Serial Printhead Alignment for Bidirectional Reaction Liquid 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 fixation of color ink on the print medium.
Innovation Solution
A printing apparatus with a printhead featuring a first nozzle array for color ink and a second nozzle array for a reaction liquid, where the print control unit adjusts the discharge position by forming an adjustment pattern that overlays color ink and reaction liquid patterns, with the reaction liquid pattern printed before the color ink to ensure accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a serial head is used to perform printing while reciprocally moving on a print medium, then productivity is improved, but the discharge position of the reaction liquid varies between the forward path and the backward path, worsening manufacturing precision
Solution Approach 1:
The nozzle array is divided into a first nozzle array for discharging color ink and a second nozzle array for discharging reaction liquid. By segmenting the functions of different nozzles and applying different control strategies to each array, the patent resolves the position variation issue while maintaining high-speed serial head printing
Solution Approach 2:
The patent changes the discharge timing parameter between forward and backward paths. Specifically, it controls which nozzle array discharges first differently depending on the printing direction, compensating for the position shift caused by serial head movement and ensuring accurate reaction liquid placement
2Reliability
If the reaction liquid is discharged to fix the color ink, then the fixation function is improved, but the discharge position adjustment becomes complex because the reaction liquid is colorless and transparent, worsening ease of operation
Solution Approach 1:
The patent uses the color difference between color ink and colorless reaction liquid as a detection basis. Optical sensors detect the colored ink patterns to determine discharge position accuracy, making the adjustment process simple despite the reaction liquid being invisible
Solution Approach 2:
The patent implements a feedback mechanism where optical sensors detect the discharged color ink patterns, and the print control unit adjusts the discharge timing based on detected position deviations. This automated feedback loop simplifies operation while ensuring accurate fixation
3Manufacturing precision
If the discharge position is adjusted to ensure accurate fixation, then manufacturing precision is improved, but the device complexity increases due to multiple nozzle arrays and control mechanisms, worsening device complexity
Solution Approach 1:
The patent makes the printhead multi-functional by incorporating both color ink discharge and reaction liquid discharge capabilities in a single device. The first and second nozzle arrays serve different functions but are controlled through a unified control system, achieving precision without proportionally increasing complexity
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 approach allows for easy adjustment of the reaction liquid discharge position, ensuring precise fixation of color ink on the print medium, even in multipass printing scenarios, by using optical sensors to detect and correct deviations.
Implementation Method 1
a second nozzle array capable of discharging a reaction liquid different from the color ink, and a print control unit configured to perform printing on a print medium by driving the printhead while reciprocally moving the printhead as a serial head
Implementation Method 2
by using optical sensors to detect and correct deviations
Data Source
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.