Acousto-Optic Beam Steering for Laser Printers

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Solution Overview

Problem

Conventional laser printing systems face noise and wear issues due to the use of rotating mechanical components for scanning the laser light beam across the photoreceptor drum.

Innovation Solution

A non-mechanical optical beam-steering mechanism using a solid-state device with a waveguide core, liquid crystal material, and a substrate, which steers the laser beam across the photoreceptor drum without mechanical parts, by controlling the refractive index to achieve high-speed scanning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rotating polygonal mirror is used to scan the laser light beam, then the beam can be scanned across the photoreceptor drum, but noise and wear are generated due to repeated rotation of mechanical parts

Engineering Contradiction:

ImprovereliabilityVSAvoidnoise and wear

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical rotating polygonal mirror system with an acousto-optic modulator (AOM) that uses sound waves to diffract and steer the laser beam. This substitution eliminates mechanical moving parts, thereby eliminating noise and wear while maintaining the beam scanning function across the photoreceptor drum

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs acoustic vibrations (sound waves) within the AOM crystal to create a moving diffraction grating effect. The ultrasonic waves vibrate the crystal lattice, causing the laser beam to be diffracted at varying angles, achieving beam steering without mechanical motion

Inventive Principle:

Principle #18Mechanical vibration

2Ease of operation

If a rotating polygonal mirror is used for beam scanning, then the scanning function is achieved, but the mechanism requires environmentally sealed packaging to protect from dust and humidity

Engineering Contradiction:

Improveease of operationVSAvoidpackaging complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

By replacing the mechanical mirror system with a solid-state acousto-optic device, the patent eliminates the need for sealed enclosures to protect moving parts from environmental contaminants. The AOM has no mechanical components that require protection, simplifying the overall device structure and packaging requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If a rotating polygonal mirror is used to scan the laser beam, then the beam can be directed across the photoreceptor drum, but the system has moving parts that require control elements and motors

Engineering Contradiction:

Improvescanning speedVSAvoidcontrol elements and moving parts

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent replaces the motor-driven rotating mirror system with an acousto-optic modulator controlled by electrical signals. The beam scanning is achieved by modulating the acoustic frequency and amplitude, eliminating motors, gears, and other mechanical control elements while maintaining high scanning speeds through electronic control

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 solution eliminates the noise and wear associated with mechanical components, enhances efficiency, speed, and reliability, while reducing costs and power requirements, and eliminates the need for environmentally sealed packaging.

Implementation Method 1

by controlling the refractive index to achieve high-speed scanning

Methodology Applied

Scientific EffectRefractive index control: Refraction

Implementation Method 2

a beam steerer according to embodiments of this disclosure may be provided as a solid-state device configured to steer a laser beam across the photoreceptor drum

Methodology Applied

Scientific EffectOptical waveguide: Waveguide (optics)

Data Source

PatentUS10462323B1Non mechanical optical beam steering mechanism for laser printers

Publication Date: 2019.10.29 CAPITAL ONE SERVICES LLC

AI summary

A laser printing system includes a laser configured to produce a beam of light modulated according to image data input to the laser printing system, a photoreceptor drum including a photoconductive layer disposed along an outer peripheral surface of the photoreceptor drum, and a non-mechanical beam steerer configured for receiving the modulated light beam from the laser and steering the light beam in a scanning motion back and forth across the photoconductive layer of the photoreceptor drum. The laser printing system also includes a printer controller configured to structure the image data input to the laser printing system, and control an amount of electrical current flowing through portions of the non-mechanical beam steerer to change an effective index of refraction of the non-mechanical beam steerer and steer the modulated light beam in the scanning motion.