Image Forming Apparatus Supply Bias Control for Toner Charge Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image forming apparatuses face issues with toner charge accumulation on the development roller, leading to reduced image density due to 'development ghost' phenomena, especially when long blank spaces are printed, causing uneven toner distribution and decreased image quality.
Innovation Solution
An image forming apparatus with a control unit that analyzes non-image regions and adjusts the supply bias dynamically based on the length of these regions to manage toner charge, ensuring optimal toner collection and distribution during image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If toner collection processing is performed for one full rotation of the development roller to suppress development ghost, then image density uniformity is improved, but downtime increases and productivity decreases
Solution Approach 1:
The supply bias is adjusted in advance before entering the non-image region to prepare for toner collection, and restored before the next image region. This preliminary action allows toner collection to occur during blank spaces without requiring a full rotation停顿, thus improving productivity while maintaining image density uniformity
Solution Approach 2:
The supply bias is dynamically adjusted based on the length of non-image regions. When blank spaces are detected, the supply bias is increased to enhance toner collection; when image regions are present, the supply bias is restored to normal levels. This dynamic adjustment allows the system to adapt to varying sheet intervals and maintain consistent image quality without fixed downtime
2Duration of action of stationary object
If toner remains on the development roller for a long time during blank spaces, then the amount of charge of toner increases proportionally, but this leads to development ghost and reduced image density
Solution Approach 1:
The supply bias is increased in advance when a non-image region of sufficient length is detected, creating an electrostatic field that actively collects toner from the development roller surface before the toner can accumulate excessive charge. This preliminary collection action prevents the development ghost effect
Solution Approach 2:
The supply bias parameter is changed from its normal value to a higher collection bias value during non-image regions. This parameter change modifies the electrostatic field strength to enhance toner collection, thereby controlling toner charge accumulation and preventing image density variations
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 suppresses the development ghost effect by controlling toner charge on the development roller, maintaining consistent image density and improving overall image quality even with varying sheet intervals and blank spaces.
Implementation Method 1
The charged toner is supplied to the development roller, and is supplied to the electrostatic latent image on the photosensitive member
Implementation Method 2
the toner is charged due to friction as a result of mechanical frictional sliding of the supply roller and the development roller
Implementation Method 3
the supply of the toner from the supply roller to the development roller and the collection of the toner from the development roller to the supply roller are performed using electrostatic force
Data Source
AI summary
An image forming apparatus includes: a development unit configured to develop, using a developer, the electrostatic latent image formed on an image carrier and form a developer image in a region where the image carrier faces the development unit; a supply unit configured to output a supply bias, supply the developer to the development unit, and collect the developer from the development unit; a reception unit configured to receive image data; an analysis unit configured to analyze a non-image region where the developer image is not formed from the image data; and a control unit configured to control the supply bias in accordance with a length of the non-image region where the developer image is not formed in a rotation direction of the image carrier.