Cam Mechanism for Controlled Cap Movement in Inkjet Printers
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Solution Overview
Problem
In ink-jet recording apparatuses, the cap lifting mechanism using a friction clutch can result in uncontrolled cap movement away from the recording head, leading to ink ejection issues and potential image spoilage due to excessive speed and pressure differences.
Innovation Solution
The implementation of a cam mechanism with a slide cam, pinion gears, and rack gears allows for controlled movement of the cap between contact and non-contact positions with the recording head, ensuring precise speed control and maintaining an airtight seal during purging operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a friction clutch mechanism is used for the cap lifting mechanism, then the structure is simple, but the cap movement speed cannot be controlled, causing uncontrolled movement away from the recording head
Solution Approach 1:
The patent replaces the friction clutch mechanism with a cam mechanism that provides positive mechanical engagement through a cam face and follower. This substitution eliminates the speed control issue inherent in friction-based systems while maintaining structural simplicity. The cam mechanism ensures controlled, deterministic motion of the cap during lifting and lowering operations.
2Productivity
If the cap moves away from the recording head at excessive speed, then the purging operation completes quickly, but ink ejection and overflow occur, spoiling the image
Solution Approach 1:
The patent employs a cam mechanism with specifically designed cam profiles that control the dynamic motion of the cap. The cam face geometry regulates the lifting and lowering speed, ensuring that the cap moves at controlled rates during purging operations. This dynamic control prevents excessive speed that would cause ink ejection while maintaining efficient purging performance.
3Loss of time
If the cap is quickly moved away from the recording head, then the cycle time is reduced, but pressure difference causes ink overflow from the cap
Solution Approach 1:
The cam mechanism provides periodic, rhythmic motion to the cap with controlled acceleration and deceleration phases. The cam profile is designed to create smooth, periodic motion cycles that prevent sudden pressure changes. This periodic action with controlled timing reduces the risk of ink overflow while maintaining efficient cycle times for purging operations.
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 prevents uncontrolled cap movement, reduces the risk of ink ejection and overflow, and ensures accurate image recording by maintaining appropriate cap positioning and speed control, thereby preventing image spoilage.
Implementation Method 1
a cam mechanism with a slide cam, pinion gears, and rack gears allows for controlled movement of the cap between contact and non-contact positions with the recording head
Implementation Method 2
pinion gears, and rack gears allows for controlled movement of the cap
Data Source
AI summary
An image recording apparatus wherein a first rack gear is not meshed with a second pinion gear when the second pinion gear faces a first moving end of a slide cam or when the second pinion gear faces a second moving end of the cam, and is meshed with the second pinion gear when a portion of the cam which faces the second pinion gear is displaced between the first and second moving ends, wherein a second rack gear is meshed with a third pinion gear over an area of the cam between the first and second moving ends, wherein teeth of a tooth chipped gear are partly chipped such that the second pinion gear faces the area of the cam, and wherein the second pinion gear is rotated relative to the third pinion gear due to play at least until the tooth chipped gear is meshed with a drive gear.