Toner Supply Control for Density Stabilization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional image forming apparatuses face usability issues after toner bottle replacement, as they cannot be used immediately due to rapid changes in toner density, leading to color changes and potential overshoots in toner supply, which are difficult to control without performing a toner density recovery sequence.

Innovation Solution

The apparatus implements a toner supply control method that restricts toner supply in the initial period after toner bottle replacement, using adjusted coefficients to gradually stabilize the toner density, preventing rapid increases in the TD ratio and allowing immediate image formation without compromising the target density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If image forming is allowed immediately after toner bottle exchange without toner density recovery sequence, then usability is improved, but toner density ratio (TD ratio) rapidly increases causing density change per sheet and color change

Engineering Contradiction:
ImproveusabilityVSAvoiddensity control precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the toner supply control adaptive and variable based on system state. The supply restricted mode dynamically adjusts toner supply parameters (such as supply amount or supply frequency) based on the detected TD ratio, allowing the system to transition from a static control mode to a dynamic one that responds to real-time conditions, thereby resolving the contradiction between immediate usability and density control precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameters of toner supply by introducing a supply restricted mode with modified supply parameters. When the TD ratio exceeds the target value after toner bottle exchange, the system switches to restricted mode where toner supply parameters are adjusted (reduced or limited) to prevent overshoot and rapid density changes, thus maintaining manufacturing precision while allowing immediate operation.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If toner density recovery sequence is performed after toner bottle exchange, then TD ratio control precision is improved, but image forming operation is delayed

Engineering Contradiction:
ImproveTD ratio control precisionVSAvoidoperation delay
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by implementing a restricted toner supply mode rather than completely stopping toner supply or performing a full recovery sequence. The supply restricted mode partially limits toner supply parameters to prevent excessive TD ratio increase while still allowing image forming to proceed, thus avoiding complete operation delay while maintaining sufficient control precision.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs preliminary action by detecting the TD ratio immediately after toner bottle exchange and proactively switching to supply restricted mode before significant density deviations occur. This preliminary detection and response prevents the need for lengthy recovery sequences by addressing potential TD ratio issues at their inception, reducing operation delay while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If target TD ratio is lowered to suppress rapid TD ratio rise, then TD ratio stability is improved, but initial TD ratio deviates significantly from desired TD ratio

Engineering Contradiction:
ImproveTD ratio stabilityVSAvoidTD ratio accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent uses dynamics by making the target TD ratio flexible rather than fixed. The system dynamically adjusts the target TD ratio based on operational context: using the normal target value when stable and switching to a restricted supply mode with adjusted target when detecting post-exchange conditions. This dynamic adjustment maintains both stability during normal operation and accuracy during transition periods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies segmentation by dividing the toner supply control into distinct modes: normal mode with standard target TD ratio and supply restricted mode with adjusted parameters. This segmentation allows the system to apply different control strategies appropriate to different operational states, maintaining TD ratio accuracy during exchange transitions while preserving stability during normal operation.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2866096B1Image forming apparatus
Publication Date: 2020.06.24 CANON KK
  • EP2866096B1 patent drawingFigure 1
  • EP2866096B1 patent drawingFigure 2
  • EP2866096B1 patent drawingFigure 3

AI summary

An image forming apparatus which prohibits an image forming operation based on a detection result of a remaining amount detecting means (26), thereafter immediately allows the image forming operation based on a detection result of a replacement detecting means (86), performs a supply restriction mode which restricts a toner supply amount such that a toner supply amount in a predetermined initial period after allowance of an image forming is smaller than a normal mode in a case where a detection result of a toner density detecting means (26) and a target value are under same conditions, respectively.