Print Head Lifting Mechanism with Biasing Member for Image Forming Apparatus

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Solution Overview

Problem

Existing exposure devices in image forming apparatuses face challenges in accurately determining and maintaining the focal position of print heads relative to photoreceptors, leading to potential image quality deterioration and uneven wear of photoreceptor drums due to variations in abutting load and inclination.

Innovation Solution

The exposure device incorporates a lifting mechanism with a biasing member, such as a pair of coil springs, to maintain a predetermined abutting load on the print head, and a configuration where the lifting holder and head position determining units abut on the photoreceptor case and gap spacer respectively, ensuring consistent alignment and load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a gap spacer and positioning unit are used to determine focal position, then the print head position can be determined, but variations in abutting load and inclination cause image quality deterioration and uneven wear

Engineering Contradiction:
Improvefocal position determinationVSAvoidimage quality consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention introduces a lifting mechanism with a lifting holder that can dynamically adjust the print head position vertically. The lifting holder includes a lifting holder position determining unit that abuts on the case, while the head position determining unit abuts on the gap spacer. This dynamic positioning system ensures that the print head maintains a predetermined abutting load on the photoreceptor through a biasing member, preventing both excessive pressure and insufficient contact, thereby resolving the contradiction between position determination and image quality consistency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of abutting load by introducing a biasing member (such as a coil spring) that applies a predetermined force between the print head and lifting holder. This ensures consistent contact pressure between the print head and photoreceptor, maintaining focal position accuracy while preventing uneven wear and image quality deterioration caused by variable abutting loads.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the print head is held firmly against the photoreceptor, then focal position accuracy is maintained, but the photoreceptor experiences uneven wear and image quality deterioration

Engineering Contradiction:
Improvefocal position accuracyVSAvoidphotoreceptor wear
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention controls the abutting load parameter by using a biasing member that applies a predetermined, optimized force. This force is sufficient to maintain focal position accuracy but controlled to prevent excessive pressure that would cause uneven wear on the photoreceptor surface, thus resolving the contradiction between maintaining contact and preventing damage.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If a lifting mechanism is added to adjust print head position, then alignment consistency is improved, but device complexity increases

Engineering Contradiction:
Improvealignment consistencyVSAvoidmechanism structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The lifting mechanism provides dynamic adjustment capability for the print head position, allowing the system to maintain alignment consistency despite variations in component dimensions or assembly tolerances. The lifting holder and its position determining units create a simple yet effective dynamic positioning system that improves stability without requiring complex control mechanisms.

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

This configuration ensures reliable and consistent alignment of the print head with the photoreceptor drum, preventing image quality deterioration and uneven wear, by maintaining a predetermined abutting load and minimizing variations in focal position, thus enhancing the stability and accuracy of the image forming process.

Implementation Method 1

a biasing member that biases the print head toward the photoreceptor, the biasing member provided between the print head and the lifting holder

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a lens that condenses light emitted from the light emitting unit on the photoreceptor

Methodology Applied
Scientific EffectLight condensation: Lens

Data Source

PatentEP3862816B1Exposure device of image forming apparatus
Publication Date: 2023.10.18 TOSHIBA TEC KK
  • EP3862816B1 patent drawingFigure 1
  • EP3862816B1 patent drawingFigure 2~4
  • EP3862816B1 patent drawingFigure 5

AI summary

According to one embodiment, there is provided an exposure device including a print head that exposes photoreceptor to form a latent image on the photoreceptor, a lifting mechanism that lifts or lowers the print head relative to the photoreceptor, and a biasing member that biases the print head toward the photoreceptor. The lifting mechanism has a lifting holder that holds the print head and is liftable with respect to the photoreceptor. The biasing member is provided between the print head and the lifting holder.