Sheet Conveyance Motor Holding Control to Prevent Reverse Rotation
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Solution Overview
Problem
Inkjet printers face issues with sheets being returned in the opposite direction due to motor rotation when stopped, causing warping or backlash, despite current methods to control motor current for precise stopping.
Innovation Solution
A control method that includes a printing apparatus with a conveyance unit, motor, and control unit to execute holding control, updating the target position based on motor rotational speed to balance against external forces during stopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the current value flowing through the motor is adjusted to eliminate the difference between the current position and target stop position, then the motor can be controlled to stop at the target stop position, but the motor may rotate in the opposite direction to return to the target position, causing sheet warping or backlash
Solution Approach 1:
The control unit applies a counteracting force in the form of holding control before the motor completes its movement to the target position. By detecting when the motor is near the target position and applying a holding current, the system prevents the motor from overshooting and then reversing direction, thereby eliminating the root cause of sheet warping and backlash while maintaining stop position accuracy
Solution Approach 2:
The control unit continuously monitors the motor's position and movement state, and based on this feedback, dynamically adjusts the current supplied to the motor. When the motor approaches the target position, the control unit detects this state and applies holding control to prevent overshooting, thus achieving precise stopping without reverse rotation
2Manufacturing precision
If the motor stops exactly at the target position by adjusting current, then positioning precision is improved, but the sheet may become warped or backlash may occur due to motor reverse rotation
Solution Approach 1:
The control unit applies a counteracting force in the form of holding control before the motor completes its movement to the target position. By detecting when the motor is near the target position and applying a holding current, the system prevents the motor from overshooting and then reversing direction, thereby eliminating the root cause of sheet warping and backlash while maintaining stop position accuracy
Solution Approach 2:
The control unit performs preliminary action by applying holding control before the motor actually reaches the target position. This preliminary application of holding current ensures that the motor maintains sufficient driving force to overcome external resistance forces and stops precisely at the target position without needing to reverse direction, thus preventing sheet warping and backlash
Data Source
AI summary
A printing apparatus includes a printing unit, a conveyance unit, a motor, and a control unit. The printing unit performs printing on a sheet. The conveyance unit conveys the sheet to a printing position for the printing unit. The motor drives the conveyance unit. The control unit executes control. The control unit stops the motor which is rotating at a target position, executes holding control to hold the motor at a stop position, and updates, during execution of the holding control, the target position to a position different than the target position based on a rotational speed of the motor.