Ink Replenishment Control for Printing Apparatus Sub Tanks
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Solution Overview
Problem
In existing printing apparatuses, the order of opening and closing drive valves and the arrangement of sub tanks can lead to excessive ink replenishment, resulting in overflow from sub tanks that do not need ink, due to ink being replenished out of sync with the color order of the drive valves.
Innovation Solution
A printing apparatus with a print head capable of ejecting multiple inks, each having a sub tank and main tank for ink storage, supply valves, atmosphere release valves, and a shared pump for negative pressure, where the pump operates with the atmosphere release valve closed and supply valves open sequentially by ink color, preventing unnecessary ink replenishment by controlling the atmosphere release valve timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump is used in common for all color inks and the drive valve is controlled independently for each color ink, then the sub tank can be replenished with ink from the main tank by making negative the pressure within the sub tank, but a sub tank that does not need replenishment may be replenished excessively causing ink overflow
Solution Approach 1:
The ink replenishment system is segmented by introducing individual supply valves for each color ink channel. These valves allow independent control of ink flow to each sub tank, enabling the system to selectively replenish only the tanks that need ink while preventing overflow in tanks that are already sufficiently filled. This segmentation resolves the contradiction by maintaining high productivity through automated pump operation while eliminating the harmful effect of ink overflow through precise individual channel control.
Solution Approach 2:
The system performs preliminary assessment of ink levels in each sub tank before initiating replenishment. By detecting which tanks require ink replenishment in advance and pre-configuring the supply valve states accordingly, the system ensures that only necessary tanks receive ink. This preliminary action prevents the harmful effect of overflow while maintaining efficient replenishment operations for tanks that actually need ink.
2Ease of operation
If the drive valves are opened in a specific color order and sub tanks are replenished in a different order, then replenishment can be performed, but ink may be supplied to sub tanks that do not need replenishment
Solution Approach 1:
The system incorporates feedback mechanisms that monitor ink levels in each sub tank and track the operational state of drive valves. This feedback information is used to dynamically control the supply valves, ensuring they are opened only when both the corresponding sub tank needs ink and the drive valve is in the appropriate state. This feedback control eliminates ink waste by preventing unnecessary replenishment while maintaining operational flexibility.
Solution Approach 2:
The system applies local quality control by treating each color ink channel independently with its own supply valve and control logic. Instead of uniform replenishment across all channels, each channel receives replenishment only when locally determined to be necessary based on its specific ink level and drive valve state. This local quality approach prevents ink waste while preserving the flexibility to operate different channels in different sequences.
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
Prevents ink overflow in sub tanks that do not require replenishment by synchronizing the ink replenishment order with the drive valve opening sequence, ensuring precise ink management and reducing waste.
Implementation Method 1
one pump for making negative the pressure within the sub tank, and performs a replenishment operation to replenish the sub tank with ink from the main tank by driving the pump
Data Source
AI summary
An object of the present invention is to prevent a sub tank the does not need replenishment from being replenished with ink. The present invention is a printing apparatus that includes: a print head; a sub tank; a main tank; a supply valve; an atmosphere release valve; and one pump, and performs a replenishment operation to replenish the sub tank with ink from the main tank by driving the pump in a state where the atmosphere release valve is closed and the supply valve is open, wherein a second ink, and a third ink, and in a case where replenishment of a first ink and the third ink is necessary and replenishment of the second ink is not necessary, the atmosphere release valve is opened after the supply valve of the first ink is closed and before the supply valve of the second ink is opened.