Cartridge Drive Train With Closed-Loop Torque Limiting

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Solution Overview

Problem

Existing image forming apparatuses face challenges in efficiently driving replaceable units, such as cartridges, due to non-loop transmission paths that can lead to inefficiencies and potential mechanical issues.

Innovation Solution

A closed-loop drive transmission system is implemented, utilizing a motor-driven body drive train with parallel first and second drive transmission portions, including a torque limiter, to provide both driving and braking forces to the replaceable units, ensuring stable operation and efficient energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a non-loop transmission path is used to drive the photosensitive drum, then the structure is simpler, but the driving efficiency and stability deteriorate

Engineering Contradiction:
Improvetransmission path structureVSAvoiddriving stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The transmission path is divided into two separate portions: a first drive transmission portion that transmits driving force in the normal rotation direction, and a second drive transmission portion that transmits braking force in the reverse rotation direction. This segmentation allows each portion to be optimized for its specific function, improving overall driving stability while maintaining structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a single transmission path that handles both driving and braking, the invention uses two separate transmission paths where one path is dedicated to driving and the other to braking. This inverted approach of separating functions that were previously combined resolves the contradiction by providing stable driving through specialized paths while keeping the overall structure manageable.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If a single transmission path is used for both driving and braking, then the device complexity is reduced, but the energy transfer efficiency deteriorates

Engineering Contradiction:
Improvetransmission path configurationVSAvoidenergy transfer efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The transmission system is segmented into two distinct paths: one optimized for transmitting driving force efficiently in the normal rotation direction, and another optimized for transmitting braking force in the reverse direction. This segmentation prevents energy loss that would occur in a single path attempting to handle both opposing force directions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The engagement member acts as an intermediary that selectively connects either the first drive transmission portion or the second drive transmission portion to the photosensitive drum based on operational requirements. This intermediary mechanism ensures efficient energy transfer by directing forces through the appropriate transmission path without energy dissipation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 closed-loop drive transmission system enhances the stability and efficiency of driving replaceable units, reducing mechanical stress and improving the overall performance and reliability of the image forming apparatus.

Implementation Method 1

a torque limiter that is interposed between the drive transmission unit and the replaceable unit and that limits torque transmitted from the drive transmission unit to the replaceable unit

Methodology Applied
Scientific EffectTorque limiting: Friction

Data Source

PatentEP4703805A1Image forming apparatus
Publication Date: 2026.03.04 CANON KK
  • EP4703805A1 patent drawingFigure 1
  • EP4703805A1 patent drawingFigure 2
  • EP4703805A1 patent drawingFigure 3

AI summary

An image forming apparatus includes a replaceable unit (P) including a driven portion (61, 63), and an apparatus body (1A) to which the replaceable unit (P) is detachably attached. The apparatus body (1A) includes (i) a driving unit (1Dd) including a drive source (301) and an output portion (302), (ii) a first drive transmission portion (1D1) connected to the output portion (302) and to the replaceable unit (P), and (iii) a second drive transmission portion (1D2) including an allowance mechanism (410, 500) and connected to the output portion (302) and to the replaceable unit (P). The allowance mechanism (410, 500) includes a first rotary member (410a, 500a) and a second rotary member (410b, 500b) and configured to transmit the driving force between the first rotary member (410a, 500a) and the second rotary member (410b, 500b).