Sheet Conveyance Apparatus Detection Accuracy Creep Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses experience deteriorated detection accuracy due to creep deformation in guides caused by prolonged reaction forces from pressing springs, affecting the distance and position of detection elements in the conveyance path.
Innovation Solution
A sheet conveyance apparatus with movable and independently positionable guides and a receiving member to absorb reaction forces, maintaining constant distances and positions between detection elements, ensuring accurate sheet detection and posture stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressing roller is urged by a pressing spring and the reaction force is received by the second guide, then the sheet posture is stabilized and detection accuracy is improved, but the second guide sustains creep deformation over time which deteriorates detection accuracy
Solution Approach 1:
The patent divides the guide system into two independent movable guides (first guide and second guide) that can move independently relative to each other. This segmentation allows each guide to be positioned independently, preventing the transmission of deformation or position changes from one guide to the other, thereby maintaining stable detection distances even when one guide experiences creep deformation.
Solution Approach 2:
The patent makes both the first guide and second guide movable rather than fixed, allowing them to adjust their positions independently. This dynamic configuration enables the system to accommodate creep deformation in one guide without affecting the relative position stability between detection elements, as each guide can move to compensate for deformations.
2Reliability
If the second guide is fixed to receive reaction force, then the pressing portion is stabilized, but the detection position and distance between detection elements change due to guide deformation
Solution Approach 1:
The patent segments the guide structure into two independent movable guides, allowing the pressing portion to be stabilized by one guide while the detection elements on each guide maintain their relative positions independently. This prevents the transmission of position changes from the pressing area to the detection area.
Solution Approach 2:
The patent introduces an intermediary positioning mechanism that allows the first and second guides to move independently relative to each other. This intermediary arrangement decouples the stability function (providing reaction force) from the detection function (maintaining detection position), enabling both functions to operate independently without interfering with each other.
3Device complexity
If the guides are fixed relative to each other, then the structure is simple, but the detection accuracy deteriorates due to creep deformation from prolonged reaction force
Solution Approach 1:
The patent transforms the fixed guide structure into a dynamic one where both guides can move independently. This adds some complexity but enables the system to maintain detection accuracy over time by allowing the guides to adjust their positions and accommodate creep deformation without affecting detection element spacing.
Solution Approach 2:
The patent divides the originally fixed guide structure into two independent movable guides, each capable of independent positioning. This segmentation increases structural complexity slightly but prevents the propagation of deformation effects, thereby maintaining long-term detection accuracy despite the added complexity.
Data Source
AI summary
A sheet conveyance apparatus includes a receiving member to hold a sheet pressing portion and receive a reaction force of an urging portion for urging the sheet pressing portion toward the first sheet guide, a detection unit having a first detection portion disposed on a first sheet guide, and a second detection portion facing the first detection portion and disposed on a second sheet guide. The detection unit changes an output value based on presence and absence of the sheet at a detection position in a sheet conveyance path, wherein the second guide provided with the second detection portion, and a receiving member are movably disposed with respect to the first guide provided with the first detection portion respectively, and are positioned with respect to the first guide independently from each other, and wherein the receiving member is pivotably supported around the pivot axis independently from the second guide.