Pre-transfer Sheet Transport Roller Hardness and Diameter Configuration
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Solution Overview
Problem
Existing sheet transport devices in image forming apparatuses face challenges in stabilizing the transport of sheets with varying widths, leading to potential creases or transfer defects due to uneven pressure-contact loads across separate rollers.
Innovation Solution
The use of pre-transfer sheet-transport rollers with a first roller having three or more separate rollers of varying hardness and a second roller with larger inner rollers, where the inner separate rollers of the first roller have lower hardness and larger diameters than the end rollers, ensuring consistent pressure-contact loads across all roller pairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate rollers have uniform hardness and diameter, then manufacturing is simple, but pressure-contact load becomes uneven across rollers causing sheet transport instability
Solution Approach 1:
The patent applies local quality by making the inner separate rollers have lower hardness and larger diameters compared to end separate rollers. This non-uniform configuration compensates for the naturally higher pressure-contact load on inner rollers, achieving uniform pressure distribution across all rollers and stable sheet transport.
2Productivity
If inner separate rollers have higher pressure-contact load, then sheet transport force increases, but sheet deformation and creases occur
Solution Approach 1:
The patent changes the physical parameters of inner separate rollers by reducing their hardness and increasing their diameters. These parameter modifications allow the inner rollers to deform elastically under load, absorbing excess pressure and preventing sheet creases while maintaining adequate transport force.
3Object-affected harmful factors
If end separate rollers have lower pressure-contact load, then sheet damage is reduced, but overall transport force becomes insufficient
Solution Approach 1:
The patent applies local quality by giving end separate rollers different characteristics (higher hardness, smaller diameter) compared to inner rollers. This creates a differentiated pressure distribution where end rollers provide gentle handling while inner rollers provide stronger transport force, achieving both sheet protection and adequate transport capability.
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 transport of sheets regardless of width, preventing creases and transfer defects by evenly distributing pressure-contact loads, ensuring reliable feeding to the second-transfer position.
Implementation Method 1
The hardness of an inner separate roller of the first roller is lower than the hardness of end separate rollers of the first roller
Implementation Method 2
The outside diameter of an inner separate roller of the second roller is greater than the outside diameter of end separate rollers of the second roller
Data Source
AI summary
A sheet transport device includes pre-transfer sheet-transport rollers that transport a sheet to a transfer position at which an unfixed image is transferred, the pre-transfer sheet-transport rollers including a first roller in which three or more separate rollers attached to a first shaft rotate, and a second roller in which three or more separate rollers attached to a second shaft are in contact with the separate rollers of the first roller and rotate. The hardness of an inner separate roller of the first roller is lower than the hardness of end separate rollers of the first roller. The outside diameter of an inner separate roller of the second roller is greater than the outside diameter of end separate rollers of the second roller.