Dual-Layer Toner Transfer for Rough Media

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Image forming apparatuses face challenges in producing high-quality images on mediums with significant surface roughness, as existing techniques struggle to evenly fill concave areas with developer, leading to image degradation.

Innovation Solution

The apparatus employs a dual-layer transfer method, where a transparent or white toner image is first transferred onto the medium at a higher transfer voltage, followed by a colored image at a lower transfer voltage, ensuring even coverage and improved filling of irregular surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-layer transfer method is used on mediums with great surface roughness, then the transfer process is simple, but the concave parts cannot be filled with developer, leading to image quality degradation

Engineering Contradiction:
Improvetransfer process simplicityVSAvoidimage quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent divides the transfer process into two separate stages: first transferring a white toner image, then transferring a colored toner image. This segmentation allows each transfer to be optimized independently - the white toner fills the concave parts of rough surfaces, while the colored toner provides the final image quality, thereby resolving the contradiction between process simplicity and image quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The white toner transfer is performed as a preliminary action before the colored toner transfer. The white toner layer is first applied to fill the concave portions of the rough medium surface, creating a smoother base layer. This preliminary filling action enables the subsequent colored toner to be transferred evenly, achieving high image quality without complicating the overall process.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If transfer voltage is increased to improve toner transfer completeness, then more toner is transferred, but fine line reproduction deteriorates due to excessive toner accumulation

Engineering Contradiction:
Improvetoner transfer amountVSAvoidfine line reproduction
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies different transfer voltages to different transfer stages: a first transfer voltage for the white toner and a second transfer voltage for the colored toner. This local differentiation of transfer conditions allows the white toner to fill concave areas adequately while the colored toner transfers with precise control for fine line reproduction, resolving the contradiction between transfer completeness and fine detail quality.

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 approach enhances image quality by effectively transferring toner onto both depressed and protruded areas, improving the filling amount and reproducibility of fine lines on mediums with great surface irregularities.

Implementation Method 1

a transfer member transfers the developer image onto the medium on the basis of a transfer condition

Methodology Applied
Scientific EffectElectrostatic induction: Electrostatic Induction

Data Source

PatentEP3324241B1Image forming apparatus
Publication Date: 2021.12.29 OKI ELECTRIC INDUSTRY CO LTD
  • EP3324241B1 patent drawingFigure 1
  • EP3324241B1 patent drawingFigure 2
  • EP3324241B1 patent drawingFigure 3A~3B

AI summary

An image forming apparatus includes an image forming section (103) and a transfer section (104). The image forming section (103) includes a first image forming unit (30T, 30W) that forms a first developer image (TT, WT, TT1) and a second image forming unit (30Y, 30M, 30C, 30K) that forms a second developer image (YT, MT, CT, TT2). The transfer section (104) transfers, on a basis of a first transfer condition, the first developer image (TT, WT, TT1) onto a medium (PM), and transfers, on a basis of a second transfer condition, the second developer image (YT, MT, CT, TT2) onto the medium (PM) onto which the first developer image (TT, WT, TT1) has been transferred. The second transfer condition is different from the first transfer condition.