Switchable Primary Transfer Rollers for Special-Color Toner Control

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Solution Overview

Problem

Existing image forming apparatuses face challenges in preventing excessive consumption of special color toner when transferring images in a desired order, as the primary transfer rollers for special colors are often separated from the photoconductor regardless of image formation, leading to unnecessary toner waste.

Innovation Solution

A transfer device with adjustable primary transfer rollers that can switch between contact and separation positions based on image formation needs, allowing for the transfer of special color toner in a desired order and minimizing unnecessary consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the primary transfer roller for special color is separated from the photoconductor when special color toner image is not formed, then excessive consumption of special color toner is prevented, but the desired order of transferring toner images cannot be controlled

Engineering Contradiction:
Improvespecial color toner consumptionVSAvoidtransfer order control
Core Design Contradiction:
Loss of substanceVSAdaptability or versatility

Solution Approach 1:

The patent makes the primary transfer roller dynamically adjustable between contact and separation positions based on whether special color toner image formation is required. This dynamic positioning allows the system to adapt to different printing needs, preventing toner waste when special color is not needed while enabling transfer order control when it is needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the positional parameter of the primary transfer roller relative to the photoconductor and intermediate transfer belt. By adjusting the distance and position parameters, the system can control both toner consumption and transfer sequence, resolving the contradiction between preventing waste and maintaining flexibility.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the primary transfer roller is always in contact with the photoconductor, then the desired order of transferring toner images can be controlled, but excessive consumption of special color toner occurs

Engineering Contradiction:
Improvetransfer order controlVSAvoidspecial color toner consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent implements periodic contact and separation of the primary transfer roller with the photoconductor based on the printing requirements. The roller is brought into contact only when special color toner image formation is needed, and separated when it is not needed, creating a periodic action pattern that prevents continuous toner consumption while maintaining transfer order control capability.

Inventive Principle:
Principle #19Periodic action

3Loss of substance

If the primary transfer roller is separated from the photoconductor, then toner consumption is reduced, but interference between photoconductors and the intermediate transfer belt may occur

Engineering Contradiction:
Improvespecial color toner consumptionVSAvoidphotoconductor and intermediate transfer belt interference
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent uses the adjustable primary transfer roller as an intermediary element that mediates between the photoconductor and the intermediate transfer belt. By controlling the roller's position, the system can prevent direct interference between the photoconductor and belt while still enabling toner transfer when needed, thus reducing toner waste without causing harmful interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4290311B1Transfer device and image forming apparatus
Publication Date: 2025.10.29 RICOH CO LTD
  • EP4290311B1 patent drawingFigure 1~2
  • EP4290311B1 patent drawingFigure 3A~3F
  • EP4290311B1 patent drawingFigure 4~5

AI summary

A transfer device (20) includes an intermediate transferor (2) and primary transfer sections (201, 202, 203) each including a primary transferor (7Y, 7M, 7C, 7K, 7T). The primary transfer sections includes most-upstream (201) and most-downstream (203) primary transfer sections. One of the primary transfer sections is a special-color primary transfer section switchable between the most-upstream and most-downstream primary transfer sections. The primary transferor of each of the most-upstream and most-downstream primary transfer sections is switchable between a contact position at which the primary transferor contacts a latent image bearer (3K, 3C, 3M, 3Y, 3T) and a separation position at which the primary transferor is separated from the latent image bearer. With only the primary transferor of the special-color primary transfer section at the separation position, the primary transferor of any other primary transfer section than the special-color primary transfer section is arranged at the contact position to transfer an image.