Register Exit Multi-Feed Detection for Printers

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Solution Overview

Problem

Conventional multi-feed detection methods in printing apparatuses are prone to instability due to variations in sheet looseness and feeding routes, leading to inaccurate detection of sheet overlap.

Innovation Solution

The use of a second light transmission sensor positioned on the sheet exit side of the register rollers, acting as both an edge part detection sensor and a multi-feed detection sensor, stabilizes the detection process by minimizing the influence of sheet looseness and feeding route variability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a light transmission sensor is provided on the sheet feeding side of the register rollers to detect multi-feeding as quickly as possible, then the detection speed is improved, but the detection accuracy becomes unstable due to variations in sheet looseness and feeding routes

Engineering Contradiction:

Improvedetection speedVSAvoiddetection accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

Instead of detecting multi-feeding on the sheet feeding side of the register rollers (conventional approach), the patent inverts the detection position to the sheet exit side of the register rollers. This inversion allows the sensor to detect sheets after they have been positioned and obliqueness adjusted, eliminating the instability caused by varying sheet looseness and feeding routes while maintaining detection speed.

Inventive Principle:

Principle #13The other way round (Inversion)

2Loss of time

If a light transmission sensor is provided on the sheet feeding side of the register rollers, then multi-feeding can be detected early, but the measurement varies per sheet due to different loose states and feeding routes

Engineering Contradiction:

Improvedetection timingVSAvoiddetection stability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent inverts the conventional detection position from the sheet feeding side to the sheet exit side of the register rollers. This inversion ensures that sheets are detected after undergoing positioning and obliqueness adjustment, making the detection results consistent across different sheets and feeding routes while maintaining early detection capability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies preliminary action by having the register perform positioning and obliqueness adjustment of sheets before the light transmission sensor detects them. This preliminary processing ensures that all sheets are in a standardized state when detected, eliminating variations caused by different loose states and feeding routes.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the light transmission sensor detects sheets in their loose state before register adjustment, then detection occurs early in the process, but the detection results vary significantly across different sheets and feeding routes

Engineering Contradiction:

Improveprocess efficiencyVSAvoiddetection consistency

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by having the register perform positioning and obliqueness adjustment of sheets before detection. This ensures that all sheets are standardized in their state when measured, achieving consistent detection results without sacrificing process efficiency since the register operation is already part of the normal sheet handling process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent inverts the detection timing from before register adjustment to after register adjustment. This inversion allows detection to occur when sheets are in a standardized state, improving consistency while maintaining productivity because the register operation precedes detection in the natural process flow.

Inventive Principle:

Principle #13The other way round (Inversion)

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 the accuracy of multi-feed detection by maintaining consistent light transmission measurements across the sheet, improving the reliability of detecting sheet overlap.

Implementation Method 1

The light transmission sensor measures the amount of light transmission of a sheet on the sheet transfer route so as to detect the multi-feeding of sheets since the amount of light transmission is dependent on a thickness of a sheet

Methodology Applied

Scientific EffectLight transmission: Absorption (EM radiation)

Data Source

PatentUS7950657B2Printing apparatus

Publication Date: 2011.05.31 RISO KAGAKU CORP

AI summary

A printing apparatus includes: a printing mechanism forming an image on a sheet transferred in a sheet transfer route; a sheet feeding mechanism feeding sheets to the sheet transfer route; a register provided between the sheet feeding mechanism and the printing mechanism on the sheet transfer route so as to position a sheet fed from the sheet feeding mechanism and adjust an obliqueness of the sheet; an edge part detector provided on the sheet transfer route having a detecting section configured between the register and the printing mechanism so as to detect edge parts of a sheet transferred to the printing mechanism by the register, wherein the edge part detector is configured to serve as a multi-feed detector to detect multi-feeding of sheets.