Movable Printhead for Extended Digital Printing on Articles
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Solution Overview
Problem
Current digital printing technologies are limited to printing on articles with axial extensions not exceeding the length of the printhead's dispensing area, typically around 72mm, due to the need for multiple printheads and increased complexity, making it impractical for larger articles.
Innovation Solution
The apparatus allows printheads to be shifted along the extension direction of the ink dispensing area in successive steps, maintaining precision and enabling printing on articles with axial extensions several times longer than the printhead's dispensing area, using auxiliary movement devices like a support plate and slider with control members, and multiple printheads operating simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple printheads are used to print on larger articles, then the printable area is increased, but the apparatus complexity and overall size increase significantly
Solution Approach 1:
The patent applies the dynamics principle by making the printhead movable along the extension axis of the article. The printhead can be positioned at different locations to print on different longitudinal portions of the article. This dynamic positioning capability allows a single printhead to cover a larger printable area without requiring multiple fixed printheads, thereby increasing the printable area while avoiding the complexity and size increase that would result from using multiple printheads simultaneously.
2Area of stationary object
If the printhead longitudinal size is increased to print on larger articles, then the printable area is increased, but the apparatus construction cost and structural complexity increase
Solution Approach 1:
Instead of increasing the longitudinal size of the printhead, the patent employs a movable printhead that can be repositioned along the extension axis. This dynamic approach allows the same compact printhead to print on articles of various sizes by adjusting its position, thereby achieving a large printable area without incurring the high construction costs and structural complexity that would result from building a physically larger printhead.
3Area of stationary object
If multiple printheads are used in axially staggered positions, then the printable area is increased, but the overall apparatus size and management complexity increase beyond acceptable limits
Solution Approach 1:
The patent replaces the static configuration of multiple axially staggered printheads with a single movable printhead that can be dynamically positioned along the extension axis. This single printhead moves to different axial positions to print on different portions of the article, achieving the same extended printable area coverage without requiring multiple printheads to be arranged axially. Consequently, the overall apparatus size and management complexity are kept within acceptable limits.
4Device complexity
If a single printhead is used, then the apparatus complexity is reduced, but the printable area is limited to the printhead's dispensing area length
Solution Approach 1:
The patent resolves this contradiction by introducing a movable printhead that can be repositioned along the extension axis of the article. While maintaining the simplicity of using a single printhead (low apparatus complexity), the printhead's ability to move to different positions allows it to print on multiple longitudinal portions of the article, thereby extending the effective printable area beyond the physical dispensing area length of the printhead itself.
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 expands the working area of the printheads without increasing the apparatus's complexity, allowing precise printing on larger articles, including those with cylindrical or frusto-conical shapes, and increases productivity while maintaining structural simplicity.
Implementation Method 1
at least one ink-jet printhead, which creates a printing pattern on the side surface of the article, by dispensing ink
Implementation Method 2
directed between a pair of plates that provide a constant high voltage field. The field causes each droplet to be deflected by an amount proportional to the size of its electrostatic charge
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
An apparatus for digital printing on articles (2), comprises a drum (3) rotatable about a central axis (C), carrying piece-holder elements (4) circumferentially distributed around said central axis (C) and each configured for carrying an article (2) being processed. The drum (3) rotates to transfer the piece-holder element (4) through printing stations (9) carrying printheads (10), each operating according to a printing area (15) of predetermined length (L), to create a printing pattern (M) on a side surface (2a) of each article (2), driven in rotation around its own axis (X). Auxiliary movement devices (21) shift the printhead (10) parallel to the main extension direction (D) of the printing area to allow the articles to be processed having an extension greater than the length of the printing area (15). It is also described a printing process implemented by the apparatus.