Stepping Motor Speed Control for Sheet Feeding Synchronization
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Solution Overview
Problem
Image forming apparatuses using low-output stepping motors face synchronization issues due to non-synchronous phenomena, leading to sheet feeding and conveying disruptions, and employing high-output motors increases costs.
Innovation Solution
The apparatus includes a movable plate with a lift unit, a feeding unit, and a control unit that adjusts the rotation speed of the driving unit to prevent synchronization loss by switching to a lower rotation speed when the feeding unit is pressed or when no sheet is detected, allowing the plate to return to a normal state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-output stepping motor is used to reduce cost, then manufacturing cost is reduced, but synchronization reliability deteriorates due to non-synchronous phenomena under overload conditions
Solution Approach 1:
The patent applies dynamics by making the rotation speed of the driving unit variable rather than fixed. The control unit dynamically adjusts the rotation speed based on operational conditions: using a first rotation number during normal sheet feeding and a second rotation number (smaller than the first) when the feeding unit is pressed or no sheet is detected. This dynamic adjustment prevents synchronization loss in low-output motors while maintaining cost effectiveness.
Solution Approach 2:
The patent changes the operational parameter (rotation number) of the stepping motor based on detected conditions. When the feeding unit is pressed by the plate or no sheet is detected, the control unit switches to a second rotation number that is smaller than the first rotation number used during normal operation. This parameter change prevents the motor from falling out of step under high-load conditions, thereby maintaining synchronization reliability without requiring a high-output motor.
2Reliability
If a high-output stepping motor is used to prevent synchronization loss, then synchronization reliability is improved, but manufacturing cost increases
Solution Approach 1:
Instead of using a high-output motor, the patent changes the rotation speed parameter dynamically. The control unit switches to a reduced rotation number (second rotation number) when high load conditions are detected, allowing a low-output motor to operate reliably without synchronization loss, thereby avoiding the increased cost of a high-output motor.
Solution Approach 2:
The patent employs feedback control where the control unit monitors operational conditions (whether the feeding unit is pressed or sheet presence) and adjusts the rotation number accordingly. This feedback mechanism ensures synchronization reliability is maintained through adaptive speed control, eliminating the need for an oversized high-output motor and reducing manufacturing costs.
3Reliability
If the rotation number is reduced to a second rotation number when the feeding unit is pressed, then synchronization reliability is improved, but sheet feeding speed decreases
Solution Approach 1:
The patent applies dynamics by implementing conditional rotation speed adjustment. The system dynamically switches between a first rotation number (higher speed for normal operation) and a second rotation number (lower speed for high-load conditions). This dynamic approach maintains high productivity during normal sheet feeding while ensuring synchronization reliability only when necessary under plate-pressing conditions.
Solution Approach 2:
The patent uses periodic action by alternating between two rotation numbers based on detected conditions. During normal operation, the first rotation number provides high-speed sheet feeding. When the plate presses the feeding unit or no sheet is detected, the system periodically switches to the second rotation number to prevent synchronization loss, then returns to the first rotation number when conditions normalize, thus minimizing impact on overall productivity.
Data Source
AI summary
The image forming apparatus includes a plate movable up and down, a control cam that moves the plate up and down, a stepping motor that derives the control cam, a sheet feeding roller that contacts the sheet on the plate moved up by the control cam to feed the sheet held in contact with the feeding unit through rotation caused by drive from the stepping motor, and a control unit that controls the stepping motor. The control unit rotates the stepping motor at a first speed so that the control cam moves the plate up. After the sheet feeding roller is rotated, when the sheet feeding roller is stopped to stop the stepping motor, the control unit changes the rotational speed of the stepping motor from the first speed to a second speed.