The removal or erosion of a surface due to thermal or mechanical stress. A phenomenon encountered in the chamber of a thermal impulse (bubble jet) system. The rapid frequent collapse of the micro bubbles formed during the heating process causes a breakdown of the surface of the chamber leading to cavitation and resultant pitting of the chamber surface.
The property of "sharpness" of the edge of letters and images formed by a matrix printing process. The scalloping or deviation from straightness of the edge of letters caused by the construction of the letters or images by individual dots. The higher the resolution, other factors being equal, the less the scalloping and the higher the acuity.
The ability to control the placement of individual droplets. Sometimes expressed as dots per inch or centimeter. (see also RESOLUTION)
Character set which contains letters and numbers.
Angstrom unit (noun)
A unit of length in the metric system equal to one ten-thousandth of a micron or ten nanometers. Frequently used to express the wavelength of light waves and therefore their color.
The property of withstanding the effects of time. In the case of printed matter, the ability of the images to retain their color or blackness over long periods of time.
A group of elements formed in a geometric pattern. An arrangement of dots. Arrays can be linear, interdigitated, or in other geometric patterns. In ink jet technology, an array usually relates to a group of individual ink jets formed in lines or groups.
automatic symbology (bar code)(noun)
Automatic symbology is the technology of encoding information that is decodable automatically by a machine or system. The most common example is bar codes but other symbology images can also be concentric circles, two dimensional arrays, that resemble checkerboards or other arrangements of images. These marks also may be visible or invisible to the human eye. The information is contained by the presence or absence of a mark, a width of a mark or space in a one dimension code. Examples of one dimension codes commonly in use are code 3 of 9 and I 2 of 5. The advantage of automatic symbology is its speed and accuracy.
Banding is a printing defect characterized by light or dark lines in an image in the direction of the printing. In the case of ink jet imaging it is caused by a jet or printhead that is not properly aligned, inoperative, or incorrectly indexed. (see also STITCHING)
bar code (noun) (see AUTOMATIC SYMBOLOGY)
barrier film (noun)
A frequently employed element in thermal impulse ink jet systems which is interposed between the electrical heating element and the ink in the chamber to protect the heating element.
1) A printing property caused by the ink spreading or diffusing on or into the substrate. Usually it is considered a defect because it causes diffusion of the edge of an image or character resulting in indistinct edges but in some cases can be desirable in solid ink printing where it can mitigate banding or other drop errors. 2) Bleed is also used when referring to eliminating the air from the chamber or manifold in either an impulse or a continuous ink jet system.
A term used to designate the action of a droplet as it is pinched off by surface tension from the ligament issuing from the orifice. The break-off point is particularly significant for continuous ink jet because subsequent to this separation it is impossible to charge the droplet since it no longer has a conductive path to ground. The break-off in an impulse system is also important because if it is improperly caused to happen it can result in ligament snap back and result in air being ingested into the firing chamber. Break-off is also related to the formation of satellite droplets.
bubble jet (noun) (see THERMAL IMPULSE)
carton coding (verb) (see LCP)
In a continuous ink jet system, the element in the printhead which catches the unwanted droplets before they reach the substrate. These vary in form and construction but the function is the same. The intercepted droplets (see CONTINUOUS INK JET) are usually re-circulated after being treated to remove air and particulate matter. In addition, the evaporated solvent is replaced.
The production of voids in a liquid system due to extreme reduction of internal pressure. Collapse of these voids or cavities produces very large impulsive pressure, which can cause considerable damage to nearby surfaces. Cavitation is frequent on high speed propeller blades and also occurs in the region of the electrical heating element in a bubble jet (THERMAL IMPULSE) system due to the rapid collapse of the bubbles. Cavitation, if prolonged and great enough, will frequently cause destruction, ablation or erosion of a solid surface.
A linear unit of measure in the metric system which is equal to one one hundredth of a meter or ten millimeters, or .3937 inches.
Usually this term refers to the ink filled cavity immediately behind the orifice plate in an impulse ink jet system. This is the location where the ink receives its pressure pulse that causes the ejection of the droplets from the orifice plate. For comparison, the ink cavity immediately behind the orifice plate in a continuous ink jet system is usually referred to as the manifold. (see also CONTINUOUS INK JET, IMPULSE INK JET)
One of the units of a printhead comprised of a piezoelectric transducer, restrictor, associated chamber, and orifice plate.
charge element (noun)
In a continuous ink jet system, the charge element, ring, or tunnel is an electrode which is used to place an electrical field or (an E-field) in the vicinity of the break up of the droplets. The presence or absence and the strength of this E-field results in various levels of charge on the separating droplets so that its trajectory can be subsequently controlled as it passes through the deflection field.
The act of combining or uniting. In ink jet, it usually refers to the recombination of the ink droplets in air before reaching the substrate. Frequently a recombination of satellite droplets with the main droplets.
To wrinkle or pucker. Paper cockles or buckles permanently when too much liquid is applied. Frequently occurs when a volume of water-based ink is applied in a small area.
The build up of and deposition of particulate material and solids on the surface of a thermal ink chamber caused by the local heating of the resistor element.
color gamut (noun)
The complete range of colors available from a printing system. For example, the extent of colors possible from the three primary (tri-stimulus) inks applied in different amounts and combinations to a specific substrate.
continuous(adjective) continuous ink jet (noun)
Without a break or synchronous. Events occurring regularly in the time domain. The adjective applied to that branch of ink jet technology where drops are generated at a regular unbroken rate. Print selection is then made by deflections of the ink droplets after they are charged so that they either are intercepted by a catcher and not permitted to impact the substrate or charged and deflected to intercept the substrate at specific locations. Continuous ink jet technology is the oldest and the most mature ink jet technology. Its advantages are long print (throw) distance (distance from the printhead to the substrate) and extremely high droplet production rate, in some cases as high as 150,000 droplets per second, per channel. Disadvantages are the requirement for conductive inks, a more expensive and complex system because of the requirement for re-circulation and less drop placement accuracy because of the requirement for deflection.
Chamber Plate/Orifice Plate
The reduction or increase of droplet velocity in an ink jet channel due to the effect of the firing of adjacent channels. Crosstalk effects are usually caused by fluidic, mechanical, or electric coupling. In an array printhead, the middle channels have the most adjacent channels on either side of them; therefore, the degree of crosstalk on these middle channels is the greatest.
A small amount of solid material which blocks an orifice or entire channel. It can be generated either externally, (paper dust) or, in rarer cases, internally from improperly cleaned units.
deflection plate (noun)
Usually a pair of electrically conductive plates that create an E-field that cause charged droplets to be deflected from their ballistic projectory as they pass through this field. Used only in continuous or hertz continuous ink jet systems. The droplets are deflected causing them to strike the catcher and be re-circulated to the ink jet system rather than impacting on the substrate or are deflected to cause the droplets to hit a specific location on the substrate.
The process of removing dissolved or entrained air from inks. Bubbles in impulse ink jet systems frequently cause failures because they act as "shock absorbers" by moderating the pressure wave required to eject the droplet from the orifice. Inks are de-gassed by pulling a vacuum on them or employing an in-line "lung."
demand printing (noun)
A term used to designate a printing process that can print any image limited only by its data system and its resolution limits. This is one of the salient features of all ink jet systems. Printing systems that are not demand types are those systems such as lithography, letter-press, gravure, and flexography which repeat an imbedded image.
The term used in impulse ink jet technology to denote a condition in the printhead. Droplets usually fail to be expelled upon firing or activation due to air entrapment in the chamber. In impulse ink jet technology, it can be caused by shock causing a drop of ink to be expelled from the orifice plate and replaced by air, or a build up of air due to improper meniscus retraction bringing air through the orifice plate from the outside into the chamber.
Drop-On-Demand. The term is generally used to indicate a valve jet type of printing process in which electromechanical valves open and ink is sprayed onto a substrate. On occasion, improperly used to designate impulse type of ink jet printing.
The term used to designate the mark or spot on the paper or substrate.
dot quality (noun)
The optical quality of an ink drop on a substrate or paper. Such properties as blackness (density) and circularity affect overall dot quality.
droplet or drop (noun)
The term used to designate an ink jet volume of ink when it is in the air before it strikes the substrate.
droplet production rate (noun)
The maximum number of droplets produced by an orifice, chamber, or print system. Expressed in droplets per second.
drying time (noun)
The amount of time required for a dot to become dry to the touch after it strikes the paper or substrate. A critical factor in many applications where printed products are shingled or piled on top of themselves immediately after printing.
duty cycle (noun)
The fraction of time a system is actually employed in performing its function. In printing systems, the percent of time that printing is carried out as opposed to the time the system is inactive.
A class of materials used to render color to inks. As opposed to pigments, dyes are normally completely dissolved in the chemical vehicle.
An electrical field.
The international bar code standard that is used in the retail market place. In the United States and Canada, the UPC code is the accepted standard.
face wetting (noun) (SEE PUDDLING)
The bleeding of the ink into a non-printed area usually due to capillary action of the fibers in the substrate.
In impulse ink jet technology, a piezo crystal or bubble rapidly reduces the volume of the ink chamber to cause a pressure wave which ejects a droplet of ink from the orifice plate at the bottom of the chamber. In the fill-before-fire mode, the piezo element is withdrawn to briefly enlarge the volume of the chamber, drawing more ink into the chamber at which time the piezo element is released, (the voltage causing the crystal deformation is removed), and the piezo crystal snaps back to its rest state or rest configuration. This causes the pressure pulse to eject the droplet. The alternative mode utilized in piezo ink jet technology is the fire-before-fill technique in which voltage is applied to the crystal causing it to constrict the volume of the chamber expelling a droplet first. Voltage is then released from the crystal which returns to its rest state and ink is drawn from the manifold to fill the chamber. The automatic re-filling of the ink chamber is one of the salient features of impulse ink jet and leads to its simplicity. No pumps are required since the system acts as its own pump.
fire-before-fill (noun) (see FILL-BEFORE-FIRE)
The perturbation or event which causes the ejection of the droplet from an impulse ink jet.
food grade (noun)
An ink that qualifies under government regulations for use on food packaging or marking of food products themselves.
Hertz Continuous Ink Jet (noun)
A branch of continuous ink jet technology that features mutual charged droplet repulsion. Dr. Helmut Hertz of Sweden invented this variation of a continuous ink jet process. In this process droplets are produced continuously from a stimulated ink chamber/orifice plate and passed through a charged tunnel or plate where they receive a charge before they become separated from the ligament. Depending upon the amount of charge imparted, they deflect one another to form a cone of ink droplets. A plate with a small hole is imposed further downstream to intercept and collect those droplets which have been deflected from their ballistic projectory. Higher charge on the droplets causes more dispersion and fewer of the droplets statistically pass through the hole to the substrate--no charge and all of the droplets pass through the hole. The advantage is high droplet production rate and the almost continuously variable half-tone system. The disadvantages are the complexities of re-circulation of the unused ink droplets attendant to all continuous ink jet systems and a slight gray background due to the few droplets always getting through the hole in the plate.
Portion of an image where there is an area representing intense light; hence, few or no ink dots are printed. The lightest part of a positive image.
hot melt ink (noun)
The class of ink jet inks which are solid at room temperature and liquid at an elevated temperature. Usually these inks are wax based and provide extremely high color saturation, very sharp edge definition, and independence from the characteristics of the printing substrates. The disadvantage is that the ink resides on the surface of the substrate with little penetration unless there is a subsequent treatment. This results in inks which can be chipped or rubbed off the surface.
impulse ink jet(noun)
The branch of ink jet technology where droplets are produced by a rapid pressure pulse created in an ink chamber causing the expulsion of an ink droplet through the orifice plate. In piezo-based impulse ink jet systems this disturbance is caused by a rapid small change in the volume of the ink chamber behind the orifice plate. In thermal impulse technology this disturbance is created by a rapidly growing and collapsing bubble due to ohmic or electrical resistive heating. Sometimes also erroneously referred to as drop-on-demand type of ink jet printing.
A unit of linear measurement in the English system equal to 2.54cm. One twelfth of a foot, one thirty-sixth of a yard.
ink manifold (noun)
An element in ink jet printheads that receives ink from the supply system and distributes it to the individual chambers or orifices.
interdigitated, interlocked, interlaced (adjective)
In ink jet technology, it refers to the orientation of two rows of orifices positioned so that one row's image is interlaced or interspaced between the images of the other row. A method for increasing the resolution available from a printhead while retaining the spacing between individual channels.
interfacial tension (noun)
A fluidic property similar to surface tension but referring to the affinity of the liquid to a solid surface. This "wetting" property is frequently measured by an instrument called a goniometer which measures the contact angle of the liquid with the surface.
ISS Imaging Subsystem (noun)
An alternative, abbreviated name for the Trident UltraJet? Ink Jet System.
A stream of fluid (ink) produced by discharge through an orifice into free space.
A unit of energy or work in the metric system. Frequently used to quantify the energy required to expel a droplet.
Large Character Printer. Ink jet demand type printing systems used to print the large characters or images on the side of consolidated shipping cartons i.e., corrugated cartons. Since the primary technology for printing large characters on the side of corrugated cartons was the valve jet, it's often used as an abbreviation for a valve jet technology based printing system.
A column of liquid connecting two droplets or the unbroken column of liquid between the orifice plate and the droplet. In a continuous ink jet system, a stream of liquid under hydrostatic pressure is expressed from the orifice plate. The liquid stream will then form into a shape of the lowest surface energy because of surface tension. Liquids in air form spheres. The ligament or connected stream will start to pinch down into varicosities or bumps. That portion of the liquid stream between the orifice plate and the separation point where the first droplet breaks off is the ligament. Also the term refers to the smaller diameter cylinder of liquid between two droplets. This shape is also not stable and this ligament between the droplets separates from the two droplets to form the smaller droplets known as satellites.
line speed (noun)
The velocity of a substrate as it passes in front of the ink jet printheads.
Large Ink Supply System. Bottle supplied ink reservoir with internal level detect system.
A physical phenomena in which ferromagnetic materials are affected by a magnetic field. A magnetostrictive transducer has a magnetostrictive core material surrounded by an electrical coil. When current is caused to pass through the electrical coil a magnetic field is created and the core magnetostrictive material changes shape. Has been infrequently used as a stimulating element for ink jet systems.
A rectangular or orthogonal arrangement of elements into rows and columns. Characters and images are constructed by a matrix of dots from ink jet printing systems.
A unit of linear measurement in the metric system equal to 39.37 inches.
An adjective meaning small or one millionth of the base unit.
micro joule (noun)
One millionth of a joule. (see JOULE)
milliliter (ml) (noun)
A unit of liquid volume in the metric system equivalent to one thousandth of a liter or approximately .03381 fluid ounces in the English system.
An undesirable, spurious pattern in a printed image caused by interference beats between two periodic structures such as patterns in the subject and dot resolution.
One color. Refers to black and white printing.
Uneven print density or uneven color. A defect in matrix color printing because of a lack of dot placement accuracy or variable dot density. Most readily apparent in the areas of solid printing.
A term used to denote color printing where more than black is employed. Frequently a highlight color in addition to black is utilized in multicolor printing. Normally a complete gamut or range of colors is not available in multi-color printing because the primary colors are not utilized.
A linear measurement in the metric system equal to 1 billionth of a meter. Abbreviation: nm.
An alternate term for orifice. In physics, a nozzle is a hole with appreciable "barrel length" as opposed to an orifice. In an ink jet printhead the nozzle or the orifice is a hole from which the ink is ejected.
Optical Character Recognition. Standard characters that are designed to provide the ability to be recognized or read by both humans and a machine, usually a scanner.
A hole or aperture without appreciable length (depth). In most cases the technically correct term for the hole employed in ink jet printing systems. (see NOZZLE)
A unit of measurement of both weight and liquid volume in the English system. An ounce is equal to approximately 28.35 grams and a fluid ounce is equal to approximately 29.57 milliliters in the metric system.
pass line (noun)
A conveyor line or mechanical system that carries the product that is to be printed. The plane of the substrate in front of the printing system.
Picture element; one discrete element of an image whose dimensional domain is defined by the printing system resolution. A pixel.
A physical phenomenon exhibited by certain crystals which change their dimensions when subjected to an E-field (has an electrical field impressed across it). Conversely, when subjected to mechanical stress it creates an electrical signal. This type of transducer is the driving element in a piezoelectric impulse system and frequently is the "stimulator" in a continuous ink jet system.
A class of colorants used in inks, paints, etc., where the color is provided by the absorption or reflection of small particulates in a vehicle. A common pigment utilized for black ink is carbon black which provides intense black color and good archival properties.
pixel (noun) (see PEL)
The act of initially introducing ink to an ink jet printhead and forcing ink out of the orifices to expel air from the chamber or the ink manifold.
print distance (noun)
The distance from the bottom of an ink jet printhead to the printing surface (substrate). (see also THROW DISTANCE)
print gap (noun) (see THROW DISTANCE)
The printing section of an ink jet printing system which can contain a single channel or multiple channels. The portion of the system which contains the transducers, orifices, charge deflectious elements, etc. The ink supply system, including the reservoir, may be attached or remotely connected by a hose.
A printed color or image that is rendered by a combination of three primary colors. In theory, all colors of the spectrum can be reproduced by combining different amounts of three primary colors. The three primary colors in the subtractive system are cyan, magenta, and yellow. Because of paper defects, show through and variations in illuminating light, it is very difficult in practice to have a complete color gamut from the three primaries. Additionally, to make black by combining the three primaries is very expensive because it utilizes much ink. Therefore, black is frequently added as a fourth ink component. This process is called under-cutting.
Synonymous with face wetting. If the bottom (exit side) of the orifice plate becomes a wetted surface, ink issuing from the orifice will frequently form a puddle and, if the puddle becomes large enough or if the inertial energy of the exit droplets are too low, the surface tension of the puddle will prevent the ink droplets from leaving the orifice plate. Much technology and quite a few trade secrets are involved in preventing this problem during operation.
purge (noun or verb)
To clean or expel. To force the ink through the manifold or through the chamber/orifice to clean out debris or air.
repeat length (noun)
The linear distance of a printed image in the web direction before a printed pattern is repeated. One advantage in a demand type printer such as an ink jet printer is that its repeat length is limited only by the capacity of the data system.
re-prime (noun or verb) (see PRIME)
reservoir (noun) (see LISS)
In matrix printing, the number of dots or picture elements per unit length. Frequently, the vertical and horizontal resolution are the same. Expressed as dots per inch in the English system and dots per centimeter in the metric system.
A fluidic element in impulse type printheads which connects the ink manifold to the chamber. One of the components that determine the properties of fluidic oscillations during firing.
restrictor plate (noun)
The narrow fluidic path which controls the flow of ink from the printhead manifold into the chambers.
Reynold's number (noun)
A dimensionless number used in fluid dynamics that relates the inertial and fluidic properties of the system. Flow properties such as laminar and turbulent flow and boundary layer thickness are determined by the Reynold's number. Low Reynold's numbers generally relate to flow conditions where viscous effects dominate. High Reynold's numbers relate to fluidic systems with predominantly inertial characteristics. In most ink jet systems, internal ink flow is in the low Reynold's number regime.
satellite droplets (noun)
Frequently during the ink stream break-off small droplets are formed between larger droplets. These undesirable "satellite" drops are deflected to a greater degree or perturbated by air currents causing erroneous dots. This problem affects continuous ink jet systems to a greater degree than impulse systems but techniques have been developed that cause these satellite droplets to have velocities different from those of the main droplets causing them to recombine with the preceding or succeeding droplets before they impact the paper.
Small Character Printing. An abbreviation used for systems employed to print small characters on labels, packages, and products. Frequently employed to print "best used by" or product expiration dates.
sense resistor (noun)
The resistor which is mounted on each printhead and determines the amount of voltage provided to the transducers.
shear mode (noun)
Method of stressing a piezo transducer which creates shear forces within the transducer causing the piezoelectric device to bend rather than changing length or volume.
A printing defect caused by the ink migrating through the substrate to its other surface (strike-thru).
side shooter (adjective)
An impulse ink jet configuration in which the ink droplets exit at a right angle to the piezo or bubble firing element.
slant configuration (noun)
A frequently employed technique to increase the resolution of a linear array printhead by tilting the array at an angle relative to the direction of motion of the substrate. The dot placement correction is supplied by buffering the data and providing the correct delay.
solid ink (noun)
A class of ink jet inks which are solid at room temperature but liquid at an elevated temperature. Frequently, the ink is in pellet or stick form when inserted in the ink jet system where it is heated until it becomes liquid and then ejected from the printhead. It cools almost instantly or freezes when it hits the substrate. Because of this freezing reaction only a slight penetration ensues and, if unaltered, leaves a hemispherical dot on the paper. This freezing process provides a printing system with the most independence from the characteristics of the paper or the substrate. Vivid intense colors and visual acuity are characteristic. If subsequently untreated by a combination of heat and pressure, the image is fragile, however, and subject to abrasion or flaking.
The component of an ink formulation which dissolves the other constituents such as dyes, humectants, etc., to form a homogeneous liquid.
spot color (noun) (see MULTI-COLOR)
The application of cyclic or periodic acoustical energy to a continuous ink jet stream to produce uniform break up of the ink jet stream or ligament.
A printing defect evidenced by a line in the direction of printing caused by a crooked or non-aligned jet or printhead. Characterized by a gap or darker line due to overlapped rows of dots. Most obvious in images. (see also BANDING)
The technique for providing a low amplitude pulse to an ink chamber to stir the ink without providing enough pressure to eject droplets.
surface tension (noun)
The contracting force on the skin of a liquid. Acts like a rubber balloon on a liquid droplet, for example, and will exert a force to form a three dimensional shape of the smallest surface energy, e.g., a sphere.
thermal impulse (bubble jet)(noun)
A branch of impulse technology in which the rapid expansion of a bubble in the ink created by localized electrical heating expels the droplets from the ink chamber. Characterized by low cost, relatively short lived printhead systems.
throw distance (print distance)(noun)
A term frequently used to define the linear distance from the orifice plate of the printhead to the substrate receiving the ink droplets.
A device that converts one type of energy to another, e.g. a toaster which converts electrical energy to heat energy. In ink jet, piezo crystals convert electrical energy to mechanical energy (motion). In bubble jet, heating elements convert electrical energy to thermal energy.
transducer foot (noun)
A circular attachment to the rectangular piezoelectric crystal. The foot increases the surface area contacting the ink.
A color image producing system utilizing the three primary colors. In an opaque or subtractive system such as printing, these three primary colors are cyan, magenta, and yellow. In an additive (light) system, the three primaries are red, green, and blue. (see PROCESS COLOR)
Two Dimension Bar Codes (noun)
High density bar code symbology which often resembles a checkerboard in appearance. PDF 417 symbology is an example.
Universal Product Code; the bar code symbol that is the standard in the retail and industrial market place in North America. Governed by the Uniform Trade Council. (see EAN)
UV curing ink (noun)
A class of ink formulations which cure (polymerize) through the application of light energy in ultraviolet wave lengths (240 - 380 nm). Its major advantages are drying speed and rugged images.
valve jet (drop-on-demand) (noun)
A non-contact printing system employing micro-electromechanical valves which open and close and permit ink under pressure to be ejected in a small spray. A relatively low resolution system, it's employed mostly for large character printing on the exterior of cartons. Characterized by low cost, low resolution or image quality, and relatively low printing speed.
In a continuous ink jet system as the ink is ejected from the orifice in an unbroken cylindrical stream or ligament, surface tension starts to squeeze or contract the stream into regular thicker and thinner areas. The thinner areas eventually are squeezed off the thicker areas and become individual droplets. This uneven thickness of the ligament is a property called varicosity.
vena contrata (noun)
The point at which the ink stream or ligament is at its smallest cross section after leaving the orifice.
vent cap (noun)
The printhead cap at the furthest end of the ink path. When removed, the printhead can then be purged of ink and excessive amounts of air.
The physical property of fluids to resist flow. In general, in liquids, increases with decreasing temperature. The unit of measure of viscosity in the metric system is poise but since it is a large unit, centipoise or 1/100th of a poise is usually employed.
Volatile Organic Compounds. Organic substances which easily become vaporous or gaseous. Frequently deemed a health hazard. Often used as quick dry solvents which, on evaporation, give off volatiles. (An increasing environmental concern.)
The property of the printed image to resist the application of water on its surface.
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