Conveyance Rolling Part Positioning for Sheet Path Reliability
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face challenges in conveying sheets with curved paths without causing damage to the image forming surface, especially when handling various sheet sizes, due to overlapping end portions of sheets and rolling members, leading to potential sheet conveyance failures.
Innovation Solution
The apparatus includes a moving conveyance rolling part that adjusts its position along the sheet feeding path to prevent contact between the image forming surface and the conveyance guide, ensuring smooth sheet conveyance by moving the upstream conveyance rolling part to a position where the sheet can be passed to the downstream rolling part without contacting the guide, thereby avoiding damage and allowing for the handling of different sheet sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conveyance rolling part with a large diameter is used to reduce sheet entering angle and avoid corner folding, then sheet conveyance reliability is improved, but rolling members may overlap each other in the sheet conveyance direction due to limited installation space, causing sheet conveyance failure
Solution Approach 1:
The patent transitions from a two-dimensional staggered arrangement (in sheet width direction) to a three-dimensional arrangement by utilizing the sheet conveyance direction dimension. Conveyance rolling parts are positioned at different locations along the conveyance path rather than being staggered side-by-side, eliminating overlapping issues while maintaining large diameter for reliable conveyance.
2Area of stationary object
If rolling members are disposed in a staggered manner in the sheet width direction to avoid interference, then conveyance rolling parts can be installed in limited space, but end portions of the sheet in the sheet width direction and end portions of the rolling members overlap, causing sheet conveyance failure
Solution Approach 1:
The patent divides the sheet conveyance path into multiple segments with different conveyance rolling parts positioned at different locations. Instead of using a single staggered arrangement, the system segments the conveyance function across multiple rolling parts (first, second, third conveyance rolling parts) positioned at different conveyance distances from the sheet feed tray, allowing each to operate independently without overlapping issues.
3Object-affected harmful factors
If multiple conveyance rolling parts are disposed at a curving part of the sheet feeding path to prevent image forming surface damage, then sheet conveyance without damage is achieved, but the apparatus size increases and design flexibility is reduced
Solution Approach 1:
The patent applies preliminary action by positioning the first conveyance rolling part upstream at a curving part of the sheet feeding path before the sheet reaches areas where image forming surface damage could occur. This upstream positioning prevents damage proactively while maintaining a compact design, as the rolling part is strategically placed where it can influence the entire subsequent conveyance path.
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 solution enables reliable sheet conveyance without damage to the image forming surface, improves design flexibility by eliminating the need for staggered rolling member placement, and ensures high-quality image production across various sheet sizes.
Implementation Method 1
a conveyance rolling part having a small frictional coefficient and protruding from the conveyance guide toward the inside of the sheet feeding path is disposed
Data Source
AI summary
An image forming apparatus includes: an image forming section configured to form an image on a sheet; conveyance guides disposed on an image forming surface side and a rear surface side of the sheet at a position on a downstream side of the image forming section in a sheet conveyance direction, and configured to form a sheet feeding path for conveying the sheet; a conveyance rolling part disposed to protrude from the conveyance guide into the sheet feeding path at a curving part of the sheet feeding path; and a rolling member moving section configured to move the conveyance rolling part along the sheet feeding path until a state where an image forming surface of a sheet being conveyed does not make contact with the conveyance guide is ensured.