Recording Head Heater Current Cutoff for Inkjet Overheat Protection
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Solution Overview
Problem
In inkjet-type image forming apparatuses, abnormal temperature rises can occur due to malfunctions in temperature sensors, switching elements, or controllers, leading to continuous power supply to the heater, which is not autonomously controlled.
Innovation Solution
A host control system with a current detection unit and a system-side switching element is implemented to detect and cut off excessive current flow in the power line, preventing abnormal temperature rises by controlling the heater through a main controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a temperature sensor, switching element, and controller are installed in the recording head to autonomously control temperature, then temperature management capability is improved, but the risk of abnormal temperature rise due to malfunction increases
Solution Approach 1:
A current detection unit is introduced as an intermediary component between the power supply and the heater. This unit monitors the current flowing to the heater and provides feedback to the main controller, which can then cut off power through a system-side switching element if abnormal conditions are detected. This intermediary monitoring mechanism resolves the contradiction by adding a safety layer that prevents autonomous control failures from causing dangerous temperature rises.
2Stability of the object's composition
If the recording head has autonomous temperature control, then temperature stability during operation is improved, but the complexity of the device increases
Solution Approach 1:
The system implements feedback control by having the temperature sensor continuously monitor the recording head temperature and feed this information back to the controller. The controller adjusts the switching element to maintain the desired temperature. Additionally, a current detection unit provides feedback on power consumption patterns, enabling the main controller to detect malfunctions and cut off power when necessary. This feedback mechanism achieves temperature stability while managing complexity through systematic monitoring and control.
3Reliability
If continuous current monitoring and system-side switching element are added to prevent malfunction, then safety against abnormal temperature rise is improved, but device complexity increases
Solution Approach 1:
The current detection unit serves as an intermediary that monitors power flow without requiring direct intervention in the temperature control logic. It detects abnormal current patterns indicative of malfunction and triggers the main controller to cut off power through the system-side switching element. This intermediary approach enhances safety while adding minimal complexity, as the monitoring function is separate from but coordinated with the existing temperature control system.
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
Prevents abnormal temperature rises in the recording head by autonomously stopping current flow when malfunctions occur, ensuring temperature stability and preventing overheating.
Implementation Method 1
a heater is installed in a recording head, and temperature management of ink ejection nozzles is performed using the heater
Implementation Method 2
it can be supposed to install temperature sensor such as thermistor
Data Source
AI summary
An image forming apparatus includes a recording head and a host control system. The recording head eject inks. The host control system controls the recording head. The recording head includes a heater, a temperature sensor, a switching element on a power line to the heater, and a controller configured to control the switching element on the basis of a measurement temperature of the temperature sensor and thereby control temperature of the recording head. Further, the host control system includes a current detection unit configured to detect a current that flows in the power line, a system-side switching element arranged on upstream side of the power line from the switching element, and a main controller configured to cut off the current using the system-side switching element if a continuous current flow time of the current detected by the current detection unit exceeds a predetermined value.