Sheet Skew Correction Control for Thin Paper Conveyance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face issues with skew correction accuracy deterioration when conveying thin or low-rigidity sheets, as the force required to abut these sheets against a reference member can cause buckling.
Innovation Solution
A sheet conveyance apparatus with a control unit that switches between nipping and non-nipping states for skewing rotary members, ensuring accurate skew correction by controlling the nipping state of skewing rotary member pairs during sheet oblique conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If multiple skewing roller pairs are used to abut sheets against the reference member, then the conveyance force is sufficient for normal and thick paper, but thin paper with small grammage and low rigidity may be buckled
Solution Approach 1:
The patent applies dynamics by making the nipping state of skewing roller pairs changeable rather than fixed. The control unit dynamically adjusts which skewing roller pairs are in the nipping state based on sheet type detection. For thin paper, the system releases the nipping state of downstream skewing roller pairs to prevent buckling, while for normal and thick paper, all skewing roller pairs maintain nipping to provide sufficient conveyance force. This dynamic adaptation resolves the contradiction between needing strong conveyance force and preventing sheet buckling.
Solution Approach 2:
The patent implements parameter changes by varying the operational state (nipping or non-nipping) of skewing roller pairs according to sheet characteristics. The control unit detects sheet type and accordingly changes the nipping parameter of skewing roller pairs. This parameter adjustment allows the system to optimize both conveyance force and skew correction accuracy for different paper types, preventing the buckling of thin paper while maintaining effective skew correction for heavier papers.
2Device complexity
If the nipping state of skewing roller pairs is fixed, then the structure is simple, but the system cannot adapt to different sheet types (thin paper vs. normal/thick paper)
Solution Approach 1:
The patent transforms the static nipping state into a dynamic one by introducing a control unit that can switch skewing roller pairs between nipping and non-nipping states. This dynamic configuration enables the system to adapt to different sheet types (thin paper, normal paper, thick paper) while maintaining a relatively simple overall structure. The switching mechanism adds minimal complexity but provides significant adaptability improvement.
Solution Approach 2:
The system implements self-service by automatically detecting sheet type and autonomously adjusting the nipping state of skewing roller pairs without requiring manual intervention. The control unit monitors sheet characteristics and self-regulates the conveyance mechanism, enabling the system to adapt to different paper types while keeping the operational interface simple for users.
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
Prevents deterioration of skew correction accuracy for thin or low-rigidity sheets by dynamically managing the nipping state of skewing rotary members, enhancing the conveyance process.
Implementation Method 1
a first skewing rotary member pair arranged downstream of the first conveying rotary member pair in the sheet conveyance direction and configured to obliquely convey the sheet toward the abutment portion
Data Source
AI summary
A sheet conveyance apparatus includes a first conveying rotary member pair, an abutment portion, a first skewing rotary member pair, a second skewing rotary member pair, a switching mechanism, and a control unit. The control unit executes a first mode of controlling the second skewing rotary member pair to be in a nipping state in a sheet oblique conveyance state which is a state from when the first skewing rotary member pair starts an oblique conveyance of the sheet having been conveyed by the first conveying rotary member pair until an edge portion in a width direction of the sheet abuts the abutment portion, and a second mode of controlling the second skewing rotary member pair to be in a non-nipping state in the sheet oblique conveyance state.