Transfer Roller with Movable Hairs for Compact Image Formation
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Solution Overview
Problem
Existing image forming apparatuses face challenges in reducing the size of transfer rollers while maintaining sufficient nips for effective toner transfer and minimizing peeling discharge, as reducing the diameter of the transfer roller compromises either the physical or downstream nip, affecting image quality.
Innovation Solution
The design incorporates a transfer member with a main roller body and movable hairs or films that extend radially and are positioned downstream of the rotation axis of the developer-image carrier, allowing the transfer member to contact the conveyance belt while maintaining a parallel alignment with the developer-image carrier, ensuring effective toner transfer and reducing peeling discharge even with a smaller diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the transfer roller is reduced to decrease the apparatus size, then the downstream nip becomes insufficient, but the patent uses movable hairs or films that extend downstream to maintain the downstream nip contact area
Solution Approach 1:
The transfer roller incorporates movable hairs or films that can dynamically extend downstream beyond the roller's physical contact point with the conveyance belt. This dynamic extension maintains the downstream nip contact area even when the roller diameter is reduced, allowing the apparatus to achieve compact size while preserving reliable toner transfer
Solution Approach 2:
The invention extends the transfer function into the downstream direction by having hairs or films protrude beyond the roller's circumferential contact point. This dimensional extension in the downstream direction compensates for the reduced roller diameter, maintaining sufficient downstream nip without increasing the overall apparatus volume
2Volume of moving object
If the diameter of the transfer roller is reduced, then the physical nip becomes insufficient, but the patent positions the rotation axis downstream to maintain adequate physical nip contact
Solution Approach 1:
The transfer roller's rotation axis is positioned asymmetrically downstream relative to the developer-image carrier rotation axis, rather than being centered. This asymmetric positioning allows the roller to maintain adequate physical nip contact with the conveyance belt while having its downstream-extending hairs or films reach further downstream, achieving compact size without sacrificing physical nip sufficiency
Solution Approach 2:
By positioning the rotation axis downstream in advance, the patent pre-configures the transfer roller to maintain both sufficient physical nip contact and extended downstream reach. This preliminary positional arrangement ensures that even with reduced diameter, the roller establishes proper contact zones before the transfer process begins
3Volume of moving object
If the diameter of the transfer roller is reduced, then peeling discharge increases, but the patent uses downstream-extending movable hairs to return electrical charge and reduce peeling discharge
Solution Approach 1:
The movable hairs or films act as intermediary elements that extend downstream from the transfer roller to contact the conveyance belt. These intermediaries facilitate the return of electrical charge from the conveyance belt to the transfer roller, reducing peeling discharge while allowing the use of a smaller-diameter roller that would otherwise generate more discharge
Solution Approach 2:
The patent replaces the traditional reliance on large roller diameter for charge return with a mechanical extension system using downstream-protruding hairs or films. This substitution allows charge return functionality to be achieved through the extended contact area of the movable elements rather than through the roller's circumferential size, reducing peeling discharge in a compact configuration
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 enables the reduction of the image forming apparatus size while maintaining image quality by ensuring sufficient toner transfer and minimizing peeling discharge, allowing for a smaller transfer roller diameter without compromising image formation.
Implementation Method 1
a physical nip I, where the conveyance belt comes into contact with both the developer-image carrier and the transfer member, through which the transfer member transfers the developer image onto the conveyance belt
Implementation Method 2
at the upstream nip H, the toner image is nipped by the photosensitive drum 101 and the intermediate transfer belt 102. Therefore, the toner image on the photosensitive drum 101 may fly from the photosensitive drum 101 before reaching the physical nip I
Implementation Method 3
at the downstream nip electrical charge having moved to the intermediate transfer belt 102 at the upstream nip H or the like returns o the transfer roller 100. Therefore, it is possible to reduce peeling discharge when the photosensitive drum 101 and the intermediate transfer belt 102 are separated from each other
Data Source
AI summary
An image forming apparatus includes: a developer-image carrier; a conveyance belt that contacts the developer-image carrier and conveys a developer image; and a transfer member contacting the conveyance belt from an opposite side of the developer-image carrier to transfer the developer image onto the conveyance belt. The transfer member includes a main roller body and a movable member including a first end portion fixed to a circumferential surface of the main roller body and a second end portion extending outward in a radial direction of the main oiler body and movable with respect to the first end portion. A rotation axis line of the main roller body is provided downstream of the rotation axis line of the developer-image carrier in a movement direction of the conveyance belt such that the main roller body contacts the developer-image carrier while interposing the conveyance belt therebetween.