Skew Correction for Index Tab Sheets via Sensor Timing
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Solution Overview
Problem
Conventional sheet conveying devices require cumbersome user operations to correct skew in index tab sheets for high-speed and accurate printing, especially when handling non-rectangular sheets like index tab sheets, which complicates the process and reduces efficiency.
Innovation Solution
A sheet conveying device equipped with first and second detection sensors orthogonal to the conveying direction, a timer to measure leading edge detection time, and a skew correction unit that controls conveying speeds of rollers to correct skew automatically, reducing the correction amount when the detection time exceeds a threshold, thus simplifying the skew correction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional skew correction mechanisms are used for index tab sheets, then skew correction can be performed, but user operations become cumbersome and complex
Solution Approach 1:
The system automatically detects the index tab sheet's leading edge position using sensors and autonomously calculates and applies the appropriate skew correction amount, eliminating the need for users to manually input sheet dimensions and tab positions. The correction mechanism self-adjusts based on detected sheet characteristics.
Solution Approach 2:
The system pre-registers multiple skew correction amounts corresponding to different index tab sheet specifications (A4, B5, etc.) in memory before operation. When a sheet is detected, the system quickly retrieves and applies the appropriate pre-calculated correction value, avoiding real-time complex calculations and user input requirements.
2Manufacturing precision
If detailed sheet information is registered in advance for skew correction, then correction accuracy improves, but device complexity increases
Solution Approach 1:
The system divides skew correction into separate handling paths: one for regular sheets using simple sensor detection, and another for index tab sheets using leading edge position detection. This segmentation allows each path to use appropriately simplified methods without requiring comprehensive information registration for all sheet types.
Solution Approach 2:
The system introduces a leading edge detection sensor as an intermediary that automatically identifies index tab sheet characteristics. This mediator enables the system to distinguish between regular sheets and index tab sheets, triggering appropriate correction routines without requiring users to manually register detailed sheet information.
3Manufacturing precision
If skew correction is performed for all sheets, then printing accuracy improves, but processing time increases
Solution Approach 1:
The system applies skew correction selectively rather than universally. It performs full skew correction only when index tab sheets are detected through leading edge position measurement, while using simpler or no correction for regular sheets. This partial application of correction maintains printing accuracy for problematic sheets while minimizing processing time for standard sheets.
Data Source
AI summary
A sheet conveying device that makes it possible to perform printing at high speed with high accuracy by easily correcting skew of a sheet, such as an index tab sheet, without requiring troublesome operations. Sheet detection sensors for detecting a sheet and skew correction rollers for conveying the sheet are disposed in a direction crosswise to a conveying direction of the sheet. A skew correction drive controller measures a leading edge detection time between respective detections of a leading edge of the sheet by the sensors, and controls the conveying speeds of the skew correction rollers independently of each other such that a skew represented by the leading edge detection time is corrected. If the leading edge detection time is not smaller than a predetermined threshold value, the skew correction drive controller reduces a skew correction amount for correcting the skew by a predetermined amount.