Serial Printhead Reaction Liquid Alignment for Bidirectional Printing
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Solution Overview
Problem
Inkjet printing apparatuses with serial heads face challenges in accurately adjusting the discharge position of a colorless and transparent reaction liquid, which varies between the forward and backward paths, and determining which ink is discharged first, complicating the adjustment of the reaction liquid's position.
Innovation Solution
The printing apparatus employs a control method that adjusts the discharge position of the reaction liquid by forming adjustment patterns with the reaction liquid before the color ink, using optical sensors to detect position deviations, and calculating correction values to synchronize discharge timings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reaction liquid is discharged using a serial head that reciprocally moves on the print medium, then the printing can be performed in forward and backward paths, but the discharge position of the reaction liquid varies between the forward path and the backward path
Solution Approach 1:
The patent applies preliminary action by forming adjustment patterns with the reaction liquid before the color ink in advance. This allows the discharge position of the reaction liquid to be determined and corrected beforehand, compensating for the position variation that occurs during reciprocal movement. The control unit stores the discharge position information obtained from the adjustment pattern and uses it to correct the discharge timing, ensuring accurate positioning despite the serial head's forward and backward movement.
2Reliability
If the discharge timing of color ink and reaction liquid is adjusted to match, then the color ink can be fixed on the print medium, but the discharge position of the reaction liquid is difficult to control because it is colorless and transparent
Solution Approach 1:
The patent uses an adjustment pattern as an intermediary to make the invisible reaction liquid discharge position detectable. By forming a visible pattern with the reaction liquid that reacts with color ink to produce a color change, the discharge position can be detected using optical sensors. This intermediary pattern serves as a mediator between the invisible reaction liquid and the detection system, enabling precise measurement and correction of the discharge position.
Solution Approach 2:
The patent utilizes color changes that occur when the reaction liquid reacts with color ink to detect the discharge position. The adjustment pattern is designed to produce a visible color change reaction, which allows optical sensors to detect the discharge position of the colorless and transparent reaction liquid. This color change mechanism transforms an invisible phenomenon into a detectable signal for position correction.
3Manufacturing precision
If the discharge position of the reaction liquid is adjusted separately for forward and backward paths, then the position accuracy can be improved, but the adjustment process becomes more complex
Solution Approach 1:
The patent applies universality by using a single adjustment pattern formation process that works for both forward and backward paths. The control unit determines the discharge position of the reaction liquid by forming adjustment patterns and detecting them with optical sensors, then stores this position information for correcting discharge timing in both forward and backward printing operations. This unified approach eliminates the need for separate adjustment procedures for each path, reducing complexity while maintaining accuracy.
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 method enables precise adjustment of the reaction liquid's discharge position, ensuring accurate overlay with the color ink, even in multipass printing, thereby improving print quality and consistency.
Implementation Method 1
using optical sensors to detect position deviations
Implementation Method 2
a reaction liquid that reacts with the color inks discharged to a print medium. When the reaction liquid reacts with a color ink, the color ink can be fixed on the print medium
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
One aspect of the invention is a printing apparatus, comprising a printhead including first and second nozzle arrays, and print control means for performing printing by driving the printhead while reciprocally moving it as a serial head, wherein the first nozzle array discharges a color ink, the second nozzle array discharges a reaction liquid, for each of a forward path and a backward path, an adjustment pattern is formed by overlaying a pattern of the reaction liquid and a pattern of the color ink, and, in a case of forming the adjustment pattern in the backward path, an underlying pattern is further formed by the second nozzle array in a preceding forward path. (Figure 16)