Capacitor-Based Inrush Current Control for Recording Head Power Supply
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Solution Overview
Problem
Current ink jet recording apparatuses face issues with high instantaneous power consumption, inrush current generation when the power supply is turned on, and inability to detect and prevent power supply to a short-circuited recording head, leading to potential overheating and secondary effects on other components.
Innovation Solution
A recording apparatus with a power source portion, a capacitor, a power supply switching unit, a power supply adjusting circuit, a power source voltage detecting circuit, and a control unit that stabilizes power supply, reduces inrush current, and detects short circuits to prevent power supply to the recording head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the power supply to the recording head is turned on using a FET switching element with low on-resistance and high response speed, then the switching characteristic is improved, but an inrush current occurs when the power supply is turned on
Solution Approach 1:
The patent applies preliminary action by detecting the attachment state of the recording head before turning on the power supply. The control unit checks whether the head is properly attached, and only if the attachment is confirmed does it proceed to supply power. This prevents inrush current by ensuring the circuit is ready to accept power before the FET switching element is activated.
2Loss of time
If the power supply to the recording head is turned on without detecting attachment state, then the response time is reduced, but electrical noise is generated and circuit malfunction occurs due to inrush current
Solution Approach 1:
The patent performs attachment detection as a preliminary action before power supply. The control unit detects whether the recording head is attached to the main body, and only proceeds with power supply when attachment is confirmed. This preliminary check prevents inrush current and electrical noise while maintaining efficient operation by quickly enabling power supply once attachment is verified.
3Loss of energy
If the power supply is stopped when the recording head is not attached, then unnecessary load current is prevented, but it becomes impossible to detect and stop power supply when the head is short-circuited
Solution Approach 1:
The patent implements feedback by continuously monitoring the power supply state and load conditions. The control unit detects the attachment state of the recording head and adjusts the power supply accordingly - stopping power when not attached to prevent unnecessary current, and maintaining power when attached unless a short circuit is detected. This feedback mechanism enables both energy efficiency and short circuit protection.
Solution Approach 2:
The control unit uses feedback from attachment detection circuits to monitor the recording head state. When the head is attached, the system continues power supply but maintains the ability to detect short circuits through ongoing monitoring of electrical parameters. This feedback loop ensures both prevention of unnecessary current consumption and detection of abnormal conditions.
4Stability of the object's composition
If a low-impedance power source is used to maintain stable power supply voltage under varying electrical load, then the ejection characteristics are stabilized, but inserting a resistor for load detection increases device cost
Solution Approach 1:
The patent uses an intermediary approach by employing a detection circuit that monitors the power supply state without significantly affecting the low-impedance power source characteristics. The detection mechanism acts as an intermediary that can sense load conditions and control power supply adjustments without requiring large resistance values that would destabilize the power source voltage.
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 effectively reduces inrush current and prevents sudden power source voltage changes, allowing for safe operation by detecting and responding to short circuits, thereby preventing overheating and maintaining stable power delivery to the recording head.
Implementation Method 1
a capacitor which stabilizes the power supply to the recording head
Data Source
AI summary
A recording apparatus includes an electrolytic capacitor for stabilizing the head power source voltage, a transistor for charging the electrolytic capacitor, a transistor for discharging the electrolytic capacitor, a push-pull circuit, a resistor for controlling the charging/discharging current to the electrolytic capacitor, and a resistor for dividing the head power source voltage. The power supply to the head is turned on with the head power source voltage increased by the capacitor.