Image Forming Apparatus Guide Unit Inclined Surface Registration
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Solution Overview
Problem
In image forming apparatuses, the accuracy of leading edge registration during vertical path conveyance is compromised due to instability in the distance between the sheet position sensor and the sheet's leading edge, leading to potential inaccuracies in image formation.
Innovation Solution
The apparatus includes a guide unit with an inclined guide surface positioned between the registration roller pair and the image forming position, ensuring the nip line of the registration roller pair intersects the guide surface upstream of the detection position, stabilizing the distance between the sheet position sensor and the sheet's leading edge, thereby enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sheet position sensor is disposed between the registration roller pair and the image forming position to detect the leading edge of the sheet, then the detection accuracy of sheet position is improved, but the distance between the sheet position sensor and the leading edge of the sheet becomes unstable during vertical path conveyance, deteriorating the detection accuracy
Solution Approach 1:
The patent introduces a guide surface that is inclined relative to the sheet conveyance direction, creating a geometric relationship where the guide surface normal forms an acute angle with the sheet conveyance direction. This dimensional transformation of the guide surface orientation stabilizes the distance between the sheet leading edge and the sheet position sensor during vertical conveyance, preventing sheet flutter and maintaining detection accuracy.
2Device complexity
If the registration roller pair conveys the sheet in a vertical path, then the image forming apparatus can achieve compact structure, but the leading edge of the sheet may flutter in the sheet surface direction, causing dispersion of distance between the sheet position sensor and the leading edge
Solution Approach 1:
The patent introduces a guide surface as an intermediary element between the registration roller pair and the sheet conveyance path. This guide surface mediates the interaction between the sheet and the conveyance system, providing a stable geometric reference that prevents sheet flutter during vertical conveyance, thereby maintaining both compact structure and detection accuracy.
3Device complexity
If the guide surface is arranged parallel to the straight line connecting centers of the first roller and the second roller, then the sheet conveyance path is simplified, but the nip line of the registration roller pair does not effectively intersect the guide surface to stabilize sheet position
Solution Approach 1:
The patent deliberately creates an asymmetric geometric relationship where the guide surface is inclined relative to the sheet conveyance direction, and the guide surface normal forms a specific acute angle with the sheet conveyance direction. This asymmetric arrangement ensures that the nip line of the registration roller pair effectively intersects the guide surface, stabilizing sheet position while maintaining conveyance path simplicity.
Data Source
AI summary
An image forming apparatus includes a casing, an opening and closing unit, an image forming unit, a registration roller pair, a detection unit, and a guide unit. The guide unit forms a sheet conveyance path that guides a sheet from the registration roller pair to an image forming position. The guide unit includes a guide surface arranged in a manner inclined toward a side of the registration roller pair from a direction parallel to a straight line connecting centers of the registration roller pair when viewed in an axial direction of the registration roller pair. The guide unit and the registration roller pair are arranged such that a nip line of the registration roller pair intersects the guide surface of the guide unit at a position upstream of a detection position of the detection unit in a sheet conveyance direction when viewed in the axial direction.