Inkjet Printing Apparatus Ink Density Control
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Solution Overview
Problem
Inkjet printing apparatuses face issues with defective ejection and wasteful ink consumption due to ink thickening in the circulation path, which cannot be fully recovered by preliminary ejection operations, leading to inefficient ink usage and print quality issues.
Innovation Solution
An inkjet printing apparatus with a circulation path system that includes a print head, a tank, and a connection channel for circulating ink, equipped with a discharging unit and a control unit that calculates ink density and performs discharging operations based on this calculation to prevent ink thickening and maintain optimal ink viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink is circulated continuously in the circulation path, then fresh ink is supplied to the ejection port at all times, but moisture evaporates from the ejection port and ink thickening gradually advances in the circulation path
Solution Approach 1:
The patent performs preliminary ejection operations before actual printing to restore proper ink flow characteristics. The control unit calculates ink density and triggers preliminary ejection when thickening is detected, proactively preventing defective ejection before it occurs during normal printing operations.
Solution Approach 2:
The control unit continuously monitors ink density by calculating it based on circulation time and ejection history. This feedback mechanism allows the system to detect ink thickening in real-time and automatically initiate corrective ejection operations when density thresholds are exceeded, maintaining optimal ink properties throughout the circulation path.
2Reliability
If preliminary ejection operation is performed frequently, then ejection state recovery is attempted, but ink is wastefully consumed
Solution Approach 1:
The control unit calculates ink density based on circulation time and triggers ejection operations only when the calculated density exceeds predetermined thresholds. This feedback-controlled approach prevents unnecessary ejection operations, thereby reducing wasteful ink consumption while still maintaining reliable ejection functionality when needed.
Solution Approach 2:
The system uses ink density as a dynamic parameter to control ejection operations. By monitoring changes in ink density over time and triggering ejection only when density reaches critical levels, the system optimizes the balance between maintaining ejection reliability and minimizing ink consumption.
3Reliability
If cleaning operation is applied uniformly, then ejection port is cleaned, but ink is wastefully consumed when ink thickening is not advanced
Solution Approach 1:
The control unit calculates ink density and compares it against predetermined thresholds before initiating cleaning operations. This feedback mechanism ensures that cleaning (ejection) operations are performed only when actually necessary, avoiding wasteful ink consumption during periods when ink thickening has not advanced significantly.
Solution Approach 2:
The system dynamically adjusts the timing and frequency of cleaning operations based on real-time ink density calculations. Rather than uniform periodic cleaning, the system adapts cleaning intensity to actual ink condition, performing operations only when density thresholds indicate thickening has occurred.
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 effectively suppresses defective ejections and wasteful ink consumption by continuously monitoring and managing ink density, ensuring stable print quality and efficient ink usage.
Implementation Method 1
a circulation path including the print head, the tank, and the connection channel and configured to circulate the ink between the print head and the tank
Implementation Method 2
a discharging unit configured to perform a discharging operation for discharging the ink in the circulation path
Implementation Method 3
a calculating unit configured to calculate a value relating to ink density in the circulation path
Data Source
AI summary
An inkjet printing apparatus and its control method which can suppress defective ejection and wasteful ink consumption are provided. For that purpose, pigment density Nx of the ink in a circulation path is calculated, and the ink in the circulation path is discharged on the basis of the pigment density Nx.