dandy pick

a defect in paper caused by the dandy roll picking up fibers from the paper or otherwise disturbing the sheet formation to leave thin spots or other imperfections.

dandy roll

a paper machine part that is a skeleton cylinder covered with a woven wire cloth. This is one method of applying watermarks to paper while it is wet.

data content codes

See data identifier

data Identifier

a specified character or string of characters that defines the general category or specific use of the data that follows.

data Integrity 2D symbols

is provided in conventional, linear bar codes, by encodation schemes which include unique start and stop codes, self checking parity within each character, and check digits which apply to the total message. In these symbols, the height of the bars may be expanded to provide for redundant scan paths and allowance for diagonal scanning. Symbols damaged in a small area may retain their integrity because of this redundancy. Among the prominent 2-D symbologies, the data characters are composed of square or near-square elements which do not provide for redundant or diagonal scan paths. This fundamental difference provides for the enormous gain in data density but dictates that an error detection and an error correction system have been instituted in addition to the character and message orientation and parity checking schemes.

decimal, binary coded BCD

a numbering system using base 2 that represents each decimal digit by four binary bits, with the place values equal to 8, 4, 2, and 1, reading from left to right.

deckle

a name for straps on the wet end of a paper machine. Usually, however, in the pressure sensitive part of the business it refers to roll widths available from a paper mill.

decoder

the electronic package which receives the signals from the scanning function.

delamination

the partial or complete separation of a material into layers in a direction approximately parallel to the surface.

delayed action adhesive

a heat sensitive adhesive than can be heated and later applied with pressure. The adhesive stays tacky for long enough for label application. It is the opposite type of heat sensitive than instantaneous.

density

the mass or weight per volumetric measure of a material. Also describes the relative amount of memory contained in a radio frequency identification tag. see Bar code density.

Depth of Field

the distance between the maximum and minimum plane in which a code reader is capable of reading symbols.

dextrine

any of various soluble polysaccharides obtained from starch by the application of heat or acids and used mainly as adhesives and thickening agents. In conventional gum, this is a type of adhesive that is primarily vegetable in basis.

die cut

the line of severance between a pressure sensitive label and its matrix or adjoining label made by the cutting edge of a die.

die cut label

a pressure sensitive label mounted on a release liner from which the matrix has been removed.

die gap

the distance between the metal faces forming the die opening.

dielectric

a nonconductor of electricity.

dielectric paper

a paper free of any metallic element or other materials which might conduct electricity. It is a dense well formed, chemically pure paper used as an insulating material in electrical equipment to prevent the flow of electrical charges.

dielectric strength

the voltage which a dielectric paper can withstand without allowing passage of the current through it.

Diffuse Reflection

the component of reflected light which emanates in all directions from the reflecting surface.

dimensional stability

the property of a material which relates to the consistency of its dimensions. Paper grows as it picks up moisture and shrinks as it gives up moisture. Different grades can vary in how much they grow and shrink.

direct thermal

a type of non impact printing that uses heat to darken printed images. There is a thermal coating that darkens with application of heat. Advantages of this printing method are high resolution, quiet printing and inexpensive printers. The main disadvantage is that the images are not permanent. They tend to fade with time and can darken when contacted with certain liquids. Direct thermal paper is more expensive than other types of white paper.

dirt

Foreign matter in the paper can provide appearance of specks. This can detract from the print job and interfere with automatic reading devises such as OCR scanners.

discrete code

a bar code or symbol where the spaces between characters inter-character gap are not part of the code, e.g., USS-39.

dot matrix

a system of printing where individual dots are printed in matrix 5x7, 7x9, etc. forming bars, alphanumeric characters and simple graphics.

dot size

Ink Jet Dot Matrix Thermal

dots per inch

a term to measure resolution of electronic data printers. Frequently the abbreviation of DPI is used. Electronic data printers form images by printing a series of dots on a material. The higher the dots per inch, the higher the resolution will be. Information printed at high DPI look natural. The eye can not see the dots. Resolution DPI has a large bearing on the ability of scanners to read bar codes. Bar code readers look for the space between the lines. When low DPI resolutions are used, the space will not be the right size. The bar code will not scan.

DPI

an abbreviation for dots per inch.

draw

the displacement of the cut by the thickness of the cutting blade during the trimming operation. This is a common cause of inaccurately cut paper. It can also be a term for the tension applied to the paper between sections of a paper machine.

dry bone glue

a glue or adhesive made from bones previously cooked for tallow and dried.

dry gum

a water sensitive adhesive that has a dull finish. It is more dimensionally stable than conventional gum. See also water sensitive.

dry seal adhesive

another term for cohesive adhesive. It is an adhesive that will not stick to other things than the adhesive itself.

DSSG

Distribution Symbology Study Group.

dull laminated foil

this is a pressure sensitive face stock that is paper laminated foil with a matte appearance. It is available in both silver and gold colors. See also paper laminated foil.

Duraform(r)

a Kimberly-Clark trade name for latex impregnated papers. See latex impregnating.

dyne level

dyne is a measurement of surface tension or energy. The level is the actual reading of the critical surface tension. Low dyne levels indicate a low surface energy which can contribute to poor ink adhesion.