Paper Guide Member with Varying Protrusion Heights

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Solution Overview

Problem

Existing paper guide members in image forming apparatuses often result in back smears due to toner adhesion on the back surface of paper, particularly when sheets with varying widths pass through the system, as the static elimination process can cause toner to adhere to the guide member, leading to unsightly and unwanted toner transfer.

Innovation Solution

A paper guide member with thread-shaped protrusions of varying heights is designed, where first protrusions support and guide paper with equal heights across the width, and second protrusions with smaller heights are placed on the outer sides to prevent toner adhesion, ensuring the paper passes close to a static elimination member without contact, thereby reducing back smears.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If all thread-shaped protrusions have equal heights to support and guide paper, then paper guidance is stable, but toner adheres to the back surface of paper causing back smears

Engineering Contradiction:

Improvepaper guidance stabilityVSAvoidback smear

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The paper guide member implements different protrusion heights at different locations: central protrusions have height H1 for stable paper guidance, while outer protrusions have reduced height H2 (where H2 < H1) to prevent toner adhesion. This local differentiation allows the same structure to simultaneously achieve stable guidance and prevent back smears by adapting the protrusion height to the specific functional requirements of each region.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The paper guide member is segmented into multiple protrusions with different heights - first protrusions (height H1) in the central region and second protrusions (height H2) in the outer regions. This segmentation allows independent optimization of each region's function: the central region provides stable guidance while the outer regions prevent toner adhesion, resolving the contradiction between guidance stability and back smear prevention.

Inventive Principle:

Principle #1Segmentation

2Reliability

If paper passes close to the static eliminator, then static electricity is effectively eliminated, but toner adheres to the paper back surface

Engineering Contradiction:

Improvestatic elimination effectivenessVSAvoidtoner adhesion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The varying protrusion heights create different local gaps between the paper back surface and the static eliminator. In central regions, the larger gap (H1) prevents toner adhesion while still allowing static elimination. In outer regions, the reduced gap (H2) maintains effective static elimination. This local differentiation resolves the contradiction by optimizing the gap distance for each region's specific requirements.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If uniform protrusions are used, then manufacturing is simple, but back smears occur on wider paper sheets

Engineering Contradiction:

Improveprotrusion manufacturing simplicityVSAvoidback smear on wide paper

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The paper guide member implements local quality differentiation by providing different protrusion heights (H1 for central, H2 for outer regions) only where needed to prevent back smears on wide paper. The central protrusions maintain the simple uniform structure for ease of manufacture, while the outer protrusions are locally modified to have reduced height. This approach maintains manufacturing simplicity for the majority of the structure while locally addressing the back smear problem.

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

The solution effectively reduces back smears by preventing toner adhesion on the back surface of paper, ensuring stable and consistent image formation across different paper widths, as the paper is guided with a distance secured from the static elimination member, minimizing toner transfer issues.

Implementation Method 1

a static eliminator that eliminates static electricity in proximity to the paper in a width direction of the paper

Methodology Applied

Scientific EffectStatic electricity elimination: Electrostatics

Data Source

PatentUS11209763B2Paper guide member and image forming apparatus

Publication Date: 2021.12.28 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A paper guide member includes plural thread-shaped protrusions extending in a passing direction of paper to guide the paper after a toner image is transferred so that the paper passes with a distance secured from a static eliminator that eliminates static electricity in proximity to the paper in a width direction of the paper. The plural thread-shaped protrusions adjoin each other across a slit in the width direction of the paper. The plural thread-shaped protrusions include first thread-shaped protrusions each having a height at which the paper is supported and guided, and second thread-shaped protrusions each having a height smaller than the height of each of the first thread-shaped protrusions and present in regions on an outer side of both ends in the width direction of each passing region where paper having each width passes.