Transfer Device Conductive Brush for Stable Image Transfer
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Solution Overview
Problem
In image-forming apparatuses using electrophotographic systems, the transfer nip section between the transfer roller and the belt is difficult to control, leading to instability in the transfer electric field and impaired transfer characteristics due to the high electrical resistance difference between metal contact members and the transfer members, causing local variations and image disturbances.
Innovation Solution
An image-forming apparatus with a transfer device featuring a sheet member with a conductive section and an electrical connection path outside the image formation area, arranged perpendicular to the belt's movement direction, which includes a conductive brush member supported by a planar member and an electrical connection path for supplying voltage, ensuring stable contact and uniform transfer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal contact member is used to apply voltage to the transfer member, then electrical connection is achieved, but local variations in the transfer electric field occur and image disturbance happens due to the large electrical resistance difference between metal and transfer member material
Solution Approach 1:
The patent introduces a conductive member as an intermediary between the metal contact member and the transfer member. This conductive member has electrical resistance characteristics that are intermediate between metal and the transfer member material, thereby reducing the electrical resistance difference and preventing local variations in the transfer electric field that would otherwise cause image disturbance.
Solution Approach 2:
The patent changes the electrical resistance parameter of the contact interface by using a conductive member with specifically controlled resistance characteristics. This parameter change ensures that the electrical resistance difference between the metal contact member and transfer member is reduced, stabilizing the transfer electric field and eliminating image disturbance in the contact region.
2Stability of the object's composition
If the transfer member is pressed against the belt with elastic material, then contact stability is improved, but the high coefficient of elasticity of metal contact members causes local instabilities in the transfer nip section
Solution Approach 1:
The conductive member serves as an intermediary between the elastic transfer member and the rigid metal contact member. This intermediary reduces the coefficient of elasticity mismatch, allowing stable contact to be maintained while preventing the local instabilities that would otherwise occur in the transfer nip section due to the high elasticity of metal.
3Power
If the electrical connection path is arranged within the image formation area, then voltage supply is achieved, but the transfer electric field is affected in the peripheral area where the connection path is located
Solution Approach 1:
The patent extracts the electrical connection path from the image formation area and relocates it to a non-image formation area. This separation ensures that the voltage supply function is maintained while the transfer electric field in the image formation area is not affected by the presence of the connection path, thereby maintaining field uniformity.
Solution Approach 2:
The patent rearranges the electrical connection path in a different spatial dimension (outside the image formation area) rather than within it. This dimensional repositioning allows voltage supply to occur without interfering with the transfer electric field in the image formation region, maintaining both power supply and field uniformity.
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 configuration stabilizes the transfer process, reduces local instabilities, and enhances transfer characteristics by maintaining a consistent transfer electric field, resulting in improved image quality and transfer performance.
Implementation Method 1
the sheet member has a conductive section and an electrical connection path section for supplying voltage from a power source to the conductive section
Implementation Method 2
A transfer step is then performed in which an electric field of opposite polarity to the normal charging polarity of the toner is applied to a transfer device, and the toner image borne on the photosensitive member is transferred electrostatically onto a recording material
Data Source
AI summary
A transfer device can make more stable contact with a belt, thus yielding preferable transfer performance. In an image-forming apparatus in which the transfer device has a sheet member, the sheet member includes a conductive sheet, and an electrical connection path section (power source connecting section) for supplying voltage to the conductive sheet from the primary transfer power source, and the power source connecting section is arranged outside an image formation enabling region where a toner image can be formed on a photosensitive drum, in a direction perpendicular to the direction of movement of the intermediate transfer belt.