Alternating Voltage Developing Roller for Toner Density Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrophotographic image-forming apparatuses experience density unevenness in both solid and dot images due to eccentricity of the photosensitive member and developing roller, making it difficult to prevent unevenness simultaneously across both types of images.
Innovation Solution
An image forming apparatus with a pair of spacedly opposed bearing members and an electric field generator producing alternating voltages to create specific electric fields that efficiently supply developer material between the members, ensuring consistent image density regardless of member eccentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precise positioning of the photosensitive member and developing roller is implemented, then density unevenness is reduced, but manufacturing cost increases significantly
Solution Approach 1:
The patent applies alternating voltage to the developing roller, dynamically changing the electric field parameters to compensate for eccentricity effects. This allows the system to maintain uniform toner supply and image density without requiring precise mechanical positioning, thereby resolving the contradiction between manufacturing precision and ease of manufacture
Solution Approach 2:
The patent introduces dynamic voltage control to the developing roller, making the electric field adjustable and responsive to eccentricity conditions. This dynamic parameter adjustment enables the system to adapt to positioning variations, achieving uniform density without precise mechanical alignment
2Manufacturing precision
If reduced alternating voltage is applied, then dot image development is improved, but density unevenness increases in dot images due to roller eccentricity
Solution Approach 1:
The patent employs periodic alternating voltage applied to the developing roller, creating cyclic electric field variations that enhance toner particle movement. This periodic action compensates for eccentricity effects during rotation, maintaining uniform dot image density without requiring complex voltage settings
3Manufacturing precision
If elevated alternating voltage is applied, then solid image development is improved, but density unevenness increases in solid images due to enhanced electric field forcing toner back to the developing roller
Solution Approach 1:
The patent uses periodic alternating voltage with optimized amplitude and duty cycle to control toner particle movement. The periodic electric field ensures sufficient toner supply to the photosensitive member while preventing excessive force that would cause toner to be forced back, maintaining uniform solid image density
4Manufacturing precision
If different voltage settings are used for solid and dot images, then density unevenness is prevented in one type, but it appears in the other type
Solution Approach 1:
The patent implements a universal alternating voltage application system on the developing roller that effectively handles both solid and dot images. The alternating voltage mechanism provides adaptable toner supply control that works across different image types, eliminating the need for separate voltage settings and preventing density unevenness in both cases
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 supplies developer material to prevent density unevenness in both solid and dot images, maintaining image quality without the need for precise positioning of the rotating members, thus reducing manufacturing costs.
Implementation Method 1
an electric field generator which forms an electric field between the first and second bearing members, the generator outputting a first voltage and a second voltage alternately, the first voltage generating between the first and second bearing members a first electric field electrically forcing the developer material from the first bearing member toward the second bearing member
Data Source
AI summary
An image forming apparatus has a pair of spacedly opposed first and second bearing members, in which a powder developer material is moved from the first bearing member to the second bearing member. The apparatus also has an electric field generator. The generator forms an electric field between the first and second bearing members and outputs a first voltage and a second voltage alternately. The first voltage generates, between the first and second bearing members, a first electric field electrically forcing the developer material from the first bearing member toward the second bearing member. The second voltage generates between the first and second bearing members a second electric field electrically forcing the developer material from the second bearing member toward the first bearing member. Durations of the first and second voltages are determined so that the developer material forced out of the first bearing member due to the first electric field is forced back from the second bearing member toward the first bearing member due to the second electric field to impinge the developer material retained on the first bearing member and thereby flick the developer material on the first bearing member away therefrom and the flicked developer material is then forced from the first bearing member toward the second bearing member by the subsequent first electric field.