Variable Carriage Space for Inkjet Density Uniformity
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Solution Overview
Problem
Ink jet printers experience density unevenness and image quality degradation due to varying airflow conditions between acceleration and constant velocity regions, causing main and subsidiary ink drops to land differently, leading to density differences and ripple effects in print results.
Innovation Solution
A printing apparatus with a space width adjustment unit that increases the space above the carriage during acceleration and decreases it during constant velocity, ensuring consistent airflow and reducing swirling airflows, thereby maintaining uniform landing positions for ink drops and minimizing density unevenness and ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the carriage moves at constant velocity, then printing efficiency is improved, but density unevenness occurs between acceleration and constant velocity regions
Solution Approach 1:
The patent applies local quality by providing different space widths above the carriage for different motion regions: a first space width for the acceleration region and a second space width for the constant velocity region. This allows the airflow characteristics to be locally optimized for each region, ensuring consistent ink drop landing positions and eliminating density unevenness while maintaining high printing efficiency.
Solution Approach 2:
The patent employs dynamics by making the space width above the carriage variable rather than fixed. The space width is dynamically adjusted based on the carriage motion state (acceleration vs. constant velocity), allowing the system to adapt to changing airflow conditions and maintain consistent printing quality across different operational phases.
2Stability of the object's composition
If the space width above the carriage is increased, then airflow consistency is improved, but apparatus size increases
Solution Approach 1:
Instead of uniformly increasing the space width throughout the entire printing width, the patent applies local quality by providing different space widths only in specific regions (acceleration vs. constant velocity regions). This localized approach achieves airflow consistency where needed while minimizing the overall apparatus volume.
3Manufacturing precision
If shutters are used to control airflow, then density unevenness is reduced, but device complexity increases
Solution Approach 1:
The patent replaces the complex shutter mechanism with a simpler structural design that provides different fixed space widths above the carriage for different regions. This approach achieves the same goal of eliminating density unevenness through local airflow optimization but without the complexity of moving parts and control systems required by shutters.
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
The solution achieves consistent ink drop landing positions across acceleration and constant velocity regions, reducing density unevenness and ripple, resulting in improved image quality by managing airflow effectively.
Implementation Method 1
an acceleration region in which the carriage accelerates while moving and a constant velocity region in which the carriage moves at a constant velocity are different from each other in the quantity and speed of airflow that occurs between the carriage and the print medium
Implementation Method 2
Satellite drops are lighter in weight than main drops and therefore more strongly affected by airflows when flying
Data Source
AI summary
A printing apparatus includes a carriage on which a print head is mounted and that discharges an ink from the print head while moving the carriage along a predetermined direction and further includes a space width adjustment unit that causes a width of a space above the carriage within the printing apparatus to be larger in an acceleration region in which the carriage is accelerated from a stopped state than in a constant velocity region in which the carriage is moved at a constant velocity after the acceleration region. The space width adjustment unit causes the width of the space above the carriage in the constant velocity region to be smaller than or equal to a paper gap that is a distance between the carriage and a print medium which is below the carriage and which receives the ink discharged from the print head.