Toner Concentration Control via Sensor Correction
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Solution Overview
Problem
Conventional image forming apparatuses using two-component developers face challenges in accurately controlling toner concentration due to changes in developer stirring/carrying speed and image size ratio, leading to inaccuracies in magnetic permeability sensor output values, which affect image quality and resolution.
Innovation Solution
The apparatus includes a developing device with a stirring and carrying member that adjusts speeds according to image forming modes and an output correction mechanism using difference values between reference and actual output values from a magnetic permeability sensor, along with revision values based on image size ratios to maintain accurate toner concentration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the process linear velocity is changed to support multiple image forming modes, then the adaptability of the image forming apparatus is improved, but the output value of the magnetic permeability sensor varies due to changes in developer stirring/carrying speed, causing measurement precision to deteriorate
Solution Approach 1:
The patent applies parameter changes by detecting the process linear velocity and identifying the corresponding image forming mode, then retrieving a mode-specific correction value from storage. This correction value compensates for the variation in magnetic permeability sensor output caused by different developer stirring/carrying speeds, thereby maintaining measurement precision across multiple image forming modes.
Solution Approach 2:
The patent implements feedback by using the detected process linear velocity to determine the current image forming mode, then applying the appropriate correction value to the sensor output. This closed-loop approach ensures that the toner concentration measurement is continuously adjusted based on the operating conditions, maintaining accuracy despite changes in stirring/carrying speed.
2Productivity
If the developer stirring/carrying speed is adjusted for different image forming modes, then the productivity of the image forming apparatus is improved, but the bulk density of the developer in the detection area changes, causing measurement precision to deteriorate
Solution Approach 1:
The patent addresses this contradiction by storing and applying correction values that correspond to different process linear velocities. When the stirring/carrying speed changes to accommodate different productivity requirements, the appropriate correction value is selected and applied to compensate for the resulting changes in bulk density, thereby maintaining measurement precision across varying productivity levels.
3Ease of operation
If the magnetic permeability sensor is used to detect toner concentration, then the ease of operation is improved, but the reliability of toner concentration control deteriorates when developer bulk density or fluidity changes
Solution Approach 1:
The patent enhances reliability by implementing a feedback mechanism where the detected process linear velocity is used to select the appropriate correction value. This ensures that the toner concentration control system accounts for changes in developer bulk density or fluidity that occur during different image forming modes, maintaining control accuracy while preserving the ease of operation provided by the magnetic permeability sensor.
Solution Approach 2:
The patent applies preliminary anti-action by pre-calculating and storing correction values for different image forming modes before operation. When a mode change occurs, the corresponding correction value is immediately applied to counteract the expected variation in sensor output, preventing reliability deterioration before it can affect toner concentration control.
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 effectively stabilizes toner concentration control across different image forming modes and image size ratios, preventing output value deviations and ensuring consistent image quality and resolution.
Implementation Method 1
a magnetic permeability sensor (a detecting unit). The magnetic permeability sensor recognizes magnetic characteristics of magnetic carriers contained in a developer present in the predetermined detection area as an electric signal
Data Source
AI summary
The image forming apparatus includes a developing device that holds a two-component developer to develop an image, a detecting unit that outputs a reference output value and a second output value when the two-component developer is stirred and carried at a stirring/carrying speed corresponding to a second image forming mode, a stirring/carrying member that stirs and carries the two-component developer, and a controlling unit that controls the toner concentration based on the reference output value when forming an image in a first image forming mode, and controls the toner concentration, when forming an image in the second image forming mode, a corrected output value obtained by correcting an output value in the second image forming mode with a difference value between the reference output value and the second output value.