Sheet Skew Correction Path for Stable Pre-Registration Conveyance
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Solution Overview
Problem
Existing image forming apparatuses face issues with unstable sheet orientation and conveyance failures due to the re-engagement of pre-registration roller pairs after skew correction, leading to potential slip and conveyance issues.
Innovation Solution
A sheet conveyance apparatus with a skew correction mechanism using a pair of abutment portions and a guide portion that forms a conveyance path with recessed areas to correct skew and improve sheet rigidity, reducing loop formation and enhancing stability during conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the pre-registration roller pair is separated to reduce loop pressure, then the loop pressure is reduced, but the pre-registration roller pair abuts on each other again causing unstable sheet orientation and conveyance failure
Solution Approach 1:
The guide portion is divided into multiple guide surfaces (first guide surface and second guide surface) positioned at different locations. The sheet is guided sequentially through these segmented guide surfaces, which prevents sudden re-engagement of the roller pair while maintaining stable orientation throughout the conveyance path.
Solution Approach 2:
The guide portion acts as an intermediary element between the separated roller pair and the sheet. It provides continuous guidance through multiple guide surfaces, preventing the sheet from deviating or causing sudden re-engagement, thus maintaining conveyance stability without requiring the roller pair to be in direct contact.
2Productivity
If the pre-registration roller pair abuts on each other after separation, then the sheet can be conveyed, but the orientation of the sheet becomes unstable and slip occurs
Solution Approach 1:
The guide portion is segmented into multiple guide surfaces positioned at different locations along the conveyance path. This segmentation allows the sheet to be guided through multiple stages, maintaining stable orientation at each stage and preventing sudden changes in direction that would cause slip or instability.
Solution Approach 2:
The guide surfaces are positioned upstream of the roller pair to pre-guide the sheet into the correct orientation before it reaches the roller pair. This preliminary guidance ensures that when the sheet contacts the roller pair, it is already properly oriented, preventing slip and maintaining stable conveyance.
3Device complexity
If a simple guide portion is used, then the device complexity is reduced, but the sheet may not be guided sufficiently to prevent skew and conveyance failure
Solution Approach 1:
The guide portion uses multiple guide surfaces positioned at different locations rather than a single complex guide structure. This segmentation achieves effective skew correction through multiple simple guiding stages, reducing overall device complexity while maintaining high reliability in preventing sheet deviation.
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 effectively corrects skew and reduces conveyance failures, improving print image accuracy and ensuring stable sheet conveyance, particularly for thin papers, with a simple and cost-effective configuration.
Implementation Method 1
The guide portion includes a guide surface that is disposed between the first abutment portion and the second abutment portion in the width direction and forms a conveyance path through which a sheet passes
Implementation Method 2
a first abutment portion against which a leading edge of the sheet conveyed by the conveyance rotating member pair abuts
Data Source
AI summary
A sheet conveyance apparatus includes a conveyance rotating member pair to convey a sheet in a sheet conveyance direction, and a skew correction portion including a first abutment surface having a first root portion and a second abutment surface having a second root portion. A guide portion includes a guide surface disposed between the first abutment surface and the second abutment surface. The first root portion is positioned within a first recess portion disposed upstream of the first abutment surface such that a leading edge of the sheet enters the first recess portion upon abutting against both the first abutment surface and the second abutment surface, and the second root portion is positioned within a second recess portion such that the leading edge of the sheet enters the second recess portion upon abutting against both the first abutment surface and the second abutment