|Tuesday, 12 December 2006|
Labels are made from a label media. The label media itself typically is made up of a roll of pressure sensitive tape that is attached, typically along a side containing an adhesive, to a continuous support roll of release liner material. The label media is fed in a media direction along a media path through the label printer. Discrete labels are formed by cutting the label media. Complex label shapes can be obtained by plotter cutting the tape layer only of the label media. Linerless media and labels are becoming increasingly popular in the label producing industry because of the many advantages over their linered counterparts. A linerless label stock is typically a continuous roll of direct thermal label or tag stock (e.g., paper, film, or combination) having a pressure sensitive adhesive on the backside without a silicone coated release liner. Linerless labels are advantageous over traditional linered media since there is no release liner to dispose of a greater amount of media may be included in a same size roll as that of linered media. Labels are generally provided in the form of a roll of web stock which is disposed within or on a label printer, where the web stock supports labels which have an adhesive backing releasably attached to one surface of the web stock, with the printing of the information to be carried out on a label surface opposite the releasably attached surface. The web stock and the releasably attached labels are transported within the printer along a defined path from the roll past a printing station which prints the information on the labels, whereupon the releasably attached printed labels are peeled from the web stock in a label peeler station and become available at a label exit port of the printer for application to a surface to be labeled. Label printers typically incorporate a media supply of "peel away" labels adhered to a coated substrate wound in a rolled configuration. The media with the labels is drawn against a printing head, which causes images to be created on the label in response to localized heating of the printing head. Generally, a label printer prints commodity information on a label sheet and thereby allow the printed label sheet to be affixed to a product. A number of label sheets are peelably attached to paper which is wound in the form of a roll, in a manner such that they are spaced apart one from another by a certain distance.
Label printers for printing and issuing labels are currently largely employed in a variety of industries. In general, the label printers are of a design wherein a ribbon of label carrier sheet carrying a row of blank labels adhering peelably to the label carrier sheet is utilized and the blank labels are successively printed and issued with data printed thereon. Label printers print information such as weight, unit price, total pirce, article name, packed-on date, and sell-by date on a label. There are many label printers which also print a bar code in association with the recent widespread use of POS systems. Label printers and label printer applicators for printing price tags and various other indicators are manufactured in accordance with individual purposes and functions. Labels are typically printed by a continuous printing process utilizing a roll label print media. Generally the continuous process for printing labels has been reserved to the flexographic, gravure and thermal printing processes. Flexographic printing, also known as aniline printing, is a form of relief printing in which a slightly raised image of the label is formed on a printing plate by engraving. In flexographic printing, the raised image is inked and the ink is transferred directly to the print media, typically by a large rotary press. Color labels are printed by passing the print media through the system multiple times. In a four color printing process, the print media is passed through the system four times, once for each of black, cyan, magenta and yellow. Another process for printing labels is known as gravure or rotogravure printing. In gravure printing, the printing area is etched into a surface of a plate or a metal cylinder. In contrast to flexographic printing, the etched out sections are filled with ink and the excess ink on the non-image area is removed by a thin stainless steel blade referred to as a doctor blade. Laser printers and ink jet printers have spawned a wide variety of options for personal printing that have not existed previously. A personal computer user can now prepare text on a word processing program and print the text directly onto sheets that pass through the laser or ink jet printer. Label printing requires that the strip to be printed on has to be fed in steps into the printer. The positioning pursuant to feeding involves usually a stroke producing device being driven in steps and in synchronism with the printer. Label printing programs are often used in connection with computing devices to print labels. Most label printing programs have a user enter text directly into a dialog box or into a document corresponding to the layout of the label sheet.
Linerless labels are becoming increasingly popular because of the environmental and other advantages associated with them. Oftentimes the linerless labels are printed, particularly with thermal printers. Thermal printing is a non-impact printing process that uses heat to register an impression on paper. A typical thermal transfer printer has a print head containing many small resistive heating pins that on contact, either melt wax-based ink onto ordinary media or burn dots onto specially coated media. Similar to flexographic printing, thermal printing is usually accomplished through a multi-pass process wherein each color is applied separately. Generally, a thermal printer has a carriage disposed in opposition to a platen and which is reciprocated along the platen. A thermal head capable of moving into contact with and away from the platen is supported by the carriage and it is possible to effect both printing of the type wherein printing is performed by pressing the thermal head directly to a thermal paper and a thermal printing using ribbon. In the thermal printing using ribbon, an ink ribbon cassette containing an ink ribbon with a part thereof drawn out so as to be positioned between printing paper and the thermal head is carried on the upper surface of the carriage. Further, a photosensor is disposed in a suitable position of the carriage. In a typical thermal transfer label printer, a label and a thermal transfer printer ribbon are compressed between a print head and a roller and fed together past the print head. The print head produces sufficient heat in the appropriate locations to transfer the ink from the ribbon to the label to print a label. The use of thermal printers has increased very rapidly over the last few years. Thermal printers are often employed as printers for performing receipt printing at cash registers, portable label printers for printing POS labels on food products or for printing labels for distribution control. The market for thermal label printers has shown significant improvement with users focusing on utilizing label printing, especially barcode labeling, to improve capital asset management, inventory control or time and attendance reporting, or to meet corporate or industry mandated labeling requirements.
In a label printer for issuing labels with information as to a commodity printed thereon, in general, an item number is established for each commodity and information necessary for controlling commodities is stored in a PLU memory according to the item number. Label application mechanisms are available that automatically apply tape and preprinted labels to cylindrical objects, such as bottles, cans, and the like. Automated label printer applicator feeds a continuous web of label material, removes the labels from the liner and applies the labels to the objects. These systems typically require the object being labeled to be conveyed past the applicator mechanism in order for the mechanism to apply a preprinted label. In some label printers, a pull-roller unit is used to advance the ribbon in order to achieve accurate winding. Such accurate tangential ribbon pulling is achieved by controlling the pull-roller unit, though this requires a mechanism that is subject to wear and tear and requires maintenance owing to friction. A printer consumes various consumables during printing operation. In receipt printers incorporated into POS (point of sale) terminals, a typical consumable is receipt paper. In label printers, a typical consumable is label paper. In thermal printers, a typical consumable is heat-sensitive paper. In thermal transfer printers, recording paper and ink ribbon are typical consumables. The printing conditions of the printer must be adjusted depending on the properties of the consumable to be used. In a thermal printer, the electrical energy supplied to the thermal head must be adjusted depending on the properties of the heat-sensitive paper to be used.