Developing Unit Toner Supply Control for High-Chroma Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-chroma printing in electrophotographic image forming apparatuses leads to increased toner consumption and deterioration, resulting in toner retention between the photosensitive drum and developing roller, which can cause striped images when printing large areas with high color density.
Innovation Solution
An image forming apparatus with a setting unit to increase the rotation speed of the developing unit relative to the image bearing member, a determining unit to assess the remaining toner amount, and a bias changing unit to reduce development bias when the toner is low, thereby optimizing toner supply and preventing image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rotation speed of the developing unit is increased relative to the image bearing member to increase toner supply, then the color density of the output image is improved, but the remaining life of toner cartridges is decreased and toner deteriorates over time
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the development bias based on the remaining toner amount. When toner remains abundant, a higher development bias is applied to achieve high color density. When toner becomes scarce, the development bias is reduced to prevent toner retention and striped images, thus adapting the printing parameters to the current toner state
Solution Approach 2:
The patent implements feedback control by monitoring the remaining toner amount and using this information to adjust the development bias. The determining unit detects the toner level, and the bias changing unit modifies the development bias accordingly, creating a closed-loop control system that prevents toner deterioration and striped images while maintaining optimal color density when possible
2Manufacturing precision
If the development bias is increased to increase color density in high-chroma printing, then the chroma of the image is improved, but toner is retained between the photosensitive drum and the developing roller causing striped images
Solution Approach 1:
The patent changes the development bias parameter dynamically based on toner availability. When toner is abundant, a high development bias is applied to achieve maximum color density. When toner becomes scarce, the development bias is reduced to prevent toner retention between the photosensitive drum and developing roller, thereby eliminating striped images and maintaining image quality
Solution Approach 2:
The patent makes the development bias dynamic rather than fixed. The bias is adjusted in real-time based on the remaining toner amount detected by the determining unit. This dynamic adjustment allows the system to optimize between color density and image quality depending on the current toner state, preventing the harmful effect of toner retention
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 high-chroma printing by maintaining optimal toner supply and reducing image defects caused by toner retention, thereby enhancing print quality and extending toner cartridge life.
Implementation Method 1
developing the electrostatic latent image by attaching toner onto the image bearing member by using a developing unit
Data Source
AI summary
A development bias to be applied onto a developing unit is reduced, in a case where it is determined that a remaining amount of toner is equal to or less than a threshold, in a mode in which a rotation speed of a developing unit is faster than a rotation speed of an image bearing member to increase an amount of toner to be supplied to the image bearing member.