Angle of Attack - The angle formed by the face of the
moving squeegee blade and the plane of the screen, under pressure. Due to the
flexibility of the blade, this angle generally differs from the squeegee angle,
which is measured without movement or pressure.
- Anilox rolls
generally are steel with ceramic coating. Etched into the ceramic are cells that
are used to transfer controlled volumes of ink to the flexographic printing
plate. Between print jobs they must be cleaned of ink. Anilox rolls used in
narrow web presses typically have face lengths up to around 30 inches. These
rolls are often installed and maneuvered by hand, and can approach 100 pounds.
Anilox rolls on wide web presses are longer (typically up to 100 inches, but can
be much longer) and can weigh several hundred pounds. They are typically moved
with cranes or robotically because of their weight and size. Anilox rolls on
corrugated presses are also very large and are normally cleaned on-press. The
design of corrugated presses allows for separation of print units.
Anilox Sleeves - Anilox
sleeves are used as a lighter alternative to anilox rolls. They are also ceramic
coated, but are hollow and slide over steel cylinders which remain on-press.
They are placed on-press by injecting air pressure into the cylinder. This
provides a cushion of air so that the sleeve can slide onto the cylinder face from a
shaft on a storage/transport cart. Once in place on the cylinder on the press,
the air pressure is released, causing the sleeve to deflate resulting in a total,
uniform grip to the cylinder surface.
Blanket (Lithography) - A rubber-coated fabric
mounted on a cylinder that receives the
inked impression from the plate and
transfers (or offsets) it to the paper.
Bundle - A stack of signatures strapped together
for later use in other binding and
Coated Screen - A printing screen with direct emulsion applied to the fabric
preparatory to exposing.
Coater (Emulsion Applicator) - A tool with a rounded, sometimes slotted edge
used for evenly spreading sensitized emulsion on the fabric of printing screens.
Where cut, trimmed, or folded printed
pieces are assembled in proper sequence to prepare printed materials for
further binding operations.
Conveyor - A set of power actuated
non-powered rollers configured to move
materials through a production process
line or between job stations.
Shaped Hand Posture - Positioning fingers and thumb in the form of a
"C" provides neutral postures for fingers and thumb eliminating pinch
grip. This is the desired hand posture for using hand tools.
Figure 1. "C" shaped hand posture illustration.
Doctor Blade -
A thin, flexible, adjustable blade mounted parallel against the anilox roll for the purpose of scraping off excess ink.
Fabric Stretcher - A mechanical device for tensioning screen printing fabrics
over the screen frame, accurately and correctly.
Fanning - An operation in which sheets,
or pages are separated so that individual pieces do not stick
Flexography -A method of direct-rotary printing, using resilient raised-image printing plates, affixed to variable-repeat plate cylinders, inked by a roll or doctor blade-wiped engraved metal or ceramic roll carrying fluid inks to virtually any substrate.
Flood Bar - The device on a screen printing press comprised of a thin metal (or
plastic) blade, which has the function of spreading a thin film of ink uniformly
over the printing screen, in the opposite direction of and preceding the printing
Folder (Lithography) - Machine that creases and scores printed
sheets of paper to particular
specifications during binding and
finishing. The process itself is called
Image Area (Lithography) - The
area that has been specially treated to
receive ink and repel water.
Ink (Flexography) –
Fast drying fluid (water- or solvent–based) or paste-type (UV cured) ink.
Job Rotation - The process of periodically moving
employees between different jobs or tasks to minimize
monotonous activities and overexertion of particular muscles or tendons. The jobs
within the rotation should use differing muscle-tendon groups allowing for rest
and recuperation. Tasks should be categorized based on parameters such as
high/low repetition, high/low force exertion, maintaining awkward postures for
prolonged periods, and the areas of the body affected. The jobs within the
rotation should use differing muscle-tendon groups or alternate between extremes
of parameters such as high or low force. This will provide the opportunity for
"working" rest and recuperation.
In small shops where a few employees perform multiple tasks the opportunity to
rotate may not exist, but in these shops the variety of tasks that are performed
during the shift will provide a built in rotation scheme. Workers in these shops
should look for chances to move between tasks where parameters such as force can
be altered between high and low. In larger shops, where there is enough work for
dedicated stations, a formalized rotation scheme should be developed which moves
people between stations.
- A device comprised of a vibrating table,
the action of which squares and neatly stacks a pile of
sheets of paper.
- The process of aligning or moving even
sheets of paper to a common edge to
produce a neat stack.
Lithography - A printing process in which the image
carrier is chemically treated so that
the non-image areas are receptive to
water (i.e., dampening or fountain
solution) and repel ink, while the image
areas are receptive to ink and repel
Neutral Postures -
Postures where the body is aligned and balanced, while sitting or standing. The
head is kept upright and is not turned to either side more than about 30 degrees
or tilted forward or backward more than about 15 degrees. When the worker is
standing, the torso is not bent more than 10 to 20 degrees from the vertical
position and the natural curves of the spine are maintained. The pelvis and
shoulders should face straight ahead to avoid twisting the torso. The shoulders
are relaxed and knees slightly bent. The arms hang normally at the side, with
elbows close to the body. The elbows are not bent more than about 90 degrees and
the palms face in toward each other and the center line of the body. The wrists
are in line with the forearms and are not bent sideways, forward (towards the
palm), or backward (towards the back of the hand.) When the worker is seated,
the buttocks and feet are firmly supported.
- An indirect printing method in which the
inked image on a press plate is first
transferred to a rubber blanket that in
turn transfers ("offsets") the inked
impression to a press sheet. In offset
lithography, the printing plate has been
photochemically treated to produce
image areas and non-image areas
receptive to ink and water, respectively.
Photopolymer Plate –A flexible, relief printing plate made of either precast
sheet or liquid light-sensitive polymers. Photopolymer plates require exposure
to UV light during the platemaking process to cure the raised image. This is
followed by washout of unusable portions and drying.
Plate (Flexography) – Flexographic printing plates are relief-printing plates
made of rubber or photopolymer. Rubber plates are engraved or molded.
Photopolymer plates require exposure to UV light during the platemaking process.
Plates are mounted on plate cylinders.
(Lithography) - A thin metal, plastic, or paper sheet
that serves as the image carrier.
- A steel cylinder to which flexographic printing plates are mounted, using a
double-sided, sticky-back tape.
Plate Sleeves - A
flexographic printing plate formed as a sleeve, in a continuous circle. The
sleeve slides over a plate cylinder.
Pockets - The hoppers on a binder that are loaded
with the signatures to be bound into a
book or magazine.
Prepress – The steps required to transform an original image into a format that
is ready for reproduction by printing, including such activities as art and copy
preparation, photography, image assembly, and platemaking.
Rack Drying - The drying of screen printing sheets in racks, usually in ambient
temperatures, but also placed in a room where temperatures are elevated.
Racking - The manual placing of screen printing sheets on racks for drying.
Ramp-Up Period – The time allowance for employees to establish the amount of
material they can safely handle using a pinch grip.
Reclaimed Screens - Printing screens conditioned for re-use by removal of excess
ink and stencil, and reconditioning if necessary of the screen printing fabric
to receive a new stencil.
Reclaiming - (1) The process of removing both ink and stencil from the screen
fabric after a printing run in order to reuse the fabric for a later job; (2)
the process of distilling used solvents to obtain a reusable, cleaner solvent
for cleaning screens.
Substrate or printed product produced in a
continuous strip and wound uniformly
around a central shaft or hollow core.
Roll Core - The hollow center of
Roll Jack - A mechanical device used to lift and/or
move rolls around the work area.
Roll Shaft - A metal rod placed in the hollow core of
a roll used to hold the roll
in place while on a web press.
Scoring - To compress or crease
heavy substrate along the
fiber line to facilitate folding or
Screen - (1) Printing Screen: an assembly of stretched screen printing fabric on
a frame with stencil attached, ready for printing; (2) Halftone Screen: a
transparent glass sheet marked with cross-hatched design to be placed before the
camera film when photographing continuous tone art to produce dot structure of
the design in the negative. Another type is produced photographically on film
with vignette dots. The latter is placed in contact with the negative film.
Screen Mesh - (1) A term generally indicating screen printing fabric; (2) that
portion of the screen printing fabric which can be counted or measured to
identify fineness or coarseness of the fabric.
Screen Printing - A printing process which involves passing ink through an open-weave screen fabric
which is coated with a stencil. The stencil blocks the non-image areas,
allowing the open areas of the fabric to pass ink to reproduce the image.
Screen Washer - A unit in which printing screens can be washed out to remove ink
residues after printing, or be reclaimed completely by removing the stencil,
usually by high pressure spray.
Sheet Fed Press - An offset lithographic printing
press that prints on individual cut sheets that are fed into the press one at a
Signature - One or more printed sheets folded to
form a multiple page section of a book
Signatures are most commonly grouped as
four, eight, sixteen, or thirty-two
pages. Various combinations of multiple
page signatures create the full complement of pages
needed in the printed piece.
Solvent - A dissolving, thinning or reducing agent. An additive used to reduce
viscosity of a screen printing ink, generally. Specifically, a solvent is a
liquid that dissolves another substance such as resin.
Spinning Disc -
A metal disc placed under a roll-off
press to allow for easier positioning or
repositioning of a roll.
Squeegee - A tool used to force ink through the openings of a screen printing
stencil when in contact with a substrate, consisting of a rubber or plastic
strip or blade held in the edge of a wooden or metallic handle.
Squeegee Angle - The angle formed by the near-vertical axis of the squeegees and
the plane of the screen, measured when the squeegee is in position, but no force
or movement has been applied.
Stacker - A
device attached to the delivery conveyor
of a web press that collects,
compresses, and bundles printed product.
Stencil - The component of a printing screen which controls the design to be
Stretch - (v) The tensioning of screen printing fabric preparatory to securing
it to the printing frame, or by self-stretching frame; (n) the degree to which a
material can accommodate deforming tension.
Stretch Frame - A screen printing frame so constructed that after the fabric is
secured, additional stretch can be applied by threaded rods bolts, cams, corner
adjustments, etc. Also called "retensionable frame".
Substrate - Any base material with a surface that
can be printed or coated. This material may differ in shape and size. Examples
plastics, pressure sensitive adhesive material (such as bumper stickers), textiles of all kinds, metal, glass, ceramic, leather, and
Web Press - A rotary press that prints on a
continuous web, or ribbon, of substrate fed
from a roll and threaded through the