Rotatable Sheet Feeder Sensor Prevents Cassette Insertion Damage

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Solution Overview

Problem

The existing sheet feeder designs are prone to damaging the remaining amount detecting member when the sheet cassette is inserted, as the sensor piece can be caught by the side wall or the uppermost sheet, leading to inaccurate detection of the remaining sheet amount.

Innovation Solution

A sheet feeder with a rotatable contact piece and a switching member that adjusts its position between a contact and retracted position, ensuring the contact piece enters the storage space only when the sheet cassette is inserted and withdrawn, preventing damage and ensuring accurate detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor piece is formed to come into contact with the uppermost sheet in a direction opposite from the inserting direction of the sheet cassette, then the remaining amount of sheets can be detected, but the sensor piece is easily caught by the side wall or uppermost sheet when the sheet cassette is inserted, causing damage

Engineering Contradiction:

Improveremaining amount detection accuracyVSAvoidsensor piece durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The contact piece is made rotatable about a rotation axis, allowing it to dynamically adjust its position. When the sheet cassette is inserted, the contact piece can rotate to avoid being caught by the side wall or uppermost sheet, preventing damage while still enabling remaining amount detection when the cassette is properly positioned

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The switching member performs preliminary action by switching the contact piece to a retracted position before the sheet cassette is inserted. This prevents the contact piece from being in a vulnerable position where it could be caught by the side wall during insertion, thereby protecting the sensor piece from damage

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the contact piece enters the storage space to come into contact with the uppermost sheet, then accurate detection of remaining sheets is enabled, but the contact piece may be damaged when the sheet cassette is inserted

Engineering Contradiction:

Improveremaining amount detection accuracyVSAvoiddamage to detecting member

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The rotatable contact piece can dynamically adjust its position between entering and retracting from the storage space. This dynamic capability allows it to make contact with the uppermost sheet for accurate detection when needed, while avoiding damage by retracting when the sheet cassette is being inserted

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The switching member acts as an intermediary that controls the position of the contact piece. It switches the contact piece between the contact position and retracted position based on whether the sheet cassette is inserted, thereby protecting the contact piece from damage while enabling detection functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution effectively prevents damage to the remaining amount detecting member and ensures accurate detection of the sheet amount, allowing for reliable notification to the user when the sheet cassette needs replenishment.

Implementation Method 1

a rotatable contact piece and detecting a remaining amount of the sheets in the sheet cassette according to a position of the contact piece

Methodology Applied

Scientific EffectRotation:

Implementation Method 2

a photosensor which is a photointerrupter, and a light shielding piece for shielding light from the photosensor

Methodology Applied

Scientific EffectLight shielding: Absorption (EM radiation)

Data Source

PatentUS8282093B2Sheet feeder and image forming apparatus provided with the same

Publication Date: 2012.10.09 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A sheet feeder includes a sheet cassette insertable into a housing in a first direction, a remaining amount detecting member including a contact piece extending in a second direction opposite to the first direction and coming into contact with an uppermost sheet, and detecting a remaining amount of sheets according to a position of the contact piece, and a switching member switching the position of the contact piece between a contact position where the contact piece enters a storage space to come into contact with the uppermost sheet and a retracted position where the contact piece is retracted from the storage space. The position is switched to the contact position when the sheet cassette is inserted into the housing in the first direction and set to a feeding position while switched to the retracted position when the sheet cassette is separated from the feeding position and withdrawn from the housing.