Dual-Height Ink Delivery System for Precision Dual-Sided Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inkjet printing systems for double-sided printing on cut paper sheets or paper webs face challenges in accurately and consistently applying ink droplets due to the limitations of inkjet printheads, which require ink to be directed downwardly with a combination of ejection pressure and gravity, making it difficult to achieve effective printing on both surfaces efficiently.
Innovation Solution
An ink delivery system comprising two inkjet printheads at different heights, with intermediate tanks and a pump to establish negative pressure in the printheads, utilizing a weir to control ink levels and overflow, and peristaltic pumps to manage ink flow, allowing for efficient ink distribution and printing on both surfaces of the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inkjet printheads are positioned to print on both surfaces of the medium, then printing efficiency is improved, but ink application accuracy deteriorates because droplets cannot be accurately applied when not directed downwardly
Solution Approach 1:
The patent positions one printhead above the medium and another below the medium, utilizing the vertical dimension to enable simultaneous dual-sided printing. The upper printhead prints on the top surface while the lower printhead prints on the bottom surface, both directing droplets downwardly onto their respective surfaces, thus maintaining accuracy while improving productivity
Solution Approach 2:
The printing system is segmented into two independent printing stations operating simultaneously - one for the top surface and one for the bottom surface. Each printhead operates independently with its own ink delivery system, allowing both surfaces to be printed at the same time without interfering with each other's droplet application accuracy
2Quantity of substance
If ink is pumped continuously to maintain supply to printheads, then ink availability is improved, but negative pressure control deteriorates leading to inconsistent droplet ejection
Solution Approach 1:
Instead of continuous pumping, the system uses periodic pumping where the pump operates in cycles to deliver ink in controlled pulses. This periodic action maintains the negative pressure regime in the printhead while ensuring adequate ink supply, preventing pressure fluctuations that would cause inconsistent droplet ejection
Solution Approach 2:
The system incorporates feedback mechanisms to monitor ink pressure and flow rates, adjusting pump operation to maintain optimal negative pressure conditions. This feedback control ensures that ink availability is maintained while preserving the pressure conditions necessary for consistent droplet ejection
3Manufacturing precision
If intermediate tanks are positioned below printheads to establish negative pressure, then droplet ejection accuracy is improved, but system complexity increases due to multiple tanks and level control devices
Solution Approach 1:
The intermediate tanks are positioned at different elevations to create hydrostatic pressure differences that establish and maintain negative pressure in the printheads. By utilizing gravitational potential energy differences, the system achieves the required pressure conditions without complex active pressure control mechanisms, reducing overall system complexity while maintaining precision
4Use of energy by moving object
If overflow ink is redirected to another intermediate tank using gravity, then energy consumption is reduced, but ink flow control precision deteriorates
Solution Approach 1:
The system uses intermediate tanks as intermediary reservoirs that receive and regulate overflow ink flow. These tanks act as buffer zones that smooth out flow variations while the system maintains precise control through level setting devices and controlled transfer mechanisms, achieving both energy efficiency and flow precision
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 system enables accurate and consistent ink application on both sides of the medium, enhancing printing efficiency and quality by maintaining negative pressure in the printheads and utilizing gravity to direct overflow ink, thus overcoming the limitations of traditional systems.
Implementation Method 1
a peristaltic pump for pumping ink from the supply tank to the intermediate tanks
Implementation Method 2
utilizing a weir to control ink levels and overflow, and peristaltic pumps to manage ink flow, allowing for efficient ink distribution
Data Source
AI summary
An ink delivery system for an inkjet printer has an ink supply tank and a pair of printheads located at different heights. A primary ink delivery circuit delivers ink to a pair of intermediate tanks, each tank maintained a precise distance below a respective one of the printheads. Ink is pumped to the higher tank to the level of a weir and overflowing ink flows under gravity to the lower tank. The overflowing ink fills the lower tank to the level of a weir and overflowing ink returns to the supply tank. Secondary ink delivery circuits have capillary lines for supply of ink from each of the intermediate tanks to the respective printhead. Ink is maintained in the supply lines ready for inkjet printing by establishing a negative pressure between each intermediate tank and the respective printhead.