Printhead Signal Wire Multiplexing for Temperature Detection
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Solution Overview
Problem
Conventional inkjet printing apparatuses face challenges in reducing the number of terminals and wires due to the integration of temperature detection elements on each element substrate, leading to increased costs and noise interference affecting temperature detection accuracy, especially in full-line printheads with multiple substrates.
Innovation Solution
A printhead arrangement where temperature detection signals and image data signals are multiplexed on signal wires connecting head control ICs to element substrates, reducing the need for dedicated wires and terminals, and using differential signal transmission to minimize noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature detection element is provided on each element substrate, then temperature detection accuracy is improved, but the number of terminals and wires increases
Solution Approach 1:
The signal wire is designed to serve dual purposes: transmitting image data signals during normal printing operations and transmitting temperature detection signals when needed. This multi-functionality eliminates the need for separate dedicated wires for temperature detection, thereby reducing the total number of wires and terminals while maintaining accurate temperature monitoring across all element substrates
Solution Approach 2:
The invention merges the temperature detection signal transmission function with the existing image data signal transmission infrastructure. By combining these functions into a single signal wire, the system reduces wire count and terminal complexity while preserving the capability to accurately detect temperatures on each element substrate
2Productivity
If the print width of printhead is increased by arranging multiple element substrates, then printing speed is improved, but noise interference on temperature detection signal increases
Solution Approach 1:
The system employs periodic time-division multiplexing where the signal wire alternates between transmitting image data signals and temperature detection signals. During printing operations, image data is transmitted; during idle periods or specific time slots, the same wire transmits temperature detection signals. This periodic action prevents continuous noise interference while maintaining both high-speed printing capability and accurate temperature detection
Solution Approach 2:
The signal wire's function is made dynamic, switching between data transmission and temperature detection modes based on operational requirements. This dynamic usage allows the system to adapt to different operational states, reducing noise interference during temperature detection by temporarily suspending data transmission activities on the same wire
3Measurement precision
If dedicated wires for temperature detection are provided, then temperature detection accuracy is improved, but cost increases
Solution Approach 1:
The signal wire is designed to serve dual purposes: transmitting image data signals during normal printing operations and transmitting temperature detection signals when needed. This multi-functionality eliminates the need for separate dedicated wires for temperature detection, thereby reducing the total number of wires and terminals while maintaining accurate temperature monitoring across all element substrates
Solution Approach 2:
The invention merges the temperature detection signal transmission function with the existing image data signal transmission infrastructure. By combining these functions into a single signal wire, the system reduces wire count and terminal complexity while preserving the capability to accurately detect temperatures on each element substrate
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 decreases the number of wires and terminals, enhances temperature detection accuracy, and reduces noise, resulting in a more cost-effective and precise temperature detection system for high-speed printing applications.
Implementation Method 1
When a diode is used as the temperature detection element, a small voltage change caused by the temperature characteristic (−2 mV/C°) of the forward voltage of a PN junction needs to be detected.
Implementation Method 2
a signal processing circuit of a printing apparatus coordinates the driving condition (driving voltage or driving pulse) of printing elements based on temperature data detected by a temperature detection element integrated on an element substrate and controls to uniform the ink discharge amount
Data Source
AI summary
A printhead includes a plurality of element substrates, each including a plurality of printing elements, arranged in the arrayed direction of the printing elements. Each element substrate includes a temperature detection element for detecting the temperature of the element substrate. The printhead includes a head control IC connected to each element substrate and configured to control driving of the printing elements integrated on the element substrates. The head control IC and the element substrates are connected via a head terminal by a signal wire for transferring a signal between the head control IC and each element substrate. A temperature detection signal output from the temperature detection element and an image data signal are multiplexed on part of the signal wires.