Return Mirror Gravity Offset for Vibration Control

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Solution Overview

Problem

Conventional optical scanning devices experience density unevenness in printed images due to bending and rotational vibrations of the return mirror, which are caused by the support pins, leading to suboptimal image quality.

Innovation Solution

A mirror position adjustment mechanism is introduced to move the return mirror in the sub-scanning direction, adjusting its gravity center position relative to the rotational axis, thereby reducing rotational vibrations and improving image stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the return mirror is supported by four support pins at its corners, then the mirror is stably supported, but rotational vibration occurs causing density unevenness across the entire printed image

Engineering Contradiction:

Improvemirror support stabilityVSAvoidrotational vibration causing density unevenness

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by intentionally misaligning the gravity center of the return mirror from the rotational axis defined by the support pins. Specifically, the gravity center is positioned offset in the sub-scanning direction, creating an asymmetric mass distribution that generates a counterbalancing moment to suppress rotational vibration. This asymmetric configuration transforms the support structure from a symmetric four-pin arrangement into an asymmetric system where the gravity center does not coincide with the rotational axis, thereby reducing harmful vibrations while maintaining support stability.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the gravitational parameter configuration by adjusting the position of the return mirror's gravity center relative to the support pins. By modifying the gravity center position offset in the sub-scanning direction, the system alters the dynamic characteristics of the mirror assembly. This parameter change transforms the support configuration from one where the gravity center coincides with the rotational axis to one where there is a controlled offset, thereby changing the vibration characteristics and suppressing rotational vibration that causes density unevenness.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the return mirror is pushed by a pressing spring against four support pins, then the mirror is firmly held, but bending vibration is generated causing density unevenness at the center of the printed image

Engineering Contradiction:

Improvemirror holding forceVSAvoidbending vibration causing center density unevenness

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by positioning the gravity center offset from the rotational axis in the sub-scanning direction, creating an asymmetric mass distribution. This asymmetric configuration generates a counterbalancing moment that suppresses bending vibration of the return mirror. The asymmetric gravity center position creates a restoring torque that opposes the bending vibration induced by the pressing spring force, thereby reducing density unevenness at the center of the printed image while maintaining firm mirror holding.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent employs a counterweight principle by using the offset gravity center position to create a counterbalancing effect. The misaligned gravity center acts as a dynamic counterweight that generates opposing forces to counteract the bending vibration caused by the pressing spring. This counterbalancing mechanism reduces the amplitude of bending vibration and its harmful effects on image density uniformity at the center region.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 effectively suppresses rotational vibrations, preventing image failures like jitter and ensuring consistent image density across the printed area, enhancing overall image quality.

Implementation Method 1

The return mirror is provided to extend in a main scanning direction, reflects the light beam reflected by the rotating polygon mirror, and leads the reflected light beam to a surface to be scanned

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

The return mirror is pushed to the four support pins by a pressing spring

Methodology Applied

Scientific EffectElastic force: Spring

Implementation Method 3

The position of the return mirror is adjusted by the mirror position adjustment mechanism such that a gravity center position of the return mirror is separated in the sub-scanning direction from a rotational axis of the return mirror

Methodology Applied

Scientific EffectGravitation: Gravitation

Data Source

PatentUS10054889B2Optical scanning device and image forming apparatus including the same

Publication Date: 2018.08.21 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

An image forming apparatus includes a mirror position adjustment mechanism capable of adjusting a position of a return mirror. The return mirror is used in a state in which its position is adjusted such that a gravity center position of the return mirror is separated from a rotational axis of the return mirror by the mirror position adjustment mechanism in a sub-scanning direction.