Printer Cap Switching Mechanism Prevents Acid Ink Reaction
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Solution Overview
Problem
In existing printing apparatuses, pretreatment agents containing acids or salts can vaporize and react with ink in nozzles, leading to issues like ink non-ejection and discoloration on the printing medium.
Innovation Solution
A printing apparatus design that includes a platen for conveying the printing medium, an ejection head with a cap that covers and uncovers the nozzle, and a cap switching mechanism to prevent the acid or salt from reacting with the ink by moving the cap to the uncapping position after a printing start instruction is received, allowing for separate or integrated pretreatment of the printing medium before or after it is set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pretreatment agent containing acid or salt is applied to the printing medium, then the ink fixation is improved, but the acid volatilizes and reacts with the ink in the nozzle causing non-ejection or discoloration
Solution Approach 1:
The cap is moved to the uncapping position after receiving a printing start instruction, which is after the pretreatment agent has been applied to the printing medium. This timing ensures that the ink in the nozzle does not react with the acid or salt in the pretreatment agent, preventing non-ejection or discoloration failures while still allowing the pretreatment to improve ink fixation.
Solution Approach 2:
The cap acts as an intermediary that isolates the ink in the nozzle from the pretreatment agent containing acid or salt. By controlling the cap's position (capped or uncapped) based on the printing start instruction, the system prevents direct contact between the ink and the harmful chemical components, thereby eliminating the harmful reaction while allowing the pretreatment to function on the printing medium.
2Ease of operation
If the cap is uncovered during pretreatment, then the pretreatment agent can be applied, but the ink in the nozzle may react with volatilized acid before printing starts
Solution Approach 1:
The system waits to uncover the cap until after the printing start instruction is received, which is after the pretreatment agent has been applied. This preliminary action of keeping the cap closed during pretreatment prevents the harmful reaction while still allowing the pretreatment to be completed, and only then does it uncover the cap to allow printing to proceed.
Solution Approach 2:
The cap serves as a protective intermediary that can be selectively positioned to either allow pretreatment agent application (when uncapped) or protect the ink from reaction (when capped). The control mechanism coordinates the cap's position with the printing process stage, ensuring the ink is protected during the vulnerable period when pretreatment agent is applied and volatilizing.
3Reliability
If the cap remains covered during printing, then the ink is protected from acid reaction, but the printing process cannot proceed
Solution Approach 1:
The cap is uncovered at the appropriate time (after printing start instruction) to allow the printing process to proceed. This timing ensures that the harmful reaction has already been prevented during pretreatment, so uncovering the cap now does not cause ink degradation, thus maintaining both reliability and productivity.
Solution Approach 2:
The cap's position is dynamically controlled based on the printing process stage. It remains closed during pretreatment to protect the ink, then opens when printing begins to allow the ejection head to function. This dynamic adjustment optimizes both protection (reliability) and operational efficiency (productivity) at different stages of the process.
Data Source
AI summary
There is provided a printing apparatus including: a platen configured to convey, in a conveying direction, a printing medium to be subjected to a pretreatment for applying a pretreatment agent before or after the platen is located at a set position; an ejection head having a nozzle surface provided with a nozzle and configured to perform an ejection process of ejecting a liquid from the nozzle onto the printing medium conveyed by the platen at a printing position; a cap configured to cover the nozzle surface; and a cap switching mechanism configured to switch a position of the cap between a capping position where the nozzle surface is covered with the cap and an uncapping position where the nozzle surface and the cap are separated from each other, wherein the cap switching mechanism moves the cap to the uncapping position after a printing start instruction is received.