Sheet Conveying Apparatus Distance Calculation for Image Registration
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Solution Overview
Problem
Existing sheet conveying apparatuses face challenges in achieving high precision sheet conveying speed control and feed amount control due to mechanical tolerance variations in the distance between detecting units, leading to positional deviations between recto and verso images, which affect image quality.
Innovation Solution
A sheet conveying apparatus with a first and second detecting unit that calculates the distance between detecting positions using detection signals from a reference sheet, allowing for precise detection of sheet length and conveying speed, thereby reducing positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between detecting units is fixed based on mechanical design, then the device construction is simple, but the measurement precision deteriorates due to mechanical tolerance variations
Solution Approach 1:
The patent uses a feedback mechanism where the actual sheet length detected by the detecting units is fed back to calculate and correct the distance between detecting units. The control unit adjusts the distance calculation based on the detected sheet length, compensating for mechanical tolerance variations and improving measurement precision without requiring complex mechanical adjustments.
Solution Approach 2:
The patent changes the parameter of distance calculation from a fixed mechanical value to a dynamically adjusted value based on detected sheet length. By using the detected sheet length to recalculate and update the distance between detecting units, the system adapts to mechanical variations and maintains high measurement precision.
2Measurement precision
If multiple sheet detecting units are used for high precision control, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent makes the detecting units multi-functional by using them for both sheet length detection and distance calculation between detecting units. The same detecting units that measure sheet length are also used to determine the distance parameter, eliminating the need for separate detection systems and reducing overall device complexity while maintaining high measurement precision.
3Manufacturing precision
If the leading edge of the sheet is used as reference for image positioning, then the ease of operation improves, but the manufacturing precision deteriorates due to sheet dimension variations
Solution Approach 1:
The patent replaces the mechanical reference system (using the physical leading edge of the sheet) with an information-based reference system. By detecting the sheet length and calculating the actual position based on detected parameters rather than relying on the physical leading edge, the system achieves higher image position precision while maintaining ease of operation through automated calculation.
Data Source
AI summary
A first detecting unit S1 for detecting a conveyed sheet at a first detecting position and a second detecting unit S2 for detecting the sheet at a second detecting position are provided. A calculation unit calculates a distance between the first and second detecting positions based on detection signals from the first detecting unit and the second detecting unit at the time when a reference sheet having a known length has been conveyed and a length of reference sheet.