Writing Head Assembly Alignment via Simultaneous Imaging
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Solution Overview
Problem
Existing assembly devices for writing head units face challenges in accurately and efficiently aligning and mounting multiple droplet discharge heads on a head holder, particularly due to environmental temperature changes affecting optical axis alignment, and are costly to produce when using alignment masks sized for the carriage rather than the heads.
Innovation Solution
An assembly device that uses an imaging unit to simultaneously image reference marks and droplet discharge heads on the same viewing field, with an adjuster adjusting the relative positions based on these images, and employs a UV adhesive curing process for secure mounting, allowing for precise alignment and reduced production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an alignment mask sized for the carriage is used to position multiple droplet discharge heads, then the positioning coverage is improved, but the production cost increases significantly
Solution Approach 1:
The patent divides the positioning system into multiple segments: instead of using one large alignment mask for the entire carriage, separate alignment masks are created for each droplet discharge head or small groups of heads. This segmentation allows each mask to be smaller and less expensive while still providing the necessary positioning coverage when used in sequence for each head.
Solution Approach 2:
The patent implements preliminary positioning actions by temporarily mounting each droplet discharge head on the carriage before final assembly. This allows individual heads to be positioned and aligned separately using smaller alignment masks, and then securely mounted in their predetermined positions, avoiding the need for one large expensive mask.
2Measurement precision
If sequential imaging of carriage and droplet discharge heads is performed, then the alignment accuracy is improved, but the assembly time increases
Solution Approach 1:
The patent merges the imaging of the carriage and droplet discharge heads into a single simultaneous imaging operation. By incorporating the carriage position information and head position information into one image capture process, the system obtains both pieces of positioning data at the same time, eliminating the need for sequential imaging and reducing assembly time while maintaining alignment accuracy.
3Device complexity
If environmental temperature changes are not compensated, then the device complexity is reduced, but the alignment precision deteriorates
Solution Approach 1:
The patent incorporates temperature compensation by monitoring environmental temperature changes and adjusting alignment parameters accordingly. The system measures temperature variations and compensates for their effect on the optical axis and mechanical components, maintaining alignment precision without requiring overly complex active compensation mechanisms by using software-based parameter adjustments.
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 solution ensures high-precision alignment and mounting of droplet discharge heads, minimizing alignment errors caused by temperature changes and reducing production costs by using reference marks sized for the heads, thus enabling efficient assembly of writing head units with improved accuracy and cost-effectiveness.
Implementation Method 1
an optical unit to focus images of reference marks indicating a reference position of the writing head disposed in a direction different from the writing head, and the writing head on the same viewing field
Implementation Method 2
employs a UV adhesive curing process for secure mounting
Data Source
AI summary
An assembly device for a writing head unit includes a head holder; a writing head; an imaging unit to image the writing head temporarily mounted on the head holder; an adjuster to adjust relative positions of the head holder and the writing head using the image of the writing head imaged by the imaging unit; and an optical unit to focus images of reference marks indicating a reference position of the writing head disposed in a direction different from the writing head, and the writing head on the same viewing field. The adjuster adjusts the writing head using the images of the writing head and the reference marks imaged simultaneously by the imaging unit.