Printer Carriage Interlock Delay Circuit for Controlled Deceleration
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Solution Overview
Problem
Large-size printers face issues with the carriage not stopping immediately during interlock operations, leading to potential collisions due to the reliance on inertia-based stopping, which is less controlled and efficient compared to controlled stopping methods.
Innovation Solution
Incorporating a delay circuit between the motor driver and the motor that maintains connection for a predetermined time after a stop signal is issued, allowing for deceleration control of the carriage before shutting off the motor, thereby enabling earlier and safer stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is immediately shut off from the motor driver when a stop signal is issued during interlock operation, then the safety response time is reduced, but the carriage cannot be controlled to decelerate and may continue traveling due to inertia
Solution Approach 1:
The interlock device performs preliminary action by maintaining the motor connection for a predetermined delay period after the stop signal is issued. During this delay time, the motor driver continues to control the motor, enabling deceleration of the carriage before the motor is completely shut off. This preliminary controlled deceleration prevents the carriage from continuing to travel due to inertia, thereby resolving the contradiction between immediate safety response and controlled stopping.
2Device complexity
If the carriage is stopped by inertia without control after power supply is cut, then the device complexity is reduced, but the carriage may hit the housing and cause damage
Solution Approach 1:
The system performs preliminary controlled deceleration during the delay period before complete motor shutdown. The motor driver receives stop signals and controls the motor to gradually reduce speed, ensuring the carriage decelerates smoothly and stops before hitting the housing. This preliminary action prevents collision damage while maintaining relatively simple device structure.
3Ease of operation
If the motor connection is maintained for a delay period after stop signal, then the carriage can be controlled to decelerate smoothly, but the safety response is delayed
Solution Approach 1:
The interlock device changes the parameter of motor connection status over time. During the predetermined delay period, the motor remains connected to the driver, allowing controlled deceleration. After the delay expires, the motor connection is immediately shut off. This time-based parameter change enables smooth deceleration during the critical period while ensuring ultimate safety response, resolving the contradiction between smooth operation and immediate safety.
Data Source
AI summary
A printer includes a carriage, a carriage moving mechanism including a motor, a motor driver that controls the motor, a stop instruction device, and an interlock device. The stop instruction device transmits a stop signal for the carriage or stops a driving permission signal for the carriage when a predetermined stop condition is satisfied. The interlock device is interposed between the motor and the motor driver and shuts off the motor from the motor driver after a lapse of a predetermined delay time of transmitting the stop signal or stopping the driving permission signal. The motor driver controls the motor to decelerate the carriage in at least a portion of a period before the delay time has elapsed.