A printer is an image formation device which receives data from a host computer and then forms a corresponding image onto different types of media (mostly paper based products). Printers are primarily used as computer peripherals, and are usually attached to a computer which serves as a document source. Printers are classified by the underlying print technology they employ, and include dot impact printers, inkjet printers, laser printers, thermoelectric printers, dye sublimation printers, serial printers, chain printers, line printers, bar printers, wheel printers and matrix printers. A barcode printer (or bar code printer) is used for printing barcode labels or tags. Scanners are electronic devices that convert a printed page or image into an electronic representation that can be viewed and manipulated on a computer. Various types of optical scanners are currently commercially available, including hand-held scanners, flat bed scanners, two-dimensional array scanners, and drum scanners. Optical scanners are widely used as a device for writing an image in the image forming apparatuses such as digital copying machines, optical printers, or facsimile machine. An image scanner acquires image data by causing an image reading sensor to execute photoelectric conversion with respect to the reflected light obtained when a read object is irradiated with light. A bar code scanner is used to read bar codes by illuminating the bars and spacings in a sequential manner, with the bars absorbing light and the background spacings reflecting light. The bar code reader then transmits that information to a computer and uses digital image processing techniques to decode the bar code.
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Wednesday, 17 January 2007 |
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A printer is an essential computer peripheral that provides printing services to a computer user. Most printers can only provide printouts of documents using print media, such as paper or transparencies, of commonly available, or standard, sizes. A large format printer or wide format printer is used for printing on wide format flexible substrates such as paper, card, vinyl and other polymers, and textiles. Inkjet printers, and thermal inkjet printers in particular, have come into widespread use in businesses and homes because of their low cost, high print quality, and color printing capability. Large format color ink jet printers generally have a printhead carriage which is mounted for reciprocal movement on the printer in a direction orthogonal to the direction of movement of the paper. |
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Wednesday, 10 January 2007 |
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The use of digital cameras has exploded in recent years. A digital camera varies from a film camera in that instead of taking pictures on film that must be developed, it takes pictures that are saved as image files within the camera. A digital image photographed by a digital camera is generally recorded in a recording medium such as a detachable memory card and a magnetic disk. If an image is output through use of a printer, a photograph can be printed without development of a film. Many different types of digitally controlled printing systems have been invented. These printing systems use a variety of actuation mechanisms, a variety of marking materials, and a variety of recording media. Examples of digital printing systems include laser printers, thermal paper printers, and inkjet printers. |
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Thursday, 04 January 2007 |
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Barcodes are widely used for a multitude of applications, such as sales order entry, inventory control, marketing data collection, and asset management. A barcode label comprises a series of parallel dark bars of varying widths with intervening light spaces, also of varying widths. The information encoded in the barcode is represented by the specific sequence of bar and space widths. A bar code label may be read by a scanner that detects reflected or refracted light from the bars and spaces that comprise the bar code characters. A typical barcode is printed on a label and includes a series of alternating dark bars and white spaces therebetween of varying width. Barcode label printers are battery powered and typically employ a thermal printhead to print the barcodes on a media. |
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Sunday, 17 December 2006 |
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Peripheral devices allow users to put information into or get information out of a computer system. Peripheral devices printers, scanners, media readers, copiers, and facsimile machines. Historically, such devices have been typically individualistic, operating singly in their own separate environments. In addition to their cost, the consumption of space by these devices may be a problem for today's limited office rooms and desktop spaces. A multifunction printer is a peripheral device that can perform the functions of more than one traditional peripheral device. All in one printers embody printing functionality along with copying, facsimile and scanning functionality. For example, a single device that can perform the functions of a printer, scanner, copier, and facsimile machine is a multifunction peripheral. |
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Tuesday, 12 December 2006 |
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Label printers are used to print labels for inventory control, price information. A label includes print imaging and an adhesive surface. The print imaging typically represents some text or graphic content identifying, characterizing, or quantifying. A typical barcode is printed on a label and includes a series of alternating dark bars which represent a digital code serving to identify the content of the bar code symbol. Label printers for printing and issuing labels are currently largely employed in a variety of industries. Labels are typically printed by a continuous printing process utilizing a roll label print media. Thermal printing is a non-impact printing process that uses heat to register an impression on paper. Thermal printers are often employed as portable label printers for printing POS labels. |
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Tuesday, 21 November 2006 |
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Optical character recognition (OCR) is the technology for character recognition that employs optical means to identify graphic characters. A character recognition device is generally used as an input device for a computer. Computerized document processing includes scanning of the document and the conversion of the actual image of a document into an electronic image of the document. The recognition system reads characters of a character code line by framing and recognizing the characters within the image data. The scanning process generates an electronic pixel representation of the image with a density of several hundred pixels per inch. The pixel image may be stored and processed directly or it may be converted into a compressed image for storage in a computer. |
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Tuesday, 21 November 2006 |
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A business card scanner is an optical image capturing device used for reading business cards and digitizing captured information for a computer to organize, store, and process. The use of an optional image scanner and optical communication avoids the complications of managing paper business cards. Optical scanners read the surface of a document having either textural or graphical information and to convert the information into digital signals which can be stored and processed by a digital computer. Optical character readers operate by causing them to scan a region on a document containing printed characters. The image of the characters is focused by means of a lens onto an array of photoelectric transducers. Scanned images can be stored in any number of different formats. |
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Tuesday, 14 November 2006 |
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Fingerprint scanners or fingerprint readers are used to capture an image of a fingerprint. A biometric is a biological characteristic that is unique to an individual and that can be accurately measured. Fingerprints provide the most reliable biometric identification. Fingerprint matching is a reliable and widely used technique for personal identification or verification. In order to verify fingerprints in the computer system, an image input device is provided to input digitized images of fingerprints to the computer system. A signal representative of the captured image is then sent over a data communication interface to a computer for further processing. Fingerprint recognition has been suggested for use in many security applications. A smartcard with fingerprint can positively authenticate the identity of the smartcard user. |
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Saturday, 04 November 2006 |
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A laser printer generates an image on a piece of paper by scanning a focused laser beam over a cylindrical photosensitive drum. Color laser printers use four laser-photoconductor developer systems to simultaneously expose, develop, and print four different color planes to produce a colored print. The photoconductor typically comprises a drum or a belt coated with a photoconductive material capable of retaining localized electrical charges. These types of color printers are known as inline color printers. A color laser printer develops successive images by using developing toners of different colors supplied from corresponding toner sources. A color laser printer includes a laser scanner for scanning laser beams onto an imaging surface of a photoreceptor belt to form a latent electrostatic image. |
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Tuesday, 24 October 2006 |
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An inkjet printer prints desired images by ejecting ink through fine nozzles of a print head. The inkjet printer uses a print cartridge including the print head and the ink. Inkjet printers operate by expelling a small volume of ink through a plurality of small orifices in an orifice plate held in proximity to a paper or other medium upon which printing or marks are to be placed. The inkjet printhead may be classified into one of a thermal transfer type and a piezoelectric device type according to a method of ejecting the ink onto a sheet of print paper. Color inkjet printers generally incorporate multiple printheads in a scanning carriage which scans left to right and right to left across a medium while the printheads eject droplets of ink. An ink jet printer includes a carriage reciprocally moving on a main frame. |
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Monday, 16 October 2006 |
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Document scanners are computer peripherals that allow users to scan documents into their computers for later storage, retrieval and/or manipulation. There have been various types of image scanners in recent use, which include flatbed, drum and handheld scanners. A handheld or portable optical scanner is an optical scanner which is designed to be moved by hand across the object or document being scanned. A hand scanner is extensively used with a personal computer or a word processor as an image inputting device for optically reading image data out of a document by being operated by hand. A portable image scanner is composed of a light source, an image sensor for converting optical image information into electric image signals and an optical system for introducing reflected light. |
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Friday, 06 October 2006 |
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A photo printer is specifically designed to print high quality digital photos on photo paper. With the rapid development of digital technology, image-capturing devices, such as mobile phones and digital cameras, have become increasingly popular. A photo printer includes a print processing section for performing the same operations as conventional printers, and a photo image processing section for processing image data read from the memory card. Thermal printers are used in computer systems to print digital images. A thermal printer is used with sheets of thermosensitive recording material. Ink-jet printers are popular and cost-effective devices for producing color images. Some photo printers are provided with an image data processing function and can print without connecting to a computer. |
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Tuesday, 19 September 2006 |
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A toner cartridge is used in an image forming system for supplying a toner for forming an image. A developing unit supplies toner to the electrostatic latent image to form a toner image. The developing unit of the image forming apparatus comprises a developing roller and a developer storage chamber having a stirring and mixing unit. During the image forming process, toner is transferred from toner carrying members to print or copy media. A developing unit has a cleaning means for cleaning waste toner remaining on the photosensitive drum. Toner that remains on the photoconductive drum after transfer is removed from the photoconductive drum and collected into a waste toner tank. Toner cartridges often include sensors that interact with the laser printer to indicate the status of the cartridge. |
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Monday, 11 September 2006 |
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A bar code label may be read by a scanner that detects reflected and/or refracted light from the bars and spaces that comprise the bar code characters. A bar code is a representation of set of binary numbers. It consists of black bars and white spaces. A typical bar code reader kit consists of a scanner, decoder, and cable which interfaces the decoder to the computer. The scanner scans the bar code symbol and captures the bars and spaces of the bar code and sends it to the decoder. The decoder translates the bars and spaces into corresponding electrical output and transmits that data to the computer in a traditional data format. Bar code scanners are used in a wide variety of applications, such as retailing, inventory control, customer identification and many other applications. |
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Sunday, 27 August 2006 |
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Image scanners are used for scanning documents into computers. Various types of optical scanners are currently commercially available, including drum scanners, hand-held scanners, and flat bed scanners. The most commonly used scanners are flatbed scanners. A flatbed scanner casing generally includes an upper housing and a lower housing in which the upper housing is a rectangular frame and a transparent platform. A typical flatbed scanner mounts the illumination system and a portion optical system to a moveable carriage assembly. Reference marks are provided on the transparent glass plate that allows the user to place the document at correct positions. A CCD builds up an electrical charge in response to exposure to light. A flatbed scanner may be provided with an automatic document feeder. |
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Saturday, 19 August 2006 |
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Laser printer uses a mechanism similar to that of a photocopy machine. The image is written on a photosensitive drum by a laser in the case of a laser printer. Laser printers typically offer a greater improvement in resolution over dot matrix and ink jet-type printers. Laser printers print images by drawing an electrostatic image on a photosensitive drum with laser beams and depositing a toner on a portion charged with a static electricity. Monochrome laser printers use a single laser scanning unit (LSU) and a single organic photoconductive cell (OPC) drum. Color laser printers employ four printing stations, one each for black, magenta, cyan and yellow toners. Laser printers are used in a wide variety of applications, from office printing, to medical printing, to bar code printing. Laser printers generally utilize replaceable toner cartridges. |
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Printers and Scanners
