Optical Scanner Startup Control via Rotation Signal Monitoring
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Solution Overview
Problem
In image forming apparatuses with multiple optical scanning devices sharing a common control signal and power supply, it is challenging to accurately determine whether an abnormality is due to the optical scanning device or the shared signal/power supply, as existing methods rely on drive current and beam detector signal monitoring.
Innovation Solution
The apparatus includes a controller with a startup controller and counter to monitor the rotation signal of a motor-driven rotatable polygon mirror, allowing for identification of power supply or path abnormalities by resetting the counter value, thereby distinguishing between optical scanning device and power supply issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple optical scanning devices share a common control signal and power supply, then device complexity is reduced, but fault identification accuracy deteriorates
Solution Approach 1:
The patent segments the power supply system by providing individual power supply devices for each optical scanning device, while maintaining a common control signal. This segmentation allows independent monitoring of each device's power status, enabling accurate fault identification without increasing overall system complexity. The counter mechanism further segments the monitoring function by tracking rotation signals individually for each optical scanning device.
Solution Approach 2:
The patent introduces a counter as an intermediary element that monitors the rotation signal from each optical scanning device's motor. This counter acts as a mediator between the motor's rotation signal and the control unit, providing quantitative feedback about motor operation status. By counting rotation signals within a predetermined time period, the intermediary counter enables precise fault detection without requiring complex direct monitoring of each device.
2Difficulty of detecting and measuring
If fault detection relies on drive current and beam detector signal monitoring, then detection capability is provided, but accurate identification of abnormality source becomes difficult
Solution Approach 1:
The patent performs preliminary action by monitoring the motor's rotation signal before the optical scanning device begins its scanning operation. The counter accumulates rotation signals during a predetermined time period prior to scanning, establishing a baseline of motor performance. This preliminary monitoring enables early detection of motor abnormalities before they affect the scanning process or generate beam detector signals, allowing distinction between motor faults and other device issues.
Solution Approach 2:
The patent implements feedback by using the counter to continuously monitor and report motor rotation status to the control unit. The control unit receives feedback about the number of rotation signals within the predetermined time period and compares this against expected values. This feedback mechanism enables real-time detection of motor abnormalities and distinguishes them from other potential fault sources, improving abnormality source identification accuracy.
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 enables accurate detection of abnormalities in optical scanning devices, reducing the risk of misidentification and improving fault diagnosis in multi-device configurations.
Implementation Method 1
a motor and an output unit, the motor rotating a rotatable polygon mirror for deflecting a light beam
Implementation Method 2
the output unit outputting a rotation signal by detecting a rotation of the motor
Implementation Method 3
the startup controller includes a counter for counting a clock signal, the counter having a counter value to be reset by the rotation signal
Data Source
AI summary
Optical scanning devices each have a Hall device for outputting a rotation signal by detecting a rotation of a motor. An optical scanning device controller has ASICs for performing startup control of the optical scanning devices, a CPU for controlling the ASICs, and a power supply path for supplying power to the optical scanning devices. The ASICs each have a FG counter for counting a clock signal and having a counter value to be reset by a rotation signal output from the Hall device. In a case where the motor is not normally driven when the optical scanning devices are started up, the CPU notifies an abnormality of the power supply device or the power supply path, based on a counter value of the FG counter acquired from each of the ASICs.