Developing Roller Speed Ratio Control for Abnormal Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image forming apparatuses using electrophotographic methods face issues with abnormal discharge occurring upstream of the primary transfer portion due to uneven toner deposition and varying toner charge amounts, leading to defective images and reduced cartridge durability.
Innovation Solution
The apparatus incorporates a control system that adjusts the circumferential speed ratio of the developing roller to the photosensitive drum and the potential difference between them, allowing for two modes: a first mode prioritizing cartridge durability and a second mode minimizing abnormal discharge, by controlling the peripheral speed ratio and developing contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the peripheral speed of the developing roller is made slower than the peripheral speed of the photosensitive drum to reduce running distance and extend cartridge life, then cartridge durability is improved, but abnormal discharge occurs upstream from the primary transfer portion due to uneven toner deposition
Solution Approach 1:
The patent applies dynamics by making the peripheral speed ratio of the developing roller adjustable rather than fixed. The speed ratio can be dynamically changed between a first value (greater than or equal to 100%) and a second value (less than 100%) based on printing conditions, allowing the system to adapt between extending cartridge life and preventing abnormal discharge as needed
Solution Approach 2:
The patent changes the parameter of peripheral speed ratio to resolve the contradiction. By adjusting this parameter between different ranges (≥100% vs <100%), the system can control both cartridge durability and abnormal discharge prevention, transforming a static design into a controllable process
2Length of moving object
If the peripheral speed of the developing roller is made slower to reduce running distance, then the distance of the developing roller is shortened, but toner deposition becomes uneven leading to abnormal discharge
Solution Approach 1:
The system dynamically adjusts the peripheral speed ratio based on printing conditions. When high-quality toner deposition is required, the speed ratio is set to the first value (≥100%) which ensures uniform toner application. When cartridge life extension is the priority, the second value (<100%) is used, accepting some trade-off in deposition uniformity
Solution Approach 2:
The peripheral speed ratio parameter is changed between two distinct ranges to control both the running distance and toner deposition quality. This parameter change allows the system to optimize for different operational priorities
3Reliability
If the peripheral speed of the developing roller is increased to improve toner deposition uniformity, then abnormal discharge is suppressed, but the running distance of the developing roller increases reducing cartridge life
Solution Approach 1:
The system uses dynamic speed ratio adjustment to balance reliability and cartridge life. The control unit selects the appropriate speed ratio based on printing conditions, allowing the system to achieve abnormal discharge suppression when needed while maintaining reasonable cartridge longevity
Solution Approach 2:
By changing the peripheral speed ratio parameter to the first value (≥100%), the system improves toner deposition uniformity and suppresses abnormal discharge. This parameter change comes with the trade-off of increased running distance but can be applied selectively based on operational requirements
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 approach effectively suppresses abnormal discharges and maintains cartridge durability by optimizing toner deposition and consumption, allowing for reliable image formation across various printing conditions.
Implementation Method 1
an exposure means configured to form an electrostatic latent image on a surface of the image bearing member by exposing the surface of the image bearing member
Implementation Method 2
a voltage applying means capable of forming a developing potential on the developing member by applying a developing voltage to the developing member
Data Source
AI summary
An image forming apparatus includes a photosensitive drum, a developing member, an applying device forming a developing potential on the developing member, a driver rotationally driving the developing member, and a controller. The controller selectively executes an operation in first and second modes by controlling a circumferential speed ratio of a circumferential speed of the developing member to a circumferential speed of the drum and a potential difference between a surface potential of the image bearing member in a region where an electrostatic latent image is formed and the developing potential. In the first mode, the ratio is a first ratio of 50% to 100% and the potential difference is a first potential difference, and in the second mode the ratio is a second ratio larger than the first ratio and less than 150% and the potential difference is a second potential difference less than the first potential difference.