Paper Discharge Roller with Segmented Forming Design
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Solution Overview
Problem
In high-speed image forming apparatuses, paper discharge failures occur due to floatage and curling of paper edges, leading to incomplete or improperly stacked paper, and existing solutions fail to effectively prevent ink transfer to rollers, causing contamination.
Innovation Solution
A paper discharge device with a lower roller having a central nip roller and tapered forming rollers at both ends, where the forming rollers are independently rotatable and have a larger outer diameter than the nip roller, reducing friction and ink transfer by maintaining a constant paper conveyance speed and linear velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the forming roller has a larger outer diameter to form paper in a predetermined shape, then paper discharge reliability is improved, but ink transfer to the roller increases causing contamination
Solution Approach 1:
The lower roller is segmented into two independently rotatable parts: the nip roller (smaller diameter) and the forming roller (larger diameter). This segmentation allows each part to rotate at different speeds optimized for its specific function, reducing ink transfer on the forming roller while maintaining effective paper holding and shaping.
Solution Approach 2:
Different regions of the roller system are given different rotational speeds and diameters suited to their local functions. The nip roller rotates faster to effectively hold and convey paper, while the forming roller rotates slower to minimize ink pickup, with each region optimized for its specific role in the paper discharge process.
2Device complexity
If the forming roller rotates at the same number of revolutions as the nip roller, then paper conveying is simplified, but linear velocity difference causes ink accumulation on the forming roller
Solution Approach 1:
The system transitions from static (both rollers rotating at the same speed) to dynamic (rollers rotating at different speeds). The independently rotatable forming roller can adjust its rotational speed to match the linear velocity requirements, reducing ink accumulation while maintaining simplified mechanical coupling through belt or gear transmission.
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 solution prevents ink contamination and ensures accurate paper discharge and stacking by forming paper in a predetermined shape, reducing friction and ink transfer to the rollers, thus enhancing paper discharge reliability.
Implementation Method 1
friction between paper and a roller having a large diameter at both ends, provided so as to form the paper in a predetermined shape, is low
Data Source
AI summary
In an image forming apparatus, a paper discharge roller of a paper discharge unit has an upper roller as a driving roller and a lower roller as a driven roller. The lower roller has a nip roller which is fixed to a shaft and holds paper between the nip roller and the upper roller, and forming rollers having a diameter larger than that of the nip roller and arranged on both sides of the nip roller. Since a conveyance speed of the paper is constant, the number of revolutions of the forming roller having a large outer diameter is smaller than that of a nip roller having a small outer diameter. The friction between the forming roller and the paper is lower than that in conventional art. Attachment and accumulation of ink are suppressed, and inconvenience of contamination of the paper with ink upon paper discharge hardly occurs.