Scanner Motor Abnormality Detection in Image Forming Apparatus
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Solution Overview
Problem
In electrophotographic image forming apparatuses, incorrect identification of abnormalities in the scanner motor leads to misdiagnosis of issues, causing unnecessary time and effort for operators to determine the actual cause, often due to power source device abnormalities being mistaken for scanner motor problems.
Innovation Solution
An image forming apparatus with a voltage detection unit, rotation detection unit, and controller to accurately differentiate between power source device and optical scanning device abnormalities by monitoring output voltage and rotation speed, providing specific notifications for each type of abnormality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the control unit determines abnormality based solely on phase lock signal timing, then the detection method is simple, but the accuracy of abnormality identification deteriorates due to false diagnosis between power source and scanner motor issues
Solution Approach 1:
The patent segments the detection process into distinct phases: voltage detection during motor activation, rotation speed detection via FG signal, and phase lock detection. This segmentation allows each aspect to be monitored independently, enabling accurate identification of whether the abnormality lies in the power source device, optical scanning device, or both, thereby resolving the false diagnosis problem without requiring an overly complex integrated system
Solution Approach 2:
The patent introduces intermediate detection signals (FG signal from Hall element, BD signal from beam detector) as mediators between the motor operation and the control unit's judgment. These intermediary signals provide objective measurement data that bridge the gap between simple timing detection and accurate component-level diagnosis, allowing the control unit to distinguish between power source failures and motor failures based on whether rotation speed and phase lock are achieved
2Reliability
If the control unit notifies scanner motor abnormality without verifying power source status, then the notification process is quick, but the reliability of error information deteriorates due to incorrect error attribution
Solution Approach 1:
The patent applies preliminary action by having the control unit detect the output voltage of the power source device before determining abnormality causes. This preliminary voltage check is performed as part of the activation sequence, allowing the system to pre-establish power source status information that can be immediately used to accurately attribute errors, thereby improving reliability without significantly increasing diagnostic time
Solution Approach 2:
The patent implements feedback mechanisms where the control unit continuously monitors voltage detection unit output, FG signal rotation speed, and BD signal phase lock status. This feedback loop provides real-time information about system state, enabling the control unit to make accurate error attributions based on actual measured data rather than assumptions, thus improving error information reliability while maintaining efficient diagnostic processes
3Measurement precision
If multiple detection units are added to accurately identify abnormality sources, then the abnormality identification accuracy improves, but the device complexity increases
Solution Approach 1:
The control unit is designed with multi-functionality, serving both as the primary controller for motor activation and phase locking, and as the abnormality detection and diagnosis unit. This universal design allows the system to achieve accurate abnormality source identification without adding separate dedicated detection hardware, as the existing control unit is enhanced to perform multiple functions including voltage monitoring, rotation speed detection, and error attribution
Solution Approach 2:
The patent merges the detection functions for voltage, rotation speed, and phase lock into a unified control and diagnosis system. By combining these detection capabilities within the existing control unit architecture and using shared signal processing resources, the system achieves comprehensive abnormality identification accuracy while avoiding the complexity increase that would result from completely separate detection subsystems
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 precise notification of abnormalities, reducing diagnostic time and effort by correctly identifying power source device issues, thus improving operational efficiency and accuracy in error handling.
Implementation Method 1
a motor used as the scanner motor includes a Hall element to detect the location of a rotor, and the rotation speed of the scanner motor is detectable by measuring the period of a frequency generator (FG) signal output by the Hall element
Implementation Method 2
a beam detector having detected the laser light outputs a beam detection (BD) signal which is a writing detection signal of a scan over the photosensitive member
Data Source
AI summary
In an image forming apparatus, if a controller detects an abnormality in an output voltage of the power source device, the controller notifies the abnormality of the power source device. If the controller detects no abnormality in the output voltage after image data is input and before a scanner motor is activated in response to the input of the image data, the controller activates the scanner motor. If a rotary polygon mirror does not reach a target speed within a predetermined time, the controller re-detects whether there is an abnormality in the output voltage. If the controller detects an abnormality in the output voltage, the controller notifies the abnormality of the power source device. If the controller detects no abnormality in the output, the controller notifies the abnormality of the optical scanning device.