Inkjet Printhead Substrate Signal Timing and Noise Control
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Solution Overview
Problem
The increasing number of nozzles and heaters in inkjet printheads leads to high-frequency noise and erroneous operations due to delayed heat enable signals exceeding latch cycles, resulting in inefficient energy application and print speed reduction.
Innovation Solution
The implementation of a substrate with a reception unit, data latch unit, delay unit, operation result latch unit, and second driving unit to manage and delay signals, ensuring proper timing and energy application to printing elements without extending the latch cycle, thereby reducing noise and maintaining print speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of nozzles and heaters is increased to improve printing capability, then printing productivity is improved, but power supply noise increases causing erroneous operations
Solution Approach 1:
The patent divides the heaters into multiple groups and drives them in different latch cycles. By segmenting the heater driving operations across multiple cycles, the peak current demand is reduced and noise is distributed over time, preventing erroneous operations while maintaining high printing capability.
2Object-generated harmful factors
If delay circuits are added to moderate heater current edges and reduce noise, then power supply noise is reduced, but the heat enable signal delay increases causing data switching during driving
Solution Approach 1:
The patent performs heater selection and data latching in advance during the first latch cycle, before the actual heater driving in the second latch cycle. This preliminary action allows the use of delay circuits to moderate noise without causing data switching issues, as the data is already latched and ready for the delayed driving operation.
3Reliability
If the latch cycle is extended to accommodate delayed heat enable signals, then printing can be executed normally, but print speed decreases
Solution Approach 1:
The patent uses periodic latch cycles with distinct phases: the first latch cycle for data reception and latching, and the second latch cycle for heater driving. This periodic structure with predetermined timing allows the heat enable signal to be delayed without extending the overall print speed, as the system is designed to operate with this periodic pattern.
4Productivity
If the heat enable signal delay is shortened to maintain print speed, then productivity is maintained, but sharp current edges generate high-frequency noise causing erroneous operations
Solution Approach 1:
The patent introduces delay circuits as intermediary elements between the heat enable signal and the heater driving operation. These delay circuits act as mediators that smooth the current edges and reduce high-frequency noise while maintaining the timing relationship within the latch cycle, thus preventing erroneous operations without sacrificing print speed.
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 effectively reduces power supply noise during heater driving without decreasing print speed, ensuring reliable operation and energy efficiency.
Implementation Method 1
the heating elements are applied with a current to generate heat, and discharge ink droplets by film boiling of ink
Implementation Method 2
discharge ink droplets by film boiling of ink
Data Source
AI summary
An element substrate comprises: a data latch unit for latching, based on a first signal, first print data and second print data which have been received by a reception unit; a first driving unit for driving printing elements based on a timing of a second signal and a logical operation result of printing element selection data and the first print data latched by the data latch unit; a delay unit for delaying the second signal by a predetermined time; an operation result latch unit for latching, based on the delayed second signal, a result of a logical operation of the printing element selection data and the second print data latched by the data latch unit; and a second driving unit for driving the printing elements in accordance with the latched operation result and the delayed second signal.