Conveyance Roller Pair Return Mechanism for Sheet Alignment
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Solution Overview
Problem
Existing sheet conveyance apparatuses face issues with reliably returning the conveyance roller pair to its home position after following a sheet in the width direction, leading to potential skew and positional deviations due to weakened returning forces, which can result in incomplete sheet conveyance.
Innovation Solution
A sheet conveyance apparatus with a conveyance roller pair movement mechanism that includes a cam system and an urging member to ensure reliable return to the home position, utilizing a slide cam with inclined surfaces and a pressing roller to counteract the movement direction, thereby maintaining accurate sheet alignment and conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If compression springs are provided at both end portions of the conveyance roller pair to enable movement in the width direction, then the conveyance roller pair can follow the sheet without a driving source, but the returning force becomes weaker and the roller pair may stop at a deviated position
Solution Approach 1:
The patent extracts one compression spring from the system, providing it only at the downstream end portion of the conveyance roller pair instead of at both end portions. This eliminates the counteracting forces between two springs and ensures a reliable returning force that consistently pushes the roller pair back to the home position without causing it to stop at deviated positions.
2Reliability
If the elastic force of compression springs is strengthened to increase returning force, then the conveyance roller pair can return more reliably to the home position, but a twist, skew, or wrinkles occur on the sheet
Solution Approach 1:
The patent applies local quality by positioning the compression spring only at the downstream end portion of the conveyance roller pair rather than distributing it symmetrically at both ends. This localized placement provides the necessary returning force while minimizing the risk of sheet distortion, as the spring force is applied in a way that follows the sheet's movement without causing twist or wrinkles.
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 ensures reliable return of the conveyance roller pair to its home position, preventing skew and positional deviations, ensuring proper sheet conveyance and alignment, and enhancing the stability of the sheet conveyance process.
Implementation Method 1
an urging member configured to urge one of the cam and the pressing member against the other
Implementation Method 2
a cam connected to one of an apparatus main body and the conveyance roller pair, and a pressing member connected to other of the apparatus main body and the conveyance roller pair and configured to come into contact with a cam surface of the cam
Data Source
AI summary
A sheet conveyance apparatus includes a conveyance roller pair and a mechanism. While following movement of the sheet nipped by the conveyance roller pair, the mechanism moves the conveyance roller pair from a home position, and, in response to a trailing edge of the sheet passing through a conveyance roller pair nip portion, the mechanism returns the pair to the home position. The mechanism includes a movement supporting portion, a cam, a pressing member, and an urging member. The pressing member urges the conveyance roller pair toward the home position by exerting an urging force to the cam. In response to the conveyance roller pair and one of the cam and the pressing member moving in the width direction from the home position, the pressing member exerts the urging force to the cam in a direction reverse to a direction in which the conveyance roller pair has moved.