Inkjet Sensor Switching for Accurate Discharge Detection
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Solution Overview
Problem
Conventional thermal ink-jet printing methods experience discontinuities in temperature sensor output signals during heater driving pulse switching, leading to inaccurate detection of feature points due to sudden cooling steps being misrecognized as discharge failures.
Innovation Solution
A configuration involving a print element substrate with multiple nozzles, heaters, and temperature sensors, where a first and second sensor generate temperature signals in alternating periods, allowing a processing unit to accurately determine discharge states by suppressing steps in the cooling direction through signal switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensor switching is performed in synchronization with heater driving pulse timing, then the temperature monitoring coverage is improved, but discontinuous steps occur in the output signal causing inaccurate feature point detection
Solution Approach 1:
The patent applies preliminary action by enabling the next temperature sensor before the current sensor is disabled. Specifically, the next temperature sensor is enabled at timing T1 (before heater driving pulse n ends), and the current sensor is disabled at timing T2 (after T1). This overlapping enable period prevents temperature monitoring gaps and eliminates discontinuous steps in the output signal, allowing accurate feature point detection during ink discharge cooling processes.
2Adaptability or versatility
If multiple temperature sensors are used to cover different nozzle groups, then the monitoring scope is improved, but signal discontinuities cause misrecognition of cooling features
Solution Approach 1:
The patent implements preliminary action by enabling the next temperature sensor (e.g., TS2) before disabling the current sensor (e.g., TS1). The enable timing T1 is set before the heater driving pulse ends, and disable timing T2 is set after T1. This ensures continuous temperature monitoring across sensor boundaries without creating artificial steps that would mislead cooling process analysis.
Solution Approach 2:
The patent ensures continuity of useful action by designing the sensor switching mechanism so that temperature monitoring never stops. The overlap period where both sensors are enabled ensures continuous coverage during the transition between nozzles N1-N4 (monitored by TS1) and N5-N8 (monitored by TS2), eliminating gaps in the temperature signal that would disrupt cooling process examination.
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 approach enables accurate examination of temperature signal cooling processes without being influenced by step portions, improving the reliability of discharge state determination in ink-jet printing.
Implementation Method 1
a thermal ink-jet printing method that causes ink to be discharged from a nozzle by thermal energy generated by a heater
Implementation Method 2
a discharge state determination method that determines whether the state of discharge of ink from a nozzle is normal or there is a discharge failure by a point where the speed at which the temperature detected by a temperature sensor drops changes suddenly
Data Source
AI summary
A print element substrate, comprises: a first generating unit that selects a first sensor, and in a first period and a second period that follows the first period, generates a first temperature signal; a second generating unit that selects a second sensor, and in the second period and a third period that follows the second period, generates a second temperature signal; a processing unit that receives the first and second temperature signals, and based on values of the received signals, outputs a signal indicating a discharge; and a switching unit that outputs to the processing unit the first temperature signal from the start of the second period until a predetermined timing of the second period, and at the predetermined timing, switches a signal outputted from the first temperature signal to the second temperature signal.