Optical Sheet Detection Mechanism for Compact Printer Feeder

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Solution Overview

Problem

Conventional sheet feeding apparatuses for image forming devices face issues with increased costs due to the need for multiple parts and complex configurations, particularly in detecting the remaining sheet amount, which can lead to unstable determination and large apparatus sizes.

Innovation Solution

A sheet feeding apparatus utilizing a stacking member with a first optical sensor and a detected member that interrupts the light path, a storage unit to store position information, and a control unit to transmit sheet amounts, allowing for efficient detection and display of remaining sheets without the need for encoders or complex gear systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an encoder is disposed in a rotation unit of a lift motor to continuously monitor sheet remaining amount, then detection accuracy is improved, but the number of parts increases and cost increases

Engineering Contradiction:

Improvesheet remaining amount detection accuracyVSAvoidnumber of parts

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from the complex encoder system and implements it using a simple optical sensor and interrupting plate mechanism. The optical sensor detects the position of the interrupting plate which moves with the stacking tray, providing sheet remaining amount detection without requiring an encoder in the lift motor rotation unit.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical encoder system with an optical detection system. Instead of using mechanical pulses from an encoder to measure rotation angle and moving amount, the system uses an optical sensor to detect the position of an interrupting plate, substituting mechanical measurement with optical detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If multiple sensors and a large flag are used to interrupt light paths for detecting sheet remaining amount, then detection reliability is improved, but apparatus size becomes large and configuration becomes complicated

Engineering Contradiction:

Improvesheet remaining amount detection reliabilityVSAvoidconfiguration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the detection function into a single optical sensor system with an interrupting plate, rather than using multiple sensors. The interrupting plate is designed to interrupt the light path of one optical sensor at specific positions, combining multiple detection functions into a single integrated mechanism.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of using multiple sensors to detect the flag position, the patent inverts the approach by using a single sensor and a moving interrupting plate that actively interrupts the light path at different positions. This reverses the traditional configuration and achieves the same detection reliability with simpler means.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If gears and pulleys are included in the apparatus mechanism, then sheet lifting function is achieved, but the overall apparatus size increases

Engineering Contradiction:

Improvesheet lifting functionVSAvoidapparatus size

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical gear and pulley transmission system with a direct optical detection mechanism. The stacking tray is directly connected to the interrupting plate without requiring intermediate mechanical transmission components, eliminating gears and pulleys while maintaining the sheet lifting function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces costs and complexity while providing stable and accurate detection of the remaining sheet amount, preventing unstable determination and ensuring a compact apparatus design.

Implementation Method 1

a first optical sensor including a light-emitting unit and a light-receiving unit, a detected member which can interrupt light in a light path of the first optical sensor

Methodology Applied

Scientific EffectLight interruption detection: Absorption (EM radiation)

Data Source

PatentUS9650220B2Sheet feeding apparatus and image forming apparatus

Publication Date: 2017.05.16 CANON KK

AI summary

A sheet feeding apparatus includes a stacking member, an optical sensor, a detected member, and a control unit. As an amount of sheets stacked on the stacking member decreases, the detected member moves from a first position in which optical sensor light is not interrupted, then once interrupts the light, and then moves to a second position in which the light is not interrupted. Information regarding an amount of sheets transmitted by the control unit, when stored information is about the detected member in the second position, is information notifying that an amount of sheets stacked on the stacking member is less than that of information regarding an amount of sheets stacked on the stacking member transmitted by the control unit when stored information is about the detected member is in the first position.