Oscillator- A driven inking or dampening roller that not only rotates but also moves from side to side, distributing and smoothing out the ink film and erasing image patterns from the form roller.
Overpacking- Packing the plate or blanker to a level that is excessively above the level of the cylinder bearer.
Molleton- A thick cotton fabric similar to flannel. It has a long nap and is used to cover rollers in conventional lithographic dampening.
On-Demand Printing-Commercial quality printing produced as needed with turnarounds of a few hours or less. Often associated with very short runs of a hundred or fewer pieces and the use of digital printing press.
Metallic Ink- An ink with fine aluminum, bronze, or copper powders in its pigment.
Metering Nip- The line of contact between two rollers in the dampening system of lithographic press.
Incline Press- A screen printing press in which the screen maintains a position parallel to the printing bed, but recedes diagonally during the feed/take-off cycle.
Leafing- The phenomena that occurs when metal flakes in metallic inks float to the surface of the ink, giving it a particular luster.
Gripper Edge- On a sheetfed press, the leading edge of the paper that rests at the head stops and is grabbed by mechanical fingers known as grippers. The press operator typicaly marks the gripper edge with an “XXX” before sending the job to the binding and finishing area.
Hickey-Picking Roller- A roller that has synthetic fibers embedded in its surface, to help it remove hickeys from the surface of an offset printing plate or to fill in the white ring o the plate surface. This roller replaces one of the ink form rollers.
Front Stops- A series of devices that halt the forward movement of a press sheet on the feedboard. he front stops square the sheet in relation to the printing cylinders and determine the print margin. The front stops are part o the three-point register system.
Alternative term- front guides
Gear Streaks- Parallel streaks appearing across the printed sheet a the same interval as gear teeth on a cylinder.
Eccentricity- A roller or cylinder that does not rotate in a true concentric circle in relation tp its axis. Alternative terms- off center; out-of-round
Flagging- (1) Indicating a web splice so that the spliced product can be removed from the press folder and discarded.
(2) Marking printed matter to indicated a change or correction.
(3) Inserting small strips of paper into a skid of press sheets as needed to indicate segments of defective printed sheets.
Dampeners-Paper, cloth, or rubber-covered rollers that distribute water to the printing plate in the lithographic process.
Discharge Printing- Pattern-printing darkly dyed textile substrates with a color-removing chemical to produce a deign into which lighter hues may be printed.
Common-Impression Press- A flexo or sheetfed or we offset press that has one large-drum impression cylinder, which holds or supports the subtrate, and several color stations (plate/blanket cylinders pairs) positioned around it.
Cutoff Length- (1) The distance between corresponding points of repeated images on a web.
(2) The circumference of the plate cylinder.
Cobwebbing- (1) FIne filaments of ink that appear between the screen fabric and the substrate during screen printing.
(2) In gravure, a filmy buildup of dried ink on the doctor blade, the ends of impression roll, or printing cylinder.
Cylinder- A press or folder component that fans the sheets to improve separation and feeding accuracy.
Backlap- In screen printing, a very heavy, rough application of color on one side of a print, which is caused by color pulling through the screen behind the squeegee at the beginning of the printing stroke.
Bounce- In lithography, an abnormal reaction to compression, which results in erratic rotational movement of the press cylinders, causing missed or imperfect impressions.
