Inkjet Printhead Nozzle Discharge Detection via Temperature Derivatives
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Solution Overview
Problem
Conventional inkjet printing methods face challenges in accurately and quickly judging ink discharge failures in nozzles, leading to bulky and expensive apparatuses, and insufficient detection of nozzle failures, especially in detecting specific nozzles with discharge issues.
Innovation Solution
A printing apparatus equipped with a printhead featuring a heater and temperature sensor, a monitoring unit to track temperature changes, an extraction unit to identify feature points in temperature changes, and a judgment unit using second derivatives to determine normal discharge or failure, allowing for precise and timely detection of discharge states without increasing apparatus size or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reading apparatus is provided to detect printed patterns for judging discharge state, then discharge state detection is possible, but the apparatus becomes bulky and expensive
Solution Approach 1:
The invention extracts the detection function from a separate reading apparatus and integrates it into the printhead itself by providing temperature sensors directly on the heater board, eliminating the need for external reading apparatus and reducing overall system complexity
Solution Approach 2:
The heater board is given multiple functions: it serves as both the heating element for ink discharge and as the mounting platform for temperature sensors, combining actuation and detection functions in a single component structure
2Speed
If detection is performed on the ink discharge source side using temperature sensors, then quick discharge state judgment is achieved, but accurate specification of failed nozzles becomes difficult
Solution Approach 1:
The invention divides the detection function into individual temperature sensors for each nozzle location on the heater board, allowing independent temperature monitoring and enabling precise identification of which specific nozzle has failed based on localized temperature anomalies
Solution Approach 2:
The temperature sensors provide real-time feedback on the thermal state of each nozzle during operation, enabling immediate detection of discharge failures through temperature deviation from expected patterns and allowing for precise localization of the failed nozzle
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
Enables accurate and timely judgment of nozzle discharge states and failure occurrences, facilitating quick recovery and complementary printing operations while maintaining a compact and cost-effective apparatus design.
Implementation Method 1
a printhead including a heater configured to generate heat energy to discharge ink
Implementation Method 2
a temperature sensor configured to detect a temperature
Data Source
AI summary
This invention has been made to judge the discharge state of each nozzle accurately at an appropriate timing. For this purpose, an apparatus using a printhead including a heater and a temperature sensor has the following arrangement. A temporal change in a detected temperature is monitored upon driving the printhead. During the temperature drop, temperatures are extracted at plural points of a time interval including a timing at which a feature point of the temporal change in the detected temperature in normal discharge appears. The second derivative of the temperature is calculated and added to obtain a total sum and intermediate sum. The total sum is compared with predetermined first and second thresholds to judge whether to normally discharge ink. If normal discharge or discharge failure is uncertain, the intermediate sum is compared with a third threshold for final judgment.