Week 7: Inkjet Printing Techniques Quiz

Direct write differs from indirect write by applying ink directly to the substrate. This is unlike indirect methods where ink is transferred by means of a stamp, stencil, or mask.

Inkjet printing is a direct write method, where ink is applied directly to the substrate in a non-contact manner. This allows for higher precision and wider ink possibilities.

In direct write methods, the pattern or image is stored digitally, allowing for precise control and flexibility in design.

Inkjet printing is advantageous because it can deposit multiple inks in layers, reducing the number of steps needed to create a final product.

The principle of inkjet printing involves ejecting small ink droplets onto a surface to create an image or pattern.

Drop-on-Demand (DoD) inkjet refers to a technique where ink droplets are ejected only when needed, creating a specific pattern. This allows for high resolution printing and minimizes ink wastage.

The size of the ink droplet is important in inkjet printing, as it influences the precision and quality of the print.

The rheological properties of the ink, like viscosity and surface tension, play a critical role in droplet formation and its behavior during ejection.

Drop-on-Demand (DOD) inkjet printing is a technology where ink droplets are ejected only when needed, unlike Continuous Inkjet printers which eject a continuous stream of ink.

DOD droplets are formed by pressure or velocity variations created by changes in volume within the printhead, usually triggered by piezoelectric materials.

Thermal Inkjet (TIJ) printing also uses heat to create ink droplets, but instead of piezoelectric materials, it uses thin film resistors that heat the ink, causing it to vaporize and form a bubble.

DOD inkjet printing has advantages such as no ink contamination, no waste since only needed droplets are produced, and a wider range of inks can be used.

DOD inkjet printing has disadvantages such as a lower droplet formation rate compared to Continuous Inkjet (CIJ) and limitations imposed by the ink's viscosity and flow properties.

In DOD inkjet, a piezoelectric material, usually a crystal, expands and contracts when an electrical voltage is applied, forcing the ink out of the printhead.

In DOD, the piezoelectric material acts as a tiny piston, pushing out ink droplets with precise control. This creates high-quality printing with sharp details.

The rate at which a DOD printhead can eject droplets is limited by the inherent speed of the piezoelectric material and the complexity of the ink formulation.

The distance between the centers of two adjacent droplets in an inkjet printing process.

A printing technology where droplets of ink are precisely deposited onto a surface to create images or patterns.

The ability of an inkjet printer to consistently produce droplets of the same size and volume.

The process where a droplet of ink, upon impacting a surface, spreads out and forms a circular shape.

The way in which a series of overlapping droplets form a continuous line in inkjet printing.

The process of liquid ink transforming into a solid film as the solvent evaporates.

The undesirable phenomenon of ink spreading beyond intended boundaries, creating irregular shapes or stains.

Techniques employed to prevent coffee staining during inkjet printing.

The Reynolds number (Re) is a dimensionless quantity that represents the ratio of inertial forces to viscous forces within a fluid. It helps determine whether fluid flow is laminar (smooth) or turbulent (chaotic).

The Weber number (We) is a dimensionless quantity that represents the ratio of inertial forces to surface tension forces within a fluid. It helps determine whether a fluid will break into droplets or remain as a continuous stream.

The 'Z' number, also known as the Ohnesorge number (Oh-1), is a dimensionless quantity that represents the ratio of viscous forces to inertial forces, all scaled by the surface tension forces. It effectively combines the Reynolds and Weber numbers.

According to Fromm's research, if the Z number is greater than 2, then drop formation in a drop-on-demand system is possible. This means that the viscous forces are strong enough relative to the inertial and surface tension forces to allow for droplet formation.

According to Reis et al, a Z number between 1 and 10 indicates that drop formation is possible, but with limitations. The lower limit of 1 is influenced by viscosity, while the upper limit of 10 represents the potential for satellite droplet formation.

The volume of a droplet increases as the 'Z' number increases, following the predictions of Fromm's research. So, higher 'Z' numbers lead to larger droplets.

The volume of the droplet is often normalized to the volume displaced by the actuator at different driving voltages. This allows for a standardized comparison of droplet volume across different conditions.

The angle formed by a retreating droplet on a solid surface. This is the angle measured when the droplet is shrinking.

The angle formed by an advancing droplet on a solid surface. It's the angle measured when the droplet is growing.

A material that repels water, causing droplets to form with a contact angle greater than 90 degrees.

A material that attracts water, causing droplets to spread out and form a contact angle less than 90 degrees.

The process of using an inkjet printer to deposit materials, like polymers, to create a pattern or structure.

A type of composite material that combines a strong but brittle material (like carbon fibers) with a more flexible material (like a polymer) to enhance its strength and durability.

The arrangement of ink droplets in a specific pattern, often in a hexagonal shape.

The ability of a material to resist deformation under applied stress. In the context of the document, it refers to the stiffness of a polymer sample measured using an interlaminar shear stress test.

The test measures the stiffness of a material by applying a force (load) and measuring the resulting displacement (extension). The slope of the resulting stress-strain curve represents the material's stiffness.

The test results show that samples containing printed polymeric agents have a higher stiffness compared to the original (virgin) samples, indicating an increase of up to 33.84% in stiffness.

The study indicates that printed polymeric agents contribute to a greater stiffness in the material, potentially due to the addition of new properties or reinforcement structures.

The error bars in the data represent the standard deviation calculated from five measurements (n = 5). This indicates the variability within the data.

The study indicates that the additional weight contributed by the printed polymeric agents is less than 1%, suggesting that the increase in stiffness is not primarily due to a significant change in mass.