Sheet Position Detection Using Roller Reflection
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Solution Overview
Problem
Existing sheet position detection systems in image formation apparatuses face challenges in achieving high accuracy due to sheet floating and increased distance between light emission and reception parts, which limits detection precision.
Innovation Solution
A sheet position detection apparatus using a pair of conveyance rollers with a light emitter and receptor arranged on the first roller, where the light is reflected off a reflective surface on the second roller, allowing for accurate detection of sheet ends despite floating and maintaining a shorter distance between the light components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light emission part and light reception part are arranged to vertically sandwich a sheet to be conveyed, then the detection accuracy is improved by eliminating sheet floating interference, but the distance between the light emission part and light reception part increases causing reduction in detection accuracy
Solution Approach 1:
The second conveyance roller acts as an intermediary by providing a reflective face that reflects light from the light emitter back to the light receptor. This allows the light path to be folded back on itself, enabling the light components to be positioned close together while still achieving accurate sheet position detection near the nip portion.
2Measurement precision
If the distance between the light emission part and light reception part is shortened, then the detection accuracy is improved, but the sheet floating interference cannot be restricted
Solution Approach 1:
The reflective face on the second conveyance roller serves as a mediator that enables the light path to pass near the nip portion where sheet floating occurs. By reflecting light back toward the light receptor, it allows detection close to the nip while maintaining a compact light component arrangement.
3Object-affected harmful factors
If a non-contact type sensor is used to detect sheet position, then the sheet is not damaged or folded, but the detection accuracy is limited due to sheet floating and distance constraints
Solution Approach 1:
The reflective face on the second conveyance roller enables the non-contact sensor to achieve high detection accuracy by folding the light path. This allows the light to pass near the nip portion for accurate floating-restricted detection while keeping the light components close together, maintaining all benefits of non-contact sensing.
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 configuration enhances detection accuracy by restricting reductions in accuracy caused by floating and distance, enabling precise sheet position detection and tilt correction, thereby improving image formation position accuracy.
Implementation Method 1
a light emitted from the light emitter is reflected on a reflective face of the second conveyance roller and enters the light receptor
Implementation Method 2
the detector detects passage of an end of the sheet on the basis of a change in the amount of light entering the light receptor when the sheet shields a light emitted from the light emitter
Data Source
AI summary
Provided are a sheet position detection apparatus, a sheet conveyance apparatus, and an image formation apparatus. The sheet position detection apparatus has a first and a second conveyance roller which are arranged to oppose across a sheet to be conveyed and to nip the sheet, and a detector configured to detect an end position of the sheet, the detector has a light emitter and a light receptor arranged on the first conveyance roller side, the light emitter and the light receptor are arranged such that a light emitted from the light emitter is reflected on a reflective face of the second conveyance roller and enters the light receptor, and the detector detects passage of an end of the sheet based on a change in the amount of light entering the light receptor when the sheet shields a light emitted from the light emitter.