Heater Chip Test Circuit for Open Heater Detection
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Solution Overview
Problem
Ink jet printing systems face challenges in detecting open heater circuits, which can lead to malfunctioning nozzles and printing artifacts, as existing methods lack effective mechanisms to identify and address non-functioning heaters.
Innovation Solution
A test circuit on a heater chip with a first power device for ink ejection and a second power device for minimal current flow is implemented, allowing for the detection of open heater circuits by switching between these devices based on a test signal and reporting the status through a test output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a heater is used to vaporize ink for droplet ejection, then ink can be ejected from the nozzle, but the heater may break or fracture and go to essentially an infinite resistance, causing the heater to fail
Solution Approach 1:
The patent implements a test circuit that performs preliminary detection of heater circuit integrity before the heater is activated for ink ejection. By testing the heater circuit in advance and identifying open circuits or high resistance conditions, the system can prevent failed heaters from causing printing defects, thus resolving the contradiction between maintaining productivity and ensuring reliability.
2Reliability
If a test circuit is added to detect open heater circuits, then heater status can be monitored, but the device complexity increases
Solution Approach 1:
The test circuit is integrated into the existing heater chip architecture and shares resources with the normal operation circuitry. The same power devices and test outputs used for detecting open heaters can also serve the ink ejection function, making the test capability multi-functional and thereby minimizing the increase in device complexity while improving reliability.
3Reliability
If manual inspection of printers is performed to detect faulty heaters, then faulty printheads can be identified, but time and labor resources are consumed
Solution Approach 1:
The heater chip performs self-diagnosis through the integrated test circuit that automatically detects open heaters and reports their status without requiring manual intervention. The system can identify faulty heaters and communicate their locations to the printing apparatus or user, eliminating the need for time-consuming manual inspection while maintaining accurate fault detection.
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
This solution enables the detection of open heater circuits, allowing the printing system to minimize printing artifacts and alert users to replace faulty printheads, thereby maintaining print quality and reducing the need for manual inspection.
Implementation Method 1
One particular configuration of such a heater includes a resistive heating element applied to a substrate of a heater chip
Implementation Method 2
a resistive heating element applied to a substrate of a heater chip
Data Source
AI summary
Test circuits on heater chips for testing a heater circuit having a heater element and a first power device. The test circuit can include a second power device, a test device configured to hold the first power device off and the second power device on for a selected heater circuit when the test device receives a signal to activate the test circuit, and a common test output to transmit a signal indicative of a state of the selected heater circuit. Methods for using the same are also provided.