Flexographic Printing Glossary Of Terms
Accelerate: To increase the pace by adding a faster drying solvent or by increasing the temperature or volume of hot air applied to the substrate.
Anchor coat: Refers to a layer of adhesive applied to the surface of the substrate to paste subsequent coatings.
Angle of wipe: The angle the doctor blade is set from the centerline of cylinder, before loading.
Aniline dyes: They are derived from coal tar and classified based on chemical composition.
Anilox inking: This refers to the double roll inking system used in flexographic printing. The fountain roll transfers ink to the meter roll which in turn transfers it to the plate cylinder.
Anilox roll: Is the second roll in the flexographic press. It is made of steel and has engravings on it. It transfers a controlled amount of ink from the fountain press to the plate cylinder.
Bare cylinder diameter: Refers to the actual diameter of the plate cylinder, before the double-sided sticky tape and plates are mounted.
Blade coating: Refers to the process of applying coatings to paper. An excess amount of coating is applied to a cylinder and then removed with a blade; the excess coating is recycled and reused.
Burn: A term commonly used for a plate exposure while making plates.
Burr: A wire-like sliver formed by blade wear.
Centipoise: is the unit of measure of viscosity; 100 centipoise equal one poise. Water has a viscosity of 1 centipoise (CP)
Central Impression Cylinder (CIC) Press: The CIC press supports all of its color stations around a single impression cylinder.
Clamp Marks: Marks produced by the clamps that hold the stock in position for guillotine trimming.
Common Impression (CI) press: A press with multiple printing units around a large impression cylinder.
Cylinder: In flexographic printing presses there are 4 rolls. The first two rolls are called Rollers (the Fountain roller and the Meter Roller) and the next two are called Cylinders (Plate cylinder and Impression cylinder).
Dilatent: Is a substance that has a direct relationship between viscosity and shear. Such fluids are solid or highly viscous when being stirred but fluid when left untouched. This is a property thought to be highly undesirable in flexographic inks and to be avoided using various formulae if need be.
Distortion copy: Because flexographic printing uses flexible plates, stretch or shrinkage may occur during mounting of plates. The plates thus have to calculate the distortion using formulae, and create plates keeping this in mind.
Doctor blade: To wipe away excess ink from the nonimage areas a sharp knife-edge blade is pressed against the engravings on the printing cylinder. This is the doctor blade.
Doctor roll: The fountain roll in a flexographic printing press.
Driving Side: is also known as the gear side. This is the side opposite to the operating side. In a flexographic printing press this refers to the side on which the main gear trains are located.
Dryer: This is an additional unit in the flexographic printing press. The printed substrate is dried prior to rewinding using a dryer. Some presses also have dryers between the printing units or different color stations.
Drying in: refers to the condition where ink dries in the cells of an anilox roller.
Equalizer rod / Meyer rod: The equalizer rod is used to evenly spread liquids at a given thickness on the substrate. It is generally made of metal and has fine wire wound around its axis.
Flexography: is a cheap and efficient method of printing. It uses flexible plates with raised image areas. The press has four rollers. The plate is inked evenly by the rollers and the substrate can be virtually any material.
Fountain: refers to the container that holds the ink in which the fountain roll revolves in a flexographic printing press.
Gear marks: These appear as evenly spaced, lateral variations in tone that exactly match the distance between gear teeth. In flexographic printing, gear marks are considered a printing defect.
Impression bar: A small diameter rod or bar, supported by a back-up member of sufficient rigidity, mounted in place of the impression cylinder for running certain types of work, e.g., porous tissue.
Ink: refers to the water or alcohol based, quick drying liquid or paste used in flexographic printing.
Lake: This term refers to a depression or dishing on the surface of the rubber plate used in flexographic printing.
Mylar: This is a substance used as a substrate in flexographic printing. Mylar is made of polyester and has great dimensional stability and mechanical strength.
Neoprene: is a kind of synthetic rubber used in making flexographic printing rollers. It is resistant to alcohol, water, aliphatic hydrocarbons, cellosolve and to a limited extent esters. It is not resistant to aromatic hydrocarbons.
Nip: Line of contact between two Rolls. The nip needs to be just right for printing to be accurate and free of defects.
Nitrocellulose: A film former widely used in flexographic and gravure inks; nitrated cellulose.
Nodule: This is a tiny piece of an irregular shape on an anilox roll that is not part of the image areas but is still raised. It needs to be removed with additional polishing to prevent defects.
Non-increment press: A type of flexographic press that does not depend on standard gear pitch increments. It can print innumerable variable repeats as it is.
Operating side: It is the side opposite to the driving side or the gear side. The printing unit adjustments are on this side of the flexographic printing press.
Premakeready: is a process required for bettering the print quality. In flexographic printing, the surface of the printing plates is varied in height which is called premakeready.
Running register: That control on a flexographic printing press, which accurately positions the printing of each color station, in the direction of the web travel. Also called Circumferential register and Longitudinal register.
Shellac: is a substance used in inks used for flexography. It is a natural alcohol-soluble resin.
Stack press: A type of flexographic printing press in which the printing stations are stacked one on top of the other and each has its own impression cylinder.
Sticky back: is the two sided tape used to stick printing plates to the plate cylinder.
Stretch: Intensity of color of flexographic printing ink.
Striation: is a defect in flexographic printing where there are streaks of parallel lines on the substrate.
Strike through: is the incident when ink penetrates through the substrate.
Turning bars: These are generally found in the newspaper or commercial flexographic printing presses. They are required when the web needs to be printed on both sides. The turning bar guides the web so that it is inverted front to back and can be printed on the reverse side.
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