Variable Speed Ratio Developing Roller Control for Banding Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing speed of image forming processes in recent years has led to unstable rotation of developing rollers due to variations in torque and vibration, resulting in density irregularities and banding in images.
Innovation Solution
An image forming apparatus with a control unit that allows for multiple modes of operation, adjusting the rotational peripheral speed ratio between the photosensitive drum and the developing roller, and varying the developing voltage and supply voltage to maintain stable operation and prevent banding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of rotations of the photosensitive drum or developing roller is increased to speed up the image forming process, then productivity is improved, but the rotation becomes unstable due to torque variation and vibration, causing banding in images
Solution Approach 1:
The patent applies dynamics by making the peripheral speed ratio between the photosensitive drum and developing roller variable rather than fixed. The control unit dynamically adjusts the rotational speeds based on the selected image forming mode (first mode with ratio ≤1, second mode with ratio >1), allowing the system to optimize between speed and stability depending on operational requirements while preventing banding through appropriate ratio selection
Solution Approach 2:
The patent changes the operational parameters by varying the peripheral speed ratio between the photosensitive drum and developing roller. By controlling the drive unit to maintain specific speed ratio ranges (≤1 or >1) depending on the image forming mode, the system resolves the contradiction between high-speed operation and rotation stability, thereby preventing banding while maintaining productivity
2Manufacturing precision
If the peripheral speed ratio between the photosensitive drum and developing roller is increased to enhance image density and tone, then image quality is improved, but rotation stability deteriorates leading to banding
Solution Approach 1:
The system dynamically adjusts the peripheral speed ratio based on the desired image quality requirements. When high density and tone enhancement are needed, the control unit selects the second image forming mode with a ratio greater than 1, while maintaining rotation stability through controlled speed variation that prevents banding
Solution Approach 2:
The patent utilizes parameter changes by controlling the peripheral speed ratio to be greater than 1 in the second image forming mode to achieve enhanced image density and tone, while simultaneously managing the ratio to prevent excessive speed variation that would cause banding, thus resolving the contradiction between image quality and rotation stability
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
The apparatus effectively forms high-quality images across various modes while suppressing the occurrence of banding, ensuring consistent image density and quality.
Implementation Method 1
a developer bearing member configured to be rotatable and develop an electrostatic latent image with a developer at a nip region formed between the developer bearing member and the image bearing member
Implementation Method 2
a supply member voltage application unit configured to apply a supply voltage to the supply member
Data Source
AI summary
An image forming apparatus includes an image bearing member, a developer bearing member, a drive unit for driving the image bearing member and the developer bearing member in varied peripheral speeds, a control unit, a developing voltage application unit, a supply member for supplying a developer to the developer bearing member, and a supply member voltage application unit. The control unit executes a first image forming mode in which a rotational peripheral speed ratio between surface movement speeds of the developer bearing member and the image bearing member is not greater than 1 and a second image forming mode in which the rotational peripheral speed ratio is greater than 1, and the control unit controls the drive unit so that a difference between developing voltage and supply voltage is greater in the second image forming mode than that in the first image forming mode.