Liquid Ejection Head Tilt Angle Detection via Dot Allocation Patterns
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Solution Overview
Problem
Existing liquid ejection apparatuses, such as inkjet printers, face challenges in precisely detecting the inclination of the ejection head with respect to the conveyance direction of the recording medium, which affects the accuracy of ink ejection and pattern formation.
Innovation Solution
A method and apparatus that utilize a conveyor and a liquid ejection head with ejection opening arrays aligned orthogonally to the conveyance direction, recording a pattern group with unit patterns featuring distinct optical characteristics in specific regions to detect tilt angles by varying dot allocations, allowing for precise adjustment of the head's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to detect head inclination, then measurement precision may be maintained, but device complexity and cost increase due to requirement of high-resolution sensors
Solution Approach 1:
The patent replaces complex optical sensing systems with a simple mechanical test pattern recording method. By recording test patterns with the liquid ejection head itself and analyzing the resulting dot allocations, the system substitutes expensive high-resolution sensors with basic recording and analysis functionality already present in the printer system.
Solution Approach 2:
The patent uses the liquid ejection head to create test pattern copies on recording medium, which then serve as measurement references. These recorded patterns are analyzed to determine tilt angle, eliminating the need for separate sensing hardware by using the head's own output as the measurement tool.
2Measurement precision
If high-resolution sensors are used to detect tilt angle, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex optical sensing systems with a simple mechanical test pattern recording method. By recording test patterns with the liquid ejection head itself and analyzing the resulting dot allocations, the system substitutes expensive high-resolution sensors with basic recording and analysis functionality already present in the printer system.
Solution Approach 2:
The patent uses inexpensive recording medium (test sheets) as disposable carriers for test patterns. These single-use recording sheets replace expensive, durable sensors by providing a cheap, throwaway method to obtain tilt angle information through pattern analysis.
3Ease of manufacture
If the ejection head is not precisely aligned orthogonal to conveyance direction, then manufacturing and assembly are easier, but manufacturing precision of the recorded pattern deteriorates
Solution Approach 1:
The patent performs preliminary recording of test patterns during assembly or before normal operation. By recording test patterns and analyzing dot allocations in advance, the system enables easy detection and correction of alignment issues, allowing manufacturers to identify and adjust head orientation problems without requiring extremely tight initial alignment tolerances.
Solution Approach 2:
The patent implements a feedback mechanism where recorded test patterns are analyzed to determine actual head alignment. The dot allocation patterns provide feedback information about tilt angle, enabling manufacturers to measure and correct alignment deviations, thereby achieving precise pattern recording even when initial assembly alignment is not perfect.
Data Source
AI summary
Each of unit patterns includes: a first region which is recorded on a recording medium by liquid ejected from ejection openings of both first and second ejection opening arrays of ejection opening arrays; and at least one second region which is recorded on the recording medium by liquid ejected from the ejection openings of one of the first and the second ejection opening arrays, the first region is a region formed based on dot allocation with which an optical characteristic varies in accordance with intervals of dots formed by the impacted liquid in a fourth direction which is orthogonal to a first direction, and the at least one second region is a region formed based on dot allocation with which the optical characteristic varies in accordance with intervals of the dots formed by the impacted liquid in the first direction.