Sheet Feed Encoder Layout for Accurate Remaining Sheet Detection

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Solution Overview

Problem

Conventional sheet feeding devices are prone to erroneous detection of the remaining number of sheets due to incorrect determination of the home position, leading to inaccurate sheet counting.

Innovation Solution

The sheet feeding device incorporates an encoder with a rotation member divided into first and second detection regions, featuring detection targets of varying lengths and intervals, and an optical sensor to adjust the pulse signal based on the rotation of the turning shaft, ensuring accurate sheet counting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple encoder with uniform detection targets is used, then the device complexity is reduced, but the measurement precision of sheet count detection deteriorates due to erroneous home position detection

Engineering Contradiction:

Improveencoder structureVSAvoidsheet count detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The encoder's detection region is segmented into first detection regions and second detection regions that are alternatively arranged in the circumferential direction. This segmentation allows the system to distinguish between different detection zones, enabling accurate home position identification and preventing erroneous detection that would occur with a uniform encoder structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The detection targets in the first detection region have a different circumferential length compared to those in the second detection region. Specifically, the detection target at the tail end of the first detection region is formed longer than other detection targets. This asymmetric design creates a unique detection pattern that allows the control unit to accurately identify the home position and distinguish it from other positions, thereby improving measurement precision without significantly increasing device complexity.

Inventive Principle:

Principle #4Asymmetry

2Manufacturing precision

If the detection targets are arranged at equal intervals, then the manufacturing precision is improved, but the reliability of sheet count detection deteriorates due to inability to distinguish home position

Engineering Contradiction:

Improvedetection target arrangementVSAvoidhome position detection accuracy

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

While detection targets are arranged at equal intervals in both first and second detection regions, the detection target in the first detection region has a different circumferential length (is formed longer) than those in the second detection region. This local quality variation creates a distinctive detection signature at the home position, allowing the control unit to reliably distinguish the home position from other positions while maintaining the simplicity of equal interval arrangement for manufacturing.

Inventive Principle:

Principle #3Local quality

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 design prevents erroneous sheet detection by providing precise control over the lift plate movement, ensuring accurate counting of remaining sheets and enhancing the reliability of the sheet feeding process.

Implementation Method 1

The optical sensor includes a light emitting portion and a light receiving portion which are arranged opposite each other across a movement path of the detection targets, and changes a level of the pulse signal depending on whether light from the light emitting portion reaches the light receiving portion.

Methodology Applied

Scientific EffectLight detection: Light

Data Source

PatentUS12613488B2Sheet feeding device and image forming apparatus including same

Publication Date: 2026.04.28 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A rotation member is divided into a first detection region and a second detection region. A first interval in the circumferential direction between the detection target located at the tail end of the first detection region in the main rotation direction and the detection target located at the front end of the second detection region in the main rotation direction is less than a second interval in the circumferential direction between the detection target located at the tail end of the second detection region in the main rotation direction and the detection target located at the front end of the first detection region in the main rotation direction.