Single Resistor Window Thermal Ink Printhead
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Solution Overview
Problem
The complex topography created by multiple resistor windows in thermal ink jet printheads leads to uneven layers and reflections, affecting the quality of ink flow channels and requiring complex control strategies due to varying firing pulses for different resistor lengths, which complicates the imaging process and fluid flow.
Innovation Solution
The use of a single resistor window across the wafer, with varying widths to control drop weight, simplifies the design by allowing the same firing pulse for all resistors and reduces topography, thereby improving the imaging of subsequent layers and fluid flow channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple resistor windows are used to create openings for heater resistors, then different resistor lengths can be achieved, but the topography becomes more complex creating reflections that make higher layers uneven
Solution Approach 1:
The patent combines multiple separate resistor windows into a single continuous resistor window that spans across all heater resistors. This merging approach eliminates the complex topography and reflections caused by multiple separate windows, while still allowing different resistor lengths to be defined by the trace patterns within the single window area.
Solution Approach 2:
The patent transitions from defining resistor lengths through vertical separation (multiple windows at different positions) to defining them through horizontal trace routing (single window with varying trace paths). This dimensional shift allows length variation without creating topography issues.
2Adaptability or versatility
If multiple resistor windows are used, then different resistor lengths can be created, but this requires complex control strategies with distinct firing pulses for different drop weights
Solution Approach 1:
The single resistor window design allows all heater resistors to be controlled by a universal firing pulse strategy. The window serves multiple functions: defining all resistor locations, allowing length variations, and enabling consistent energy application across different drop weight requirements without needing distinct control strategies.
Solution Approach 2:
The patent changes the physical parameter of the resistor window from multiple separate regions to a single continuous region. This parameter change simplifies the control strategy by allowing consistent electrical pulse application, while drop weight variation is achieved through geometric parameters (trace width, length, routing) rather than control strategy complexity.
3Ease of manufacture
If multiple resistor windows are used, then openings can be created for heater resistors, but the complex topography affects the quality of ink flow channels
Solution Approach 1:
The patent merges multiple separate resistor openings into a single continuous opening structure. This eliminates the complex topography that would otherwise interfere with subsequent ink flow channel formation, while still providing all necessary access points for the heater resistors through the unified window design.
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 reduces reflections and simplifies the control strategy, enhancing the quality of ink flow channels and printhead performance by ensuring consistent energy application across resistors of the same length, leading to improved imaging and fluid flow.
Implementation Method 1
Thermal ink jet printheads are fabricated with multiple columns of heater resistors
Data Source
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AI summary
Printheads and methods for forming printheads are described herein. In one example, a printhead includes a single resistor window in a conducting layer within the printhead. The printhead also includes a number of resistors formed in a resistor film deposited over the single resistor window. The resistors have two different widths, and each of the two different widths ejects a different droplet size when energized.