Transfer Member Cleaning Control for Envelope Flap Printing

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Solution Overview

Problem

Image forming apparatuses face contamination of transfer members due to toner protruding from envelope flaps, leading to back contamination of subsequent recording materials.

Innovation Solution

An image forming apparatus with a controller that alternates application of cleaning voltages of the same and opposite polarity to the toner's normal charge polarity during continuous printing when an envelope is used, ensuring effective cleaning of the transfer member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If images are formed on envelope flaps, then the image forming capability is improved, but the transfer member becomes contaminated with protruded toner

Engineering Contradiction:

Improveimage forming capability on envelope flapsVSAvoidtransfer member contamination

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection of envelope flaps and executes cleaning operations before the transfer member becomes contaminated with protruded toner. The controller detects when a flap is present and activates the cleaning mechanism in advance, preventing toner deposition on the transfer member surface.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful effect of protruded toner into a beneficial cleaning mechanism. By applying alternating polarity voltages, the system uses the toner's own electrical charge properties to attract and remove deposited toner particles from the transfer member, turning potential contamination into a self-cleaning process.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If cleaning operations are performed frequently, then the transfer member contamination is reduced, but the printing productivity is decreased

Engineering Contradiction:

Improvetransfer member contaminationVSAvoidprinting productivity

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

Instead of continuous cleaning, the system employs periodic cleaning operations triggered only when envelopes with flaps are detected. The controller monitors the printing sequence and activates cleaning at specific intervals when needed, rather than performing cleaning operations continuously or at fixed intervals, thus maintaining productivity while preventing contamination.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses feedback from envelope detection to control cleaning operations. When an envelope flap is detected, the controller receives this information and adjusts the cleaning frequency accordingly, activating cleaning only when contamination risk is present. This feedback mechanism ensures cleaning is performed optimally without unnecessary interruptions to printing productivity.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If alternating polarity voltages are applied, then the toner removal efficiency is improved, but the energy consumption is increased

Engineering Contradiction:

Improvetoner removal efficiencyVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The system applies alternating polarity voltages in advance during detected flap conditions, removing toner before it becomes firmly deposited. This preliminary cleaning action reduces the overall energy required compared to intensive cleaning operations needed after heavy contamination occurs, as prevention requires less energy than remediation.

Inventive Principle:

Principle #10Preliminary action

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

Prevents contamination of subsequent recording materials by efficiently removing toner from the transfer member, even when images are formed on envelope flaps.

Implementation Method 1

a transfer voltage of an opposite polarity to a normal charge polarity of toner is applied, and the toner is electrostatically attracted to the recording material

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

a voltage of an opposite polarity to a voltage during the transfer is applied to the transfer member, so that an electric field in a direction opposite to an electric field during the transfer is formed between the transfer member and the image bearing member

Methodology Applied

Scientific EffectElectric field: Electric Field

Data Source

PatentUS20260064062A1Image forming apparatus

Publication Date: 2026.03.05 CANON KK

AI summary

An image forming apparatus includes an image bearing member; a toner image forming portion, a transfer member, a voltage applying portion, an acquiring portion, and a controller. In continuous printing in which toner images are continuously transferred onto a first recording material and a second recording material, in a case that the first recording material is an envelope on the basis of recording material information, the controller carries out control so that a transfer member cleaning operation, in which a first cleaning voltage of the same polarity as a normal charge polarity of toner and a second cleaning voltage of an opposite polarity to the normal charge polarity of the toner are alternately applied by the voltage applying portion, is executed after the first recording material passes through the transfer portion and before the second recording material reaches the transfer portion.