Cleaning Toner Image for Fixing Roller Maintenance

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Solution Overview

Problem

Existing image forming apparatuses face issues with toner adhesion and offset during the fixing process, leading to faulty toner images due to stain toner on the fixing rollers, which affects the quality of printed images.

Innovation Solution

An image forming apparatus and method that includes a cleaning toner image with increased toner density in a cleaning region and a check toner image with decreased toner density in a check region on a cleaning sheet, which is conveyed through a fixing nip with at least one rotator adhered with stain toner, allowing effective removal and verification of stain toner adhesion without causing offset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the fixing roller is heated to a high fixing temperature to ensure proper toner fixation, then the toner image quality is improved, but stain toner adheres to the fixing roller surface, causing faulty toner images in subsequent printing

Engineering Contradiction:

Improvetoner image qualityVSAvoidstain toner adhesion

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by forming a cleaning toner image on the cleaning sheet before it enters the fixing nip. This pre-formed toner image serves as a cleaning medium that will remove stain toner from the fixing roller surface during the fixing process, preventing the stain toner from causing faulty images in subsequent printing operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cleaning sheet with the cleaning toner image acts as an intermediary substance between the fixing roller and the subsequent toner images. The cleaning toner on the sheet surface facilitates the removal of stain toner from the fixing roller through adhesion and transfer mechanisms, thereby preventing direct contact between stain toner and the next toner image

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If the fixing roller is heated to a low temperature to prevent stain toner adhesion, then stain toner removal is improved, but the toner image may not fix properly

Engineering Contradiction:

Improvestain toner removalVSAvoidtoner image fixation

Core Design Contradiction:

Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by carefully controlling the fixing roller temperature to be within a specific range (90°C to 150°C) that balances two opposing requirements: high enough to ensure proper toner fixation and low enough to prevent excessive stain toner adhesion. This optimized temperature parameter allows the cleaning toner image to effectively remove stain toner while maintaining proper image fixation quality

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If a cleaning sheet without toner image is used to remove stain toner, then the process is simple, but the cleaning effectiveness is insufficient

Engineering Contradiction:

Improvecleaning process simplicityVSAvoidcleaning effectiveness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The cleaning toner image on the cleaning sheet acts as a copy or replica of the toner image that will be used for cleaning purposes. This toner copy facilitates the cleaning process by providing a controlled amount of toner that can adhere to and remove stain toner from the fixing roller surface

Inventive Principle:

Principle #26Copying

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 removes stain toner from the fixing rollers, preventing faulty toner images and improving the usability and reducing toner waste by ensuring proper adhesion and fixation of images during the printing process.

Implementation Method 1

a heater heats the first rotator to a cleaning temperature that is lower than a fixing temperature to which the first rotator is heated in a print job and higher than a cold offset temperature at which toner adheres to the first rotator by cold offset

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

higher than a cold offset temperature at which toner adheres to the first rotator by cold offset

Methodology Applied

Scientific EffectCold offset: Adsorption

Data Source

PatentUS9395660B2Image forming apparatus and image forming method including forming a cleaning toner image

Publication Date: 2016.07.19 RICOH CO LTD

AI summary

An image forming apparatus includes an image forming device to form a cleaning toner image in a cleaning region on a cleaning sheet and a check toner image in a check region on the cleaning sheet. The image forming apparatus further includes a fixing device including a first rotator and a heater to heat the first rotator to a cleaning temperature that is lower than a fixing temperature to which the first rotator is heated in a print job and higher than a cold offset temperature at which toner adheres to the first rotator by cold offset. Each of the cleaning region and the check region has a length greater than a circumferential length of the first rotator. The cleaning region and the check region are disposed at a leading section and a trailing section of the cleaning sheet in a cleaning sheet conveyance direction, respectively.