Intermediate Transfer Belt Current Supply for Image Forming Apparatus

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Solution Overview

Problem

Conventional image forming apparatuses require multiple voltage power supplies for primary transfer members, leading to increased size and cost due to the need for appropriate primary transfer voltage settings for each image forming unit.

Innovation Solution

Supplying current in the circumferential direction of an intermediate transfer belt from a current supply member eliminates the need for multiple voltage power supplies, allowing for both primary and secondary transfer using a single current supply member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple voltage power supplies are used for primary transfer members in each image forming unit, then appropriate primary transfer voltage settings can be achieved for each unit, but the size of the image forming apparatus and the number of power supplies increase, resulting in cost increase

Engineering Contradiction:
Improveprimary transfer voltage setting appropriatenessVSAvoidnumber of power supplies
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the primary transfer function and secondary transfer function into a single transfer roller that performs both functions. By applying a single voltage to this combined transfer roller, the patent eliminates the need for separate voltage power supplies for primary and secondary transfer, thereby reducing the number of power supplies while maintaining appropriate transfer voltage settings for both functions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transfer roller is designed to serve multiple functions: it acts as both the primary transfer member for transferring toner from the photosensitive drum to the intermediate transfer belt, and as the secondary transfer member for transferring the toner image from the intermediate transfer belt to the recording sheet. This multi-functionality allows a single voltage power supply to control both transfer stages

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple voltage power supplies are used for primary transfer members, then each image forming unit can have optimized transfer voltage, but the cost of the image forming apparatus increases

Engineering Contradiction:
Improvetransfer voltage optimizationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines primary and secondary transfer functions into a single transfer roller system controlled by one voltage power supply. This merging reduces the total number of power supplies from multiple (one for each primary transfer member) to a single power supply, thereby reducing manufacturing cost while maintaining transfer voltage optimization through proper voltage selection

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple voltage power supplies are used for primary transfer members, then appropriate voltage control for each transfer stage is possible, but the overall size of the image forming apparatus increases

Engineering Contradiction:
Improvevoltage control precisionVSAvoidapparatus size
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges primary and secondary transfer functions into a single transfer roller, eliminating the need for separate power supplies and their associated control circuits. This consolidation reduces the spatial requirements for housing multiple power supplies and control components, thereby reducing the overall apparatus size while maintaining voltage control precision for both transfer stages through a single optimized voltage application

Inventive Principle:
Principle #5Merging (Combining)

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 configuration reduces the number of power supplies required, minimizing the size and cost of the image forming apparatus while maintaining effective primary and secondary transfer performance.

Implementation Method 1

an intermediate transfer belt for collectively and simultaneously transferring a plurality of toner images formed on a surface of a photosensitive drum onto a transfer material

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 2

a charging member for charging the photosensitive drum and a developing unit for developing a toner image on the photosensitive drum. The charging member of each image forming unit contacts the photosensitive drum with a predetermined pressure contact force to uniformly charge the surface of the photosensitive drum at a predetermined polarity and potential by using a charging voltage applied from a voltage power supply dedicated for charging

Methodology Applied
Scientific EffectElectrical charge: Electrostatics

Implementation Method 3

The developing unit of each image forming unit applies toner to an electrostatic latent image formed on the photosensitive drum to develop a toner image (visible image)

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 4

a primary transfer roller (primary transfer member) facing the photosensitive drum via the intermediate transfer belt primarily transfers the developed toner image from the photosensitive drum onto the intermediate transfer belt. The primary transfer roller is connected to a voltage power supply dedicated for primary transfer

Methodology Applied
Scientific EffectElectrical charge transfer: Electrostatics

Implementation Method 5

A secondary transfer member secondarily transfers the primarily transferred toner image from the intermediate transfer belt onto a transfer material. A secondary transfer roller (secondary transfer member) is connected to a voltage power supply dedicated for secondary transfer

Methodology Applied
Scientific EffectElectrical charge transfer: Electrostatics

Data Source

PatentEP2625572B1Image forming apparatus
Publication Date: 2019.09.11 CANON KK
  • EP2625572B1 patent drawingFigure 1
  • EP2625572B1 patent drawingFigure 2A~2B
  • EP2625572B1 patent drawingFigure 3A~3B

AI summary

An image forming apparatus sequentially transfers toner images formed on a plurality of photosensitive drums onto an intermediate transfer member or a transfer material to form an image. The image forming apparatus includes an intermediate transfer belt provided with electrical conductivity, and a power supply for applying a voltage to a secondary transfer roller to pass a current from the secondary transfer roller to the plurality of photosensitive drums via the intermediate transfer belt, thus primarily transferring the toner images from the plurality of photosensitive drums onto the intermediate transfer belt.