Collating means to collect and combine. And in the business forms and documents environment, collating is the process that brings a number of printed webs together to make multi-part forms and unit sets.
After all the parts of a unit set or multi-part continuous form are printed, the reels are positioned on individual stations of a collator, which then assembles the various components with accurate registration from part to part.
Typical functions performed by collators include fastening, punching, numbering, perforating, self-seal application, unit set construction and special folding.
FASTENING
Collators can produce a wide variety of form fastenings, the most common of which are gluing and crimping.
Gluing is often used where there are many parts in the form, or where there is excessive handling.
Collators are capable of applying spot and line glue parallel to the web. Collators that are fitted with a cross-glue applicator can apply glue perpendicular to the web.
Also known as a ‘cold glue locking system’, the knurl lock is a cold glue and paper-fibre fusing process that creates a permanent bond between form parts. After a line of cold glue is laid down, a knurled wheel fuses the paper and glue together.
Spot gluing parallel to the web is a common method of fastening forms. The glue nozzle is stationary, and, depending on the configuration of the collator, makes contact above or below the web. As the web passes, a bar that is perpendicular to the web intermittently swings into the web, forcing the web to swing away from the glue nozzle. Each time the paper swings back and touches the glue nozzle, it takes a spot of glue from the nozzle, producing dots of glue that are evenly spaced on the form.
Not to be confused with spot gluing, skip gluing is the application of specific lengths of glue at precise intervals. This process is controlled by a computer, and is also known as computer-controlled or programmable gluing. Skip gluing offers the most flexibility in the fastening of forms.
Glued forms may experience a problem referred to as tenting, which is a failure of the paper parts to fully straighten out when processed. A solution to this problem is to use skip gluing, where the line of glue is computer-controlled to skip over the between-set perforation. With no glue at the cross perforation, tenting is minimised and refolding is simplified.
Line gluing is predominantly used in forms that contain a pocket. Cross-web glue is applied similarly to cross perforations. A roller with rubber strips along its length revolves with the collator, picks glue up from a fountain and lays down either or a dotted line of glue where the rubber strip meets the web.
Patterned glue is applied with a relief plate in a process similar to the way carbon is applied to a form. A photopolymer or rubber plate is cut to the desired shape and placed onto the cylinder. The glue is placed in a fountain, and is picked up by the plate (much like ink).
Crimping (also known as hook-locking) is the most common temporary forms fastening method for continuous forms.
With this method, a special tool cuts several small prongs through the form margin of the parts to be fastened (paper and carbon).
Crimping can have two, three or four fingers. The standard configuration is four fingers, with two fingers striking through the carbon and two through the paper. Spacing is at 2" intervals.
The crimped fingers trail away from the direction of travel, helping to prevent feeding and jamming problems on computer printers.
Most collators are capable of double crimping, which ensures a more secure lock.
Flexing or tablocking uses a narrow strip of gummed tape that is fed through the sprocket hole to fasten the top and bottom parts of a form. This technique, which can be used on a form with any number of parts, enhances the fastening performed by crimping, and allows for ease-of-flow on end-user equipment.
PUNCHING
Holes can be punched into the form at specific locations and distances to facilitate filing. Round holes are the most common punching feature for binder filing. Round holes usually come in pairs and can be punched parallel or perpendicular to the web.
NUMBERING
Business forms are normally numbered for stock control or transaction sequence purposes.
While some presses offer numbering, collator numbering is dominant. Prior to final delivery, the numbering box on the collator crashes the number (hence the term crash numbering) through the parts – thus ensuring that each part of the form has an identical number.
‘Gothic’ numbering that is 5mm in height is the most common, as it is clear and easy to read.
Most numbering heads have 7 digits, although numbering heads with 9 and 11 digits are also available. An alpha prefix/suffix wheel can be substituted for one of the numeric wheels, thus enabling the form to be numbered with an alpha character prefix or suffix (such as Q123456 or 123456B).
Prefixes and suffixes are often used to distinguish forms used for different purposes or locations.
Variable Size Numbers
A Domino numbering system (ink-jet technology) can be attached to a collator. The Domino system is capable of printing numbers 4-10mm in height, and whilst it is not a ‘crash’ process, its strength is its ability to have numbers placed relatively close to each other.
Number Positions
Forms are generally numbered in one position only. However, it is possible to number in two places, such as on a tear-off receipt, providing there is sufficient space between the numbers.
Back Numbering
Although uncommon, a form can be back numbered (numbers placed on the back of a form) by turning the web over so that the back of the web is exposed to the numbering machine. Back numbering precludes the front of the form to be numbered.
An example of the use of this feature is when a receiving report format is pre-printed on the back of the receiving copy of a purchase order. With the purchase order number printed on both sides, the receiving copy can be easily located from either side.
Guaranteed No Missing Numbers
Guaranteed no missing numbers means that an order cannot be despatched with any numbers missing. This is costly because of the extra labour involved in checking for and replacing missing numbers.
End-users sometimes order additional unnumbered sets to allow any spoiled forms to be replaced with forms with hand-stamped numbers that maintain the numbering sequence.
MICR Consecutive Numbers
MICR consecutive numbers can be part of the encoded MICR (magnetic ink character recognition) field on cheques. These numbers are added to cheques so that they can be placed in numerical order after they pass through the bank’s processing system, and aid the issuer in reconciling their bank statement. MICR consecutive numbers can be printed on a collator or an off-line encoder.
Modulus Numbers
Modulus numbers are self-checking numbers used with consecutive numbers. The consecutive number includes a check digit that is used by a computer to verify the consecutive number on a document before it is accepted as a legitimate.
Mechanical self-checking number systems include Modulus7 and Modulus 9.
These mechanical systems improve error-detection rates by approximately 60%.
For critical applications that require an almost perfect error-detection rate (over 99%), computer-controlled numbering systems are used. Such systems include Weighted Modulus 10 and Weighted Modulus 11.
PERFORATING
Perforating that is done on the collator is through all parts of the form, not on individual parts. Fan-fold perforations are added on the collator, and perforations that are not done on the press can be added on the collator.
SELF-SEAL APPLICATION
Self-seal is a thin film of pressure-sensitive adhesive applied to a silicone-treated carrier strip, and protected by a release-liner. When the release liner is removed, the exposed tape can be applied to many different materials.
Self-seal tape is often applied on the collator, and is usually applied parallel to the web direction. It is used for pay envelopes and mailers
UNIT SET CONSTRUCTION
A unit set collator cuts the collated sets into individual unit sets. Sets with or without sprockets (line-holes) in the stub can be produced. If the sprockets are to be removed, the form is trimmed before being cut into a set.
SPECIAL FOLDING
Collators are often used to fold single-part forms that cannot be folded on a press.
