Liquid Ejection Head Position Control via Multi-Point Detection
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Solution Overview
Problem
Existing liquid ejection apparatuses face challenges in accurately controlling the landing position of ejected liquid in the orthogonal direction of a conveyed object, leading to potential color shifts and reduced image quality due to positional variations of the recording medium.
Innovation Solution
A liquid ejection apparatus with multiple liquid ejection head units, supported by first and second rollers, and equipped with detection units to detect positional variations, allowing for precise movement control of the ejection heads based on combined detection results to compensate for these variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single detection unit is used to detect positional variations of the conveyed object, then the device complexity is reduced, but the manufacturing precision of liquid landing position deteriorates
Solution Approach 1:
The detection system is segmented into multiple detection units positioned at different locations (upstream and between support members) to independently measure positional variations at different points along the conveying path. This segmentation allows for more comprehensive detection of conveyance variations, enabling higher precision correction of liquid landing positions without requiring an overly complex integrated system.
Solution Approach 2:
The patent transitions from single-point detection to multi-point detection by adding detection units in the conveying direction dimension. This dimensional expansion of the detection system provides more comprehensive spatial information about conveyed object position variations, enabling more accurate compensation while maintaining reasonable system complexity.
2Manufacturing precision
If multiple detection units are installed to detect positional variations at different locations, then the manufacturing precision of liquid landing position is improved, but the device complexity increases
Solution Approach 1:
Detection units are positioned upstream and at intermediate points along the conveying path to detect positional variations before the liquid ejection occurs. This preliminary detection allows the control unit to calculate and compensate for conveyance variations in advance, ensuring accurate liquid landing positions without requiring complex real-time adjustment mechanisms during the ejection process.
Solution Approach 2:
Multiple detection units provide feedback information about conveyed object position variations at different locations and times. The control unit processes this feedback to calculate correction amounts and adjusts the liquid ejection positions accordingly, creating a closed-loop control system that improves landing precision while using a manageable number of detection units.
3Manufacturing precision
If the position of the liquid ejection head is adjusted based on single detection result, then the ease of operation is improved, but the manufacturing precision of liquid landing position deteriorates
Solution Approach 1:
The control unit receives feedback from multiple detection units measuring positional variations at different locations along the conveying path. It processes these multiple detection results to calculate comprehensive correction amounts, then adjusts the liquid ejection head positions accordingly. This feedback mechanism maintains ease of operation through automatic control while significantly improving landing position accuracy through multi-point measurement.
Solution Approach 2:
The system changes the parameter of detection location by using multiple detection units at different positions along the conveying path. This allows the control unit to capture variations in conveyed object position at multiple points, enabling more accurate calculation of correction amounts and improving liquid landing precision without complicating the operational interface.
Data Source
AI summary
A liquid ejection apparatus includes a plurality of liquid ejection head units that eject liquid onto a conveyed object at different positions along a conveying path; a first support member and a second support member that are respectively provided at an upstream side and a downstream side of a landing position of liquid ejected by a corresponding liquid ejection head unit; a first detection unit that is installed between the first support member and the second support member and is configured to detect a position of the conveyed object in a direction orthogonal to a conveying direction of the conveyed object; a second detection unit that is installed upstream of the first detection unit; and a movement control unit that moves each liquid ejection head unit based on a plurality of detection results output by the first detection unit and/or the second detection unit.