Ink Supply Pressure Control for Stable Digital Printing
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Solution Overview
Problem
Existing ink supply systems in digital printing devices suffer from pressure variations leading to printing flaws, difficulty in inverting ink flow, and inability to independently control ink flowrate and meniscus pressure, limiting the flexibility and performance of the printing devices.
Innovation Solution
An ink supply system with continuous level control using analog level sensors and PID controllers for both delivery and return tanks, along with independent pressure adjusting means, allowing for separate control of pressures in both tanks and enabling automatic flow inversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure control systems are used to maintain ink flow, then ink delivery is maintained, but abrupt pressure variations cause printing flaws such as thickened lines and white lines
Solution Approach 1:
The patent implements a feedback control system where level sensors continuously monitor the ink level in the delivery tank and provide signals to a control unit. The control unit adjusts the supply pump operation based on this feedback to maintain constant ink level and pressure, eliminating abrupt pressure variations that cause printing flaws.
Solution Approach 2:
The system uses automatic level control where the supply pump self-regulates based on ink level feedback, maintaining constant pressure without manual intervention. The control unit automatically adjusts pump operation to keep the ink level within a predetermined range, ensuring stable pressure and consistent print quality.
2Adaptability or versatility
If mechanical adjustment systems are used to invert ink flow, then flow direction can be changed, but the operation cannot be executed automatically and requires local mechanical adjustment
Solution Approach 1:
The patent replaces manual mechanical adjustment systems with an automated control system. The control unit receives signals from level sensors and automatically controls the supply pump to invert ink flow direction when needed, eliminating the need for local mechanical adjustments and enabling fully automatic operation.
Solution Approach 2:
The system automatically detects when flow inversion is needed based on level sensor feedback and executes the inversion operation without human intervention. The control unit manages the entire process, making the system self-sufficient and eliminating manual mechanical operations.
3Reliability
If single circuit pressure control is used, then pressure is maintained, but flowrate and meniscus pressure cannot be controlled independently, limiting functioning range
Solution Approach 1:
The patent segments the pressure control into two independent systems: one controlling the delivery tank pressure (affecting flowrate) and another controlling the return tank pressure (affecting meniscus pressure). This segmentation allows independent adjustment of both parameters to match specific print head requirements, expanding the system's adaptability.
Solution Approach 2:
The system dynamically adjusts both delivery and return tank pressures independently based on different control parameters. The control unit can vary pressure settings for each tank separately, enabling flexible adaptation to different print head specifications and operating conditions.
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
Achieves stable ink pressure and flowrate, reducing printing errors and enabling a wide range of adjustments, including automatic purging, thereby enhancing printing quality and flexibility.
Implementation Method 1
a supply pump (6) suitable for moving ink from said supply tank (9) to said delivery tank (2)
Implementation Method 2
a first level sensor (7) suitable for continuously acquiring a level signal of the ink inside the delivery tank (2)
Implementation Method 3
first pressure adjusting means (10) suitable for controlling the pressure inside the delivery tank (2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Ink supply system (1) for digital printing device comprising: a supply tank (9) suitable for containing ink; a delivery tank (2), in fluid connection with said supply tank (9), suitable for containing ink; one or more delivery conduits (4) suitable for connecting said delivery tank (2) to one or more print heads (100) associatable with said supply system (1); first pressure adjusting means (10) suitable for controlling the pressure inside the delivery tank (2); a supply pump (6) suitable for moving ink from said supply tank (9) to said delivery tank (2); a first level sensor (7) suitable for performing the continuous reading of the level variations inside the delivery tank (2); wherein said supply pump (6) is continuously feed-back controlled on the basis of the reading of said first level sensor (7) for keeping a pre-defined level inside said delivery tank (2).