Single-Facet Spindle Laser Scanner Moiré Defect Reduction

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Solution Overview

Problem

Laser scanner systems with multiple facets suffer from print and scan defects such as moiré due to variations in positioning, orientation, and flatness, which degrade image quality, especially in multi-color implementations.

Innovation Solution

Implementing a laser scanner system with a single facet spindle assembly that reflects the optical scanning beam only from a single facet during each scan operation, eliminating the need for a polygon mirror arrangement and reducing the spindle's size and air drag, thereby minimizing defects and maintaining rapid scanning speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If multiple facets are used in the spindle, then scanning speed is improved, but print and scan defects such as moiré increase due to variations in positioning, orientation, and flatness

Engineering Contradiction:
Improvescanning speedVSAvoidfacet positioning and orientation precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent extracts and eliminates the problematic multi-facet structure, retaining only a single facet in the spindle assembly. This removes the source of positioning and orientation variations between multiple facets, thereby eliminating moiré defects while preserving scanning functionality through the single remaining facet.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies extreme local quality by making the entire scanning function depend on a single facet with optimized local properties. Rather than having multiple facets with varying qualities, the system concentrates all scanning requirements on one precisely manufactured facet, ensuring uniformity and eliminating inter-facet variability.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If multiple facets are used in the spindle, then scanning coverage is improved, but device complexity increases

Engineering Contradiction:
Improvescanning coverageVSAvoidspindle structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent simplifies the spindle structure by extracting only the essential scanning function from the complex multi-facet arrangement. The single-facet design removes unnecessary structural elements while maintaining the core scanning capability, thereby reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The single facet is designed to perform multiple functions: it provides scanning coverage, maintains precise positioning, and eliminates the need for complex synchronization between multiple facets. This universal facet replaces the entire multi-facet system, reducing overall structural complexity.

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

3Speed

If multiple facets are used in the spindle, then scanning speed is improved, but acoustic noise increases due to air drag

Engineering Contradiction:
Improvescanning speedVSAvoidacoustic noise from air drag
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent removes the source of air drag-induced noise by extracting the multi-facet structure and replacing it with a single facet. This reduction in structural complexity and surface area minimizes air resistance during rotation, thereby decreasing acoustic noise generation while maintaining scanning speed.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If a polygon mirror arrangement is used, then scanning functionality is achieved, but spindle size increases

Engineering Contradiction:
Improvescanning functionalityVSAvoidspindle size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent extracts only the essential reflecting surface from the polygon mirror arrangement, retaining a single facet instead of multiple mirrors. This eliminates the need for a complex polygon structure while preserving the scanning functionality, thereby significantly reducing spindle volume.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution significantly reduces print and scan defects like moiré, allows for high-speed scanning comparable to multi-facet systems, and decreases acoustic noise, while maintaining performance and reducing the spindle's size and power consumption.

Implementation Method 1

a laser scanner system with a single facet spindle assembly that reflects the optical scanning beam only from a single facet

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2951982B1Single-facet spindle implementation for a laser scanner system
Publication Date: 2019.10.09 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2951982B1 patent drawingFigure 1~2
  • EP2951982B1 patent drawingFigure 3~4

AI summary

A system includes a laser scanner system. The system includes a scanner laser to generate an optical scanning beam. The system also includes a spindle assembly comprising a spindle that extends along an axis and reflects the optical scanning beam. The system also includes a beam detector to receive the reflected optical scanning beam from the single facet and to indicate when to generate a latent image corresponding to an image based on the optical scanning beam for a given scan operation. The system further includes a scan controller to control the scanner laser such that the optical scanning beam is reflected from only a single facet of the spindle during the given scan operation.