Portable barcode printer

Thursday, 04 January 2007

Barcodes are information carrying graphical patterns designed for easy and reliable automatic retrieval. A bar code is a technique for describing characters (alphabet, numerals, symbols, etc.) by a combination of parallel (vertical) lines (bars) of different thickness (width) or arranged at different intervals. Each bar code represents binary information which can be optically read by optical reading means, such as an optical scanner provided in a bar code reader. A barcode is a pattern representing numeric, alphanumeric, alpha, or other coding schemes whereby the barcode pattern represents an associated symbol or value. Barcodes can be read or scanned optically by non-contacting remote barcode reading devices. A barcode can be a series of machine-readable vertical lines organized according to a pattern representing, for example, a numeric or alphanumeric sequence. There are a number of different bar codes in common use, such as the UPC code found on most packages in grocery stores; the 2 of 5 code, Codabar, Code 39 widely used for non grocery product identification and other applications; Code 93, similar to Code 39 but with the capability of encoding the full ASCII character set. These codes all carry their information in the linear domain along the code pattern. The most common barcodes are known as one-dimensional barcodes. These graphical patterns vary in a single dimension (e.g. the horizontal dimension), and are constant in the other dimension. One-dimensional barcodes are employed in low information content applications like product index registry, or serial number registry. These barcodes typically can only encode limited information, such as the price of the item and the manufacturer. The items having the barcodes are scanned at a checkout counter to facilitate the tallying up of a total receipt. In order to convey more information on the same surface area, two-dimensional barcodes were developed. Two-dimensional barcodes involve intricate patterns that vary in both the horizontal and the vertical dimensions. Two-dimensional barcodes are used in applications that require more information contents. For example, two-dimensional barcodes can be used to encode mail addresses for automated mail reading and distribution systems. These bar codes are printed on labels and the like, which are attached to books, food products, and like articles, or directly printed on surfaces of articles, thereby permitting them to be input by input means (reading means) which quickly inputs binary information, at libraries, hospitals, groceries, etc. Barcodes are useful in a broad spectrum of applications from grocery checkout applications, where a barcode can represent a product and basis for calculating a charge, to labeling applications where a barcode can represent content or process information relative to a given article. Barcodes can support automated tracking and database reference throughout many industries and applications.

A barcode printer is used in various management systems utilizing bar code information representing various data. A bar code printing or reading apparatus is required to make a bar code label by printing bar code information, to read bar code information from a bar code label, and to collect and store bar code data obtained by reading bar code information. A barcode may be directly printed on the packing material of the commodity. Alternatively, the barcode can be printed on a label and then adhered to the commodity. Barcode patterns or indicia can be applied to media that includes an adhesive surface to provide a barcode label. The adhesive surface attaches the barcode-bearing media to an article associated with the barcode. By means of reading the barcode through a barcode reader, the commodity number and price of the commodity are immediately known. Typical bar code printing may be accomplished in a dot matrix impact line printer, in a thermal printer or in other non-impact printers. Many of bar code printers are based on a thermal transfer system, in which a number of heating elements are arrayed at a specified pitch on a line thermal head, and ink on a thermal transfer ink ribbon is transferred onto such a material as label paper by selectively heating some of the heating elements to print a bar code comprising a number of bars, each having different width, on the material. The use of electronically controlled thermal printers has increased very rapidly over the last few years. In particular, the market for thermal label printers has shown significant improvement with users focusing on utilizing label printing to improve capital asset management, inventory control or time and attendance reporting or to meet corporate or industry mandated labeling requirements. Types of thermal transfer ink ribbon used in a bar code printer based on the thermal transfer system are largely divided to wax-based ribbons and plastics-based ones. Waxed-based ribbons have an advantage that they easily melt and spread to a wide area under low temperature, but the life of letters printed with this type of ribbon is short because their abrasion resistance and chemical resistance are rather low. As compared to this type, plastics-based ribbons have a shortcoming that they do not melt and spread to a wide area under low temperature, but are widely used especially for bar code printers because the life of letters printed with this type of ribbon is excellent. General-purpose printers do not provide a most desirable choice when producing barcode labels. Mass production of barcodes is often supported by specialized equipment dedicated to high volume operation. Barcode labels when produced in great volume place particular value on efficiency. Some expensive printing devices are especially designed for barcode label printing. Yet, not all applications or users have sufficient need for mass production of barcode labels to justify access to or ownership of such dedicated barcode label-making printing devices. Such equipment finds little alternative uses, e.g. in other more general printing operations. Barcodes are becoming used more frequently throughout industries and in applications where special or dedicated barcode print imaging equipment may not be available or where cost is excessively prohibitive. Hence, portable o n-demand printers are more preferred.

Poratble label printers are known that are battery powered and typically employ a thermal printhead to print the barcodes on a media. The printhead comprises a series of adjacent thermal elements that print the pixels or dots on the surface of the media. The media can have a thermally activated surface which turns dark when subjected to heat or there can be a "ribbon" of "ink" which is transferred to and fused to the surface of the media by heat. By selectively heating the various thermal elements in the printhead as the media passes beneath it, a series of narrow bars and wide bars separated by wide and narrow spaces are created as depicted. The bars and spaces are created in pre-established patterns which define the barcodes which contain the desired information. Barcode printers, such as on-demand barcode printers, use label formats to print labels. Portable barcode printers receive data to be printed on a tag, label or the like from an external host device. The data information includes a data packet and a format packet that controls a printing operation of the barcode printer. The format packet defines the various fields to be printed on the tag or label, the position of each field on the tag or label, the font type and size, as well as other attributes of the tag or label to be printed. The data packet defines the information to be printed in the various fields defined by the format packet. The external device may be a data collector, a remote host computer, or the like. The printers receive the data via a hard wired connection or wireless communications such as radio frequency (RF) and infra-red (IR) communications. Portable battery powered barcode label printers are known that use a static random access memory to store information, such as programmable software routines and/or programmable font and format data which is necessary for the intended operation of the label printer. A user can use software packages to create and edit printer label formats. For example, there are a variety of software packages for the PC (personal computer) which a user can use to design barcode label formats. The software packages which are generally available are user friendly and generally make creating and editing a label format easy for a user. Such software packages generally provide that the label formats is displayed on a computer monitor as the user uses the software package to design the label format.

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