Compact Image Forming Apparatus High-Speed Photoreceptor

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Solution Overview

Problem

Current image forming apparatuses face challenges in producing high-quality, high-speed images with resolutions of at least 1,200 dpi in a compact form, as they struggle with the limitations of photoreceptor diameter, charger capabilities, and irradiation-development time, leading to issues with image density and color balance.

Innovation Solution

A compact image forming apparatus with an electrostatic latent image bearer, a charger, an irradiator, an image developer, a transferer, and a fixer, where the traveling time from the irradiator to the image developer is optimized to be shorter than 50 msec but longer than the transit time, utilizing a photoreceptor with a photosensitive layer comprising a charge generation layer and a charge transport layer, and optionally including a cleaner, discharger, recycler, and controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the photoreceptor diameter is reduced to make the apparatus compact, then the apparatus size decreases, but the image forming speed decreases

Engineering Contradiction:
Improveapparatus sizeVSAvoidimage forming speed
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent changes the rotational speed parameter of the photoreceptor to a high-speed rotation (not less than 40,000 rpm) to compensate for the reduced diameter. This allows the photoreceptor to maintain high image forming speed despite the compact size, resolving the contradiction between apparatus compactness and imaging speed.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the photoreceptor diameter is reduced to make the apparatus compact, then the apparatus size decreases, but the image quality deteriorates

Engineering Contradiction:
Improveapparatus sizeVSAvoidimage quality
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs high-speed rotation (not less than 40,000 rpm) and precise control of the traveling time (50-200 msec) to maintain image quality. The charge transport layer composition and photoreceptor surface potential responsiveness are optimized to ensure high-resolution images (not less than 1,200 dpi) despite the reduced diameter.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the traveling time is reduced to increase image forming speed, then the productivity increases, but the image density decreases

Engineering Contradiction:
Improveimage forming speedVSAvoidimage density
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the traveling time parameter to a specific range (50-200 msec) that balances speed and quality. The charge transport layer is designed with specific composition and thickness to control charge transport speed, ensuring that images are formed at high speed while maintaining sufficient image density and potential reduction.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the chargeability is improved to increase image forming speed, then the productivity increases, but the charger complexity increases

Engineering Contradiction:
Improveimage forming speedVSAvoidcharger complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical charging structures with a roller-shaped charger that uses electrical field control. By applying DC bias overlapped with AC bias to the roller, the chargeability is significantly improved without requiring complex multi-component charging systems, thus increasing productivity while controlling device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables the production of high-quality, durable, and stable images at high speeds with reduced abnormal images, improving image density and color reproducibility by controlling the transit time and optimizing the photoreceptor's surface potential responsiveness.

Implementation Method 1

an irradiator irradiating the electrostatic latent image bearer with imagewise light having an image resolution not less than 1,200 dpi to form an electrostatic latent image thereon

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

an image developer developing the electrostatic latent image with a toner to form a toner image on the electrostatic latent image bearer

Methodology Applied
Scientific EffectElectrostatic Attraction: Electrostatic Induction

Data Source

PatentEP1857884B1Image forming apparatus and image forming method
Publication Date: 2014.09.10 RICOH CO LTD
  • EP1857884B1 patent drawingFigure 1~2
  • EP1857884B1 patent drawingFigure 3~4
  • EP1857884B1 patent drawingFigure 5~8

AI summary

An image forming apparatus, including an electrostatic latent image bearer; a charger charging the electrostatic latent image bearer; an irradiator irradiating the electrostatic latent image bearer with imagewise light having an image resolution not less than 1,200 dpi to form an electrostatic latent image thereon; an image developer developing the electrostatic latent image with a toner to form a toner image on the electrostatic latent image bearer; a transferer transferring the toner image onto a recording medium; and a fixer fixing the toner image on the recording medium, wherein a time for a given point on the electrostatic latent image bearer to travel from a position right in front of the irradiator to a position right in front of the image developer is shorter than 50 msec and longer than a transit time of the electrostatic latent image bearer.