This invention relates to apparatus and method for folding, stacking and separating continuous forms in a moving web and, more particularly, continuous forms which have been prefabricated with regard to width, margin line holes and transverse perforations intended for zigzag folding of the web to form it into a stack after it has been printed in a printer having a supply of series of preferably personalized forms, wherein each series includes an initial form marked with an address and optionally with a separation mark.
In printing all kinds of information on a moving web of continuous forms, such as messages, wage statements, invoices, etc., the printout with current technique takes place in high-speed printers of the "impact" or preferably laser type. The printer is controlled by a computer with memory that contains all data required. The endless web of forms runs through the printer under automatic control of the feed simultaneously as printing is effected. The printing speed is high, which also means that the web advances at high speed.
The web is usually wound as a roll onto a bobbin which may be mounted on a shaft in a roll stand from which the web is fed, continuously or intermittently, into the printer. The roll stand operates as an independent unit and has drive and control means of its own, including, among other things, a depending loop of the web which is sensed by means of a photo-electric cell, so that the tension of the web when fed into the printer practically equals zero. The same applies to the output side of the printer.
Before being rolled onto the bobbin, the web is also prefabricated with regard to width, margin line holes, perforations and preprint, if desired. These preparatory operations are carried out in separate machinery, usually referred to as presses. Thereafter, the web roll is delivered to the data processing center fully ready for printing and the roll may be of jumbo size with a diameter of up to 1250 mm.
As for the perforations of the web it should be observed that a transverse perforation is always located at a separating line between two sheets (or form lengths) so that the web can be either folded or torn off along the perforation. Other perforations may also be arranged in each separate form, e.g., for tearing off a counterfoil, a payment notice or the like.
After the passage through the printer, various expedients have been tried out to ascertain the simplest and most rational way of taking care of the printed forms.
By the folds/perforations the web is fully prepared for the folding of the forms into a stack. Some printers are also equipped with a built-in folding and stacking device. However, the ever higher printing speeds, particularly in modern laser printers, with the attendant great web lengths per unit of time, mean that such an expedient is unsatisfactory, the more so as further demands are placed on the processing procedure.
Development in the art has resulted in a system where all after-processing of the printed web takes place outside the printer in separate machines. According to a prior art method, it is thus necessary to prefold the web in a machine before the final folding, stacking and simultaneous so-called job separation can be performed in another machine. Job separation implies that a division of the web is effected by cutting or tearing a web at a transverse perforation between two jobs. A job is defined as a number of forms having common characteristics, for instance the same text, the same customer, the same order number or the like. At the final folding/stacking with job separation it is also previously known to insert a tab in the stack where separation has been made to permit later separation of the jobs from one another in a simple manner.
Recently, the market has raised a further important demand under the term "first page up". Obviously, it is justified to require not only that the jobs in a stack shall be separated from one another but also that each job shall be rapidly and positively identifiable. For that purpose, the first page of each job is printed with a distinct address or other suitable marking which is included from the very outset in the printing program.
In the prior art folding and stacking technique there is a 50% risk that the page or sheet bearing the address, which for natural reasons is the first sheet of each job, will lie at the bottom of the job and with the printed face turned inwardly toward the other sheets of the job.
After inverting the stack, it is therefore necessary first to turn over the first sheet before the address can be read. This is very inconvenient. Besides, an essential disadvantage of the existing technique with regard to folding and stacking is the already-mentioned fact that separate process operations are required for prefolding and folding/stacking, respectively, with attendant demands for manual intervention and space etc.
One object of the present invention is to eliminate the inconveniences of existing technique and to provide machine wherein the prefolding operation and the contemplated unit therefor are dispensed with.
Another object of the invention is to provide the so-called "first page up" function in the machine.
According to the invention, the prefolding operation and the contemplated unit therefor are dispensed within that the machine presents cooperating means for advancing the web, for alternately changing web direction incident to folding, holding down the folded web and stack removal.
According to the invention, the so-called "first page up" function is attained with the aid of a method and machine for selectively changing the orientation of the means for directing the web into the folded stack.