Developing Device Toner Concentration Control
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Solution Overview
Problem
Conventional trickle developing devices face issues with fluctuations in toner concentration and developer volume, leading to uneven supply and reduced image quality due to inaccurate toner concentration detection and delayed replenishment.
Innovation Solution
A developing device with stirring members, a toner concentration detecting sensor, and a control unit that adjusts the reference toner concentration dynamically to facilitate timely replenishment, preventing volume level drops and maintaining consistent image formation.
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 carrier is maintained, but the toner concentration detection accuracy is insufficient leading to incorrect replenishment control
Solution Approach 1:
The patent implements a feedback control mechanism where the toner concentration detecting sensor continuously monitors developer composition and the control unit adjusts replenishment based on detected values. Although measurement accuracy is limited, the feedback loop allows the system to adapt and maintain acceptable charging performance through continuous adjustment rather than single-point control.
Solution Approach 2:
The patent changes the control parameter from direct toner concentration control to developer volume level control. By maintaining constant developer volume through discharge mechanisms while allowing toner concentration to fluctuate within acceptable ranges, the system compensates for detection inaccuracies and maintains reliable charging performance.
2Stability of the object's composition
If the toner concentration is detected to be higher than reference concentration, then replenishment is delayed to maintain concentration balance, but the developer volume level lowers indicating insufficient developer
Solution Approach 1:
The patent separates the control of toner concentration from the control of developer volume. The toner concentration is managed through selective replenishment of toner versus carrier, while developer volume is independently maintained through a discharge mechanism. This segmentation allows simultaneous optimization of both parameters despite their interdependence.
Solution Approach 2:
The patent implements preliminary discharge of deteriorated developer before toner concentration becomes critically low. By proactively removing spent carrier and maintaining volume levels, the system prevents the situation where delayed replenishment leads to volume depletion, ensuring continuous adequate developer supply.
3Stability of the object's composition
If the stirring screw conveys developer in the longitudinal direction while stirring, then the developer is mixed, but uneven supply to the developing roller occurs causing screw irregularity phenomenon
Solution Approach 1:
The patent extracts the conveying function from the stirring screw, separating mixing and supply functions. The stirring screw is dedicated solely to mixing developer components, while a separate developer supply mechanism handles conveyance to the developing roller. This eliminates the screw irregularity phenomenon caused by the dual-function design.
Solution Approach 2:
The patent introduces an intermediary developer supply mechanism between the stirring chamber and the developing roller. This intermediary component receives uniformly mixed developer from the stirring screw and delivers it to the roller, decoupling the mixing action from the supply action and preventing uneven distribution.
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 solution ensures stable toner concentration and developer volume, enhancing long-term image formation quality by preventing screw irregularity and maintaining high-quality image output.
Implementation Method 1
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
Implementation Method 2
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
Data Source
AI summary
A developing including a developer replenishing tank for replenishing a replenishment developer to a developer tank; a toner concentration detecting sensor; a discharging mechanism for discharging an excessive amount of the developer-tank-contained developer outside the developer tank when the amount of the developer-tank-contained developer inside the developer tank exceeds a predetermined amount; and control unit having a memory for storing the current toner concentration inside the developer tank, the reference toner concentration inside the developer tank, a corrected reference toner concentration calculated according to the formula of (the current toner concentration —a correction value), a predetermined replenishment amount to the developer tank and an allowable value for the current toner concentration with respect to the reference toner concentration, and a computer for calculating the corrected reference toner concentration and comparing the current toner concentration with the reference toner concentration and the corrected reference toner concentration.