and volume level of the developer inside a trickle developing device that uses a two-component developer as small as possible. The developing device, containing a developer and a developer holder, includes a developer replenishing tank; a toner concentration detecting sensor, a trickle discharging mechanism, developer amount detecting member, and control unit for controlling the replenishment operation of replenishment toner and carrier at the time when the toner concentration is lower than a predetermined reference toner concentration, wherein the control unit carries out forced consumption operation for the toner inside the developer tank and replenishment operation for the replenishment toner and carrier in the case that the amount of the developer-tank-contained developer inside the developer tank is judged to be low using the developer amount detecting member.