Cam-Driven Cap Movement for Inkjet Printhead Capping
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Solution Overview
Problem
Existing liquid jetting apparatuses face challenges in reducing the time required for cap movement while minimizing the cap movement speed perpendicular to the nozzle surface, which can lead to ink spillage and meniscus destruction during cap contact and separation.
Innovation Solution
A liquid jetting apparatus with a cap movement device featuring a cam system with inclined surfaces of different angles, allowing for controlled cap movement between capping, intermediate, and uncapping positions, utilizing a suction pump and controller for optimized movement speeds and processes to balance time reduction and cap speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the inclined angles of the cam surfaces are increased to reduce cap movement time, then the cap movement speed perpendicular to the nozzle surface increases, but this causes ink spillage and meniscus destruction during cap contact and separation
Solution Approach 1:
The cam profile is segmented into multiple sections with different inclined angles: a first inclined surface with a smaller angle for controlled contact/separation, and a second inclined surface with a larger angle for rapid movement. This segmentation allows the cap movement to be divided into phases where speed control is prioritized during contact events, while overall movement time is reduced through faster intermediate phases.
Solution Approach 2:
The cam mechanism provides dynamic control of cap movement speed by varying the inclined angle along the cam profile. The angle is dynamically adjusted to be smaller during contact and separation events, and larger during intermediate movement phases, enabling optimization of both speed and ink protection throughout the movement cycle.
2Productivity
If the cam follower moves quickly between cam surfaces to reduce overall cap movement time, then productivity increases, but the cap contact and separation speeds become too high causing harmful effects
Solution Approach 1:
The cam profile is divided into distinct functional segments: contact phases with smaller inclined angles for reliability, and intermediate phases with larger angles for productivity. This segmentation enables the system to achieve high overall productivity while maintaining ink meniscus integrity during critical contact events.
Solution Approach 2:
The cam mechanism implements periodic variation in movement speed, with slower phases during contact and separation events, and faster phases during intermediate movement. This periodic modulation of speed allows the system to maintain high average productivity while ensuring reliability during critical moments.
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
The apparatus achieves a well-balanced reduction in cap movement time and speed, preventing ink spillage and meniscus destruction by employing a cam system with varying inclined angles and a suction pump, ensuring efficient and reliable operation.
Implementation Method 1
the slide surface includes: a first inclined surface extending while being inclined by a predetermined first angle relative to the slide direction and on which the cam follower is positioned under a condition that the cap is positioned between the capping position and an intermediate position
Implementation Method 2
a cap movement device including a cam having a slide surface and a cam follower configured to be slid on the slide surface
Implementation Method 3
a suction pump fluidly connected to the cap
Data Source
AI summary
A liquid jetting apparatus includes: a head unit including nozzles; a cap which covers the nozzles in a state of being in contact with the head unit at a capping position; and a cap movement device including a cam having a slide surface and a cam follower which is slid on the slide surface. One of the cam and the cam follower is provided integrally with the cap, and the other of the cam and the cam follower is moved in a slide direction. The slide surface includes a first inclined surface inclined by a first angle relative to the slide direction and a second inclined surface inclined by a second angle greater than the first angle relative to the slide direction.