Printer Power Supply Circuit Inrush Current Management
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Solution Overview
Problem
Thermal printers face a trade-off between high-speed printing and the occurrence of large inrush currents when using high-capacitance capacitors to overcome power supply limitations, leading to decreased printing speed and potential malfunctions.
Innovation Solution
A printer system that includes a processor, a thermal head driver circuit, a motor driver circuit, and a power supply circuit with a capacitor and switching circuits, which controls the discharge of the capacitor through the motor driver circuit and motor upon stopping the printer to reduce inrush currents and enable high-speed printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high-capacitance capacitor is used to supply high current for high-speed printing, then printing speed is improved, but inrush current of large magnitude occurs when voltage is applied to the capacitor
Solution Approach 1:
The patent applies preliminary action by controlling the charging process of the capacitor before actual printing operation. The processor monitors the voltage across the capacitor and controls the first switching circuit to limit inrush current during the charging phase, ensuring the capacitor is ready for high-current printing without causing harmful inrush currents when power is initially applied or after shutdown.
2Power
If divided printing is used to work around power supply capacity limitations, then power supply limitations are overcome, but printing speed decreases due to increased printing time
Solution Approach 1:
The patent applies dynamics by making the printing system adaptable to different power conditions. The processor dynamically determines whether to perform one-time printing or divided printing based on real-time assessment of power supply capacity and capacitor charge state. This dynamic adjustment allows the system to achieve high-speed one-time printing when power is sufficient, while still operating within power supply limitations when necessary.
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
The solution allows for high-speed printing while minimizing large inrush currents, preventing malfunctions and extending the lifespan of the thermal head by effectively managing power supply and discharge processes.
Implementation Method 1
a power supply circuit that includes a capacitor and a first switching circuit to charge the capacitor, the power supply circuit supplying electrical power to the thermal head driver circuit and the motor driver circuit via the capacitor
Implementation Method 2
a thermal head driver circuit that drives a thermal head for printing on a printing medium
Implementation Method 3
a motor driver circuit that drives a motor configured to convey the printing medium
Data Source
AI summary
A printer includes a processor; a thermal head driver circuit that drives a thermal head for printing on a printing medium; a motor driver circuit that drives a motor configured to convey the printing medium; and a power supply circuit that includes a capacitor and a first switching circuit to charge the capacitor, the power supply circuit supplying electrical power to the thermal head driver circuit and the motor driver circuit via the capacitor, wherein the processor, when stopping operation of the printer, performs a control process of discharging the capacitor via the motor driver circuit and the motor.