Transfer Roller Contact Mechanism for Short-Circuit Prevention

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Solution Overview

Problem

The high cost of interlock switches used to prevent short circuits when the cover of an image forming apparatus is opened, making it difficult to reduce the overall cost of the device.

Innovation Solution

A contact mechanism in the opening and closing unit that ensures the separation of electrical contacts without the need for an interlock switch, using a contact portion to move a second contact into and out of contact with a first contact based on the unit's opening and closing, utilizing the elastic force of a power supply line to maintain contact when closed and separate when opened.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an interlock switch is provided to prevent short circuits when the cover is opened, then safety is improved, but cost increases

Engineering Contradiction:

Improveshort circuit preventionVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the electrical contact function with the mechanical opening/closing motion of the cover. The contact portion is integrated into the opening and closing unit, so that the same mechanical motion that opens/closes the cover also automatically makes or breaks the electrical contact. This eliminates the need for a separate interlock switch while maintaining safety.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The opening and closing unit serves multiple functions: it mechanically opens/closes the cover for access, and simultaneously controls the electrical circuit through the contact portion. This multi-functionality reduces the number of separate components needed, particularly eliminating the need for an additional interlock switch.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If an interlock switch is provided to prevent short circuits when the cover is opened, then safety is improved, but device complexity increases

Engineering Contradiction:

Improveshort circuit preventionVSAvoidcomponent count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the electrical contact control function from a separate interlock switch and integrates it directly into the opening and closing unit's mechanical structure. The contact portion is positioned such that it naturally makes or breaks the electrical circuit based on the cover's position, removing the need for additional safety switches.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If the transfer roller is separated from the image carrier when the cover is opened, then maintenance access is improved, but electrical contact reliability deteriorates

Engineering Contradiction:

Improvemaintenance accessVSAvoidelectrical contact

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by ensuring that the electrical contact is made before the transfer roller fully separates from the image carrier. The contact portion is positioned to establish electrical connection during the closing motion, and the spring-biased second contact ensures reliable contact before the roller is completely detached, allowing maintenance access while maintaining electrical reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a spring-biased contact mechanism that provides beforehand cushioning for electrical contact. The spring ensures that the second contact maintains sufficient pressure on the first contact to ensure reliable electrical connection, compensating for any variations in the closing motion and ensuring contact is established before full separation occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 short circuits during cover opening without the need for an interlock switch, reducing component count and cost, while ensuring reliable electrical contact separation.

Implementation Method 1

The power supply line includes a spring, and the second contact is biased toward the first contact by the spring

Methodology Applied

Scientific EffectElastic force: Elasticity

Data Source

PatentUS12602004B2Image forming apparatus

Publication Date: 2026.04.14 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

An image forming apparatus includes a body housing, an opening and closing unit, an image carrier, a transfer roller, a power supply line, a power supply line side contact and a transfer roller side contact. The body housing has an opening. The opening and closing unit can be opened and closed in the opening. The image carrier is provided in the body housing. The transfer roller is provided in the opening and closing unit. The power supply line includes a first contact, and a second contact. The opening and closing unit includes a contact portion which comes into contact with the second contact and moves the second contact. The contact portion makes the second contact come into contact with the first contact when the opening and closing unit is closed, and makes the second contact separate from the first contact when the opening and closing unit is opened.