Scanner Motor Phase Control for Jitter Reduction
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately controlling the rotation of scanner motors at various steady rotation speeds, leading to increased rotation jitter due to weight reduction and low rotation speeds, which affects image quality.
Innovation Solution
An image forming apparatus with a deflection unit using a rotary polygon mirror and a drive unit, along with a first output unit for detecting light beam deflection and a second output unit for phase control, employs a controller to perform phase control based on rotation speed, optimizing pulse width and frequency of the drive signal to match position and reference signals, thereby reducing rotation jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the rotation portion of the scanner motor is reduced in weight to decrease activation time and power consumption, then the activation time and power consumption are reduced, but the rotation jitter increases and stability deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the pulse width of the drive signal based on the rotation speed of the scanner motor. During acceleration and deceleration phases, a longer pulse width is used to provide stronger control, while during steady rotation, a shorter pulse width is used. This parameter adjustment compensates for the reduced rotational inertia caused by weight reduction, maintaining stability across different operational states without increasing overall weight or power consumption.
2Use of energy by moving object
If the rotation portion of the scanner motor is reduced in weight to reduce power consumption, then the power consumption is reduced, but the rotation jitter increases and phase control becomes difficult
Solution Approach 1:
The patent implements dynamics by making the drive signal characteristics adaptive rather than fixed. The control system dynamically adjusts the pulse width of the drive signal based on real-time rotation speed feedback. During acceleration and deceleration when phase control is most critical, the extended pulse width provides enhanced control authority. During steady-state operation, the reduced pulse width minimizes power consumption. This dynamic adaptation resolves the contradiction between power consumption and phase control stability.
3Measurement precision
If phase control is applied to the scanner motor to improve rotation accuracy, then the rotation phase control is improved, but the rotation jitter increases due to interference with rotation period control
Solution Approach 1:
The patent applies segmentation by separating the control functions into distinct phases. Phase control is applied selectively during acceleration and deceleration periods when rotation phase accuracy is most critical, rather than continuously during all operation. This temporal segmentation allows phase control to operate without interfering with rotation period control during steady-state operation, thereby improving phase accuracy without introducing continuous rotation jitter.
4Adaptability or versatility
If the scanner motor operates at multiple steady rotation speeds to support different image forming speeds, then the adaptability is improved, but maintaining accurate rotation phase control at all speeds becomes difficult
Solution Approach 1:
The patent implements dynamics by making the drive signal characteristics adaptive to different operating conditions. The control system adjusts the pulse width based on both the current rotation speed and the operational phase (acceleration, deceleration, or steady-state). This dynamic adaptation enables accurate phase control across multiple steady rotation speeds while maintaining stability, as the control parameters are optimized for each specific operating condition rather than using a fixed setting for all speeds.
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 effectively optimizes rotation jitter for each steady rotation speed, improving image quality by ensuring accurate control of scanner motors across multiple image forming speeds, reducing jitter by 5% to 10% compared to conventional methods.
Implementation Method 1
a deflection unit 10 including a rotary polygon mirror 102 configured to deflect a light beam emitted from a light source 101
Data Source
AI summary
An image forming apparatus including a first output unit configured to detect a light beam deflected by a rotary polygon mirror rotated by a drive unit to output a first signal, a second output unit configured to output a second signal to be used as a reference, and a first controller configured to perform the phase control based on the first signal and the second signal. The phase control is performed in accordance with a condition set based on a rotation speed of the drive unit corresponding to an image forming speed by outputting a drive signal having a predetermined pulse width to the drive unit to accelerate or decelerate the drive unit so that the first signal and a position signal, based on the second signal, substantially match. The condition being a pulse width of the drive signal and/or a frequency of performing the phase control.