Ink Jet Printing Apparatus Ink Circulation and Absorption
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Solution Overview
Problem
Ink jet printing systems face issues with curl, cockling, and insufficient transferability due to excessive liquid absorption by the printing medium, leading to defects in image formation and transfer, particularly when using heating units or environments that promote solvent evaporation, resulting in uneven solvent and coloring material concentrations near the ejection orifice.
Innovation Solution
An ink jet printing apparatus with a circulation unit that manages ink between the pressure chamber and outside, utilizing a reaction solution for ink thickening and a liquid absorbing unit with a porous body to absorb liquid components from the ink image, ensuring stable image formation and transfer without thermal energy, and maintaining adequate agglomeration of coloring materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a heating unit is used to promote evaporation of water from the ejection orifice, then evaporation is enhanced, but solvent concentration and coloring material concentration become uneven near the ejection orifice
Solution Approach 1:
The circulation unit circulates ink through the pressure chamber before ejection, pre-mixing and uniformizing the ink composition to prevent concentration variations that would otherwise occur during evaporation at the ejection orifice
2Quantity of substance
If a liquid absorbing member is brought into contact with the ink image to remove liquid component, then liquid removal is achieved, but adhesion of ink solid matter to the porous body is facilitated when agglomeration is insufficient
Solution Approach 1:
The reaction solution is applied to the discharge receiving medium before ink ejection, preliminarily preparing the surface to promote proper agglomeration of coloring materials and resin particles, ensuring they form stable clusters before the liquid absorbing member contacts the ink image
Solution Approach 2:
The reaction solution acts as an intermediary substance between the ink and the liquid absorbing member, facilitating proper agglomeration of ink components and preventing direct adhesion of coloring materials to the porous body during liquid removal
3Reliability
If transfer is performed by abutting ink image on printing medium without liquid absorption step, then transferability is improved, but transfer residues are generated on the transfer body due to insufficient agglomeration
Solution Approach 1:
The reaction solution is applied in advance to promote agglomeration of coloring materials and resin particles, ensuring proper cluster formation before transfer, which prevents transfer residues while maintaining good transferability
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 solution stabilizes image printing by controlling ink circulation and absorption, preventing defects and ensuring effective transfer of ink images onto printing media while maintaining the quality of the liquid absorbing member, thus enhancing printing reliability and image quality.
Implementation Method 1
a circulation unit which circulates the ink between the inside of the pressure chamber and the outside of the pressure chamber
Implementation Method 2
a liquid absorbing unit for absorbing at least a portion of a liquid component from the ink image by bringing a porous body into contact with the ink image
Implementation Method 3
a liquid absorbing member having the porous body
Implementation Method 4
a reaction solution applying unit which applies a reaction solution containing a reactive component for ink thickening to the discharge receiving medium
Implementation Method 5
a plurality of printing element substrates each having an element which generates energy that is utilized for discharging ink
Data Source
AI summary
An ink jet printing apparatus including: an image forming unit which forms an ink image containing an aqueous liquid component and a coloring material, including a reaction solution applying unit and an ink applying unit; and a liquid absorbing unit for absorbing at least a portion of a liquid component from the ink image by bringing a porous body into contact with the ink image, the liquid absorbing unit including a liquid absorbing member having the porous body, wherein the ink applying unit includes a liquid ejection head including a plurality of printing element substrates each having an element which generates energy that is utilized for discharging a liquid, a pressure chamber which has the element in the inside, and a plurality of ejection orifices which discharge a liquid, and the ink is circulated between the inside of the pressure chamber and the outside of the pressure chamber.