Drum Cover Ozone Blocking in Corona-Charged Image Forming Units

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Solution Overview

Problem

Existing image forming apparatuses with corona charging devices face issues of increased parts and size due to the need for charging exhaust ducts and ozone remaining spaces, which increase costs and complexity.

Innovation Solution

An image forming apparatus with a drum unit that includes a photosensitive drum, corona discharging device, and a turnable drum cover that blocks the flow path to the outside when attached, allowing ozone to be retained within the apparatus, eliminating the need for additional parts and spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a charging exhaust duct and filter are provided to prevent ozone discharge, then ozone containment is improved, but the number of parts increases and cost increases

Engineering Contradiction:
Improveozone dischargeVSAvoidnumber of parts
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The drum cover is designed to serve dual functions: protecting the photosensitive drum when closed and blocking the ozone flow path when opened. This multi-functionality eliminates the need for separate exhaust ducts and filters, reducing part count while maintaining ozone containment effectiveness.

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

Solution Approach 2:

The invention merges the ozone blocking function with the existing drum cover structure. By integrating the flow path blocking capability into the drum cover that already exists for drum protection, the design combines multiple functions into a single component, avoiding additional parts.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If an ozone remaining space is formed to contain ozone, then ozone discharge is prevented, but the apparatus size increases

Engineering Contradiction:
Improveozone dischargeVSAvoidapparatus size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The drum cover serves as both a protective cover for the photosensitive drum and a dynamic barrier for ozone containment. When opened, it blocks the flow path between the corona charging device and the exterior, using the existing cover structure rather than requiring additional containment spaces.

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

Solution Approach 2:

The drum cover transitions between closed and open states dynamically. When closed, it protects the drum; when opened, it blocks the ozone flow path. This dynamic positioning allows the system to adapt to different operational states without requiring permanent structural modifications or additional space.

Inventive Principle:
Principle #15Dynamics

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

Reduces ozone discharge to the outside by retaining it within the apparatus, simplifying the mechanism and reducing the number of parts and apparatus size without additional space requirements.

Implementation Method 1

The corona discharging device corona-charges the photosensitive drum

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Data Source

PatentEP4671874A1Image forming apparatus
Publication Date: 2025.12.31 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4671874A1 patent drawingFigure 1
  • EP4671874A1 patent drawingFigure 2
  • EP4671874A1 patent drawingFigure 3

AI summary

An image forming apparatus (1) includes an apparatus main body (3) and a drum unit (31). The apparatus main body (3) has an opening (27) and a drum unit storage part (21) communicating with the opening (27). The drum unit (31) is detachably attached to the drum unit storage part (21) through the opening (27). The drum unit (31) includes photosensitive drum (41), a corona discharging device (43) and a drum cover (47). The corona discharging device (43) corona-charges the photosensitive drum (41). The drum cover (47) is turnable in a protective posture for covering the photosensitive drum (41) and an exposure posture for exposing the photosensitive drum (41). When the drum unit (31) is attached to the drum unit storage part (21), the drum cover (47) is turned from the protective posture into the expose posture to block a flow path communicating a space around the corona charging device (43) with an outside of the apparatus main body (3).